JP2024048329A - Paddy field methane reduction support device, paddy field methane reduction support system - Google Patents

Abstract

[Problem] To objectively detect the state and period of water management for reducing methane emissions from paddy fields. [Solution] A paddy field methane reduction support device includes an acquisition unit that acquires paddy field information about paddy fields, work information about agricultural work for cultivating crops in the paddy fields, and observation image data of the area including the paddy fields observed by an observation device, a control unit that identifies the state of water management of the paddy field for reducing methane emitted from the paddy field during the cultivation of the crop and the period during which the state continued based on the paddy field information, the work information, and the observation image data, and generates specific water management information indicating the state and period of the water management, and a storage unit that stores the specific water management information. [Selected Figure] Figure 1

Description

The present invention relates to a paddy field methane reduction support device and a methane reduction support system that support the reduction of methane emitted from paddy fields.

Methane is one of the greenhouse gases that contribute to global warming. It is known that methane is emitted from paddy fields where crops such as rice are cultivated. For example, as disclosed in Non-Patent Documents 1 and 2, changing agricultural practices such as water management and organic application in paddy fields is effective in reducing methane emissions from paddy fields. In addition, Non-Patent Document 2 and other documents disclose a model (DNDC-Rice model) and calculation formulas for calculating methane emissions from rice paddies.

On the other hand, a technology has been developed to identify rice-planted fields at a regional level based on remote sensing data obtained by observing the ground using observation equipment mounted on artificial satellites or aircraft. For example, as disclosed in Patent Document 1 and Non-Patent Document 3, when observing an area including fields using a synthetic aperture radar, if microwaves emitted from the synthetic aperture radar are reflected by the water surface of a flooded field, the intensity of the backscattered waves (backscattering coefficient) decreases, and if the microwaves are reflected by the ground surface or the leaves of grown rice plants, the intensity of the backscattered waves increases. The technology disclosed in Patent Document 1 and Non-Patent Document 3 focuses on this characteristic, and a calculation processing device or the like identifies rice fields based on the backscattering intensity represented by the pixel values of multiple observation images observed by the synthetic aperture radar during the rice planting period, the field preparation period, and the rice growth period.

August 2012, National Institute for Agro-Environmental Sciences, "New Water Management Technology Manual for Suppressing Methane Emissions from Paddy Fields" (revised edition), [ON LINE] [Retrieved April 28, 2022] Internet (URL: https://www.naro.affrc.go.jp//archive/niaes/techdoc/methane_manual.pdf) Ministry of the Environment website, Calculation and reporting of greenhouse gas emissions and absorption, 3.C rice cultivation, "3.C.1 Rice Cultivation - Irrigated Intermittently Flooded (CH4)", [ON LINE] [Retrieved April 28, 2022] Internet (URL: https://www.env.go.jp/earth/ondanka/ghg-mrv/methodology/material/methodology_3C1.pdf) Naoki Ishizuka, "Highly accurate estimation of rice planting areas using microwave satellite images and geographic information systems," National Institute for Agro-Environmental Sciences, 2006 Innovative Agricultural Technology Training Textbook, [ON LINE] [Retrieved November 18, 2009] Internet (URL: http://www.niaes.affrc.go.jp/techdoc/inovlec2006/4_ishitsuka.pdf)

Patent No. 4810604

For example, when determining the state of water management in rice paddies carried out to reduce methane emissions and the period during which such state continued from farmers' declarations or records in their work diaries, there is a risk that such records will not be objective enough or be evidential enough to be incorrect or falsified.

In view of the above problems, an object of the present invention is to objectively detect the state and period of water management for reducing methane emissions from paddy fields.

The technical means of the present invention to solve the above technical problems are characterized as follows:

The paddy field methane reduction support device according to one embodiment of the present invention includes an acquisition unit that acquires paddy field information about paddy fields, work information about agricultural work for cultivating crops in the paddy fields, and observation image data of an area including the paddy fields observed by an observation device; a control unit that identifies the state of water management of the paddy field and the period during which the state continued based on the paddy field information, the work information, and the observation image data to reduce methane emitted from the paddy field during the cultivation of the crop, and generates specific water management information indicating the state and period of the water management; and a storage unit that stores the specific water management information.

In one aspect of the present invention, the work information includes input water management information indicating the state and period of the water management of the paddy field that has been input in advance, and the control unit acquires data of a plurality of the observation images based on the input water management information using the acquisition unit, verifies the state and period of the water management indicated in the input water management information based on the data of the plurality of observation images, stores verification information indicating the verification results in the storage unit, and, if the state and period of the water management indicated in the input water management information are valid, stores the input water management information in the storage unit as the specific water management information.

In one aspect of the present invention, the control unit may acquire data of the observation image observed by the observation device during the water management period indicated by the input water management information.

In one aspect of the present invention, the control unit may determine the water management state from the data of the multiple observation images, and if the determined water management state corresponds to the water management state indicated by the input water management information, may include information indicating that the input water management information is valid in the verification information, and may store the input water management information in the storage unit as the specific water management information.

In one aspect of the present invention, the control unit may acquire farmer information related to the farmer corresponding to the paddy field by the acquisition unit, determine the state of water management from the data of the plurality of observation images, and if the determined water management state does not correspond to the water management state indicated by the input water management information, notify the farmer of the verification information based on the farmer information.

In one aspect of the present invention, the control unit may acquire data of a plurality of observation images observed by the observation device during a predetermined period based on the paddy field information and the work information, using the acquisition unit, and identify the state and period of the water management of the paddy field from the data of the plurality of observation images.

In one aspect of the present invention, the control unit may determine the period from the tillering stage to the panicle formation stage of the crop planted in the paddy field based on the paddy field information and the work information, and may acquire data of the multiple observation images observed by the observation device during the determined period using the acquisition unit.

In addition, in one aspect of the present invention, the control unit may acquire data of a plurality of observation images observed by a synthetic aperture radar possessed by the observation device mounted on an airborne vehicle or an aircraft, using the acquisition unit, extract one or more pixels indicating the paddy field from each of the plurality of observation images, detect a backscattering coefficient associated with the pixel value of the pixel, and identify the state and period of the water management of the paddy field based on the detected backscattering coefficient.

In one aspect of the present invention, the storage unit stores one or more preset thresholds, and the control unit may determine at least one of whether the paddy field is in a semi-dried state or whether the paddy field is in a flooded state based on a result of comparing the backscattering coefficient detected from the data of the multiple observation images with the thresholds.

In one aspect of the present invention, the control unit may identify water level change information indicating time series changes in the actual water level of the paddy field from information indicating the actual water level of the paddy field acquired by the acquisition unit, detect backscattering coefficients corresponding to the paddy field from data of the multiple observation images acquired by the acquisition unit, detect a correlation between the actual water level of the paddy field indicated by the water level change information and the backscattering coefficient corresponding to the paddy field, and set the threshold value based on the correlation and the backscattering coefficient corresponding to the paddy field, and store the threshold value in the memory unit.

In one aspect of the present invention, the control unit may apply the threshold value stored in the memory unit to determine at least one of the drained and flooded states of other rice paddies.

In one aspect of the present invention, the storage unit stores model data for calculating the amount of methane emissions from the paddy field, and the control unit may calculate an amount of methane reduction that is reduced from a predetermined basic methane emission amount from the paddy field based on the paddy field information, the work information, the specific water management information, and the model data, and store the amount of methane reduction in the storage unit.

In one aspect of the present invention, the control unit may set a calculation formula for calculating the methane emission amount of the paddy field based on the paddy field information, the work information, and the model data, acquire conventional water management information indicating the state and period of the conventional water management of the paddy field by the acquisition unit, calculate the basic methane emission amount of the paddy field based on the conventional water management information and the calculation formula, calculate the methane emission amount of the paddy field based on the specific water management information of the paddy field and the calculation formula, and calculate the methane reduction amount of the paddy field by subtracting the methane emission amount from the basic methane emission of the paddy field.

In one aspect of the present invention, the acquisition unit may be configured with a communication interface, and the control unit may acquire farmer information related to the farmer corresponding to the paddy field through the communication interface, transmit report information including the methane reduction amount of the paddy field and the farmer information to a credit management device through the communication interface, acquire credit information indicating an electronic credit issued by the credit management device according to the methane reduction amount through the communication interface, and notify the farmer of the credit information based on the farmer information. The control unit may also include the verification information in the report information and transmit it to the credit management device through the acquisition unit.

1. A paddy field methane reduction support system according to one embodiment of the present invention includes a paddy field methane reduction support device that supports the reduction of methane emissions from paddy fields in which crops are grown, and an agricultural management device in which a database is constructed storing information on the paddy fields and the agriculture carried out in the paddy fields. The paddy field methane reduction support device is equipped with an acquisition unit that acquires paddy field information on the paddy field and work information on agricultural work for cultivating the crop in the paddy field from at least one of the agricultural management device and a farmer terminal device used by a farmer corresponding to the paddy field, and acquires observation image data of an area including the paddy field observed by an observation device that observes the ground, based on the paddy field information, the work information, and the observation image data, and identifies the state of water management of the paddy field and the period during which the state continued in order to reduce methane emitted from the paddy field during the cultivation of the crop, and generates specific water management information indicating the state and period of the water management, and a memory unit that stores the specific water management information.

In one aspect of the present invention, in the paddy field methane reduction support system, the control unit may acquire data of the plurality of observation images from the observation management device using the acquisition unit based on the input water management information included in the work information.

In one aspect of the present invention, in the paddy field methane reduction support system, the control unit may acquire data of a plurality of observation images observed by the observation device during a predetermined period from the observation management device using the acquisition unit based on the paddy field information and the work information.

In one aspect of the present invention, in the paddy field methane reduction support system, the memory unit stores model data for calculating methane emissions from the paddy field, the acquisition unit is configured with a communication interface, and the control unit calculates an amount of methane reduction that is reduced from a predetermined basic methane emission amount of the paddy field based on the paddy field information, the work information, the specific water management information, and the model data, and stores the amount of methane reduction in the memory unit.

In one aspect of the present invention, in the paddy field methane reduction support system, the control unit may acquire the farmer information from at least one of the agricultural management device and the farmer terminal device via the communication interface, transmit report information including the methane reduction amount of the paddy field and the farmer information to a credit management device via the communication interface, acquire credit information indicating an electronic credit issued by the credit management device according to the methane reduction amount via the communication interface, and notify the farmer terminal device of the credit information based on the farmer information via the communication interface. The control unit may also include the verification information in the report information and transmit it to the credit management device via the communication interface.

The present invention makes it possible to objectively detect the state and duration of water management to reduce methane emissions from rice paddies.

FIG. 1 is a configuration diagram of an example of a paddy field methane reduction support system. FIG. 1 is a diagram showing an example of the timing and water level when cultivating rice in a paddy field. 1 is a flowchart showing an example of a schematic operation of the paddy field methane reduction support device. 11 is a flowchart showing an example of an initial setting operation of the paddy field methane reduction support device. FIG. 1 is a diagram showing an example of a model formula of a paddy field methane reduction support device. 11 is a flowchart showing an example of a methane evaluation operation of the paddy field methane reduction support device. FIG. 11 is a diagram showing an example of first correlation data showing the correlation between the mid-drying period of paddy fields and the amount of methane reduction. 13 is a flowchart showing an example of an intermediate drainage proposal operation of the paddy field methane reduction support device. 13 is a flowchart showing an example of a calculation formula update operation of the paddy field methane reduction support device. 13 is a flowchart showing an example of a crediting operation of the paddy field methane reduction support device. 13 is a flowchart showing another example of the crediting operation of the paddy field methane reduction support device. 13 is a flowchart showing an example of a credit purchasing operation of the paddy field methane reduction support device. 13 is a flowchart showing an example of a credit transaction operation of the paddy field methane reduction support device. FIG. 1 is a diagram showing an example of the reflection state of X-band microwaves irradiated from a synthetic aperture radar onto a flooded rice paddy field. FIG. 1 is a diagram showing an example of the reflection state of X-band microwaves irradiated from a synthetic aperture radar onto a paddy field that has been drained of water. FIG. 1 is a diagram showing an example of a SAR image of an area including multiple rice paddies before a mid-dry period. FIG. 1 is a diagram showing an example of a SAR image taken during a mid-drainage period in an area including multiple rice paddies. FIG. 1 is a diagram showing an example of a SAR image of an area including multiple rice paddies after a mid-dry period. 1 is a graph showing histograms of backscattering coefficients corresponding to paddy fields in SAR images before and during a mid-dried period; 1 is a graph showing histograms of backscattering coefficients corresponding to paddy fields in SAR images after and during a mid-dried period; 1 is a graph showing the change in the ratio of backscattering coefficients corresponding to paddy fields in SAR images before and after a mid-dried period. 11 is a flowchart showing an example of a water management specification operation of the paddy field methane reduction support device. 11 is a flowchart showing an example of a verification and specification operation of the paddy field methane reduction support device. This is a continuation of the flowchart in Figure 19A. 13 is a flowchart showing an example of an image specifying operation of the paddy field methane reduction support device. This is a continuation of the flowchart in Figure 20A. FIG. 1 is a diagram showing an example of the reflection state of L-band microwaves irradiated from a synthetic aperture radar onto a flooded rice paddy. 1 is a diagram showing an example of the reflection state of L-band microwaves irradiated from a synthetic aperture radar onto a paddy field that has been drained of water. FIG.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 is a configuration diagram of an example of a paddy field methane reduction support system 100. In the paddy field methane reduction support system 100, the paddy field methane reduction support device 1 and the agricultural management device 2 are configured, for example, by at least one of a computer and a server installed in a management center.

The paddy field methane reduction support device 1 is a device that supports the reduction of methane emitted from paddy fields, and is equipped with a control unit 1a, a memory unit 1b, a communication unit 1c, and an input/output interface 1d. The control unit 1a is a controller, and is composed of a CPU (or microcomputer), memory, etc.

The memory unit 1b is a storage device and is composed of a volatile memory, a non-volatile memory, a hard disk, or the like. The memory unit 1b stores software programs executed by the control unit 1a, and stores various control data used by the control unit 1a in a readable and writable manner. The memory unit 1b also stores model data for calculating the amount of methane emitted from paddy fields. The control unit 1a calculates the amount of methane emission and the amount of methane reduction from paddy fields based on the model data stored in the memory unit 1b.

The communication unit 1c is a communication interface for communicating with external devices via a public communication network and the Internet. The communication unit 1c is also an acquisition unit that acquires information from external devices. The input/output interface 1d is composed of an input interface such as a mouse, keyboard, or touch panel, and an output interface such as a display, speaker, or touch panel.

The agricultural management device 2 is a device that manages various information related to agriculture. Although one agricultural management device 2 is illustrated in FIG. 1, there may be two or more agricultural management devices 2. The agricultural management device 2 also has a control unit, a memory unit, a communication unit, and an input/output interface (not illustrated). The agricultural management device 2 also has a database 2d that stores various information related to multiple paddy fields and multiple farmers who cultivate crops in the paddy fields. In detail, the database 2d stores multiple pieces of farmer information related to farmers, paddy field information related to paddy fields, and work information related to agricultural work carried out to cultivate crops in the paddy fields. The farmer information, paddy field information, and work information are associated with each farmer or each paddy field and stored in the database 2d.

The farmer information includes information such as the farmer's personal information, identification information such as the farmer's account, and the IP address of the farmer terminal device 3 used by the farmer. The paddy field information includes information such as the identification information of the paddy field, the region in which the paddy field is located, the position of the paddy field (latitude, longitude, etc.), area, outline shape, soil condition, drainage, crops being cultivated, and sensors and devices installed in the paddy field. The work information includes agricultural work plans for cultivating crops in the paddy field, the content of the agricultural work, and the status of the agricultural work. In addition, the agricultural work included in the work information includes water management work such as flooding, irrigation, and drainage in paddy fields, and the work information includes water management information that indicates the water management work and its implementation status (water management status).

The control unit 1a of the paddy field methane reduction support device 1 communicates with the agricultural management device 2 via the communication unit 1c, and acquires (receives) farmer information, paddy field information, and work information from the database 2d. The control unit 1a also transmits information relating to the reduction of methane from paddy fields to the agricultural management device 2 via the communication unit 1c, and stores the information in the database 2d.

The farmer terminal device 3 is composed of a personal computer, tablet terminal device, smartphone, etc. used by the farmer. Although two farmer terminal devices 3 are illustrated in FIG. 1, there may be three or more farmer terminal devices 3. The farmer terminal device 3 also has a control unit, a memory unit, a communication unit, and an input/output interface (not shown). The farmer inputs various information such as farmer information, paddy field information, and work information into the farmer terminal device 3. The farmer terminal device 3 transmits the input farmer information, paddy field information, work information, etc. to the agricultural management device 2 or paddy field methane reduction support device 1.

When the agricultural management device 2 receives farmer information, paddy field information, work information, etc. transmitted from the farmer terminal device 3, it stores the information in the database 2d. When the paddy field methane reduction support device 1 (control unit 1a) receives farmer information, paddy field information, work information, etc. transmitted from the farmer terminal device 3 via the communication unit 1c, it stores the information in the memory unit 1b.

The water management device 4 is installed on the bank of the paddy field or in the paddy field, and the water level sensor 5 is installed in the paddy field. The water management device 4 and the water level sensor 5 are electrically connected by wire or wirelessly. Although one water management device 4 and one water level sensor 5 are illustrated in FIG. 1, one or more water management devices 4 and water level sensors 5 are installed in each paddy field. The water management device 4 also has a control unit, a memory unit, and a communication unit (not shown). The water management device 4 also has an operation switch, an actuator, a storage battery, a solar power generation device, and the like. The water management device 4 opens and closes the water gate of the paddy field using the actuator to supply or drain water to or from the paddy field.

The water level sensor 5 detects the water level of the paddy field and transmits the detection result to the water management device 4. Based on the detection result of the water level sensor 5, the water management device 4 detects the water management state of the paddy field, such as flooding, irrigation, or drainage. Then, depending on the detection result of the water level sensor 5 and the water management state of the paddy field, the water management device 4 controls the operation of the actuator to supply or drain water to the paddy field, thereby flooding, intermittent irrigation, and draining the paddy field.

The water management device 4 also transmits water management information indicating the detection results of the water level sensor 5 and the water management status of the paddy field to the agricultural management device 2 or the paddy field methane reduction support device 1. When the agricultural management device 2 receives water management information transmitted from the water management device 4, it stores the water management information in the database 2d so that it is included in (associated with) the work information for the corresponding paddy field. When the paddy field methane reduction support device 1 (control unit 1a) receives water management information transmitted from the water management device 4, it stores the water management information in the memory unit 1b.

The earth observation satellite 7 is an example of an aerial vehicle and an observation device, and observes the earth's surface. In the paddy field methane reduction support system 100, the earth observation satellite 7 is composed of a SAR (Synthetic Aperture Radar) satellite, and observes paddy fields using a synthetic aperture radar. The monitoring device 6 acquires the observation results of the earth observation satellite 7. The monitoring device 6 also has a control unit, a memory unit, a communication unit, and an input/output interface (not shown). Although FIG. 1 shows one monitoring device 6 and one earth observation satellite 7, there may be two or more monitoring devices 6 and two or more earth observation satellites 7.

The monitoring device 6 detects the water management state of the paddy field, such as flooding, irrigation, and drainage, from the observation results of the earth observation satellite 7. Specifically, the monitoring device 6 acquires SAR images (observation images) of the paddy field observed by a synthetic aperture radar mounted on the earth observation satellite 7, and detects uneven parts of the paddy field based on the SAR images. The monitoring device 6 then calculates, for example, the ratio of the area of the uneven parts to the surface area of the paddy field, and determines that the surface of the paddy field is underwater and the paddy field is in a flooded state if the ratio is less than a predetermined value. Furthermore, the monitoring device 6 determines that the surface of the paddy field is not underwater (the water level of the paddy field is zero) and the paddy field is in a drainage state if the ratio of the area of the uneven parts to the surface area of the paddy field is equal to or greater than a predetermined value. Furthermore, the monitoring device 6 may determine that the paddy field is in an irrigated state from a change in the ratio of the area of the uneven parts to the surface area of the paddy field.

The method of determining the water management status of paddy fields, such as flooding, irrigation, and drainage, using synthetic aperture radar SAR images is not limited to the above, and may be determined by other methods. In addition, the paddy field methane reduction support device 1 may be equipped with AI (Artificial Intelligence), and the water management status of paddy fields may be detected from the synthetic aperture radar SAR images using machine learning using the AI.

The monitoring device 6 transmits water management information indicating the water management status of the paddy field to the agricultural management device 2 or the paddy field methane reduction support device 1. When the agricultural management device 2 receives water management information transmitted from the monitoring device 6, it stores the water management information in the database 2d so that it is included in (associated with) the work information for the corresponding paddy field. When the paddy field methane reduction support device 1 (control unit 1a) receives water management information transmitted from the monitoring device 6, it stores the water management information in the memory unit 1b.

To detect the water management status of the paddy field, at least one of the first detection configuration including the water level sensor 5 and the water management device 4 and the second detection configuration including the earth observation satellite 7 and the monitoring device 6 may be applied to the paddy field methane reduction support system 100. In addition to or instead of at least one of the first detection configuration and the second detection configuration, the farmer may input the water management status of the paddy field using the farmer terminal device 3. Furthermore, the paddy field may be observed by mounting an observation device such as a synthetic aperture radar, a three-dimensional laser surveyor, or an imaging device on an air vehicle other than the earth observation satellite 7, or an air vehicle such as a drone or UAV (Unmanned Aerial Vehicles).

The credit management device 8 is a device that manages electronic credits according to the amount of greenhouse gas reduction, and is used by a credit management company. The credit management device 8 also has a control unit, a memory unit, a communication unit, and an input/output interface (not shown). Although one credit management device 8 is shown as an example in FIG. 1, there may be two or more credit management devices 8. There may also be multiple credit management companies.

The paddy field methane reduction support device 1 (control unit 1a) transmits report information including the amount of methane reduction in the paddy field and farmer information corresponding to the paddy field to the credit management device 8. The credit management device 8 issues credits according to the amount of methane reduction in the paddy field included in the report information received from the paddy field methane reduction support device 1, and transmits credit information indicating the credits to the paddy field methane reduction support device 1. When the paddy field methane reduction support device 1 (control unit 1a) receives the credit information from the credit management device 8, it transmits (transfers) the credit information to the farmer terminal device 3 used by the corresponding farmer. In addition, the paddy field methane reduction support device 1 (control unit 1a) executes processing to purchase credits from the farmers.

The demand terminal device 9 is a terminal device used by demanders such as companies, organizations, or individuals who buy and sell credits. The demand terminal device 9 also has a control unit, a memory unit, a communication unit, and an input/output interface (not shown). Although one demand terminal device 9 is shown as an example in FIG. 1, there may be two or more demand terminal devices 9. There may also be multiple demanders. The paddy field methane reduction support device 1 (control unit 1a) executes processing for trading (buying and selling) credits with the demand terminal device 9.

Figure 2 shows an example of the time and water level WL when rice R is cultivated in a paddy field H. When rice R is cultivated as a crop in a paddy field H, the paddy field H is irrigated from the puddling stage, and the paddy field H is kept deep water during the rice planting and rooting stages. Then, for a while from the tillering stage, the paddy field H is irrigated intermittently to make the paddy field H shallow water, after which the water is drained from the paddy field H and the paddy field H is left dry for a while (when the water level of the paddy field is zero). During this dry period, the soil of the paddy field H is dried until it cracks, which supplies oxygen to the soil and allows the roots of the rice R to grow strong in the soil. Also, if the paddy field H remains flooded during the tillering stage when the temperature is high, the reduction of the soil progresses, the activity of methanogens in the soil becomes active, and methane (a greenhouse gas) is produced using organic matter such as rice straw as a substrate. The produced methane is released into the atmosphere through the organs of the rice R.

In order to reduce the amount of methane emissions from such paddy fields H, for example, paddy fields H are intermittently irrigated or dried out, allowing oxygen to enter the soil and changing the soil from a reduced state to an oxidized state. Also, by extending the dry-out period of paddy fields H, the amount of methane emissions from paddy fields H can be further reduced. However, paddy fields H are intermittently irrigated (intermittent irrigation) before and after the young panicle formation stage of rice R. In order to reduce methane emissions between the tillering stage and the young panicle formation stage of paddy fields H without adversely affecting the young panicle formation of rice R, it is more effective to extend the dry-out period forward (towards the tillering stage) than to extend it backward (towards the young panicle formation stage).

Before and after the heading stage, the paddy field H is flooded to make it deeply watered. Thereafter, when the rice R is ripening, the paddy field H is intermittently irrigated, and when it is ripening, the water is drained from the paddy field H to bring the water level to zero and dry the soil. Plowing rice straw into the soil after the rice R is harvested also reduces methane emissions from the paddy field H. Furthermore, applying compost when plowing in the soil (autumn plow-in) further reduces methane emissions from the paddy field H.

Figure 3 is a flowchart showing an example of the general operation of the paddy field methane reduction support device 1. Each process is executed by the control unit 1a. (The control unit 1a also executes each process (each step) of the other flowcharts described below.)

The control unit 1a of the paddy field methane reduction support device 1 first registers the farmer and paddy field for which methane emissions are to be reduced (S1 in FIG. 3). Next, the control unit 1a performs settings for evaluating the reduction of methane from the paddy field (S2). The control unit 1a then evaluates the status of the reduction of methane from the paddy field based on the status of agricultural work being carried out in the paddy field by the farmer (S3). During this evaluation, the control unit 1a calculates the amount of methane reduction from the paddy field. The control unit 1a then converts the amount of methane reduction from the paddy field into credits using the credit management device 8 (S4), and trades these credits with farmers via the farmer terminal device 3 and with consumers via the consumer terminal device 9 (S5).

Figure 4 is a flowchart showing an example of the initial setting operation (operation at the time of initial setting) of the paddy field methane reduction support device 1. The initial setting operation in Figure 4 shows details of processes S1 and S2 in Figure 3. For example, a farmer connects to the paddy field methane reduction support device 1 using the farmer terminal device 3 and inputs identification information of the paddy field in which methane is to be reduced. The farmer terminal device 3 then generates registration information including the identification information of the paddy field and the farmer's identification information, and transmits the registration information to the paddy field methane reduction support device 1.

The control unit 1a of the paddy field methane reduction support device 1 receives registration information from the farmer terminal device 3 via the communication unit 1c (S11 in FIG. 4). The control unit 1a then transmits an information request signal via the communication unit 1c to the agricultural management device 2, requesting the transmission of farmer information, paddy field information, and work information corresponding to the farmer identification information and paddy field identification information contained in the registration information (S12).

The agricultural management device 2 receives an information request signal from the paddy field methane reduction support device 1 and searches the database 2d. If the farmer information, paddy field information, and work information corresponding to the requested farmer identification information and paddy field identification information are stored in the database 2d, the agricultural management device 2 transmits the farmer information, paddy field information, and work information to the paddy field methane reduction support device 1. When the control unit 1a of the paddy field methane reduction support device 1 receives (acquires) the farmer information, paddy field information, and work information from the farmer terminal device 3 via the communication unit 1c (S13: YES), it stores the farmer information, paddy field information, and work information in the memory unit 1b (S18). At this time, the farmer information, paddy field information, and work information acquired by the control unit 1a correspond to each other.

On the other hand, if the farmer information, past paddy field information, and work information corresponding to the farmer identification information and paddy field identification information requested by the paddy field methane reduction support device 1 are not stored in the database 2d, the agricultural management device 2 notifies the paddy field methane reduction support device 1 that there is no corresponding information. When the control unit 1a of the paddy field methane reduction support device 1 receives a notification via the communication unit 1c indicating that there is no corresponding information (S14), it transmits an information request signal via the communication unit 1c to the farmer terminal device 3 corresponding to the farmer identification information, requesting the farmer information, paddy field information, and work information (S15).

When the farmer terminal device 3 receives an information request signal from the paddy field methane reduction support device 1, it displays a screen for inputting farmer information, paddy field information, and work information on the display of the input/output interface. Then, when the farmer information, paddy field information, and work information are input by the keyboard of the input/output interface, the farmer terminal device 3 transmits the farmer information, paddy field information, and work information to the paddy field methane reduction support device 1. When the control unit 1a of the paddy field methane reduction support device 1 receives the farmer information, paddy field information, and work information from the farmer terminal device 3 by the communication unit 1c (S16), it transmits the farmer information, paddy field information, and work information to the agricultural management device 2 and stores it in the database 2d (S17). In addition, the control unit 1a stores the farmer information, paddy field information, and work information in the memory unit 1b (S18). At this time, the farmer information, paddy field information, and work information acquired by the control unit 1a also correspond to each other.

Next, the control unit 1a sets a calculation formula for calculating the amount of methane emissions from the paddy field based on the paddy field information and work information received (acquired) from the agricultural management device 2 or the farmer terminal device 3, and the model data stored in the memory unit 1b (S19a). The model data includes, for example, the well-known model formulas (1) and (2) as shown in FIG. 5, and table data (not shown) for setting the variables A, fd, fw, fo, EF, α, a, X, and b in the model formulas (1) and (2). Model formula (1) is a formula for calculating the amount of methane emissions E from the paddy field. Model formula (2) is a formula for calculating the emission coefficient included in model formula (1).

The control unit 1a determines the calculation formula (formula (1) and (2) after the variables are determined) for calculating the methane emissions from the paddy field by setting the variables A, fd, fw, fo, α, EF, X, a, and b (A: paddy rice planting area by region, fd: drainage ratio, fw: water management ratio, fo: organic matter ratio, α: correction coefficient, EF: emission coefficient, X: organic matter application amount by region and applied organic matter, a: slope by region, drainage type, and water management, b: intercept by region, drainage type, and water management) of the model formulas (1) and (2) based on the paddy field information and work information of the paddy field and the corresponding table data.

The variables fw, EF, a, and b in model formula (2) are values determined by the water management state of the paddy field. The control unit 1a sets the basic paddy field drying state based on the conventional water management information contained in the paddy field work information received (acquired) from the agricultural management device 2 or the farmer terminal device 3 (S19b in FIG. 4). The conventional water management information indicates, for example, the paddy field water management state that has been customarily carried out in an area where the paddy field is located. The basic paddy field drying state includes whether or not drying is being carried out and the drying period (for example, the duration during which the water level of the paddy field is zero).

The control unit 1a also sets the variable a based on the basic dry land state and a predetermined slope calculation formula included in the model data. The control unit 1a also sets the variable b based on the basic dry land state and a predetermined intercept calculation formula included in the model data. The control unit 1a also sets the variable fw based on the basic dry land state and a predetermined table data included in the model data. The control unit 1a then applies the set variables a, b, and fw to the model formulas (1) and (2) to determine the calculation formulas (1) and (2), and calculates the basic methane emission amount of the paddy field using the determined calculation formulas (1) and (2) (S19c). That is, the control unit 1a calculates the basic methane emission amount of the paddy field based on the determined calculation formulas (1) and (2) and the basic dry land state. The control unit 1a also stores the determined calculation formulas (1) and (2), the basic dry land state, and the basic methane emission amount in the memory unit 1b (S19d).

The model data and calculation formula for calculating methane emissions from paddy fields are not limited to the above, and may be a formula or data other than formulas (1) and (2) in FIG. 5. Furthermore, methane emissions from paddy fields may be calculated using model data and a calculation formula that takes into account information other than paddy field information and work information for paddy fields, such as weather information. Furthermore, a calculation formula for methane emissions from paddy fields may be set and the methane emissions from paddy fields may be calculated using machine learning using AI.

Figure 6 is a flow chart showing an example of a methane evaluation operation (operation during methane evaluation) of the paddy field methane reduction support device 1. The methane evaluation operation in Figure 6 is an operation for evaluating the reduction status of methane from paddy fields, and shows details of process S3 in Figure 3. For example, a farmer changes agricultural work such as water management work in the paddy field in order to reduce methane from the paddy field, and then harvests the crop (rice) in the paddy field, completing the agricultural work for this year. Then, when the farmer connects to the paddy field methane reduction support device 1 using the farmer terminal device 3 and instructs to perform a methane evaluation of the paddy field, the farmer terminal device 3 transmits a methane evaluation command to the paddy field methane reduction support device 1.

The control unit 1a of the paddy field methane reduction support device 1 receives a methane evaluation command from the farmer terminal device 3 via the communication unit 1c (S21 in FIG. 6). The control unit 1a then acquires farmer information, paddy field information, and work information corresponding to the farmer identification information and paddy field identification information contained in the methane evaluation command from the agricultural management device 2 or farmer terminal device 3 (S22). The process S22 for acquiring this information is executed in the same procedure as steps S12 to S18 in FIG. 4. (The same applies to the information acquisition processes of step S31 in FIG. 8 and step S41 in FIG. 9, which will be described later.)

Next, the control unit 1a reads the implementation status of the agricultural work included in the acquired work information, and identifies the dry paddy field state where the work was carried out based on the water management information included in the work information (S23). The dry paddy field state identified at this time includes whether or not dry paddy fields are implemented and the dry paddy field period. Next, the control unit 1a reads out the calculation formula corresponding to the paddy field (the above-mentioned confirmed formulas (1) and (2)) from the storage unit 1b, and calculates the methane emission amount of the paddy field based on the calculation formula, the implementation status of the agricultural work read out, and the identified dry paddy field state (S24). Next, the control unit 1a reads out the basic methane emission amount corresponding to the paddy field from the storage unit 1b, and calculates the methane reduction amount of the paddy field by subtracting the methane emission amount of the paddy field from the basic methane emission amount (S25). That is, the control unit 1a calculates the methane reduction amount of the paddy field that has been reduced due to a change in the agricultural work in the paddy field or a change in the identified dry paddy field state to the basic dry paddy field state.

Then, the control unit 1a generates evaluation information including the calculated amount of methane reduction in the paddy field, and transmits the evaluation information to the farmer terminal device 3 based on the farmer information via the communication unit 1c (S26). The evaluation information may include not only the amount of methane reduction in the paddy field, but also the specified mid-drainage period or the calculated amount of methane emission.

In the methane evaluation operation shown in FIG. 6, an example is shown in which the methane emission amount is calculated using a calculation formula corresponding to paddy fields, and the methane emission amount is subtracted from the basic methane emission amount to calculate the methane reduction amount. However, in addition to this, for example, a correlation between the mid-drainage period of paddy fields and the methane reduction amount may be derived in advance based on a calculation formula, and the methane reduction amount may be calculated based on the correlation and the identified mid-drainage period.

Specifically, for example, in advance during initial setting operations, the control unit 1a calculates the methane emission amount based on the extended dry period and a calculation formula corresponding to the paddy field each time the basic dry period included in the basic dry state of the paddy field in the simulation is extended forward or backward (advance or delay) by a predetermined interval. The control unit 1a also calculates the methane emission amount of the paddy field by subtracting the methane emission amount from the basic methane emission amount. The control unit 1a then derives the correlation between the dry period of the paddy field and the methane reduction amount, and stores first correlation data indicating the correlation in the memory unit 1b.

Figure 7 is a diagram showing an example of the first correlation data showing the correlation between the paddy field dry-out period and the methane reduction amount. The first correlation data shown in Figure 7 shows the correlation between the paddy field dry-out period and the methane reduction amount in the form of a table. The first correlation data also shows the methane reduction amount in the case of the basic paddy field dry-out period (5 days), the methane reduction amount when the basic dry-out period is extended forward by 7 days and 14 days, the methane reduction amount when the basic dry-out period is extended backward by 7 days and 14 days, the methane reduction amount when the basic dry-out period is extended forward by 7 days and backward by 7 days, and the methane reduction amount when the basic dry-out period is extended forward by 14 days and backward by 14 days.

In this case, the control unit 1a, in the methane evaluation operation, identifies the mid-dry state of the paddy field, and calculates the methane reduction amount without calculating the methane emission amount of the paddy field based on the mid-dry period included in the mid-dry state and the first correlation data. Specifically, for example, if the mid-dry period of the paddy field is extended by 10 days ahead of the basic mid-dry period, the control unit 1a calculates the methane reduction amount for the mid-dry period brought forward by 10 days based on the methane reduction amount Ya for the first correlation data brought forward by 7 days and the methane reduction amount Yc for the first correlation data brought forward by 14 days.

The method of calculating the methane reduction amount of paddy fields is not limited to the above-mentioned calculation method, and the methane reduction amount of paddy fields may be calculated based on other calculation formulas or data. Furthermore, at least one of the methane reduction amount of the entire paddy field (and methane emission amount) and the methane reduction amount (and methane emission amount) per unit area of the paddy field may be calculated as the methane reduction amount of the paddy field. Alternatively, the methane reduction rate (%) of the paddy field may be calculated as the methane reduction amount. Furthermore, the methane reduction amount of paddy fields may be calculated using model data and calculation formulas that take into account information other than paddy field information and work information of paddy fields, such as weather information. Furthermore, the methane reduction amount of paddy fields may be calculated using AI machine learning.

Figure 8 is a flowchart showing an example of the drainage suggestion operation of the paddy field methane reduction support device 1. The drainage suggestion operation of Figure 8 is an operation that proposes a recommended drainage period that effectively and beneficially reduces methane from paddy fields. For example, before a farmer starts drainage work on a paddy field, the control unit 1a of the paddy field methane reduction support device 1 acquires farmer information, paddy field information, and work information corresponding to the paddy field from the agricultural management device 2 or farmer terminal device 3 (S31 in Figure 8). This information acquisition process S31 is executed in the same procedure as processes S12 to S18 in Figure 4.

Next, as described above, the control unit 1a calculates the amount of methane reduction in the paddy field each time the basic dry period included in the basic dry state of the paddy field in the simulation is extended by a predetermined interval, derives the correlation between the dry period of the paddy field and the amount of methane reduction, and stores the first correlation data indicating the correlation in the memory unit 1b (S32 in Figure 8).

The control unit 1a also calculates the amount of crop yield loss in the paddy field each time the basic dry-up period of the paddy field is extended by a specified interval in the simulation, derives a correlation between the dry-up period of the paddy field and the amount of crop yield loss, and stores second correlation data indicating this correlation in the memory unit 1b (S33).

Specifically, for example, the control unit 1a estimates the basic yield of the crop in the paddy field based on the basic dry-off period of the paddy field, the paddy field information, and the work information. In addition, the control unit 1a estimates the crop yield of the paddy field based on the dry-off period after the extension and the paddy field information and work information of the paddy field each time the basic dry-off period of the paddy field is extended by a predetermined interval in the simulation. The longer the dry-off period of the paddy field, the lower the crop yield. For this reason, the control unit 1a calculates the crop yield loss by subtracting the crop yield calculated for each extended dry-off period from the basic yield, derives the correlation between the dry-off period of the paddy field and the crop yield loss, and generates second correlation data indicating the correlation. The second correlation data may be data in a table format or may be an arithmetic expression.

Next, the control unit 1a determines the recommended dry-drainage period for the paddy field in which the methane reduction amount is equal to or greater than the first predetermined value and the crop yield loss amount is equal to or less than the second predetermined value based on the first correlation data and the second correlation data (S34). Then, the control unit 1a transmits the work proposal information including the determined recommended dry-drainage period to the farmer terminal device 3 corresponding to the paddy field via the communication unit 1c (S35). If the basic dry-drainage period is 0 days, that is, if dry-drainage has not been implemented in the paddy field in the past, the control unit 1a may include information recommending the implementation of dry-drainage in the work proposal information in process S35. If the basic dry-drainage period is 1 day or more, that is, if dry-drainage has been implemented in the paddy field in the past, the control unit 1a may include the extension date and time of the conventional dry-drainage period in the work proposal information in process S35. The control unit 1a may also determine at least one of the start date and end date of the recommended dry-drainage period and include at least one of the start date and end date in the work proposal information.

The farmer terminal device 3 receives work proposal information from the paddy field methane reduction support device 1 and displays the recommended paddy field irrigation period indicated in the work proposal information on the input/output interface display, etc.

As another example, the control unit 1a may derive either the first correlation data or the second correlation data, and determine the optimal recommended drainage period based on the derived correlation data and the identified drainage period of the paddy field. As another example, in order to reduce methane in paddy fields, the control unit 1a may propose water management work such as intermittent irrigation of paddy fields, agricultural work such as incorporation of rice straw or application of compost after harvesting crops, in addition to or instead of implementing drainage of paddy fields and extending the drainage period. Furthermore, suggestions such as the recommended drainage period of paddy fields, recommended water management work, incorporation of rice straw, or application of compost may be derived by machine learning using AI.

Figure 9 is a flow chart showing an example of the calculation formula update operation of the paddy field methane reduction support device 1. The calculation formula update operation of Figure 9 is an operation for updating the calculation formula for methane emissions from paddy fields. For example, when the manager of the paddy field methane reduction support device 1 inputs an instruction to update the calculation formula for a certain paddy field through the input/output interface 1d (S41 in Figure 9), the control unit 1a acquires paddy field information and work information corresponding to the paddy field from the agricultural management device 2 or farmer terminal device 3 (S42). Then, if there is a change in information related to the calculation of methane emissions from the paddy field among the information contained in the acquired paddy field information and work information (S43: YES), the control unit 1a updates the calculation formula for methane emissions from the paddy field in accordance with the change in information (S44).

Specifically, for example, if there is a change in the drainage of the paddy field contained in the paddy field information or in the applied organic matter contained in the work information, the control unit 1a updates the calculation formula for the amount of methane emissions from the paddy field (Figure 5) by changing the variables fd, fo, EF, a, and b in accordance with the change (S44).

In addition, the control unit 1a may also update the basic methane emission amount in conjunction with updating the above calculation formula. In addition, an operator may operate the input/output interface 1d (mouse, keyboard, etc.) of the paddy field methane reduction support device 1 to update the model data stored in the memory unit 1b based on the actual methane concentration or emission amount in the paddy field measured by the methane meter.

Figure 10 is a flow chart showing an example of the crediting operation of the paddy field methane reduction support device 1. The crediting operation in Figure 10 is an operation when converting the amount of methane reduction in a paddy field into an electronic credit, and shows details of process S4 in Figure 3. After calculating the amount of methane reduction in a paddy field, the control unit 1a of the paddy field methane reduction support device 1 generates report information including the amount of methane reduction in the paddy field and farmer information corresponding to the paddy field, and transmits the report information to the credit management device 8 via the communication unit 1c (S51 in Figure 10).

When the credit management device 8 receives report information from the paddy field methane reduction support device 1, it issues credits according to the amount of methane reduction in the paddy field contained in the report information, and transmits credit information indicating the credits to the paddy field methane reduction support device 1. The credit information includes information such as the credit value, identification information (management number), and the owner of the credit. When the control unit 1a receives credit information from the credit management device 8 (S52), it identifies the farmer who is the owner of the credit indicated by the credit information, and transmits the received credit information to the farmer terminal device 3 used by that farmer (S53).

In the crediting operation in FIG. 10, the methane reduction amount is credited for each paddy field. However, in addition to this, the methane reduction amounts for multiple paddy fields may be credited together as shown in FIG. 11, for example.

Figure 11 is a flowchart showing another example of the crediting operation of the paddy field methane reduction support device 1. The control unit 1a of the paddy field methane reduction support device 1 adds up the methane reduction amounts of multiple paddy fields (S54 in Figure 11), generates report information including the added up methane reduction amount, and transmits the report information to the credit management device 8 via the communication unit 1c (S51a).

Then, when the control unit 1a receives (obtains) credit information indicating the credits issued by the credit management device 8 according to the combined methane reduction amount via the communication unit 1c (S52a), the control unit 1a distributes the credits indicated by the credit information according to the methane reduction amount of the multiple rice paddies (S55). The control unit 1a also generates new credit information indicating the distributed credits, and transmits the credit information via the communication unit 1c to the farmer terminal device 3 of the farmers corresponding to the multiple rice paddies (S53a).

Figure 12 is a flowchart showing an example of the credit purchasing operation of the paddy field methane reduction support device 1. The credit purchasing operation of Figure 12 is the operation when purchasing credits from a farmer, and shows an example of process S7 of Figure 3. For example, when a farmer inputs information indicating that he or she wishes to sell credits he or she owns into the farmer terminal device 3, the farmer terminal device 3 generates sales request information indicating that the farmer wishes to sell the credits, and transmits the sales request information to the paddy field methane reduction support device 1. The sales request information includes not only the desire to sell the credits, but also credit information indicating the credit value and identification number, etc.

When the control unit 1a of the paddy field methane reduction support device 1 receives sales request information from the farmer terminal device 3 via the communication unit 1c (S61), it determines the price of the credits indicated in the sales request information, and outputs payment instruction information indicating an instruction to pay the price to a specified trader via the input/output interface 1d (S62). At this time, for example, the control unit 1a displays the payment instruction information on a display included in the input/output interface 1d. Alternatively, the payment instruction information may be transferred to a trader terminal device (not shown) used by the specified trader.

After that, when payment completion information indicating that the trader has paid the price to the farmer is input via the input/output interface 1d (mouse, keyboard, etc.) (S63), the control unit 1a changes the owner of the corresponding credit from the farmer to the trader and manages the credit on behalf of the trader (S64). The control unit 1a also generates change report information including credit information indicating the corresponding credit and information indicating that the owner of the credit has changed from the farmer to the trader, and transmits the change report information to the credit management device 8 via the communication unit 1c (S65).

When the credit management device 8 receives change report information from the paddy field methane reduction support device 1, it accepts the change in the owner of the credit indicated in the change report information and updates the management information for that credit.

Figure 13 is a flow chart showing an example of the credit transaction operation of the paddy field methane reduction support device 1. The credit transaction operation of Figure 13 is an operation when selling credits to a consumer, and shows an example of process S7 of Figure 3. For example, when the control unit 1a of the paddy field methane reduction support device 1 receives purchase request information indicating a desire to purchase managed credits from a consumer terminal device 9 used by a consumer (S71), the control unit 1a determines the price of the credits indicated in the purchase request information and transmits a payment command to the consumer terminal device 9 to have the consumer pay the price (S72).

Then, when the control unit 1a receives payment completion information from the consumer terminal device 9 via the communication unit 1c indicating that the consumer has paid the price to the transactor (S73), it changes the owner of the corresponding credit from the transactor to the consumer (S74) and removes the credit from the management subject. In addition, the control unit 1a generates change report information including credit information indicating the credit and information indicating that the owner of the credit has changed from the transactor to the consumer, and transmits the change report information to the credit management device 8 via the communication unit 1c (S75).

In the above embodiment, the agricultural management device 2 and the farmer terminal device 3 are external devices to the paddy field methane reduction support device 1, but this is not limited to the above. For example, the paddy field methane reduction support device 1 and the agricultural management device 2 may be configured as the same computer or server, or the paddy field methane reduction support device 1 and the farmer terminal device 3 may be configured as the same computer or terminal device. Furthermore, the paddy field methane reduction support device 1, the agricultural management device 2, and the farmer terminal device 3 may be provided on a cloud, and information may be input and output to and from each other on the cloud. In this case, evaluation information indicating the amount of methane reduction in the paddy field, work proposal information including the recommended irrigation period for the paddy field, and credit information indicating credits corresponding to the amount of methane reduction may be input and output to and from the same computer or cloud.

In the above embodiment, examples have been shown in which the water management state of a paddy field to reduce methane emissions from the paddy field during the cultivation of crops in the paddy field is detected by the water management device 4 based on the detection results of the water level sensor 5, or by the monitoring device 6 based on the observation results of the synthetic aperture radar of the earth observation satellite 7, or by the farmer inputting the information via the farmer terminal device 3.

However, if the water management device 4 or water level sensor 5 is not installed in a paddy field and the paddy field is not monitored by the monitoring device 6, the water management status of the paddy field cannot be detected. Furthermore, the information (records) on the water management status of the paddy field entered by the farmer using the farmer terminal device 3 lacks objectivity and evidentiary value and may be incorrect or tampered with.

To address the above problem, the paddy field methane reduction support device 1 is configured to identify the state of water management for reducing methane in paddy fields and the period during which that state has continued, based on data from SAR images (observation images) captured by the synthetic aperture radar of the Earth observation satellite 7. An embodiment of this case will be described in detail below.

Figure 14A is a diagram showing an example of the reflection state of microwaves irradiated from a synthetic aperture radar of an Earth observation satellite 7 to a flooded rice paddy H. As shown in Figure 14A, when microwaves Wa are irradiated from the synthetic aperture radar of an Earth observation satellite 7 to a flooded rice paddy H, the microwaves Wa are reflected by the smooth water surface Hw of the rice paddy H. For this reason, in a flooded rice paddy H, the intensity of the forward scattered waves Wf of the microwaves Wa becomes high and the intensity of the backscattered waves becomes low, i.e., the backscattering coefficient σ becomes small.

Figure 14B is a diagram showing an example of the reflection state of microwaves irradiated from the synthetic aperture radar of the Earth observation satellite 7 to a paddy field H in a waterlogged state. As shown in Figure 14B, when microwaves Wa are irradiated from the synthetic aperture radar of the Earth observation satellite 7 to a paddy field H in a waterlogged state, the microwaves Wa are reflected by the uneven (uneven, uneven, not smooth) or cracked ground surface Hg of the paddy field H. For this reason, in a paddy field H in a waterlogged state, the intensity of the forward scattered waves Wf of the microwaves Wa is lower and the intensity (backscattering coefficient) of the backscattered waves Wb of the microwaves Wa is higher than in the case of a flooded paddy H (Figure 14A), i.e., the backscattering coefficient σ is larger.

In addition, when a crop (rice) R is cultivated in a paddy field H, and X-band microwaves Wa are irradiated onto the paddy field H from the synthetic aperture radar of the Earth observation satellite 7, as shown in Figures 14A and 14B, the X-band microwaves Wa are not only reflected by the water surface Hw or ground surface Hg of the paddy field H, but also by the grown leaves of the crop R. In this way, when the X-band microwaves Wa are reflected by the crop R, the intensity of the forward scattered waves Wf of the microwaves Wa decreases and the intensity of the backscattered waves Wb of the microwaves Wa increases, resulting in a large backscattering coefficient.

Figures 15A to 15C are diagrams showing an example of a SAR image of an area including multiple rice paddies H in which crops (rice) are being cultivated, observed by a synthetic aperture radar on an Earth observation satellite 7. In particular, Figure 15A shows a SAR image of an area including multiple rice paddies H before the mid-drainage period (observation date: June 21, 2021). Figure 15B shows a SAR image of multiple rice paddies H during the mid-drainage period (observation date: July 3, 2021). Figure 15C shows a SAR image of multiple rice paddies H after the mid-drainage period (observation date: July 15, 2021).

Each SAR image shown in Figures 15A to 15C shows the intensity of backscattered waves when X-band microwaves are irradiated from a synthetic aperture radar. For ease of illustration, each SAR image includes multiple rice paddies H in the hatched area, and visible rice paddies H are shown separated by dashed lines.

By detecting pixel values that represent at least one of the shade and brightness of the color of each pixel in the SAR image and converting each pixel value using conversion data such as a predetermined LUT (Look Up Table) or an arithmetic formula that is pre-stored in the memory unit 1b, it is possible to determine the intensity of the backscattered waves, i.e., the backscattering coefficient, at the actual location, such as a rice field H, indicated by each pixel.

In SAR images, the smaller the backscattering coefficient, the darker the black appears. That is, in each SAR image, paddy fields H in a flooded state, which has a small backscattering coefficient, are displayed as darker, while paddy fields H in a drained state, which has a large backscattering coefficient, are displayed as lighter. In Figures 15A to 15C, the narrower the spacing between the hatches, the darker the black appears.

In the SAR image of paddy field H before the mid-drainage period shown in Figure 15A, and the SAR image of paddy field H after the mid-drainage period shown in Figure 15C, paddy field H is in a waterlogged state, so it appears dark. In contrast, in the SAR image of paddy field H during the mid-drainage period shown in Figure 15B, paddy field H is in a drained state, so it appears light.

Figures 16A and 16B are graphs showing histograms of the backscattering coefficients of a certain paddy field H1 included in the SAR images shown in Figures 15A to 15C. In more detail, Figure 16A is a graph showing a histogram Gb of the backscattering coefficients corresponding to a number of pixels representing the paddy field H1 in the SAR image before the inter-dried period, and a histogram Gc of the backscattering coefficients corresponding to a number of pixels representing the paddy field H1 in the SAR image during the inter-dried period. Figure 16B is a graph showing the histogram Gc and a histogram Ga of the backscattering coefficients corresponding to a number of pixels representing the paddy field H1 after the inter-dried period.

In Figures 16A and 16B, the horizontal axis shows the range of the backscattering coefficient, and the vertical axis shows the ratio of the number of pixels associated with each backscattering coefficient to the total number of pixels showing paddy field H1. As shown in Figures 16A and 16B, the histogram Gb of the backscattering coefficient of paddy field H1 before the inter-dried period, the histogram Gc of the backscattering coefficient of paddy field H1 during the inter-dried period, and the histogram Ga of the backscattering coefficient of paddy field H1 before the inter-dried period each show a normal distribution.

As shown in Figure 16A, the histogram Gb of the backscattering coefficient of the paddy field H1 before the inter-dried period has a wider range of small backscattering coefficients and a larger distribution range than the histogram Gc of the backscattering coefficient of the paddy field H1 during the inter-dried period. In addition, the mode Gbm of the histogram Gb before the inter-dried period is smaller than the mode Gcm of the histogram Gc during the inter-dried period. The average and median of the histogram Gb before the inter-dried period are also smaller than the average of the histogram Gc during the inter-dried period (reference symbols omitted).

As shown in FIG. 16B, the histogram Ga of the backscattering coefficient of the SAR image of paddy field H1 after the inter-dried period spreads over a smaller range of backscattering coefficients than the histogram Gc of the backscattering coefficient of the SAR image of paddy field H1 during the inter-dried period. In addition, the mode Gam of the histogram Ga after the inter-dried period is smaller than the mode Gcm of the histogram Gc during the inter-dried period. The average and median of the histogram Ga after the inter-dried period are also smaller than the average of the histogram Gc during the inter-dried period (symbols omitted).

Based on the histograms Ga to Gc as described above, a threshold value is set to determine the water management state of the paddy field H1. For example, as shown in FIG. 16A, the backscattering coefficient of the apex P1 of the part where the histogram Gb before the mid-drainage period and the histogram Gc during the mid-drainage period overlap is detected. Also, as shown in FIG. 16B, the backscattering coefficient of the apex P2 of the part where the histogram Ga after the mid-drainage period and the histogram Gc during the mid-drainage period overlap is detected. Then, based on the backscattering coefficient of the apex P1 and the backscattering coefficient of the apex P2, a first threshold value σ1 is set to determine whether the paddy field H1 is in a mid-drainage state. At this time, for example, the mode, average, median, maximum, or minimum value of the backscattering coefficient of the apex P1 and the backscattering coefficient of the apex P2 may be set as the first threshold value σ1. The first threshold value σ1 can be used to determine whether the paddy field H1 is in a drainage state or a flooded state.

As another example, a normal distribution curve corresponding to each of the histograms Ga to Gc may be calculated, and the first threshold value σ1 may be set based on the normal distribution curve. Specifically, the backscattering coefficient of the intersection between the normal distribution curve of the histogram Gb before the mid-term and the normal distribution curve of the histogram Gc during the mid-term is detected. Also, the backscattering coefficient of the intersection between the normal distribution curve of the histogram Ga after the mid-term and the normal distribution curve of the histogram Gc during the mid-term is detected. Then, the mode, average, median, maximum, or minimum of the backscattering coefficient of these two intersections may be set as the first threshold value σ1.

In addition, a second threshold value σ2 for determining whether the paddy field H1 is in a flooded state is set based on the minimum value of the backscattering coefficient shown in the histogram Gc during the mid-drainage period shown in Figures 16A and 16B (the backscattering coefficient at the leftmost point P3 in Figures 16A and 16B). At this time, for example, the second threshold value σ2 may be set to the minimum value of the histogram Gc, or a value smaller than the minimum value by a predetermined margin value. The second threshold value σ2 can also be used to determine whether the paddy field H1 is not in a drained state or in a mid-drainage state.

The setting of the first threshold value σ1 and the second threshold value σ2 as described above may be performed, for example, by an operator operating a computer, or may be performed by the control unit 1a of the paddy field methane reduction support device 1 according to a software program. The first threshold value σ1 and the second threshold value σ2 may also be set by machine learning using AI (artificial intelligence). However, the first threshold value σ1 and the second threshold value σ2 are stored in the memory unit 1b (Figure 1) of the paddy field methane reduction support device 1.

The method of setting the first threshold value σ1 and the second threshold value σ2 is not limited to the above. For example, at least one of the operator, the paddy field methane reduction support device 1, another computer, and the AI may set the first threshold value σ1 and the second threshold value σ2 by referring to the SAR image of the paddy field and the state and period of water management such as flooding, drainage, and intermittent drainage confirmed in the actual paddy field by a worker or the like.

The first threshold value σ1 and the second threshold value σ2 may be set for each paddy field, or a common first threshold value σ1 and a common second threshold value σ2 may be set for multiple paddy fields. Also, pixels representing multiple paddy fields included in each of multiple regions may be extracted from multiple SAR images obtained by observing each of the multiple regions using a synthetic aperture radar, and the first threshold value σ1 and the second threshold value σ2 may be set based on the backscattering coefficients corresponding to the pixel values of the multiple pixels.

Moreover, the first threshold σ1 and the second threshold σ2 may be set statistically or typologically based on SAR images and empirical data of paddy fields. The first threshold σ1 and the second threshold σ2 may be set based on SAR images and empirical data of different paddy fields, or may be set using different algorithms. The first threshold σ1 and the second threshold σ2 may be set to different values, or may be set to the same value. At least one of the first threshold σ1 and the second threshold σ2 may be set. The first threshold σ1 and the second threshold σ2 may be updated every predetermined number of years based on SAR images and empirical data of paddy fields that have been collected up to that point.

Figure 17 is a graph showing the change in the proportion of backscattering coefficients corresponding to paddy field H1 in SAR images before and after the mid-drainage period. In detail, Figure 17 shows the proportions of each section when the backscattering coefficients corresponding to each pixel of the SAR images of paddy field H1 observed by the synthetic aperture radar of the Earth Observation Satellite 7 on June 9, June 21, July 3, July 15, and July 27 in 2021 are divided into three stages. June 9 and 21 are observation dates before the mid-drainage period of paddy field H1, July 3 is observation date during the mid-drainage period of paddy field H1, and July 15 and 27 are observation dates after the mid-drainage period of paddy field H1. The horizontal axis of Figure 17 indicates the date, and the vertical axis indicates the proportion.

The SAR images from June 9th and July 27th are omitted from the illustration. However, in the SAR image from June 9th, the flooded rice fields H are displayed in a dark color, as in the SAR image from June 21st shown in FIG. 15A. In addition, in the SAR image from July 27th, the water-logged rice fields H are displayed in a light color, as in the SAR image from July 15th shown in FIG. 15C.

In FIG. 17, the step of the backscattering coefficient σ greater than the first threshold σ1 is set as the intermediate tidal area Cm. The step of the backscattering coefficient σ less than the second threshold σ2 is set as the flooded area Cf. The step of the backscattering coefficient σ greater than the second threshold σ2 and less than the first threshold σ1 is set as the partially flooded area Cp. In addition, the first threshold σ1 is set to "-14 [db]" and the second threshold σ2 is set to "-20 [db]". In the graph of FIG. 17, the backscattering coefficient ratio of the intermediate tidal area Cm is shown by a solid line, the backscattering coefficient ratio of the partially flooded area Cp is shown by a two-dot chain line, and the backscattering coefficient ratio of the flooded area Cf is shown by a dashed dot line.

As shown in Figure 17, before the mid-drainage period of paddy field H1 (June 9th and 21st), the proportion of backscattering coefficients σ belonging to the flooded area Cf (99.36% on June 9th and 61.37% on the 21st) is higher than the proportions of backscattering coefficients σ belonging to the mid-drainage area Cm and partially flooded area Cp (0.02% on June 9th and 10.09% on the 21st for mid-drainage area Cm, and 0.03% on June 9th and 28.54% on the 21st for partially flooded area Cp). Also, about one week before the mid-drainage period when crop R in paddy field H1 has grown to a certain extent (June 21st), the proportion of backscattering coefficients σ belonging to the mid-drainage area Cm is lower than the proportion of backscattering coefficients σ belonging to the partially flooded area Cp.

During the mid-drainage period of paddy field H1 (July 3rd), the proportion of backscattering coefficient σ belonging to the mid-drainage area Cm (88.5%) is significantly higher than the proportion of backscattering coefficient σ belonging to the flooded area Cf and partially flooded area Cp (flooded area Cf: 0.72%, partially flooded area Cp: 10.78%).

After the mid-drainage period of paddy field H1 (July 15th and 27th), the proportion of backscattering coefficients σ belonging to the mid-drainage area Cm (3.17% on July 15th and 0.75% on July 27th) is lower than the proportions of backscattering coefficients σ belonging to the flooded area Cf and partially flooded area Cp (55.24% on July 15th and 81.68% on July 27th for flooded area Cf, and 41.59% on July 15th and 17.57% on July 27th for partially flooded area Cp). Also, after the mid-drainage period of paddy field H1, the proportion of backscattering coefficients σ belonging to the flooded area Cf is higher than the proportion of backscattering coefficients σ belonging to the partially flooded area Cp.

As described above, the proportions of the backscattering coefficient σ belonging to the dry zone Cm and the flooded zone Cf vary significantly depending on whether the paddy field H1 is in an actual dry zone or not. This demonstrates that the first threshold value σ1 that determines the dry zone Cm and the second threshold value σ2 that determines the flooded zone Cf are appropriate threshold values for determining the dry zone state of the paddy field H1.

Figure 18 is a flowchart showing an example of the water management specification operation of the paddy field methane reduction support device 1. The water management specification operation of Figure 18 is an operation for specifying the state of water management for reducing methane in paddy fields and the period during which said state has continued, and is executed by the control unit 1a (Figure 1) of the paddy field methane reduction support device 1 instead of process S23 after process S22 of Figure 6 described above.

In the methane evaluation operation shown in FIG. 6, the control unit 1a of the paddy field methane reduction support device 1 receives a methane evaluation command from the farmer terminal device 3 via the communication unit 1c (communication interface) as described above (S21 in FIG. 6). The control unit 1a then acquires (receives) farmer information, paddy field information, and work information corresponding to the farmer identification information and paddy field identification information included in the methane evaluation command from the agricultural management device 2 or the farmer terminal device 3 via the communication unit 1c (S22). The communication unit 1c is an example of an acquisition unit that acquires information. Alternatively, the acquisition unit may be configured with an input interface that can input information and data to the paddy field methane reduction support device 1 via a storage medium.

After process S22 in FIG. 6, the control unit 1a executes the water management specification operation in FIG. 18. First, the control unit 1a reads the acquired paddy field information and work information (S81 in FIG. 18) and checks whether the work information includes water management information for the target paddy field indicated in the paddy field information. For example, if a water management device 4 or the like (which may include the water level sensor 5 in FIG. 1) is installed in the target paddy field, the control unit 1a checks whether the work information includes water management information (hereinafter referred to as "detected water management information") that indicates the water management state of the target paddy field, such as flooding, irrigation, or drainage, detected by the water management device 4 (S82 in FIG. 18: YES).

In addition, if the target paddy field is included in the monitoring targets registered in the monitoring device 6 (Figure 1), the control unit 1a confirms that the water management information of the target paddy field detected by the monitoring device 6 (hereinafter referred to as "detected water management information") is included in the work information (S82 in Figure 18: YES).

Next, the control unit 1a identifies the state (presence or absence) and period of water management implemented to reduce methane in the target paddy field based on the detected water management information, and stores specific water management information indicating the state and period of the mid-drainage in the memory unit 1b (S83). The control unit 1a then stores the detected water management information based on which the specific water management information was identified in the memory unit 1b in association with the specific water management information as evidence information (S84).

Specifically, in process S83, for example, the control unit 1a first identifies the tillering stage and young panicle formation stage of the crop (rice) planted in the target paddy field based on the paddy field information and work information. Next, the control unit 1a reads the detected water management information and checks whether the target paddy field has remained unflooded for a predetermined number of days (e.g., 5 days) or more between the tillering stage and the young panicle formation stage.

For example, when the control unit 1a confirms from the detected water management information that the target paddy field has remained unflooded (water-drained) for a predetermined number of days (e.g., 5 days) or more, it determines that mid-drying has been carried out in the target paddy field. The control unit 1a then identifies the start and end dates of the target paddy field's unflooded state as the mid-drying start date and end date, respectively, and identifies the period from the mid-drying start date to the end date as the mid-drying period. Furthermore, the control unit 1a generates specific water management information indicating that mid-drying has been carried out in the target paddy field and the mid-drying period, and stores the specific water management information in the memory unit 1b (S84).

If no mid-drainage was carried out in the target paddy field, the control unit 1a cannot identify the mid-drainage state of the target paddy field based on the detected water management information in process S83. In this case, the control unit 1a generates specific water management information indicating that no mid-drainage was carried out in the target paddy field in process S84, and stores the specific water management information in the memory unit 1b.

When process S84 is executed as described above and the water management specific operation of FIG. 18 is completed, the control unit 1a then calculates the methane emission amount from the target paddy field based on the calculation formula corresponding to the target paddy field, the status of agricultural work in the target paddy field included in the work information, and the specific water management information stored in the memory unit 1b (S24 in FIG. 6). The control unit 1a then calculates the methane reduction amount for the target paddy field as described above (S25), stores the methane reduction amount in the memory unit 1b, and transmits evaluation information including the methane reduction amount to the farmer terminal device 3 based on the farmer information (S26).

On the other hand, there are cases where the water level sensor 5 and water management device 4 are not installed in the target paddy field, and the target paddy field is not included in the monitoring targets of the monitoring device 6. In this situation, for example, a farmer inputs water management information, which is information indicating the water management status of the target paddy field, such as flooding, irrigation, drainage, and mid-drainage, using the farmer terminal device 3.

In this case, the control unit 1a confirms that the work information does not include the detected water management information (S82: NO in FIG. 18), but that the work information includes the water management information input by the farmer via the farmer terminal device 3 (hereinafter referred to as "input water management information") (S85: YES). Then, the control unit 1a verifies the input water management information of the target paddy field based on the SAR image data from the synthetic aperture radar of the earth observation satellite 7, and identifies the state and period of the water management implemented to reduce methane (S86).

Figures 19A and 19B are flow charts showing an example of the verification and specification operation of the paddy field methane reduction support device 1. The verification and specification operation shown in Figures 19A and 19B shows the details of process S86 in Figure 18. In this verification and specification operation, the control unit 1a acquires data of multiple SAR images observed by the synthetic aperture radar of the Earth observation satellite 7 based on the input water management information, determines the state and period of water management of the target paddy field based on the data of the multiple SAR images, verifies the state and period of water management of the target paddy field indicated in the input water management information based on the determined water management state and period, and specifies the state and period of water management for reducing methane in the target paddy field. This verification and specification operation will be described in detail below.

The input water management information included in the work information for the target paddy field includes the mid-drying state and mid-drying period as the state and period of water management for reducing methane in the target paddy field. For this reason, the control unit 1a of the paddy field methane reduction support device 1 first determines the start date and the last date of the mid-drying period of the target paddy field indicated in the input water management information (S91 in Figure 19A). Note that the start date of the mid-drying is the day on which the target paddy field changes from a flooded state to a drained state in order to be drained. The last day of the mid-drying is the day before the day on which the target paddy field that is being drained changes from a drained state to a flooded state.

Next, the control unit 1a communicates with the monitoring device 6, which stores data observed by the synthetic aperture radar of the Earth observation satellite 7, via the communication unit 1c, and acquires (receives) SAR image data of the area including the target rice field observed by the synthetic aperture radar on the first and last days of the inter-drainage of the target rice field (S92).

When the synthetic aperture radar observation data is stored in, for example, an observation data server (not shown) rather than in the monitoring device 6, the control unit 1a acquires SAR image data of the area including the target paddy field observed by the synthetic aperture radar on the first day and the last day of the inter-drainage of the target paddy field from the observation data server via the communication unit 1c. The monitoring device 6 and the observation data server are examples of observation management devices.

The positions (latitude, longitude) of the target paddy field and the area including the target paddy field are indicated in the paddy field information for the target paddy field. The control unit 1a determines the position of the area including the target paddy field based on the paddy field information, and obtains SAR images of the synthetic aperture radar that observed the position from the monitoring device 6 or the observation data server.

Next, the control unit 1a extracts one or more pixels representing the target paddy field from the SAR image observed on the day when the paddy field began to be irrigated, and detects the backscattering coefficient corresponding to the pixel value of the pixel (S93). At this time, the control unit 1a counts the number of detected backscattering coefficients, i.e., the total number Na of backscattering coefficients for the target paddy field.

The number of pixels showing the target rice field in the SAR image varies depending on the resolution (observation width) of the SAR image. For this reason, taking into consideration the area of the target rice field and the number of backscattering coefficients extracted, a SAR image with an appropriate resolution is acquired from the monitoring device 6 or the like and sent to the rice field methane reduction support device 1.

Next, the control unit 1a compares the backscattering coefficient of the target paddy field detected based on the SAR image on the day of the start of inter-irrigation with the first threshold value σ1 stored in the memory unit 1b, and counts the number Nb of backscattering coefficients greater than the first threshold value σ1. The control unit 1a then calculates the ratio Rs (Rs = Nb/Na x 100 [%]) of the number Nb of backscattering coefficients to the total number Na of paddy fields (S94).

Next, if the ratio Rs is equal to or greater than a predetermined third threshold value Rt (e.g., 80%) stored in the memory unit 1b (S95: YES), the control unit 1a determines that the target paddy field is in a drained and dry state on the dry-out start date indicated in the input water management information, and records the determination result in the memory unit 1b (S96).

On the other hand, if the ratio Rs is less than the third threshold value Rt (S95: NO), the control unit 1a determines that the subject paddy field was neither in a drainage state nor in a drainage state on the start date of the drainage indicated in the input water management information, and records the determination result in the memory unit 1b (S97). The third threshold value Rt is set based on empirical data on the backscattering coefficient of paddy fields, for example, as shown in FIG. 17.

Next, the control unit 1a extracts pixels representing the target paddy field from the SAR image on the last day of the interim drainage period, and detects the backscattering coefficient corresponding to the pixel value of the pixel (S98 in FIG. 19B). The control unit 1a also calculates the ratio Re of the number Nb of backscattering coefficients greater than the first threshold value σ1 to the total number Na of backscattering coefficients of the target paddy field extracted as described above (S99).

If the ratio Re is equal to or greater than the third threshold value Rt (S100: YES), the control unit 1a determines that the target paddy field is in a drained and dry state on the final day of dry season indicated in the input water management information, and records the determination result in the memory unit 1b (S101).

On the other hand, if the ratio Re is less than the third threshold value Rt (S100: NO), the control unit 1a determines that the target paddy field was not in a drainage state or a mid-drainage state on the final day of the mid-drainage period indicated in the input water management information, and records the determination result in the memory unit 1b (S102).

As described above, if the control unit 1a determines in step S96 of FIG. 19A and step S101 of FIG. 19B that the target paddy field was in a dried-up state on the start date and the last date of the dried-up period, it determines that the dried-up state and period of the target paddy field determined from the SAR image data correspond to the dried-up state and period of the target paddy field indicated in the input water management information (S103: YES in FIG. 19B). The control unit 1a then determines that the water management state and period indicated in the input water management information are valid (S104), and stores the input water management information in the memory unit 1b as specific water management information (S105).

In the above example, the control unit 1a determines that the state and period of the target paddy field determined from the SAR image data correspond to the state and period of the target paddy field indicated in the input water management information, but this is not limited to the above. For example, if the input water management information indicates the drainage date and flooding date of the target paddy field and the number of days from the drainage date to the flooding date is a predetermined number of days (e.g., 5 days) or more, the control unit 1a may estimate that the input drainage date to the flooding date is the drainage date. Then, when the control unit 1a can confirm from the SAR image data that the target paddy field is in a drainage state on the drainage date and in a flooded state on the flooding date, it may determine that the state and period of the target paddy field determined from the SAR image data correspond to the state and period of the target paddy field indicated in the input water management information.

For example, when the input water management information indicates the date of work to lower the water level of the target paddy field, the date of drainage work to lower the water level of the target paddy field to approximately zero, and the date of water supply work to raise the water level of the target paddy field, the control unit 1a may estimate a reasonable time required for water drainage to lower the water level to approximately zero based on the drainage properties of the target paddy field, and may estimate a reasonable time required for water retention to raise the water level to a flooded state based on the water supply of the target paddy field. Then, when the control unit 1a can confirm from the SAR image data that the water level of the target paddy field has dropped to approximately zero after the required time for water drainage has elapsed from the date of drainage work, and that the water level of the target paddy field has risen to a flooded state after the required time for water retention has elapsed from the date of water supply work, it may determine that the state and period of mid-drainage (or intermittent irrigation) of the target paddy field determined from the SAR image data correspond to the state and period of mid-drainage (or intermittent irrigation) of the target paddy field indicated in the input water management information. In other words, the control unit 1a can determine that the water management status of the target paddy field indicated by the input water management information corresponds to the water management status of the target paddy field obtained from the SAR image data if there is an appropriate relationship between the two.

As described above, the control unit 1a judges that the water management state and period indicated by the input water management information are valid (S104 in FIG. 19B), stores the input water management information in the storage unit 1b as specific water management information (S105), and then generates verification information including the specific water management information, the input water management information, information indicating that the specific water management information and the input water management information correspond to each other, and information indicating that the input water management information is valid, and stores the verification information in the storage unit 1b (S106). At this time, the control unit 1a may include, in the verification information, display data of the SAR image as shown in FIGS. 15A to 15C, or display data of the image of the target paddy field extracted from the SAR image, among the data of the SAR image of the target paddy field on the start day and the last day of the mid-drainage. In this case, an explanation or a legend of the SAR image or the image of the target paddy field may also be included in the verification information.

As described above, steps S104 to S106 are executed, and the verification and identification operations in Fig. 19A and Fig. 19B and the water management identification operation in Fig. 18 are completed, whereby the input water management information is verified, and the mid-drainage state and mid-drainage period of the target paddy field are identified by the control unit 1a. In this case, the control unit 1a then calculates the methane emission amount of the paddy field based on the calculation formula corresponding to the target paddy field, the state of agricultural work in the target paddy field included in the work information, and the identified water management information (S24 in Fig. 6). The control unit 1a then calculates the methane reduction amount of the target paddy field as described above (S25), stores the methane reduction amount in the storage unit 1b, and transmits evaluation information including the methane reduction amount of the target paddy field to the farmer terminal device 3 based on the farmer information (S26).

On the other hand, if the control unit 1a determines in step S97 of FIG. 19 that the target paddy field was not in a dry state on the start date of the dry period, or in step S102 of FIG. 19B that the target paddy field was not in a dry state on the last day of the dry period, it cannot determine the dry period of the paddy field from the SAR image data. Therefore, the control unit 1a determines that the water management state of the target paddy field determined from the SAR image data does not correspond to the water management state of the target paddy field indicated in the input water management information (S103: NO in FIG. 19B). In addition to the above, if there is no appropriate relationship between the water management state of the target paddy field determined from the SAR image data and the water management state of the target paddy field indicated in the input water management information, the control unit 1a may also determine that the water management state of the target paddy field determined from the SAR image data does not correspond to the water management state of the target paddy field indicated in the input water management information (S103: NO).

Then, the control unit 1a determines that the state and period of water management indicated by the input water management information are inappropriate, generates image water management information indicating the water management state of the target paddy field determined from the SAR image data, and stores the image water management information in the storage unit 1b (S107). At this time, the image water management information indicates that the target paddy field was not in a drained or semi-dried state on at least one of the days of the start of the semi-dried period and the last day of the semi-dried period.

Next, the control unit 1a generates verification information including the image water management information of the target paddy field, the input water management information, information indicating that the image water management information and the input water management information do not correspond, and information indicating that the input water management information is invalid, and stores the verification information in the storage unit 1b (S108). At this time, the control unit 1a may also store in the storage unit 1b the verification information including, from the SAR image data of the target paddy field on the start day of inter-drainage and the last day of inter-drainage, the display data of the SAR image as shown in Figures 15A to 15C or the display data of the image of the target paddy field extracted from the SAR image.

Furthermore, the control unit 1a transmits verification information to the farmer terminal device 3 used by the farmer via the communication unit 1c based on the farmer information, and notifies the farmer of the verification information via the farmer terminal device 3 (S109 in FIG. 19B). In detail, the farmer terminal device 3 receives the verification information and displays the verification information on its display, thereby notifying the farmer of the contents of the verification information. The control unit 1a may also transmit, together with the verification information, request information for re-entering the input water management information for the target paddy field to the farmer terminal device 3, and display the request information on the display of the farmer terminal device 3. In this way, the request information is also notified to the farmer via the farmer terminal device 3.

When steps S107 to S109 are executed as described above and the verification and identification operations in Figures 19A and 19B are completed, the input water management information is verified, the subject paddy field is not identified as being in a mid-drainage state, and the mid-drainage period has not been identified. In this case, the control unit 1a does not execute step S24 in Figure 6 (calculation of methane emissions), but re-executes steps S81 and onward in Figure 18.

For example, a farmer who has seen the verification information notified in process S109 in Fig. 19B operates the farmer terminal device 3 to re-input (change) the input water management information for the target paddy field. As a result, in process S85 in Fig. 18, the control unit 1a confirms that the input water management information is included in the work information (S85: YES), and re-executes the verification specification operation in Fig. 19 corresponding to process S86. In this way, while the control unit 1a is unable to specify the mid-drying state and mid-drying period of the target paddy field, it does not calculate the methane emission amount and methane reduction amount for the target paddy field, and does not transmit evaluation information to the farmer terminal device 3.

In addition, for example, if the water level sensor 5 and water management device 4 are not installed in the target paddy field and the target paddy field is not included in the monitoring targets of the monitoring device 6, the farmer may not input the input water management information for the target paddy field to the farmer terminal device 3. In this case, the control unit 1a confirms that the work information does not include the detected water management information and input water management information for the target paddy field (S82: NO, S85: NO in FIG. 18). Then, the control unit 1a identifies the state and period of water management implemented to reduce methane in the target paddy field based on the data of the SAR image taken by the synthetic aperture radar of the earth observation satellite 7 (S87).

Figures 20A and 20B are flow charts showing an example of an image identification operation of the paddy field methane reduction support device 1. The image identification operation shown in Figures 20A and 20B shows details of process S87 in Figure 18. In this image identification operation, the control unit 1a acquires data of multiple SAR images observed by the synthetic aperture radar of the Earth observation satellite 7 during a specified period based on the paddy field information and work information, and identifies the state and period of water management to reduce methane in the target paddy field based on the data of the multiple SAR images. This image identification operation is described in detail below.

The control unit 1a of the paddy field methane reduction support device 1 determines the tillering stage and young panicle formation stage of the crop (rice) planted in the target paddy field based on the paddy field information and work information (S111 in FIG. 20A). Next, the control unit 1a acquires data of multiple SAR images of the area including the target paddy field observed by the synthetic aperture radar of the earth observation satellite 7 during the period from the tillering stage to the young panicle formation stage from the monitoring device 6 or the observation data server via the communication unit 1c (S112).

In process S112, for example, the control unit 1a may acquire all SAR image data of the area including the target paddy field observed multiple times by the synthetic aperture radar of the Earth observation satellite 7 during the period from the tillering stage to the young panicle formation stage. In this case, the paddy field methane reduction support device 1 acquires a number of SAR image data corresponding to the number of recurrent days of the Earth observation satellite 7.

Instead of steps S111 and S112, the control unit 1a may obtain data on multiple SAR images of the area including the target paddy field observed by the synthetic aperture radar of the Earth observation satellite 7 during the specific period indicated in the work information from the monitoring device 6, etc., via the communication unit 1c. In addition, the specific period may be, for example, a period during which the farmer plans to dry out the paddy field, as input by the farmer terminal device 3, or a period from a day a specified number of days before the typical dry-out period for paddy fields in the area to a day a specified number of days after the dry-out period.

The control unit 1a reads the SAR image data with the oldest observation date from among multiple SAR image data acquired from the monitoring device 6, etc. (S113), extracts pixels representing the target paddy field from the read SAR image data, and detects the backscattering coefficient corresponding to the pixel value of the pixel (S114). At this time, the control unit 1a counts the total number Na of backscattering coefficients of the extracted target paddy field. Next, the control unit 1a counts the number Nb of backscattering coefficients greater than the first threshold value σ1 among the backscattering coefficients of the target paddy field extracted from the read SAR image data, and calculates the ratio Rs of the number Nb to the total number Na of backscattering coefficients of the target paddy field (S115).

If the ratio Rs is equal to or greater than the third threshold value Rt (S116: YES), the control unit 1a judges that the target paddy field was drained and in a semi-dried state on the observation date of the loaded SAR image data, and records the judgment result in the storage unit 1b (S117). On the other hand, if the ratio Rs is less than the third threshold value Rt (S116: NO), the control unit 1a judges that the target paddy field was neither drained nor in a semi-dried state on the observation date of the loaded SAR image data, and records the judgment result in the storage unit 1b (S118).

Next, if the control unit 1a has not yet loaded all of the acquired SAR image data (S119: NO in FIG. 20B), it loads the SAR image data with the next oldest observation date (S120). The control unit 1a then extracts pixels representing the target paddy field from the loaded SAR image, detects the backscattering coefficient corresponding to the pixel value of the extracted pixel (S114 in FIG. 20A), and executes steps S115 to S118 as described above.

Furthermore, the control unit 1a repeatedly executes steps S114 to S120 as described above until all acquired SAR image data has been read (S119: NO in FIG. 20B). This allows the control unit 1a to determine whether the target paddy field was in a semi-dried state or not and whether it was in a drained state or not on the observation date of multiple SAR image data acquired from the monitoring device 6 or the like, and to store the determination results in the memory unit 1b.

Then, when the control unit 1a confirms that all acquired SAR image data has been read (S119: YES), it refers to the information indicating the dry-up state and water-shedding state of the target paddy field for each observation date stored in the memory unit 1b, and identifies the dry-up state (whether dry-up was carried out or not) and dry-up period of the target paddy field (S121).

At this time, for example, the control unit 1a refers to the information indicating the presence or absence of the dried-up state and water-draining state of the target paddy field for each observation date stored in the memory unit 1b, starting with the oldest observation date. Then, if the number of days from the oldest observation date to the latest observation date among multiple observation dates on which the dried-up state and water-draining state are consecutive is a predetermined number of days (for example, 5 days) or more, the control unit 1a determines that the dried-up state of the target paddy field will be implemented, and the period from the oldest observation date to the latest observation date will be identified as the dried-up period.

Then, the control unit 1a generates specific water management information indicating the state and period of mid-drainage of the identified target paddy field, and stores the specific water management information in the memory unit 1b (S122). The control unit 1a also generates grounds information including display data of the SAR image based on which the specific water management information is identified, and stores the grounds information in the memory unit 1b in association with the specific water management information (S123). At this time, the control unit 1a may include display data of the image of the target paddy field extracted from the SAR image based on which the specific water management information is identified in the grounds information. The control unit 1a may also include an explanation or legend of the SAR image or the image of the target paddy field in the grounds information.

When processes S121 and S122 are executed as described above and the image identification operation of Figures 20A and 20B is completed, the control unit 1a identifies the mid-drainage state and mid-drainage period of the target paddy field. In this case, the control unit 1a then calculates the methane emission amount of the target paddy field based on the calculation formula corresponding to the target paddy field, the implementation status of agricultural work, and the specific water management information (S24 in Figure 6). The control unit 1a then calculates the methane reduction amount of the target paddy field (S25), stores the methane reduction amount in the memory unit 1b, and transmits evaluation information including the methane reduction amount to the farmer terminal device 3 (S26).

The control unit 1a also executes the crediting operation of FIG. 10 after executing process S123 of FIG. 20B or process S84 of FIG. 18 and the methane evaluation operation of FIG. 6. In this case, in process S51 of FIG. 10, the control unit 1a generates report information including the farmer information corresponding to the target paddy field, the methane reduction amount of the target paddy field, and the grounds information stored in process S123 of FIG. 20 or process S84 of FIG. 18, and transmits the report information to the credit management device 8.

The control unit 1a also executes the crediting operation of Fig. 10 after executing process S106 of Fig. 19 and the methane evaluation operation of Fig. 6. In this case, in process S51 of Fig. 10, the control unit 1a generates report information including farmer information corresponding to the target paddy field, the methane reduction amount of the target paddy field, and the verification information stored in process S106 of Fig. 19, and transmits the report information to the credit management device 8.

In the embodiment shown in Figures 18 to 20B, an example is shown in which the mid-drying state (whether or not mid-drying is being implemented) and the mid-drying period are specified as the state and period of water management to reduce methane in paddy fields, but this is not limited to this. The control unit 1a of the paddy field methane reduction support device 1 may specify not only the mid-drying of paddy fields, but also the presence or absence and implementation period of other water management to reduce methane in paddy fields, such as intermittent irrigation, based on data from SAR images from a synthetic aperture radar.

For example, in the case of intermittent irrigation, the control unit 1a may compare the backscattering coefficient of the target paddy field extracted from the SAR image data not only with a first threshold value σ1 for determining whether the target paddy field is in a drained state, but also with a second threshold value σ2 for determining whether the target paddy field is in a flooded state.

Specifically, for example, the control unit 1a may calculate not only the ratio Rs (Rs = Nb/Na) of the number Nb of backscattering coefficients larger than the first threshold value σ1 to the total number Na of backscattering coefficients of the target paddy field extracted from the SAR image data, but also the ratio Rf (Rf = Nc/Na) of the number Nc of backscattering coefficients smaller than the second threshold value σ2. If the ratio Rs is equal to or greater than a third threshold value (e.g., 80%) Rt, the control unit 1a may determine that the target paddy field was in a waterlogged state on the observation date of the SAR image data, and if the ratio Rf is equal to or greater than a predetermined fourth threshold value (e.g., 50%) Ru, the control unit 1a may determine that the target paddy field was in a waterlogged state on the observation date of the SAR image data. The fourth threshold value Ru may also be set based on the empirical data of paddy fields as shown in FIG. 17 and stored in the storage unit 1b.

The control unit 1a of the paddy field methane reduction support device 1 may acquire, via the acquisition unit 1c, any of information from the detection results of the water level sensor 5 installed in a certain first paddy field, an image of the first paddy field taken by a surveillance camera (e.g., an optical camera), and the actual water level of the first paddy field recorded or input by a farmer or the like, and identify water level change information (i.e., empirical data) that indicates time-series changes in the actual water level during rice cultivation in the first paddy field from the acquired information. The control unit 1a may then associate the water level change information with data on SAR images observed multiple times during rice cultivation in the first paddy field, and store (preserve) the information in the memory unit 1b. Furthermore, the control unit 1a may detect the correlation between the water level information of the first paddy field and the SAR image data (i.e., the correlation between the water level indicated by the water level information and the backscattering coefficient indicated by the data of the multiple SAR images), set the first threshold σ1 and the third threshold Rt, etc. (which may include the second threshold σ2 and the fourth threshold Rg) from the correlation and the SAR image data, and verify (demonstrate) the suitability of the first threshold σ1 and the third threshold Rt, etc.

The control unit 1a may also store (save) the first threshold value σ1 and the third threshold value Rt, etc., verified (demonstrated) as described above, in the storage unit 1b in association with the water level information and multiple SAR image data of the first paddy field. After that, the control unit 1a may apply the correlation between the water level information and the SAR image data of the first paddy field, and the first threshold value σ1 and the third threshold value Rt, etc., to identify the water management state (including water level, mid-drain state, intermittent irrigation, etc.) of the second paddy field for which actual water level information cannot be obtained. In addition, the detection of the correlation between the water level information and the SAR image data of the first paddy field as described above may be performed by an operator using at least one of a computer and AI, instead of the control unit 1a of the paddy field methane reduction support device 1.

Also, for example, the control unit 1a may determine that the target paddy field is in a drainage state and that the period from the earliest observation date to the latest observation date is a drainage period when the observation dates of the SAR image data on which the target paddy field is determined to be in a drainage state are consecutive and the period from the earliest observation date to the latest observation date is equal to or longer than a predetermined number of days. Furthermore, the control unit 1a may determine that the target paddy field is in an intermittent irrigation state when the control unit 1a repeats a predetermined number of times the determination that the target paddy field is in a drainage state based on a certain SAR image data and the determination that the target paddy field is in a flooded state based on newer SAR image data.

As described above, when intermittent irrigation is performed in the target paddy field, the control unit 1a sets a calculation formula for calculating the amount of methane emission in the case of intermittent irrigation, for example, based on model formulas (1) and (2) shown in FIG. 5. The control unit 1a then calculates the amount of methane emission from the target paddy field using the calculation formula for intermittent irrigation, and calculates the amount of methane reduction by subtracting the amount of methane emission from a preset basic amount of methane emission.

The SAR images acquired by the paddy field methane reduction support device 1 may be appropriately selected based on the recurrent period of an Earth observation satellite 7 equipped with a synthetic aperture radar that observes the SAR images, or the wavelength of the microwaves irradiated from the synthetic aperture radar.

For example, as shown in Figures 14A and 14B, when X-band microwaves Wa are irradiated from a synthetic aperture radar, the microwaves Wa are reflected by the leaves of the crop (paddy rice) R cultivated in the paddy field H. Also, when C-band microwaves Wa are irradiated from a synthetic aperture radar, the microwaves Wa are reflected by the stems of the crop R that has grown to a certain extent in the paddy field. Therefore, as the growth of the crop R progresses, the intensity of the backscattered waves Wb of the X-band or C-band microwaves Wa, i.e., the backscattering coefficient, increases, and the progress of the growth of the crop R can be detected based on the backscattering coefficient.

In addition, when L-band microwaves Wa are irradiated from a synthetic aperture radar, if the paddy field H is flooded as shown in FIG. 21A, the microwaves Wa pass through the leaves of the crops R in the paddy field H and are reflected by the water surface Hw. This reduces the intensity of the backscattered waves Wb, i.e., the backscattering coefficient, making it easier to detect that the paddy field H is flooded based on the backscattered waves Wb.

In contrast, when the paddy field H is in a drained state as shown in FIG. 21B, the microwaves Wa pass through the leaves of the crops R in the paddy field H and are reflected by the ground surface Hg. This increases the intensity of the backscattered waves Wb, i.e., the backscattering coefficient, making it easier to detect that the paddy field H is in a drained state based on the backscattered waves Wb.

Taking the above characteristics into consideration, the microwave wavelength can be appropriately selected, and the paddy field methane reduction support device 1 can acquire SAR images from a synthetic aperture radar that irradiates microwaves of the selected wavelength.

Paddy fields may also be observed using a synthetic aperture radar that employs interferometric SAR technology. This allows the synthetic aperture radar to observe changes in the ground surface at the level of a few centimeters, so the paddy field methane reduction support device 1 can detect in detail whether the paddy field is partially flooded or partially drained, based on the SAR images observed by the synthetic aperture radar.

The method of identifying the state and period of water management of paddy fields based on SAR images of a synthetic aperture radar described in the above embodiment is one example and is not limiting. The paddy field methane reduction support device 1 may identify the state and period of water management, such as mid-drainage or intermittent irrigation of paddy fields, based on a synthetic aperture radar using other methods.

The synthetic aperture radar may be mounted on an aircraft, a drone, or another flying object, instead of the Earth observation satellite 7, to observe paddy fields. The state and period of water management of paddy fields may be identified based on optical image data observed (captured) by the flying object or an imaging device mounted on the flying object, other than the SAR image of the synthetic aperture radar.

In the embodiment shown in Figures 18 to 19B, an example is shown in which the water management information of the paddy field input by the farmer using the farmer terminal device 3 is verified based on SAR image data, but in addition to this, for example, information indicating the water management status of the paddy field detected by the water management device 4 using a water level sensor 5 or the like and input (transmitted) to the agricultural management device 2 may be verified based on SAR image data. In other words, the detected water management information of the paddy field detected by a detection device or sensor used by the farmer and input to the agricultural management device 2 or the like may also be considered as input water management information and verified based on SAR image data.

Furthermore, in addition to using the specific water management information of paddy fields to calculate methane emissions and reductions in the paddy field methane reduction support device 1, the specific water management information can also be used for other purposes, such as the growth status of crops grown in the paddy fields, the status of water management work in the paddy fields, or the water supply and drainage status of the paddy fields. Also, a computer constituting the paddy field methane reduction support device 1 may be used to calculate the emissions and reductions of greenhouse gases other than methane (such as carbon dioxide) emitted from farm fields such as paddy fields. In this case, model data for calculating the emissions and reductions of greenhouse gases can be used.

The paddy field methane reduction support device 1 and paddy field methane reduction support system 100 of the present embodiment described above have the following configuration and provide the following effects.

The paddy field methane reduction support device 1 of this embodiment includes an acquisition unit (communication unit, communication interface) 1c that acquires paddy field information about paddy fields, work information about agricultural work for cultivating crops in paddy fields, and observation image data of the area including the paddy fields observed by an observation device (earth observation device) 7, a control unit 1a that identifies the state of water management of the paddy field and the period during which the state continued based on the paddy field information, work information, and observation image data to reduce methane emitted from the paddy field during crop cultivation, and generates specific water management information indicating the state and period of the water management, and a memory unit 1b that stores the specific water management information.

The paddy field methane reduction support system 100 of this embodiment includes a paddy field methane reduction support device 1 that supports the reduction of methane emissions from paddy fields where crops are cultivated, and an agricultural management device 2 in which a database 2d has been constructed that stores information about paddy fields and the agriculture carried out in the paddy fields. The paddy field methane reduction support device 1 has the above-mentioned control unit 1a, memory unit 1b, and acquisition unit 1c, and acquires paddy field information and work information from at least one of the agricultural management device 2 and the farmer terminal device 3 used by the farmer corresponding to the paddy field by the acquisition unit 1c, and acquires observation image data of the area including the paddy field observed by the observation device 7 from an observation management device (monitoring device 6 or observation data server) that stores observation data from an observation device 7 that observes the ground by the observation device 7 by the acquisition unit 1c.

With the above configuration, the state and period of water management for reducing methane emissions from paddy fields can be objectively detected from the data of the observation images from the observation device 7. In addition, it is possible to ensure a high degree of evidentiality and legitimacy of the specific water management information indicating the state and period of water management for the detected paddy fields, and it is also possible to prevent falsification. Furthermore, as a result, the water management work carried out by farmers to reduce methane emissions from paddy fields can be objectively recognized, making it easier for farmers to promote such efforts.

In this embodiment, the work information includes input water management information indicating the state and period of water management of the paddy field that has been input in advance, and the control unit 1a acquires data of multiple observation images based on the input water management information using the acquisition unit 1c, verifies the state and period of water management indicated in the input water management information based on the data of the multiple observation images, stores verification information indicating the verification results in the memory unit 1b, and if the state and period of water management indicated in the input water management information are valid, stores the input water management information in the memory unit 1b as specific water management information.

This makes it possible to obtain data on multiple observation images related to input water management information input by a farmer using the farmer terminal device 3, and to confirm whether the input water management information indicating the state and period of water management of the paddy field indicated by the input water management information is valid or invalid. Then, since the valid input water management information is stored in the memory unit 1b as specific water management information, the specific water management information can be used reliably thereafter. Also, for example, when information indicating the water management state of a paddy field detected by a detection device such as a water management device 4 or a water level sensor 5 used by a farmer is input to the agricultural management device 2, the information can be regarded as input water management information, and data on multiple observation images related to the input water management information can be obtained, and it can be confirmed whether the input water management information is valid or invalid. Furthermore, in this case, it becomes possible to determine an abnormality in the detection device from the verification results.

In addition, in this embodiment, the control unit 1a acquires data of observation images observed by the observation device 7 during the water management period indicated in the input water management information. This makes it possible to reduce the amount of data of observation images observed by the observation device 7 acquired to verify the input water management information, thereby reducing the cost required to acquire the data.

In addition, in this embodiment, the control unit 1a determines the water management state from the data of multiple observation images, and if the determined water management state corresponds to the water management state indicated by the input water management information, the control unit 1a includes information indicating that the input water management information is valid in the verification information, and stores the input water management information as specific water management information in the storage unit 1b. This makes it possible to further ensure high evidentiality and validity of the input water management information and the specific water management information.

In addition, in this embodiment, the control unit 1a acquires farmer information related to the farmer corresponding to the paddy field, i.e., the farmer who performs farm work in the paddy field or the farmer who input the input water management information, using the acquisition unit 1c, judges the state of water management from data from multiple observation images, and if the judged water management state does not correspond to the water management state indicated in the input water management information, notifies the farmer of the verification information indicating the verification result based on the farmer information. At this time, the control unit 1a transmits the verification information to the farmer terminal device 3 used by the farmer via the communication interface (communication unit 1c) based on the farmer information, and notifies the farmer of the verification information via the farmer terminal device 3. This makes it possible to make the farmer recognize that the state and period of water management of the paddy field indicated in the input water management information are inappropriate, and to encourage the farmer to re-enter the input water management information.

In addition, in this embodiment, the control unit 1a acquires data on multiple observation images observed by an observation device during a specified period based on the paddy field information and work information, using the acquisition unit, and identifies the state and period of water management of the paddy field from the data on the multiple observation images. As a result, even if input water management information is not input, it is possible to acquire data on multiple observation images of an area including paddy fields observed during a specified period and identify the state and period of water management for reducing methane emissions from the paddy field. In addition, by limiting the number of acquired observation image data, the cost required for acquiring the data can be reduced, and the state and period of water management of the paddy field can be efficiently identified. Furthermore, since the state and period of water management of the paddy field can be identified without installing a detection device such as a water management device 4 or a water level sensor 5 in the paddy field, the cost of installing the detection device can be reduced.

Furthermore, in this embodiment, the control unit 1a determines the period from the tillering stage to the young panicle formation stage of the crop planted in the paddy field based on the paddy field information and the work information, and acquires data of a plurality of observation images observed by the observation device during the determined period using the acquisition unit. This makes it possible to acquire data of a plurality of observation images of the paddy field observed by the observation device 7 during the period from the tillering stage to the young panicle formation stage, when water management work effective for reducing methane from the paddy field is carried out. Then, from the acquired data of the plurality of observation images, it is possible to identify the state and period of water management for reducing methane emissions from the paddy field. Furthermore, by more limitedly reducing the number of acquired observation image data, it is possible to further reduce the cost required for acquiring the data, and more efficiently identify the state and period of water management of the paddy field.

In this embodiment, the control unit 1a acquires data of multiple observation images observed by a synthetic aperture radar possessed by an observation device 7 mounted on an air vehicle or aircraft using the acquisition unit 1c, extracts one or more pixels representing a paddy field from each of the multiple observation images, detects a backscattering coefficient associated with a pixel value that indicates at least one of the shade and brightness of the color of the pixel, and identifies the state and period of water management of the paddy field based on the detected backscattering coefficient. In this way, it is possible to detect the state of flooding/drainage of the paddy field and the period during which this state continued from the data of multiple observation images observed by the synthetic aperture radar without being affected by weather or clouds, and to identify the state and period of water management such as mid-drainage or intermittent irrigation.

In addition, in this embodiment, the memory unit 1b stores one or more preset thresholds (first threshold σ1, second threshold σ2, third threshold Rt, and fourth threshold Ru), and the control unit 1a determines whether the paddy field is in a semi-dried state or a flooded state based on the result of comparing the backscattering coefficient detected from the data of multiple observation images with the thresholds. This makes it possible to identify the state and period of water management, such as semi-dried state or intermittent irrigation of the paddy field.

In addition, in this embodiment, the control unit 1a identifies water level change information indicating time-series changes in the actual water level of the paddy field from information indicating the actual water level of the paddy field acquired by the acquisition unit 1c, detects backscattering coefficients corresponding to the paddy field from data of multiple observation images acquired by the acquisition unit 1c, detects a correlation between the actual water level of the paddy field indicated by the water level change information and the backscattering coefficient corresponding to the paddy field, sets a threshold value based on the backscattering coefficient corresponding to the paddy field and the correlation, and stores the threshold value in the memory unit 1b. This makes it possible to improve the suitability of the threshold value for identifying the state and period of water management, such as mid-drainage or intermittent irrigation of the paddy field.

In addition, in this embodiment, the control unit 1a applies the threshold value stored in the memory unit 1b to determine at least one of the dry and flooded states of other paddy fields. This eliminates the need to set a threshold value for each paddy field, and even for paddy fields where the actual water level cannot be confirmed using a water level sensor 5 or the like, it is possible to identify the state and period of water management, such as dry or intermittent irrigation, of the paddy field, improving convenience.

In this embodiment, the memory unit 1b stores model data for calculating the amount of methane emissions from the paddy field, and the control unit 1a calculates the amount of methane reduction that is reduced from a predetermined basic methane emission from the paddy field based on the paddy field information, work information, specific water management information, and model data, and stores the methane reduction amount in the memory unit 1b. This makes it possible to calculate the amount of methane reduction from the paddy field based on the paddy field information, work information, the highly reliable water management state and period identified by the data of the observation image of the observation device 7, and the model data, and to increase the reliability of the amount of methane reduction. In addition, the amount of methane reduction from the paddy field can be quantitatively evaluated to improve convenience, and water management that reduces methane from paddy fields can be promoted by farmers, making it possible to stimulate methane reduction in the agricultural field.

Furthermore, in this embodiment, the control unit 1a sets a calculation formula for calculating the amount of methane emission from the paddy field based on the paddy field information, work information, and model data, acquires conventional water management information indicating the state and period of conventional water management of the paddy field using the acquisition unit 1c, calculates a basic methane emission from the paddy field based on the conventional water management information and the calculation formula, calculates the methane emission from the paddy field based on the specific water management information of the paddy field and the calculation formula, and calculates the methane reduction amount from the paddy field by subtracting the methane emission from the basic methane emission from the paddy field. In this way, it is possible to calculate the conventional methane emission from the paddy field (basic methane emission) and the methane emission after efforts have been made in accordance with the specific water management information indicating the state and period of water management implemented to reduce methane from the paddy field, and to calculate the reduction amount of methane emission after the efforts relative to the conventional methane emission.

In this embodiment, the acquisition unit 1c is composed of a communication interface (communication unit 1c), and the control unit 1a acquires farmer information related to the farmer corresponding to the paddy field from at least one of the agricultural management device 2 and the farmer terminal device 3 through the communication interface 1c, transmits report information including the amount of methane reduction in the paddy field and the farmer information to the credit management device 8 through the communication interface 1c, acquires credit information indicating an electronic credit issued by the credit management device 8 according to the amount of methane reduction through the communication interface 1c, and notifies the farmer of the credit information based on the farmer information. At this time, the control unit 1a transmits the credit information to the farmer terminal device 3 through the communication interface 1c based on the farmer information, and notifies the farmer of the credit information via the farmer terminal device 3. As a result, the farmer corresponding to the paddy field can obtain a credit according to the amount of methane reduction caused by a change in water management work in the paddy field without having to go through complicated procedures, which makes it possible to improve the convenience and benefit of the farmer.

Furthermore, in this embodiment, when the control unit 1a verifies the state and period of water management of the paddy field indicated by the input water management information as described above, the control unit 1a includes verification information in addition to the methane reduction amount of the paddy field and farmer information in the report information sent to the credit management device 8. This makes it possible to prove to the credit management company via the credit management device 8 the high legitimacy and evidentiality of the specific water management information indicating the state and period of water management implemented to reduce methane emissions from the paddy field, and the methane reduction amount calculated based on the specific water management information. As a result, it becomes easier to issue credits according to the methane reduction amount of the paddy field, making it possible to improve convenience, benefit, and credibility for farmers.

The present invention has been described above, but the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

1 Paddy field methane reduction support device 1a Control unit 1b Memory unit 1c Communication unit (acquisition unit, communication interface)
2 Agricultural management device 2d Database 3 Farmer terminal device 6 Monitoring device (observation management device)
7 Earth Observation Satellites (Observation Equipment)
8 Credit management device 100 Paddy field methane reduction support system

Claims (20)

an acquisition unit that acquires paddy field information on paddy fields, work information on agricultural work for cultivating crops in the paddy fields, and observation image data of an area including the paddy fields observed by an observation device;
a control unit that identifies a state of water management of the paddy field for reducing methane emitted from the paddy field during cultivation of the crop and a period during which the state has continued based on the paddy field information, the work information, and the observation image data, and generates specific water management information that indicates the state and period of the water management;
A paddy field methane reduction support device comprising a memory unit that stores the specific water management information. The work information includes input water management information indicating a state and period of the water management of the paddy field that has been input in advance,
The control unit is
The acquisition unit acquires data of the plurality of observation images based on the input water management information;
Verifying the state and period of the water management indicated by the input water management information based on data of the plurality of observation images, and storing verification information indicating the verification result in the storage unit;
A paddy field methane reduction support device as described in claim 1, wherein when the water management state and period indicated in the input water management information are valid, the input water management information is stored in the memory unit as the specific water management information. The paddy field methane reduction support device according to claim 2, wherein the control unit acquires data of the observation image observed by the observation device during the period of the water management indicated by the input water management information. The paddy field methane reduction support device according to claim 2 or 3, wherein the control unit determines the water management state from the data of the plurality of observation images, and when the determined water management state corresponds to the water management state indicated by the input water management information, includes information indicating that the input water management information is valid in the verification information, and stores the input water management information in the storage unit as the specific water management information. The control unit is
The acquisition unit acquires farmer information relating to the farmer corresponding to the paddy field,
A paddy field methane reduction support device as described in claim 4, which judges the water management state from data of the multiple observation images, and if the judged water management state does not correspond to the water management state indicated in the input water management information, notifies the farmer of the verification information based on the farmer information. The control unit is
acquiring, by the acquiring unit, data of a plurality of the observation images observed by the observation device during a predetermined period based on the paddy field information and the work information;
The paddy field methane reduction support device according to claim 1 , wherein the state and period of the water management of the paddy field are identified from data of the multiple observation images. The paddy field methane reduction support device according to claim 6, wherein the control unit determines the period from the tillering stage to the panicle formation stage of the crop planted in the paddy field based on the paddy field information and the work information, and acquires data of the multiple observation images observed by the observation device during the determined period using the acquisition unit. The control unit is
The acquisition unit acquires data of a plurality of observation images observed by a synthetic aperture radar of the flying object or the observation device mounted on the flying object,
extracting one or more pixels representing the paddy field from each of the plurality of observation images, and detecting a backscattering coefficient associated with a pixel value of the pixel;
The paddy field methane reduction support device according to claim 2 or 6, wherein the state and period of the water management of the paddy field are identified based on the detected backscattering coefficient. The storage unit stores one or more preset threshold values,
The paddy field methane reduction support device of claim 8, wherein the control unit determines at least one of whether the paddy field is in a semi-dried state or whether the paddy field is in a flooded state based on a result of comparing the backscattering coefficient detected from the data of the multiple observation images with the threshold value. The control unit is
Identifying water level change information indicating a time series change in the actual water level of the paddy field from the information indicating the actual water level of the paddy field acquired by the acquisition unit;
Detecting backscattering coefficients corresponding to the paddy fields from the data of the plurality of observation images acquired by the acquisition unit,
Detecting a correlation between an actual water level of the paddy field indicated by the water level change information and a backscattering coefficient corresponding to the paddy field;
The paddy field methane reduction support device according to claim 9 , wherein the threshold value is set based on the backscattering coefficient corresponding to the paddy field and the correlation, and is stored in the memory unit. The paddy field methane reduction support device according to claim 10, wherein the control unit applies the threshold value stored in the memory unit to determine at least one of the drained and flooded states of other paddy fields. The storage unit stores model data for calculating the amount of methane emission from the paddy field,
The paddy field methane reduction support device of claim 1, wherein the control unit calculates an amount of methane reduction reduced from a specified basic methane emission amount of the paddy field based on the paddy field information, the work information, the specific water management information, and the model data, and stores the amount of methane reduction in the memory unit. The control unit is
setting a calculation formula for calculating the amount of methane emission from the paddy field based on the paddy field information, the work information, and the model data;
The acquisition unit acquires conventional water management information indicating a state and period of the conventional water management of the paddy field,
Calculating the basic methane emission amount for the paddy field based on the conventional water management information and the calculation formula;
Calculating the methane emission amount from the paddy field based on the specific water management information of the paddy field and the calculation formula;
The paddy field methane reduction support device according to claim 12, wherein the methane emission amount is subtracted from the basic methane emission amount of the paddy field to calculate the methane reduction amount of the paddy field. The acquisition unit is composed of a communication interface,
The control unit is
acquiring farmer information relating to a farmer corresponding to the paddy field through the communication interface;
Sending report information including the methane reduction amount of the paddy field and the farmer information to a credit management device via the communication interface;
acquiring, via the communication interface, credit information indicating an electronic credit issued by the credit management device in accordance with the methane reduction amount;
The paddy field methane reduction support device according to claim 12 or 13, wherein the credit information is notified to the farmer based on the farmer information. The storage unit stores model data for calculating the amount of methane emission from the paddy field,
The acquisition unit is composed of a communication interface,
The control unit is
acquiring farmer information relating to a farmer corresponding to the paddy field through the communication interface;
Calculating a methane reduction amount that is reduced from a predetermined basic methane emission amount of the paddy field based on the paddy field information, the work information, the specific water management information, and the model data, and storing the calculated methane amount in the storage unit;
transmitting report information including the farmer information, the methane reduction amount of the paddy field, and the verification information to a credit management device via the communication interface;
acquiring, via the communication interface, credit information indicating an electronic credit issued by the credit management device in accordance with the methane reduction amount;
The paddy field methane reduction support device according to claim 2, wherein the credit information is notified to the farmer based on the farmer information. A paddy field methane reduction support device that supports the reduction of methane emissions from rice paddies where crops are grown;
an agricultural management device in which a database is constructed that stores information regarding the paddy field and agriculture carried out in the paddy field;
The paddy field methane reduction support device is
an acquisition unit that acquires paddy field information related to the paddy field and work information related to agricultural work for cultivating the crop in the paddy field from at least one of the agricultural management device and a farmer terminal device used by a farmer corresponding to the paddy field, and acquires observation image data of an area including the paddy field observed by an observation device that observes the ground from an observation management device that stores observation data of the observation device;
a control unit that identifies a state of water management of the paddy field for reducing methane emitted from the paddy field during cultivation of the crop and a period during which the state has continued based on the paddy field information, the work information, and the observation image data, and generates specific water management information that indicates the state and period of the water management;
A paddy field methane reduction support system comprising: a memory unit that stores the specific water management information. The work information includes input water management information indicating a state and period of the water management of the paddy field that has been input in advance,
The control unit is
acquiring data of the plurality of observation images from the observation management device by the acquisition unit based on the input water management information;
Verifying the state and period of the water management indicated by the input water management information based on data of the plurality of observation images, and storing verification information indicating the verification result in the storage unit;
A paddy field methane reduction support system as described in claim 16, wherein when the water management state and period indicated in the input water management information are valid, the input water management information is stored in the memory unit as the specific water management information. The storage unit stores model data for calculating the amount of methane emission from the paddy field,
The acquisition unit is composed of a communication interface,
The control unit is
Calculating a methane reduction amount that is reduced from a predetermined basic methane emission amount of the paddy field based on the paddy field information, the work information, the specific water management information, and the model data, and storing the methane reduction amount in the storage unit;
acquiring farmer information relating to the farmer from at least one of the agricultural management device and the farmer terminal device via the communication interface;
transmitting report information including the methane reduction amount of the paddy field, the farmer information, and the verification information to a credit management device via the communication interface;
acquiring, via the communication interface, credit information indicating an electronic credit issued by the credit management device in accordance with the methane reduction amount;
The paddy field methane reduction support system according to claim 17, wherein the credit information based on the farmer information is notified to the farmer terminal device via the communication interface. The control unit is
acquiring data of a plurality of the observation images observed by the observation device during a predetermined confirmation period from the observation management device by the acquisition unit based on the paddy field information and the work information;
The paddy field methane reduction support system according to claim 16, wherein the state and period of the water management of the paddy field are identified from data of the plurality of observation images. The storage unit stores model data for calculating the amount of methane emission from the paddy field,
The acquisition unit is composed of a communication interface,
The control unit is
Calculating a methane reduction amount that is reduced from a predetermined basic methane emission amount of the paddy field based on the paddy field information, the work information, the specific water management information, and the model data, and storing the methane reduction amount in the storage unit;
acquiring farmer information relating to the farmer from at least one of the agricultural management device and the farmer terminal device via the communication interface;
Sending report information including the methane reduction amount of the paddy field and the farmer information to a credit management device via the communication interface;
acquiring, via the communication interface, credit information indicating an electronic credit issued by the credit management device in accordance with the methane reduction amount;
The paddy field methane reduction support system according to claim 19, wherein the credit information based on the farmer information is notified to the farmer terminal device via the communication interface.

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