AU2017100206A4 - Quantitative water irrigation method and apparatus - Google Patents

Abstract

- 26 A method for use in performing quantitative water irrigation of an area of soil planted with a particular crop, the method being performed using one or more electronic processing devices, the method including: receiving, from at least one soil moisture sensor located in the soil, at least one moisture measurement indicative of a moisture content of the soil; determining whether irrigation is required based on the at least one moisture measurement; in response to determining that irrigation is required, determining an irrigation quantity indicative of a quantity of water to be supplied to the area of land over a subsequent time period by: obtaining, from a meteorological data source, meteorological data for a geographical region corresponding to the area of soil for a prior time period; determining at least one evapotranspiration value for the prior time period based on at least some of the meteorological data; and calculating the irrigation quantity based at least in part on: crop data for the particular crop; and the at least one evapotranspiration value. Fig. 1 Receive moisture measurement from soil moisture sensor Determine whether irrigation required based on moisture measurement Obtain meteorological data from meteorological data source Determine evapotranspiration value for prior time period Calculate irrigation quantity based on crop data and the evapotranspiration value Control irrigation system to supply determined _ quantity of water Fig. 1

Description

QUANTITATIVE WATER IRRIGATION METHOD AND APPARATUS Background of the Invention [0001] This invention relates to a method and apparatus for use in performing quantitative water irrigation of an area of soil planted with a particular crop.

Description of the Prior Art [0002] The irrigation of agricultural crops involves the supply of a precise amount of water to plants. Traditional irrigation techniques have placed significant strain on water supplies, especially in arid regions where water is a scarce resource. Modern irrigation techniques have focussed on improving water use efficiency, but these typically rely on coarse assumptions regarding the water requirements of crops and opportunities remain for further water use efficiency gains.

[0003] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Summary of the Present Invention [0004] In one broad form an aspect of the present invention seeks to provide a method for use in performing quantitative water irrigation of an area of soil planted with a particular crop, the method being performed using one or more electronic processing devices, the method including: receiving, from at least one soil moisture sensor located in the soil, at least one moisture measurement indicative of a moisture content of the soil; determining whether irrigation is required based on the at least one moisture measurement; in response to determining that irrigation is required, determining an irrigation quantity indicative of a quantity of water to be supplied to the area of land over a subsequent time period by: obtaining, from a meteorological data source, meteorological data for a geographical region corresponding to the area of soil for a prior time period; determining at least one evapotranspiration value for the prior time period based on at least some of the meteorological data; and calculating the irrigation quantity based at least in part on: crop data for the particular crop; and the at least one evapotranspiration value.

[0005] In one embodiment the method further includes controlling an irrigation system to supply the determined irrigation quantity to the area of land over the subsequent time period.

[0006] In one embodiment the method includes: determining a plurality of evapotranspiration values using different techniques; determining a maximum evapotranspiration value from the plurality of evapotranspiration values; and calculating the irrigation quantity based at least in part on the maximum evapotranspiration value.

[0007] In one embodiment the at least one evapotranspiration value is determined using at least one of: an evapotranspiration value calculated using the meteorological data using a Priestley Taylor method; an evapotranspiration value calculated using the meteorological data using a Turc method; and an evapotranspiration value calculated by the meteorological data source and included in the meteorological data.

[0008] In one embodiment the method includes: determining a crop evapotranspiration value for the particular crop based on the evapotranspiration value and the crop data; and calculating the irrigation quantity based at least in part on the crop evapotranspiration value.

[0009] In one embodiment the method includes: determining a crop coefficient using the crop data; and determining the crop evapotranspiration value by multiplying the evapotranspiration value and the crop coefficient.

[0010] In one embodiment the method includes: determining, using the crop data: an identification of the particular crop; and a current growth phase of the particular crop; and determining the crop coefficient in accordance with the identification of the particular crop and the growth phase.

[0011] In one embodiment the method includes: determining a readily available water value using soil data for the soil; determining a crop net irrigation application depth using the readily available water value and the crop data; and calculating the irrigation quantity using the crop net irrigation application depth and the crop evapotranspiration value.

[0012] In one embodiment the method includes: determining, using the crop data, a crop root depth of the particular crop; and determining the crop net irrigation application depth using the readily available water value and the root depth.

[0013] In one embodiment the method includes obtaining the meteorological data based on location data for the area of soil.

[0014] In one embodiment the method includes obtaining the meteorological data using at least one of: file transfer protocol (FTP); and; an application programming interface (API).

[0015] In one embodiment the meteorological data includes at least one of: a relative humidity observation; a maximum temperature observation; a minimum temperature observation; an air temperature observation; a water surface temperature observation; an atmospheric pressure observation; and a solar radiation exposure observation.

[0016] In one embodiment the meteorological data further includes a rainfall observation, the method including adjusting the determined irrigation quantity to account for the rainfall observation.

[0017] In one embodiment the method includes: comparing the moisture measurement with a predetermined refill threshold; and determining that irrigation is required only if the moisture measurement is less than the refill threshold.

[0018] In one embodiment the method includes: receiving a plurality of moisture measurements from a plurality of soil moisture sensors; determining a lowest moisture measurement from the plurality of moisture measurements; and determining that irrigation is required only if the lowest moisture measurement is less than the refill threshold.

[0019] In one broad form an aspect of the present invention seeks to provide apparatus for use in performing quantitative water irrigation of an area of soil planted with a particular crop, the apparatus including: at least one soil moisture sensor located in the soil; and one or more electronic processing devices coupled to the at least one soil moisture sensor and a meteorological data source via one or more communications networks, the one or more electronic processing devices being configured to: receive, from the at least one soil moisture sensor, at least one moisture measurement indicative of a moisture content of the soil; determine whether irrigation is required based on the at least one moisture measurement; in response to determining that irrigation is required, determine an irrigation quantity indicative of a quantity of water to be supplied to the area of land over a subsequent time period by: obtaining, from a meteorological data source, meteorological data for a geographical region corresponding to the area of soil for a prior time period; determining at least one evapotranspiration value for the prior time period based on at least some of the meteorological data; and calculating the irrigation quantity based at least in part on: crop data for the particular crop; and the at least one evapotranspiration value.

[0020] In one embodiment the one or more electronic processing devices are configured to provide an indication of the determined irrigation quantity to an irrigation controller for controlling an irrigation system to cause the determined irrigation quantity to be supplied to the area of land over the subsequent time period.

[0021] In one embodiment the apparatus includes a plurality of soil moisture sensors, the plurality of soil moisture sensors being coupled together via a sensor communication network.

[0022] In one embodiment the apparatus includes: a gateway unit configured to act as a parent node in the sensor communication network; and a plurality of sensor units each including a respective soil moisture sensor and configured to act as a child node in the sensor communication network, the gateway unit being configured to receive moisture measurements from the sensor units and transfer the moisture measurements to the one or more electronic processing devices.

[0023] In one embodiment the one or more electronic processing devices are coupled to the gateway unit and the meteorological data source via the Internet.

[0024] It will be appreciated that the broad forms of the invention and their respective features can be used in conjunction, interchangeably and/or independently, and reference to separate broad forms is not intended to be limiting.

Brief Description of the Drawings [0025] Various examples and embodiments of the present invention will now be described with reference to the accompanying drawings, in which: - [0026] Figure lisa flow chart of an example of a method for use in performing quantitative water irrigation of an area of soil planted with a particular crop; [0027] Figure 2 is a schematic diagram of an example of a distributed architecture; [0028] Figure 3 is a schematic diagram of an example of a server processing system; [0029] Figure 4 is a schematic diagram of an example of a client processing system; and [0030] Figures 5A to 5C are a flow chart of an example of a method for use in quantitative water irrigation of an area of soil planted with a particular crop.

Detailed Description of the Preferred Embodiments [0031] An example of a method for use in performing quantitative water irrigation of an area of soil planted with a particular crop will now be described with reference to Figure 1.

[0032] The method will typically be performed using one or more electronic processing devices, which may be provided in the form of discrete devices such as servers or personal computers, or shared computer processing resources which may be obtained using Internet-based cloud computing services. The one or more electronic processing devices will typically be coupled to one or more communication networks to allow data to be received or transferred as required to perform the steps of the method.

[0033] In step 100, the method involves receiving, from at least one soil moisture sensor located in the soil, at least one moisture measurement indicative of a moisture content of the soil. Although a single soil moisture sensor may be used, embodiments of the method may utilise a plurality of soil moisture sensors which may be strategically distributed across the area of soil to allow multiple moisture measurements to be obtained.

[0034] Step 110 involves then involves determining whether irrigation is required based on the at least one moisture measurement. This may be based on a predetermined refill point for the soil, whereby irrigation will be deemed to be required if the moisture measurement is indicative of a moisture content that is less than the refill point.

[0035] In the event that it is determined that irrigation is required, the method will transition to carrying out the following steps for determining an irrigation quantity indicative of a quantity of water to be irrigated to the area of land over a subsequent time period. On the other hand, if it is determined that irrigation is required then no further steps to determine the irrigation quantity will be required.

[0036] Assuming irrigation is determined to be required in step 110 in this example, the subsequent step 120 involves obtaining, from a meteorological data source, meteorological data for a geographical region corresponding to the area of soil for a prior time period. The meteorological data source may be provided by an organisation that provides weather services, such as the Bureau of Meteorology in Australia. Typically, the meteorological data source will facilitate access to meteorological data such as weather observations and forecasts for different geographical regions. This access may be facilitated via the Internet, for instance by using File Transfer Protocol (FTP) or an Application Programming Interface (API). Accordingly, the meteorological data may be readily accessed via a suitable Internet-enabled interface of the meteorological data source.

[0037] In step 130, the method involves determining at least one evapotranspiration value for the prior time period based on at least some of the meteorological data. Evapotranspiration represents the total movement of water from soil due to evaporation and transpiration effects. The evapotranspiration value may be determined in a variety of different ways, such as by calculating the evapotranspiration value based on known formulae using parameters that may be extracted from the meteorological data. Alternatively, an evapotranspiration value may be directly obtained from the meteorological data. In some cases, a number of evapotranspiration values may be obtained using different sources/techniques and a worst case evapotranspiration value may be determined from the different obtained evapotranspiration values for use in the method.

[0038] Next, step 140 involves calculating the irrigation quantity based at least in part on crop data for the particular crop and the at least one evapotranspiration value. Taking the crop data and the evapotranspiration value into account allows the irrigation quantity to be calculated that will the loss of moisture over the previous period due to evapotranspiration in a manner that is specifically tailored to the particular crop. For example, the crop data may include information regarding the growth stage and root depth of the crop which can be used to determine crop specific evapotranspiration moisture losses and water requirements.

[0039] Accordingly, an irrigation quantity can be determined that, when supplied to the soil, can specifically support optimal growth conditions for the crop with a reduced risk of overwatering.

[0040] It should be noted in particular that the use of meteorological data for the prior time period to determine the evapotranspiration value will mean that the irrigation quantity is calculated to replenish previous moisture loss over that prior time period. Furthermore, under such an approach there is no need to predict future evapotranspiration or account for any future weather forecasts or the like, which are often unreliable.

[0041] The method may optionally include a further step 150 of controlling an irrigation system to supply the determined irrigation quantity to the area of soil over the subsequent time period. In one example, the one or more electronic processing devices may cause an irrigation controller to control an irrigation system to automatically supply the determined irrigation quantity to the area of land. However, it should be noted that this is not essential to the method as performed by the one or more electronic processing devices, since the actual control of the irrigation system may be carried out manually in some implementations. For instance, an indication of the determined irrigation quantity may be provided to a farmer to allow the farmer to separately control the irrigation system to allow the determined irrigation quantity of water to be supplied.

[0042] Further optional implementation features of the method will now be described.

[0043] As mentioned above, the evapotranspiration value may be determined in different ways, and thus in some implementations, the method may include determining a plurality of evapotranspiration values using different techniques, determining a maximum evapotranspiration value from the plurality of evapotranspiration values; and then calculating the irrigation quantity based at least in part on the maximum evapotranspiration value. This may provide a more conservative approach to ensure the irrigation quantity is calculated based on a worst case evapotranspiration scenario, and thus avoid the situation where an evapotranspiration calculation based on a particular set of parameters might not accurately model the full extent of evapotranspiration in certain circumstances. Whilst the use of a maximum evapotranspiration might lead to a tendency to over-watering, this will at least help to reduce the possibility of under-watering which has a higher risk of inhibiting crop growth.

[0044] Implementations of the method may involve calculating evapotranspiration values using the meteorological data, for instance by using known calculation evapotranspiration methods such as the Priestley Taylor method and/or the Turc method.

[0045] The Priestley Taylor method for calculating evapotranspiration can be expressed using the formula:

[0046] Where:

Tm is the maximum temperature;

Tm is the minimum temperature; T is the air temperature;

Ts is the surface temperature of water R m is the relative humidity;

Rs is the solar radiation exposure; and P is the atmospheric pressure (kPa).

[0047] It will thus be appreciated that calculation of the evapotranspiration value using the Priestley Taylor method may require access to meteorological data including observations of a range of different measurements including the maximum temperature, the minimum temperature, the air temperature, the water surface temperature, the relative humidity observation, the solar radiation exposure and the atmospheric pressure. However, it should be appreciated that different formulations of the Priestley Taylor method may be used which may require different observations.

[0048] On the other hand, the Turc method for calculating evapotranspiration can be expressed using the formula:

[0049] Where:

Tm is the maximum temperature;

Tm is the minimum temperature; and Rs is the solar radiation exposure.

[0050] Accordingly, the Turc method provides a simpler technique only requiring observations of the maximum temperature, the minimum temperature and the solar radiation exposure. However, it should be appreciated that different formulations of the Turc method may be used which may require different observations.

[0051] Alternatively or additionally, the evapotranspiration value may be determined based on a value calculated by the meteorological data source and included in the meteorological data. As mentioned above multiple techniques can be used and a worst-value may be used for calculating the irrigation quantity.

[0052] In order to more specifically account for the particular crop in the irrigation quantity calculation, the method may include determining a crop evapotranspiration value for the particular crop based on the evapotranspiration value and the crop data and calculating the irrigation quantity based at least in part on the crop evapotranspiration value. This will allow a crop-specific evapotranspiration amount to be determined, which may better reflect the amount of water loss for the particular crop planted in the area of soil.

[0053] In particular, this may involve determining a crop coefficient using the crop data and subsequently determining the crop evapotranspiration value by multiplying the evapotranspiration value and the crop coefficient. In one example, the method may include determining, using the crop data, an identification of the particular crop and a current growth phase of the particular crop, and then determining the crop coefficient in accordance with the identification of the particular crop and the growth phase. The crop coefficient will reflect the particular evapotranspiration effects associated with the particular crop and its growth phase, accounting for parameters such as the canopy size and amount of moisture loss expected from the foliage of the particular crop. Crop coefficients may be based on known values for particular crops or may be determined empirically.

[0054] The crop data may include predetermined crop coefficients for different crops at different growth phases, such as initial growth, intermediate growth or mature growth. Other parameters such as root depth may also be stored, again based on growth phase. Practical implementations of the method may track the age of a crop in days from the planting date and determine the growth phase on a given date based on known growth patterns for the particular crop. It should be appreciated that the particular set of crop data that is stored may depend on the specific techniques used for determining the crop evapotranspiration value and/or the irrigation quantity. In any event, the crop data may be stored in a database or the like and in some examples may be organised into tables for each crop.

[0055] In some examples, the method may specifically include determining a readily available water value using soil data for the soil, determining a crop net irrigation application depth using the readily available water value and the crop data, and calculating the irrigation quantity using the crop net irrigation application depth and the crop evapotranspiration value. This approach can allow particular soil properties to be taken into account in the calculation of the irrigation quantity, together with other crop-specific parameters.

[0056] It will be appreciated that the crop net irrigation application depth provides a measure of the particular irrigation requirements for a particular crop. In one example, the method may include determining, using the crop data, a crop root depth of the particular crop, and determining the crop net irrigation application depth using the readily available water value and the root depth. As mentioned above, the crop root depth may also be stored based on the growth phase of the crop. The readily available water value will typically be a property of the soil and may be provided as part of the soil data mentioned above.

[0057] With regard to the meteorological data, which is used for at least determining the evapotranspiration value, this may be obtained based on location data for the area of soil. For example, a geographical location for a particular site to which this method is to be applied may be used to obtain meteorological data corresponding to that location. In some cases, meteorological data may only be available for neighbouring regions, and the method may either use meteorological data for the closest region or may use averaged values of the meteorological data for more than one neighbouring region if desired.

[0058] Particular implementations of the method may include obtaining the meteorological data using file transfer protocol (FTP) or an application programming interface (API). The particular technique used for accessing the meteorological data will largely depend on the techniques supported by the meteorological data source.

[0059] The specific types of meteorological data that may be obtained and used in the method include a relative humidity observation, a maximum temperature observation, a minimum temperature observation, an air temperature observation, a water surface temperature observation, an atmospheric pressure observation, and a solar radiation exposure observation. The aforementioned observations can support the calculation of evapotranspiration values using the Priestley Taylor method or the Turc method as discussed above, but it should be appreciated that not all of these need to be obtained in all implementations of the method. On the other hand, additional types of meteorological data may also be obtained to support the use of other techniques or for providing extended functionalities.

[0060] As mentioned above, an evapotranspiration value may be obtained directly as part of the meteorological data. This can be useful to allow comparisons to the values derived from other techniques, but it should be understood that this is not essential.

[0061] In some examples, the meteorological data may further include a rainfall observation, and the method may include adjusting the determined irrigation quantity to account for the rainfall observation. However, this is not essential and it is noted that the use of the moisture measurement to determine whether irrigation is required can indirectly account for any rainfall in the prior time period.

[0062] With regard to the step of determining whether irrigation is required based on the at least one moisture measurement, in some implementations this may be performed by comparing the moisture measurement with a predetermined refill threshold and determining that irrigation is required only if the moisture measurement is less than the refill threshold. The refill threshold (which may also be referred to as a refill point) is a predetermined minimum moisture content level for the soil, whereby a moisture measurement below this level will indicate that readily available water in the soil has been used and plant roots cannot extract water from the soil as easily. The refill threshold may vary significantly based on the soil type, the particular crop and its growth phase, and so will preferably be selected based on these parameters.

[0063] The method may be used in sites that cover large areas such that it may be desirable to use a plurality of soil moisture sensors. Accordingly, some implementations may involve receiving a plurality of moisture measurements from a plurality of soil moisture sensors, determining a lowest moisture measurement from the plurality of moisture measurements; and determining that irrigation is required only if the lowest moisture measurement is less than the refill threshold. This can help to account for varying moisture levels across a site and ensure that irrigation will be performed if the level drops below the fill threshold in the vicinity of any of the soil moisture sensors.

[0064] In another aspect, an apparatus may be provided for use in performing quantitative water irrigation of an area of soil planted with a particular crop. The apparatus may include at least one soil moisture sensor located in the soil, and one or more electronic processing devices coupled to the at least one soil moisture sensor and a meteorological data source via one or more communications networks. In this regard, the one or more electronic processing devices will be configured to perform the method as described above.

[0065] In some implementations, the one or more electronic processing devices may be configured to provide an indication of the determined irrigation quantity to an irrigation controller for controlling an irrigation system to cause the determined irrigation quantity to be supplied to the area of land over the subsequent time period. However, the irrigation controller may not necessarily form part of the apparatus and may be provided separately or replaced with purely manual control of the irrigation system.

[0066] As mentioned above, a plurality of soil moisture sensors may be used, and in this respect the apparatus may include the plurality of soil moisture sensors, which may be coupled together via a sensor communication network. In one example, the apparatus may include a gateway unit configured to act as a parent node in the sensor communication network and a plurality of sensor units. Each sensor unit may include a respective soil moisture sensor and be configured to act as a child node in the sensor communication network. The gateway unit may in turn be configured to receive moisture measurements from the sensor units and transfer the moisture measurements to the one or more electronic processing devices.

[0067] The one or more electronic processing devices may be coupled to the gateway unit and the meteorological data source via the Internet. In one specific embodiment, the one or more electronic processing devices may be provided using a cloud computing system and the meteorological data source may be accessed via an Internet API.

[0068] In one example, the process is performed by one or more processing systems operating as part of a distributed architecture, an example of which will now be described with reference to Figure 2.

[0069] In this example, the arrangement includes a number of processing systems 201, 203 along with gateway and sensor units 205, 207, each interconnected via one or more communications networks, such as the Internet 202, and/or a number of local area networks (LANs) 204.

[0070] It will be appreciated that the configuration of the networks 202, 204 are for the purpose of example only, and in practice the processing systems 201, 203 and gateway and sensor units 205, 207 can communicate via any appropriate mechanism, such as via wired or wireless connections, including, but not limited to mobile networks, private networks, such as an 802.11 networks, the Internet, LANs, WANs, or the like, as well as via direct or point-to-point connections, such as Bluetooth, Zigbee or the like.

[0071] The nature of the processing systems 201, 203 and their functionality will vary depending on their particular requirements. In one particular example, the processing systems 201, 203 represent servers (such as for determining the irrigation quantity) and clients (for allowing farmers to monitor irrigation processes or updating data), although this is not essential and is used primarily for the purpose of illustration.

[0072] An example of a suitable processing system 201 is shown in Figure 3. In this example, the processing system 201 includes an electronic processing device, such as at least one microprocessor 300, a memory 301, an optional input/output device 302, such as a keyboard and/or display, and an external interface 303, interconnected via a bus 304 as shown. In this example the external interface 303 can be utilised for connecting the processing system 201 to peripheral devices, such as the communications networks 202, 204, databases 211, other storage devices, or the like. Although a single external interface 303 is shown, this is for the purpose of example only, and in practice multiple interfaces using various methods (e.g. Ethernet, serial, USB, wireless or the like) may be provided.

[0073] In use, the microprocessor 300 executes instructions in the form of applications software stored in the memory 301 to perform required processes, such as communicating with other processing systems 201, 203 or the gateway and/or sensor units 205, 207 depending on the sensor network topology. Thus, actions performed by a processing system 201 are performed by the processor 300 in accordance with instructions stored as applications software in the memory 301 and/or input commands received via the I/O device 302, or commands received from other processing systems 201, 203. The applications software may include one or more software modules, and may be executed in a suitable execution environment, such as an operating system environment, or the like.

[0074] Accordingly, it will be appreciated that the processing systems 201 may be formed from any suitable processing system, such as a suitably programmed computer system, PC, web server, network server, or the like. In one particular example, the processing system 201 is a standard processing system such as a 32-bit or 64-bit Intel Architecture based processing system, which executes software applications stored on non-volatile (e.g., hard disk) storage, although this is not essential. However, it will also be understood that the processing systems 201 could be or could include any electronic processing device such as a microprocessor, microchip processor, logic gate configuration, firmware optionally associated with implementing logic such as an FPGA (Field Programmable Gate Array), or any other electronic device, system or arrangement.

[0075] As shown in Figure 4, in one example, the processing systems 203 include an electronic processing device, such as at least one microprocessor 400, a memory 401, an input/output device 402, such as a keyboard and/or display, and an external interface 403, interconnected via a bus 404 as shown. In this example the external interface 403 can be utilised for connecting the processing system 203 to peripheral devices, such as the communications networks 202, 204, databases, other storage devices, or the like. Although a single external interface 403 is shown, this is for the purpose of example only, and in practice multiple interfaces using various methods (e.g. Ethernet, serial, USB, wireless or the like) may be provided.

[0076] In use, the microprocessor 400 executes instructions in the form of applications software stored in the memory 401 to perform required processes, for example to allow communication with other processing systems 201, 203. Thus, actions performed by a processing system 203 are performed by the processor 401 in accordance with instructions stored as applications software in the memory 402 and/or input commands received from a user via the I/O device 403. The applications software may include one or more software modules, and may be executed in a suitable execution environment, such as an operating system environment, or the like.

[0077] Accordingly, it will be appreciated that the processing systems 203 may be formed from any suitable processing system, such as a suitably programmed PC, Internet terminal, lap-top, hand-held PC, smart phone, PDA, tablet, or the like. Thus, in one example, the processing system 203 is a standard processing system such as a 32-bit or 64-bit Intel Architecture based processing system, which executes software applications stored on nonvolatile (e.g., hard disk) storage, although this is not essential. However, it will also be understood that the processing systems 203 can be any electronic processing device such as a microprocessor, microchip processor, logic gate configuration, firmware optionally associated with implementing logic such as an FPGA (Field Programmable Gate Array), or any other electronic device, system or arrangement.

[0078] It will also be noted that whilst the processing systems 201, 203 are shown as single entities, it will be appreciated that this is not essential, and instead one or more of the processing systems 201, 203 can be distributed over geographically separate locations, for example by using processing systems provided as part of a cloud based environment.

[0079] In a preferred implementation, the processing systems 201 may be provided as part of a cloud computing service and will communicate with other elements of the arrangement via the Internet 202. The use of other processing systems 203 in the form of client devices is not essential to the method, but in practice will be advantageous to allow users such as farmers or the like to monitor the irrigation status for a site or access associated information such as moisture measurements. Furthermore, users can interact with the processing systems 201 or data stored on the database 211 to update data for use in the method, such as the crop data or soil data, if necessary. Further functionalities for monitoring and/or controlling the irrigation of crops via client devices could also be implemented although these will be outside the scope of this application.

[0080] The gateway and sensor units 205, 207 may be provided as specialised versions of the processing systems 203 as shown in Figure 4, whereby the external interfaces 403 include dedicated sensor interfaces for interfacing with respective soil moisture sensors along with network interfaces as required for the particular sensor network topology. For instance, the gateway unit 205 may differ from the sensor units 207 in terms of the particular network connectivity provided. The gateway unit 205 may include external network connectivity for allowing communications with the processing systems 201 via the Internet or any other external network, along with internal network connectivity for enabling communications within a localised sensor network, such as by using Zigbee or any other suitable networking protocol. On the other hand, the sensor units 2017 may only include internal network connectivity.

[0081] Since the gateway and sensor units 205, 207 may need to be deployed in remote locations these may include localised power sources such as a solar panel and rechargeable batteries. To conserve power, the microprocessor 400 and other hardware used in the gateway and sensor units 205, 207 may be selected for energy efficiency.

[0082] However, it will be appreciated that the above described arrangement is shown as an example only, and numerous other configurations may be used.

[0083] A detailed example of a method for use in quantitative water irrigation will now be described with regard to the flow chart of Figures 5 A to 5C.

[0084] In this particular example, it is assumed that the main data processing functionalities of this method are provided as part of a cloud computing service which is able to communicate with meteorological data services and gateway and sensor units having respective soil moisture sensors via the Internet. This example will illustrate a typical loop of the irrigation method which may be carried out periodically and potentially only at predetermined times of the day.

[0085] As an initial process, the method will involve checking the field status at step 500. This may include accessing a field table including particular information regarding a field (i.e. a planted area of soil), such as the crop planting date, the refill threshold, irrigation flow information and the aforementioned field status, which may be active or inactive. If the field status is inactive the method may proceed no further, however if the field status is active a determination may be made on whether the field status should be changed to inactive, such as if the crop age (calculated based on the current date and the crop planting date) exceeds a predetermined maximum lifecycle for the particular crop.

[0086] Assuming the field status is active, the soil moisture sensors will be monitored at step 501, such as by communicating with a gateway unit that is in turn networked with sensor units each having their own respective soil moisture sensors. Moisture measurements will be received at step 502, and in the event that these are received for multiple soil moisture sensors in the same field, these may be processed by averaging or taking a maximum measurement. In any event, at step 503 the moisture measurements (or determined average/maximum moisture measurement) may be compared to the refill threshold from the field table to determine whether irrigation will be required. For example, if one or more of the moisture measurements is below the refill threshold then irrigation may be deemed to be required, in which case the method will proceed towards obtaining the required information for calculating the irrigation quantity.

[0087] At step 504, meteorological data will be obtained for the previous day. In this example, the meteorological data may be obtained from three separate meteorological data sources via Internet APIs. Average or worst case values of the meteorological data may be taken based on the three sets of meteorological data.

[0088] At steps 505 and 506, crop data and soil data will be obtained for the particular crop and soil of the field, typically by retrieving tables from one or more databases including the required information. The crop data may include information regarding the growth phases of the particular crop (for instance, classified as initial, intermediate and mature growth phases), along with growth depth information and crop coefficient values corresponding to each growth phase, along with a depletion factor for the crop. The soil data may include values for the total available water and readily available water.

[0089] Moving on to step 507, the method may then include determining the growth phase of the crop. For instance, the growth phases may be represented as age ranges in days, so the growth phase can be determined by calculating the current age of the crop using the current date and the planting date from the field table. Then, once the growth phase is known, this can be used to determine a corresponding root depth at step 508.

[0090] Evapotranspiration values may then be determined based on the meteorological data at step 509. As discussed previously, multiple values may be calculated using different techniques and values provided by the different meteorological data sources may also be used. At step 510 the maximum evapotranspiration value will be selected as a worst case scenario.

[0091] In step 511, a crop coefficient will be determined from the crop data based on the growth phase of step 507. As mentioned above, the crop coefficient will account for specific properties of the particular crop that will impact on the specific evapotranspiration for the crop, which will also be based on the growth phase. For instance, mature crops may experience relatively higher degrees of evapotranspiration due to increased foliage surface area through which transpiration will take place, which will be accounted for by a higher crop coefficient. In step 512, the readily available water value for the soil will also be determined from the soil data.

[0092] The calculation of the irrigation quantity can then be performed in step 513. In this particular example, the calculation will involve determining a crop-specific evapotranspiration value by multiplying the worst case evapotranspiration value determined in step 510 by the crop coefficient determined in step 511. In addition to this, the basic irrigation amount to provide sufficient water to the roots of the crop will be determined by multiplying the readily available water value from step 512 and the root depth from step 508. The sum of the crop-specific evapotranspiration value and the basic irrigation amount will represent the total height of water required to be supplied. The irrigation quantity can then be derived by multiplying height and the area of the soil to be irrigated.

[0093] Once the irrigation quantity has been calculated, this can be used to ensure that a sufficient quantity of water is supplied to the field. In this example, attributes of the irrigation system are determined at step 514, such as from a stored irrigation table for the field. These irrigation system attributes may include information regarding the number of irrigation outputs, the flow properties of the irrigation system, and the like.

[0094] Then, at step 515 the irrigation time required for supplying the calculated irrigation quantity can be determined based on the irrigation system attributes. This may include allowances priming the irrigation system. Finally, at step 516 the method may involve causing the irrigation system to run for the determined irrigation time, to thereby supply the irrigation quantity to the crop.

[0095] It will be appreciated that this method will allow a quantity of water to be supplied for irrigating the crop that is specifically determined to replenish evapotranspiration losses from the previous day and to ensure an appropriate amount of water is available to the roots of the plant for ensuring optimal growth.

[0096] The use of multiple meteorological data sources and multiple evapotranspiration calculation techniques in the above example can help to provide robustness so that irrigation is not missed due to potential inaccuracies in any one source or technique.

[0097] Nevertheless, the calculated irrigation quantity will be tailored to the particular crop and growth phase and thus will help to ensure optimal watering with reduced risk of significant under or over watering.

[0098] Throughout this specification and claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

[0099] Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.

Claims (20)

1. THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1) A method for use in performing quantitative water irrigation of an area of soil planted with a particular crop, the method being performed using one or more electronic processing devices, the method including: a) receiving, from at least one soil moisture sensor located in the soil, at least one moisture measurement indicative of a moisture content of the soil; b) determining whether irrigation is required based on the at least one moisture measurement; c) in response to determining that irrigation is required, determining an irrigation quantity indicative of a quantity of water to be supplied to the area of land over a subsequent time period by: i) obtaining, from a meteorological data source, meteorological data for a geographical region corresponding to the area of soil for a prior time period; ii) determining at least one evapotranspiration value for the prior time period based on at least some of the meteorological data; and iii) calculating the irrigation quantity based at least in part on: (1) crop data for the particular crop; and (2) the at least one evapotranspiration value.
2. 2) A method according to claim 1, wherein the method further includes controlling an irrigation system to supply the determined irrigation quantity to the area of land over the subsequent time period.
3. 3) A method according to claim 1 or claim 2, wherein the method includes: a) determining a plurality of evapotranspiration values using different techniques; b) determining a maximum evapotranspiration value from the plurality of evapotranspiration values; and c) calculating the irrigation quantity based at least in part on the maximum evapotranspiration value.
4. 4) A method according to any one of claims 1 to 3, wherein the at least one evapotranspiration value is determined using at least one of: a) an evapotranspiration value calculated using the meteorological data using a Priestley Taylor method; b) an evapotranspiration value calculated using the meteorological data using a Turc method; and c) an evapotranspiration value calculated by the meteorological data source and included in the meteorological data.
5. 5) A method according to any one of claims 1 to 4, wherein the method includes: a) determining a crop evapotranspiration value for the particular crop based on the evapotranspiration value and the crop data; and b) calculating the irrigation quantity based at least in part on the crop evapotranspiration value.
6. 6) A method according to claim 5, wherein the method includes: a) determining a crop coefficient using the crop data; and b) determining the crop evapotranspiration value by multiplying the evapotranspiration value and the crop coefficient.
7. 7) A method according to claim 6, wherein the method includes: a) determining, using the crop data: i) an identification of the particular crop; and ii) a current growth phase of the particular crop; and b) determining the crop coefficient in accordance with the identification of the particular crop and the growth phase.
8. 8) A method according to any one of claims 1 to 7, wherein the method includes: a) determining a readily available water value using soil data for the soil; b) determining a crop net irrigation application depth using the readily available water value and the crop data; and c) calculating the irrigation quantity using the crop net irrigation application depth and the crop evapotranspiration value.
9. 9) A method according to claim 8, wherein the method includes: a) determining, using the crop data, a crop root depth of the particular crop; and b) determining the crop net irrigation application depth using the readily available water value and the root depth.
10. 10) A method according to any one of claims 1 to 9, wherein the method includes obtaining the meteorological data based on location data for the area of soil.
11. 11) A method according to any one of claims 1 to 10, wherein the method includes obtaining the meteorological data using at least one of: a) file transfer protocol (FTP); and; b) an application programming interface (API).
12. 12) A method according to any one of claims 1 to 11, wherein the meteorological data includes at least one of: a) a relative humidity observation; b) a maximum temperature observation; c) a minimum temperature observation; d) an air temperature observation; e) a water surface temperature observation; f) an atmospheric pressure observation; and g) a solar radiation exposure observation.
13. 13) A method according to claim 12, wherein the meteorological data further includes a rainfall observation, the method including adjusting the determined irrigation quantity to account for the rainfall observation.
14. 14) A method according to any one of claims 1 to 13, wherein the method includes: a) comparing the moisture measurement with a predetermined refill threshold; and b) determining that irrigation is required only if the moisture measurement is less than the refill threshold.
15. 15) A method according to claim 14, wherein the method includes: a) receiving a plurality of moisture measurements from a plurality of soil moisture sensors; b) determining a lowest moisture measurement from the plurality of moisture measurements; and c) determining that irrigation is required only if the lowest moisture measurement is less than the refill threshold.
16. 16) Apparatus for use in performing quantitative water irrigation of an area of soil planted with a particular crop, the apparatus including: a) at least one soil moisture sensor located in the soil; and b) one or more electronic processing devices coupled to the at least one soil moisture sensor and a meteorological data source via one or more communications networks, the one or more electronic processing devices being configured to: i) receive, from the at least one soil moisture sensor, at least one moisture measurement indicative of a moisture content of the soil; ii) determine whether irrigation is required based on the at least one moisture measurement; iii) in response to determining that irrigation is required, determine an irrigation quantity indicative of a quantity of water to be supplied to the area of land over a subsequent time period by: (1) obtaining, from a meteorological data source, meteorological data for a geographical region corresponding to the area of soil for a prior time period; (2) determining at least one evapotranspiration value for the prior time period based on at least some of the meteorological data; and (3) calculating the irrigation quantity based at least in part on: (a) crop data for the particular crop; and (b) the at least one evapotranspiration value.
17. 17) Apparatus according to claim 16, wherein the one or more electronic processing devices are configured to provide an indication of the determined irrigation quantity to an irrigation controller for controlling an irrigation system to cause the determined irrigation quantity to be supplied to the area of land over the subsequent time period.
18. 18) Apparatus according to claim 16 or claim 17, wherein the apparatus includes a plurality of soil moisture sensors, the plurality of soil moisture sensors being coupled together via a sensor communication network.
19. 19) Apparatus according to claim 18, wherein the apparatus includes: a) a gateway unit configured to act as a parent node in the sensor communication network; and b) a plurality of sensor units each including a respective soil moisture sensor and configured to act as a child node in the sensor communication network, the gateway unit being configured to receive moisture measurements from the sensor units and transfer the moisture measurements to the one or more electronic processing devices.
20. 20) Apparatus according to claim 19, wherein the one or more electronic processing devices are coupled to the gateway unit and the meteorological data source via the Internet.