JPH09149737A - Judgment of optimal amount of irrigation, apparatus for informing optimal amount of irrigation and irrigation controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge that the amount of irrigation attains the optimal one so as not to deteriorate the growth of the germination ratio after seeding or growth of a plant when irrigating a field in a structure or the plant during the cultivation thereof. SOLUTION: When an operating means 103 is operated, the ground temperature just before irrigation is sensed on a signal from temperature sensors 31 to 3n installed in soil of a field in a structure with a sensing means 100a-1. The ground temperature after starting the irrigation is sensed on a signal from the temperature sensors with a sensing means 100a-2. When a sensing means 100a-3 for lowering of temperature senses that the ground temperature after starting the irrigation is lowered from that just before the irrigation by a prescribed value or above, an informing means 105 informs that the optimal amount of irrigation attains. Water supply is started for irrigation with a water supply controlling means 100a-4 by operating the operating means 103 and stopped by lowering the ground temperature by the prescribed value or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is optimum for determining that the optimum watering amount is obtained when watering is carried out after sowing in a field in a facility such as a rain shelter house for growing plants or a glass greenhouse or during planting. The present invention relates to an irrigation amount determination method, an optimum irrigation amount notification device that notifies that the irrigation amount has reached an optimum value, and an irrigation control device that controls irrigation so that the optimum irrigation amount is achieved.

[0002]

2. Description of the Related Art Generally, when a plant is cultivated in a field or the like, if the amount of watering is not appropriate, the germination rate after planting and the growth of the plant are deteriorated.

Conventionally, irrigation of a farm field has largely depended on the experience and intuition of farmers. Depending on the intuition and experience of the farmer, the irrigation amount can be determined by observing the condition of the cultivation environment and irrigating the appropriate irrigation amount, or the irrigation amount can be determined individually and irrigated a fixed amount. It didn't pass. There is a large error in the former method of determining irrigation volume,
Even if the optimum amount of irrigation can always be obtained, considerable skill is required to reach the area. Also, in the latter method, the optimal watering amount for plants and soil will naturally change according to changes in the cultivation environment, so the temperature and humidity during watering, and the amount of water remaining in the field. If the tillage condition of the field, the type of soil in the field, the amount of fertilizer, and the sunshine duration are different, the optimum watering amount cannot be obtained.

However, in recent years, there is a method using a moisture meter as a method for obtaining an optimum amount of irrigation regardless of intuition or experience. In addition, a system that directly measures soil moisture by this method to implement irrigation control has begun to appear. Although a moisture meter is used to measure soil moisture, there are four types of moisture meters: an infrared type that uses infrared rays, a specific heat type that uses a thermal sensor probe, an electrical conduction type that measures soil electrical resistance, and a tension meter type that applies osmotic pressure. There is a measurement principle of.

[0005]

At first glance, control by soil moisture seems optimal, but there are many problems in terms of soil moisture measurement. Can only understand the water condition on the soil surface. Is not suitable for control because it takes time for measurement and real-time output cannot be obtained.
Is susceptible to the concentration of fertilizer in soil. Can only measure water at a position considerably deeper than the ground surface. In summary, although some soil moisture is measured to control irrigation, it is doubtful whether the measured soil moisture itself is effective for plants. In addition, since soil moisture is a physical quantity that varies widely in the field, it is necessary to perform multipoint measurement for accurate measurement, but the moisture sensor itself is very expensive, and it is not economically practical.

Among these, the only moisture meter that can see the optimum soil moisture condition for plants at a glance is the tension meter type, and other moisture meters simply find the water content in a unit soil and the environment is different. It becomes impossible to grasp the optimal water supply for plant cultivation in that environment. Since the tension meter method is a moisture meter that measures the amount of water that can be used by plants, regardless of changes in the environment, it is possible to always know the optimal watering amount for plants in that environment. However, since it is necessary to bury the sensor part quite deeply (shallow, 15 cm),
Not suitable for sowing or cultivation of plants with shallow root areas. In addition, it is at least 1 to indicate an accurate measurement value by blending with the surrounding soil.
Since it requires weeks, it is not suitable for cultivating plants with a short cultivation period.

Therefore, in view of the above-mentioned conventional problems, the present invention provides a method for sowing after seeding in a field in a facility such as a rain shelter house for cultivating a plant or a glass greenhouse, or after watering during cultivating a plant. It is an object of the present invention to provide an optimal watering amount determination method for determining that the optimal watering amount has been achieved so that the germination rate and the growth of plants are not deteriorated.

In view of the above-mentioned conventional problems, the present invention also provides a method for sowing after seeding in a field in a facility such as a rain shelter house for cultivating plants or a glass greenhouse, or when irrigating during cultivating plants. An object of the present invention is to provide an optimum watering amount notification device that notifies that the optimum watering amount has been reached so that the germination rate and the growth of plants are not deteriorated.

In view of the above-mentioned conventional problems, the present invention further provides a method for sowing after sowing in a field in a facility such as a rain shelter house for cultivating a plant or a glass greenhouse, or when irrigating during cultivating a plant. An object of the present invention is to provide an irrigation control device that controls irrigation so that the germination rate and the growth of plants are not deteriorated so that the optimal irrigation amount is achieved.

[0010]

The optimum irrigation amount determination method according to claim 1, which is made according to the present invention to solve the above problems, monitors a change in soil temperature from the start of irrigation to a field in a facility, The feature is that it is determined that the optimum irrigation amount has been reached when the ground temperature has dropped by a predetermined temperature from the temperature at the start of irrigation.

In the above structure, the change in the soil temperature after the start of irrigation to the field in the facility is monitored, and it is determined that the optimum irrigation amount has been reached when the soil temperature drops from the temperature at the start of irrigation by a predetermined temperature. By stopping the irrigation when the determined optimum irrigation amount is reached, the optimum irrigation can be performed.

In order to solve the above-mentioned problems, the optimum irrigation amount informing device according to the present invention, which is made according to the present invention, is shown in FIG. 1 (a).
As shown in the basic configuration diagram of _1., temperature sensors 3 _{1 to} 3 _n that are installed at a predetermined depth of soil in the field in the facility and that detect the ground temperature and output a ground temperature detection signal, and the operation that is performed when starting the irrigation Means 103, and irrigation start time ground temperature detecting means 100a-1 for detecting the ground temperature immediately before irrigation by the ground temperature detection signal from the temperature sensor in response to the operation of the operating means,
Post-irrigation ground temperature detecting means 100a-2 for detecting the ground temperature after the start of irrigation based on the ground temperature detection signal from the temperature sensor.
And a temperature drop detecting means 100a-3 for detecting that the ground temperature after the start of irrigation detected by the ground temperature detecting means after the start of irrigation is lower than the ground temperature immediately before the irrigation by a predetermined value or more, and the detection by the temperature decrease detecting means. It is characterized by including an informing means 105 for informing that the optimum irrigation amount has been reached.

In the above structure, when the operation means 103 is operated to start irrigation, the irrigation start time ground temperature detecting means 100a-1 is responsive to the operation and the temperature sensor is installed at a predetermined depth of soil in the field in the facility. The ground temperature immediately before irrigation is detected by the ground temperature detection signals from 3 _{1 to} 3 _n . The post-irrigation ground temperature detecting means 100a-2 detects the ground temperature after the start of irrigation by the ground temperature detection signal from the temperature sensor, and detects that the ground temperature after the start of irrigation is lower than the ground temperature immediately before irrigation by a predetermined value or more. When the means 100a-3 detects,
Since the notification means 105 notifies that the optimal irrigation amount has been reached, optimal irrigation can be performed by stopping the irrigation at the time when it is known that the optimal irrigation amount has been reached by this notification.

In order to solve the above-mentioned problems, the irrigation control device according to the third aspect of the present invention is installed at a predetermined depth of soil in a field in a facility, as shown in the basic configuration diagram of FIG. 1 (b). Temperature sensors 3 _{1 to} 3 _n that detect the ground temperature and output a ground temperature detection signal, operation means 103 that is operated when starting watering, and a ground temperature detection signal from the temperature sensor according to the operation of the operation means. Irrigation start time ground temperature detecting means 100a-1 for detecting the ground temperature immediately before irrigation, the post irrigation start temperature detection means 100a-2 for detecting the ground temperature after irrigation start by the ground temperature detection signal from the temperature sensor, and the irrigation start Depending on the operation of the temperature drop detecting means 100a-3 for detecting that the ground temperature after the start of irrigation detected by the rear ground temperature detecting means is lower than the ground temperature immediately before the irrigation by a predetermined value or more, and the operation means. Water was started for water, is characterized in that it comprises a water supply control means 100a-4 to terminate irrigation is stopped the water supply in response to detection by the temperature decrease detector.

In the above structure, when the operation means 103 is operated to start watering, the water supply control means 10
0a-4 starts watering for irrigation. Further, according to the operation of this operation means, the water temperature detection means 100 at the start of irrigation
a-1 detects the ground temperature immediately before irrigation by the ground temperature detection signals from the temperature sensors 3 _{1 to} 3 _n installed at a predetermined depth of soil in the field in the facility. After irrigation is started by the start of water supply, the post-irrigation ground temperature detecting means 100a-2 detects the ground temperature after irrigation start by the ground temperature detection signal from the temperature sensor, and the ground temperature after irrigation start is the ground temperature immediately before irrigation. When the temperature drop detecting means 100a-3 detects that the temperature has dropped by a predetermined value or more, the water supply control means 100a-4 stops the water supply and terminates the irrigation, so that the water supply is automatically performed when the optimum irrigation amount is reached. By being stopped, optimal watering can be automatically performed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an example of irrigation equipment inside a facility such as a rain shelter house or a glass greenhouse where irrigation of the optimum irrigation amount determined by the optimum irrigation amount determination method of the present invention is performed. numerous irrigation nozzles 2 ₁ to 2 _n are provided in the pipe 2a, 2b which arranged to. The irrigation equipment inside the facility is not limited as long as it can irrigate the soil surface substantially uniformly from the house ceiling direction with a irrigation nozzle, an irrigation hose, an irrigation tube, etc. .

In the soil in the house 1 equipped with the above-mentioned irrigation equipment, temperature sensors 3 such as a thermistor for temperature measurement and a resistance temperature detector are provided at at least three places on the center and both sides of the house.
Are installed so that the depth is approximately equal to the seeding depth of 10 mm to 20 mm. The temperature sensor 3 measures the soil temperature immediately before the irrigation, and then the irrigation is performed. When the soil temperature drops by a predetermined temperature, the irrigation is stopped.

The above-mentioned predetermined temperature is set to a temperature of 2 ° C. ± 0.5 ° C., which is a pF value indicating soil moisture which is a value that hardly changes even if the type of soil changes, and which corresponds to around 2. The suitable water condition for plants varies slightly depending on the type of plant,
Generally, the pF value is in the range of 1.8 to 2.2. However, the predetermined temperature does not have to be a temperature corresponding to the above range 1.8 to 2.2 unless it is a temperature corresponding to pF1 or less or pF2.8 or more that adversely affects plants. By the way, the soil temperature decrease temperature from the start of irrigation to the stop is
For spinach, stop irrigation at 2 ° C and drop around 2 ° C.

When the soil temperature is lowered by 2 ° C. by irrigation, the soil water content is around pF2 as measured by the tension meter. This value is the optimum value for plants to grow,
A high germination rate can be obtained constantly, and the configuration is extremely simple.

(Embodiment 1) Forty-eight irrigation nozzles having a spray diameter of 1.5 m (4) are used in a sandy soil field of a vinyl house (opening 5.4 m, depth 18 m) having an area of about 1 are.
(12 × 12) are arranged, and irrigation equipment is installed so that water can be almost uniformly irrigated from the ceiling direction of the house to the soil surface.
In addition, ten thermocouples as temperature sensors for soil temperature measurement were installed in the soil at arbitrary positions to a depth of 10 mm to 20 mm, and a tension meter for soil moisture measurement was installed in the vicinity thereof. The soil moisture measurement position by the tension meter is about 20 cm deep from the ground surface.

Table 1 shows the results of measurement of soil temperature and soil moisture when irrigation was carried out from the irrigation nozzle using this system. The ground temperature and soil moisture used were averages of data at 10 measurement points. In the table, the field soil temperature is shown by the decrease from the soil temperature 22 ° C at the start of measurement. In addition, the pF value indicating soil moisture is a value that does not easily change even when the type of soil changes, and for plants, it is around pF2 (1.8 to 2.2).
Is a suitable moisture state.

[0022]

[Table 1]

Example 2 Table 2 shows the results of soil temperature and soil moisture measurements in the same system as in Example 1 except that the soil was volcanic ash soil. In the table, the field soil temperature is indicated by the decrease from the soil temperature 19 ° C at the start of measurement.

[0024]

[Table 2]

(Example 3) Table 3 shows the results of soil temperature and soil moisture measurements in the same system as in Example 1 except that the soil was clay-based soil. In the table, the field soil temperature is indicated by the decrease from the soil temperature 24 ° C at the start of measurement.

[0026]

[Table 3]

It can be seen that a suitable water environment for the plant is established if the decrease in soil temperature is about 2 ° C. regardless of the type of soil, the outside temperature, and the weather. However, since the tension meter for measuring water content is located at a deep position, it is expected that the water content in the vicinity of the rhizosphere has reached a more suitable condition.
Therefore, the field soil temperature decrease of 2 ° C. is 75 in Example 1.
Minutes, 90-105 minutes of Example 2, and 12 of Example 3.
Optimal watering is obtained at 0 minutes.

(Example 4) Two vinyl greenhouses of Example 2 were prepared, and ginseng-coated seeds were sown in each vinyl greenhouse with a 12000 seeder so that the distance between the plants was 5 cm and the distance between the plants was 15 cm. In addition, the reason why the coated seeds are used is that the soil is difficult to germinate in a low water state and the property is utilized. The depth at the time of sowing was set to 1.5 cm, and the squeezing after sowing was performed only by the squeezing wheel of the sowing machine. One of the houses after sowing was subjected to irrigation with a irrigation nozzle until the soil temperature decreased by 2 ° C, and this was designated as test section 1. The soil temperature was measured at 10 points as in Example 2. The other house was subjected to irrigation with the irrigation nozzle for 90 minutes, which is the irrigation time when the suitable water content was reached in Example 2, and was designated as test section 2. Table 4 shows the results of investigating the germination rate of each test plot at the same time after the start of the test, without performing any irrigation on both vinyl houses after the irrigation treatment. The outside air temperature of the house during irrigation was 31 ° C, and the inside temperature of the house was 36 ° C. Control such as opening and closing the side windows of the vinyl house was performed under the same conditions in both test sections.

[0029]

[Table 4]

Since the temperature during the germination test was high,
In test area 2, it is expected that poor emergence occurred due to lack of soil water content. From this Table 4, even if the optimum irrigation time is set under other conditions, the optimum irrigation time will not be achieved if the conditions are different, but if the irrigation amount is determined by lowering the predetermined temperature of the soil temperature, a good emergence rate is obtained. It turns out that

(Embodiment 5) Three temperature sensors are used for ground temperature measurement.
Except for using this, using the same in-house field as in Example 1 shows the results of measuring soil water content in various soils when irrigation was performed with a irrigation nozzle until the soil temperature decreased by 2 ° C. It becomes like Table 5. For the soil temperature to which the timing of stopping the irrigation was applied, the average of the measured values of 3 points was used, and for the soil moisture, the average of the data of 3 points was used. The outside temperature of the house at the start of the test was 27 ° C and the inside temperature of the house was 33 ° C, and there was almost no change until the end of the test. The initial moisture content of soil in each greenhouse was pF2.8.

[0032]

[Table 5]

(Example 6) The field soil shown in Example 5 was prepared with two greenhouses of volcanic ash soil, and the inter-strain ratio was 5
spinach-coated seeds (the germination of the coated seeds was apt to be affected by soil moisture) were sowed in each vinyl house with a 12000 seeding machine so that the length of the spinach was 15 cm and the distance between them was 15 cm. The depth of sowing is 1.
The pressure was set to 5 cm, and the squeezing after seeding was performed only by the squeeze wheel after seeding.

After seeding, one of the houses was irrigated with a irrigation system equipped with a control mechanism for stopping irrigation when the soil temperature decreased by 2 ° C. The ground temperature was measured with three temperature sensors (Test Section 1). The other house was subjected to irrigation with the irrigation nozzle for the irrigation time (100 minutes) when the water content reached the suitable level in Example 5 (Test Group 2). After this irrigation treatment, neither vinyl house was irrigated at all. By the way, the outside temperature of the house during irrigation is 23 ° C and the inside temperature of the house is 28 ° C.
° C. The opening and closing of the side windows of the vinyl house were managed under the same conditions for both buildings. In addition, Table 6 shows the results of investigating the number of germinated seeds at the same time after the start of the test.

[0035]

[Table 6]

Since the temperature in Test Group 2 was lower than that in Example 5, the soil moisture environment was unsuitable for spinach which causes poor germination in the humidified state. Further, the decrease in the emergence rate is because the seeds became dead due to excessive water content after emergence.

Next, an embodiment of the optimum irrigation amount notification device according to the present invention for notifying that the optimum irrigation amount has been determined by the above-described optimum irrigation amount determination method will be described with reference to FIG. In the figure, the apparatus has a μCOM having a CPU 100a that operates according to a predetermined program, a ROM 100b that stores the program, and a RAM 100c that has a work area other than the area for storing various data.
Has 100.

The input of μCOM100 is 10 mm to 20 which is about the same as the seed sowing depth in the soil of the field in the house.
The output of an AD converter 101 that AD-converts and outputs the temperature signals from the temperature sensors 3 _{1 to} 3 _n installed between mm is connected. The AD converter 101 and the temperature sensor 3 ₁
AD converter 101 selects one of the temperature signal from the temperature sensor under the control of the CPU100a between the to 3 _n
There is an intervening selector 102 for inputting.

The other inputs of the μCOM100 are irrigation
A switch as an operation means that is turned on when starting water.
The start switch 103 is connected. Above temperature sensor
Sa3 ₁~ 3_nThe reference voltage under the control of the CPU 100a.
A constant voltage is supplied from the pressure source 104.
You. Each temperature sensor has a reference voltage as shown in FIG.
Of the thermistor connected in series between the pressure source 104 and ground
Such a temperature sensitive element 3a and a resistor 3b.
The voltage at the connection point between a and the resistor 3b passes through the selector 102.
Then, it is input to the AD converter 101.
The output of μCOM100 is when the optimal irrigation volume is reached.
The buzzer 105 is connected as a notification means to notify that
Have been. As a notification means, a sile other than a buzzer
Sound-emitting device such as a microphone or a light-emitting device such as a flashing device.
Is also good.

In the above structure, when the irrigation operator turns on the start switch 103 before opening the water tap (not shown) provided in the middle of the water supply pipe 2 for supplying water to the pipes 2a and 2b in the house 1 for watering. , CP
The U100a responds to this ON operation with the temperature sensors 3 _{1 to} 3 _n.
The temperature signal from is input through the AD converter 101, the soil temperature of each part in the house 1 in which each temperature sensor is installed is measured at a predetermined depth, and the average is taken to obtain the in-house soil temperature immediately before the start of watering. To detect.

The CPU 100a continues to use the temperature sensor 3 ₁
The temperature signal from ~ 3 _n is input to monitor the change of soil temperature in the house due to irrigation, and it is detected whether the soil temperature is lower than the predetermined temperature from the soil temperature at the start of irrigation. 105 is operated and made to ring, and it is notified that the optimal watering amount has been reached. By the sounding of the buzzer 105, it is determined that the irrigation operator has performed the irrigation at the optimum irrigation amount, the water tap is closed, the water supply to the pipes 2a and 2b in the house 1 is stopped, and the inside of the house 1 is stopped. Irrigation in can be completed.

The details of the operation of the optimum irrigation amount notification device outlined above will be described below with reference to the flowchart of FIG. 5 showing the processing performed by the CPU 100a in accordance with a predetermined program.

The CPU 100a starts its operation when the power is turned on, and waits for the ON operation of the start switch 103 in the first step S1. Start switch 10
3 is turned on, and when the determination in step S1 is YES, the process proceeds to step S2, the output port O ₁ is changed from L level to H level, for example, and the reference voltage source 104 is turned on, and the temperature sensors 3 _{1 to} 3 _n are supplied with operating power. After being supplied, the process proceeds to step S3. In step S3, the AD values of the output voltages from the temperature sensors 3 _{1 to} 3 _n are sequentially read and temporarily stored in a predetermined storage area of the RAM 100c.

For this purpose, the CPU 100a sequentially outputs a selection signal of, for example, a plurality of bits from the output port O ₂ to the selector 102, and outputs a sampling signal synchronized with the selection signal from the output port O ₃ to the AD converter 101. A / D converter 1 that sequentially outputs and outputs through selector 102
1 of the output voltage from the temperature sensors 3 _{1 to} 3 _n input to 01
One by one, and the selected output voltage is AD
Conversion is performed, and the AD value obtained as a result is sequentially read from the input port I.

After that, the process proceeds to step S4 and the output port O
For example, ₁ is changed from H level to L level to turn off the reference voltage source 104 which has been turned on until then, and supply of operating power to the temperature sensors 3 _{1 to} 3 _n is stopped.

Then, in step S5, the average value of the AD values of the output voltages of the temperature sensors 3 _{1 to} 3 _n read in step S3 is calculated, and the average value is stored in advance in the ROM 100a. The ground temperature is detected by referring to the stored voltage-temperature table, and the detected value is stored in a predetermined area of the RAM 100c as the water temperature at the start of irrigation T ₁ . The above steps S2 to 5 constitute irrigation start time ground temperature detection means for detecting the ground temperature immediately before irrigation by the ground temperature detection signals from the temperature sensors 3 _{1 to} 3 _n according to the ON operation of the start switch 103 which is the operation means. ing.

Thereafter, the process proceeds to step S6, the process corresponding to step S2, that is, the output port O ₁ is changed from L level to H level to turn on the reference voltage source 104, and the operating power is supplied to the temperature sensors 3 _{1 to} 3 _n. Do what Subsequently processing corresponding to step S3 proceeds to step S7, i.e., the output voltage from the temperature sensor 3 ₁ to 3 _n A
The D value is sequentially read and temporarily stored in a predetermined storage area of the RAM 100c. Then step S8
Proceed to step S4, that is,
For example, the output port O ₁ is changed from H level to L level to turn off the reference voltage source 104 which has been turned on until then, and to stop the supply of operating power to the temperature sensors 3 _{1 to} 3 _n .

After that, the process proceeds to step S9, where the temperature sensors 3 _{1 to} 3 _n read in step S7 are read.
Calculate the average value of the AD value of the output voltage of
Based on this average value, the ground temperature T ₂ after the start of irrigation is detected by referring to the voltage-temperature table stored in advance in the ROM 100a. Above steps S6~9, the temperature sensor 3 ₁
It constitutes a watering start after soil temperature detecting means for detecting the soil temperature after the start of irrigation by soil temperature detection signal from to 3 _n.

Next, in step S10, a difference ΔT between the irrigation start soil temperature T ₁ detected in step S5 and stored in the RAM 100c and the irrigation start soil temperature T ₂ detected in step S9 is calculated. After that, the process proceeds to step S11, and it is determined whether ΔT is equal to or higher than a predetermined temperature T ₀ . If the determination in step S11 is N
When it is O, the process proceeds to step S12, waits for a certain period of time to elapse, and then returns to step S6.
The processes of steps S6 to S11 described above are repeated until the determination is YES. The above steps S10 and S11 constitute a temperature drop detecting means for detecting that the ground temperature after the start of irrigation is lower than the ground temperature immediately before the irrigation by a predetermined value or more.

If the determination in step S11 is YES, the process proceeds to step S13, in which the output port O ₄ is changed from L to H.
After setting the level, the buzzer 105 as an informing means is turned on and sounded to notify that the optimal watering amount has been reached, and then the process proceeds to step S14. In step S14, waiting for the operation of the start switch 103, the start switch 10
When 3 is turned on, the determination in step S14 becomes YES, the process proceeds to step S15, the output port O ₄ is changed from H level to L level, the buzzer 105 is turned off to stop the ringing, and then the process returns to step S1. Wait for the operation of the start switch 103 that is operated at the start of irrigation.

Next, an embodiment of the irrigation controller according to the present invention for automatically irrigating the optimum irrigation amount determined by the above-mentioned optimum irrigation amount determination method will be described with reference to FIG. In the figure, the same parts as those described with reference to FIG. 3 are designated by the same reference numerals, and detailed description thereof will be omitted. In the figure, the temperature sensors 3 _{1 to} 3 _n and the AD converter 1
01, the selector 102, the start switch 103, and the reference voltage source 104 are the same as those of the alarm device of FIG. 3, but the output of the μCOM 100 is replaced by a pipe 2a and 2b in the house 1 of FIG. 2 instead of the buzzer. Water pipe 2 to supply water to
Driver 10 for opening and closing a solenoid valve 21 provided in the middle of
6 are connected.

In the above structure, when the irrigation operator turns on the start switch 103 during irrigation, C
In response to this ON operation, the PU 100a drives the driver 106 to open the electromagnetic valve 21 in the closed state, and the electromagnetic valve 21
Water is supplied to the pipes 2a and 2b in the house 1 via the water to start irrigation in the house 1. CPU100a also, AD converter 1 the temperature signals from the temperature sensor 3 ₁ to 3 _n
The temperature is input via 01 to measure the ground temperature of each part in the house 1 in which each temperature sensor is installed at a predetermined depth, and the average is taken to detect the ground temperature in the house immediately before the start of watering. CPU
100a also inputs the temperature signals from the temperature sensors 3 _{1 to} 3 _n thereafter to monitor the change in the ground temperature in the house due to the watering,
It is detected whether or not the ground temperature has dropped from the ground temperature at the start of irrigation by a predetermined temperature, and the electromagnetic valve 21 in the open state is closed according to this detection, and the pipes 2a and 2b in the house 1 are checked. It is possible to automatically stop the water supply in the house 1 by stopping the water supply.

The details of the operation of the irrigation control device outlined above will be described below with reference to the flowchart of FIG. 7 showing the processing performed by the CPU 100a in accordance with a predetermined program, but the same steps as those in the flowchart of FIG. The same reference numerals are given and detailed description thereof is omitted.

The CPU 100a starts its operation when the power is turned on, and waits for the ON operation of the start switch 103 in the first step S1. Start switch 10
3 is turned on, and when the determination in step S1 is YES, the process proceeds to step S21, the output port O ₅ is changed from L level to H level, and the driver 106 is used to connect the pipe 2
Solenoid valve 2 provided in the middle of water supply pipe 2 for supplying water to a and 2b
1 is opened to supply water, which starts irrigation.

After the irrigation can be performed, steps S2 to 5 described above with reference to FIG. 5 are executed, and at the start of irrigation by the ground temperature detection signals from the temperature sensors 3 _{1 to} 3 _n according to the ON operation of the start switch 103. Detect ₁ afterwards,
Perform steps S6-12 described above with respect to FIG.
The soil temperature T ₂ is detected after the start of irrigation, and the soil temperature T ₁ at the start of irrigation is detected.
The difference ΔT between the water temperature and the soil temperature T ₂ after the start of irrigation is calculated to obtain ΔT
Is above a predetermined temperature T _0, for example, 2 ° C ± 0.5 ° C or more, and it is detected that the soil temperature after the start of irrigation is lower than the soil temperature immediately before irrigation by a predetermined value or more.

When it is detected that the ground temperature after the start of irrigation is lower than the ground temperature immediately before the irrigation by a predetermined value or more, the process proceeds to step S22, the output port O ₅ is changed from H level to L level, and the solenoid valve 21 is closed by the driver 106. Then, the water supply is stopped to end the irrigation, and then the process returns to step S1 to wait for the next irrigation start operation.

The steps S21 and S22 are
A water supply control unit that starts water supply for irrigation in response to operation of the start switch 103 and stops water supply and ends irrigation in response to detection of an optimum watering state is configured.

When the soil temperature is lowered by 2 ° C. by irrigation, the soil water content is around pF2 as measured by the tension meter. This value is the optimum value for plants to grow,
A high germination rate can be obtained constantly, and the configuration is extremely simple.

In the above-mentioned example, irrigation is started after the seeding is finished in the facility, and it is set so that the irrigation is stopped when the soil temperature in the field drops by 2 ° C ± 0.5 ° C from the start of irrigation, and the temperature sensor is set. Was installed between 10 mm and 20 mm, which is about the same as the seeding depth of seeds, but when watering during the cultivation of plants, it is desirable to install a temperature sensor near the rhizosphere of the plant,
It is necessary to take a slightly large set value for the soil temperature drop. However, since water adheres to the leaf surface of the plant and causes a disease, irrigation is often avoided in practice. Regarding the number of temperature sensors, the more the number of temperature sensors is, the more the accuracy of grasping soil moisture is improved, but if at least three temperature sensors are installed, it is sufficient for control.

[0060]

As described above, according to the method of determining the optimum amount of irrigation according to the first aspect, the change in the soil temperature after the start of irrigation to the field in the facility is monitored, and the soil temperature is the temperature at the start of irrigation. Since it is determined that the optimum irrigation amount has been reached when the predetermined temperature has decreased, the optimum irrigation can be performed by stopping the irrigation when the determined optimum irrigation amount is reached.

Further, according to the optimum irrigation amount notification device of the second aspect, a ground temperature detection signal from a temperature sensor installed at a predetermined depth of soil in the field in the facility according to an operation performed at the time of starting the irrigation. The ground temperature immediately before irrigation was detected by the water temperature detection, and the ground temperature after the irrigation was started was detected by the ground temperature detection signal from the same temperature sensor after the irrigation was started. When the notification is made, the fact that the optimal irrigation amount has been reached is notified, so that the optimal irrigation can be performed by stopping the irrigation at the time when it is known that the optimal irrigation amount has been reached by this notification.

Further, according to the irrigation control device of the third aspect, the water supply for irrigation is started in accordance with the operation performed at the time of starting the irrigation, and the soil temperature at the start of this irrigation is set to the soil of the field in the facility. Detected by the ground temperature detection signal from the temperature sensor installed at a predetermined depth, after the irrigation is started by the start of water supply, the ground temperature after the irrigation start is detected by the ground temperature detection signal from the same temperature sensor, and this irrigation start When it detects that the subsequent soil temperature is lower than the soil temperature immediately before irrigation by a predetermined value or more, water supply is stopped and irrigation is terminated, so water supply is automatically stopped at the time when the optimal irrigation volume is reached. Irrigation can be done automatically.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an optimum irrigation amount notification device and an irrigation control device to which an optimum irrigation amount determination method according to the present invention is applied.

FIG. 2 is a diagram showing irrigation equipment inside a facility to which the optimum irrigation amount determination method, the optimum irrigation amount notification device, and the irrigation control device according to the present invention are applied.

FIG. 3 is a diagram showing an embodiment of an optimum irrigation amount notification device according to the present invention.

FIG. 4 is a circuit diagram showing a specific example of a temperature sensor in FIG.

5 is a flowchart showing a process performed by a CPU in FIG.

FIG. 6 is a diagram showing an embodiment of a watering control device according to the present invention.

FIG. 7 is a flowchart showing a process performed by a CPU in FIG.

[Explanation of symbols]

3 _{1 to} 3 _n Temperature sensor 100a-1 Ground temperature detection means (CPU) at the start of irrigation 100a-2 Ground temperature detection means (CPU) after irrigation start 100a-3 Temperature drop detection means (CPU) 100a-4 Water supply control means (CPU) 103 Operation Means (Start Switch) 105 Notification Means (Buzzer)

Claims (3)

[Claims] 1. A change in soil temperature at a predetermined depth of soil from the start of irrigation to a field in the facility is monitored, and when the soil temperature drops from a temperature at the start of irrigation to a predetermined temperature, it is determined that the optimum irrigation amount has been reached. A method for determining an optimum irrigation amount, which is characterized by the following. 2. A temperature sensor that is installed at a predetermined depth of soil in a field in a facility and that detects a ground temperature and outputs a ground temperature detection signal, an operating unit that is operated when starting watering, and an operating unit that operates the operating unit. Depending on the ground temperature detection means from the temperature sensor to detect the soil temperature immediately before irrigation ground temperature detection means, and the ground temperature detection signal from the temperature sensor to detect the ground temperature after irrigation start soil temperature detection means after irrigation start A temperature drop detecting means for detecting that the ground temperature after the start of irrigation detected by the irrigation start temperature detecting means is lower than the ground temperature immediately before the irrigation by a predetermined value or more, and an optimum irrigation according to the detection by the temperature drop detecting means An optimum irrigation amount informing device, comprising: an informing unit for informing that the water amount has been reached. 3. A temperature sensor that is installed at a predetermined depth of soil in a field in a facility and that detects the ground temperature and outputs a ground temperature detection signal, an operating unit that is operated when starting watering, and an operation unit that operates the operating unit. Depending on the ground temperature detection means from the temperature sensor to detect the soil temperature immediately before irrigation ground temperature detection means, and the ground temperature detection signal from the temperature sensor to detect the ground temperature after irrigation start soil temperature detection means after irrigation start A temperature drop detecting means for detecting that the soil temperature after starting the irrigation detected by the soil temperature detecting means after the irrigation is lower than the soil temperature immediately before the irrigation by a predetermined value or more; An irrigation control device comprising: water supply control means for starting water supply and stopping water supply according to detection by the temperature decrease detection means to end irrigation.