Paddy field water management device, paddy field water management system, and paddy field water management method

Abstract

To provide a paddy field water management device capable of appropriately managing the growth of rice plants in response to environmental changes such as weather conditions, without increasing the labor burden on a paddy field manager.SOLUTION: The device comprises: an irrigation schedule management unit configured to divide the rice growth period from transplanting to harvest into a plurality of growth stages, generate an irrigation schedule that defines irrigation modes for each growth stage, and update the irrigation schedule based on the accumulated temperature after the transplanting; and a paddy field water level control unit configured to remotely control water level control devices installed in respective paddy fields based on the irrigation schedule, so as to adjust water levels of the respective paddy fields according to the irrigation mode for each growth stage. The paddy field water level control unit is configured to, when rice reaches a specific growth stage according to the irrigation schedule, select whether to adjust the water levels of the respective paddy fields according to the irrigation mode corresponding to the specific growth stage, or to adjust the water levels of the respective paddy fields according to a different specific irrigation mode than the irrigation mode, based on temperature indices of the respective paddy fields.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a field water management device, a field water management system, and a field water management method.

Background Art

[0002] In recent years, in order to address the issues of the departure of skilled farmers and the fragmentation of farmland associated with such departures, the consolidation of fields into larger areas and the mechanization of farming operations are being promoted. Along with this, automation technologies for field water management are also being developed.

[0003] Patent Document 1 discloses a water supply faucet and a drain faucet equipped with a field electric actuator that operates a displacement mechanism for controlling water supply to a field or drainage from a field. By using these water supply faucets and drain faucets, it becomes possible to remotely control water supply to a field and drainage from a field via a field water management device.

[0004] Patent Document 2 discloses a generation device that generates a water level management schedule for controlling water supply and drainage to and from a paddy field and managing the water level of the paddy field. The generation device receives a water level management schedule created by assigning one or more water management elements selected from a plurality of water management elements with different water level management patterns to each of a plurality of divided periods obtained by dividing the management period for managing the water level of the paddy field, and includes a change unit that changes the water level management pattern of the water management elements included in the water level management schedule based on an input from a user.

[0005] The water level management pattern includes information such as the method of managing the water level, the maximum water level, the repetition period of the method of managing the water level, and the start date of the period of the method of managing the water level. The water management elements include constant flooding, water level reduction management, intermittent irrigation, or deep water management, etc.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] By constructing a field water management device that combines a water supply faucet, a drain faucet, and a generation device described in the above-mentioned Patent Documents 1 and 2, it is expected to reduce the labor imposed on a small number of field managers responsible for field water management, that is, to reduce the labor for appropriately managing the water level of the field according to the growth stage of paddy rice.

[0008] However, the growth of paddy rice varies from year to year depending on the environment such as weather conditions. If the water level of the field is uniformly managed according to the water level management schedule set in the field water management device, it is often difficult to cultivate paddy rice appropriately. In such cases, it is extremely contrary to the reduction of labor for the field manager to judge the situation and manually correct the water level management schedule.

[0009] An object of the present invention is to provide a field water management device, a field water management system, and a field water management method that can appropriately grow and manage paddy rice in response to changes in the environment such as weather conditions without causing an increase in the labor of the field manager. [Means for Solving the Problems]

[0010] To achieve the above object, a first characteristic configuration of the paddy field water management device according to the present invention is a paddy field water management device that manages water supply to a paddy field, which divides the growth period of rice from transplantation to harvest into a plurality of growth stages, generates an irrigation schedule that determines an irrigation mode according to each growth stage, and updates the irrigation schedule based on the accumulated temperature after transplantation. A paddy field water level control unit that adjusts the water level of each paddy field so as to achieve the irrigation mode according to the growth period by remotely controlling the water level control equipment provided in each paddy field based on the irrigation schedule. The paddy field water level control unit is configured to select, based on the temperature index of each paddy field, whether to adjust the water level of each paddy field in an irrigation mode corresponding to the specific growth stage or to adjust the water level of each paddy field in a specific irrigation mode different from the irrigation mode when the rice reaches a specific growth stage according to the irrigation schedule.

[0011] The paddy field water level control unit remotely controls the water level control equipment provided in each paddy field according to the irrigation schedule, so that the water level of each paddy field is controlled to an appropriate value. The irrigation schedule divides the growth period of rice from transplantation to harvest into a plurality of growth stages, and determines the irrigation mode of each paddy field according to each growth stage. For example, according to each growth stage such as transplantation, survival period, tillering period, young panicle formation period, meiosis period (early stage of panicle thinning), heading period, ripening period, and harvesting period, irrigation modes such as deep water, shallow water, intermittent irrigation, medium drying, and water drainage are determined.

[0012] The initially generated irrigation schedule may vary according to the meteorological conditions after transplantation. If there is a deviation between the actual growth stage and the irrigation mode specified in the irrigation schedule, it may prevent the growth of rice. Even in such a case, the irrigation schedule is updated by the irrigation schedule management unit based on the accumulated temperature after transplantation, so that the irrigation mode is appropriately managed.

[0013] Then, when the paddy field water level control unit reaches a specific growth stage of the rice based on the irrigation schedule, it selects whether to adjust the water level of each paddy field in an irrigation mode corresponding to the specific growth stage or to adjust the water level of each paddy field in a specific irrigation mode different from the irrigation mode, based on the temperature index of each paddy field. Therefore, even when the temperature index of the paddy field shows an abnormal value, the rice can grow appropriately in an appropriate irrigation mode.

[0014] The second characteristic configuration, in addition to the first characteristic configuration described above, is that when the specific growth stage is the meiosis stage and it is determined based on the temperature index that there is a risk of being affected by cold damage, the paddy field water level control unit selects deep water management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding paddy field.

[0015] When the growth stage is from the young panicle formation stage to the subsequent meiosis stage (early stage of panicle elongation), if it is affected by low temperature, cold damage that inhibits panicle formation will occur. When such a situation is predicted, since it is automatically managed with deep water and the rice is kept warm, the occurrence of cold damage can be appropriately suppressed.

[0016] The third characteristic configuration, in addition to the first characteristic configuration described above, is that when the specific growth stage is the heading and flowering stage and it is determined based on the temperature index that there is a risk of being affected by high temperature damage, the paddy field water level control unit selects continuous - flow irrigation management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding paddy field.

[0017] When the growth stage is the heading and flowering stage and high temperature above 35°C continues, there is a risk of "high temperature damage" occurring, where the rice's water absorption cannot keep up with transpiration, causing the rice to wither and die. When such a situation is predicted, since it is automatically managed with continuous - flow irrigation and the rice is cooled, the occurrence of high temperature damage can be appropriately suppressed.

[0018] The fourth characteristic configuration, in addition to the first characteristic configuration described above, is such that the irrigation schedule management unit is configured to update the irrigation schedule based on a prediction model that predicts the specific growth stage or a growth stage before it based on the accumulated temperature after the transplantation. The prediction model is a regression model obtained by regression analysis with the accumulated temperature from the transplantation date before the previous year until the specific growth stage or a growth stage before it as an explanatory variable and the specific growth stage or a growth stage before it as an objective variable. The accumulated temperature at the time of calculation of the regression model from the transplantation date of the current year is calculated by adopting the daily average temperature of the current year, and the accumulated temperature after the time of calculation is calculated by adopting the predicted temperature or the normal value, so as to predict the time when the specific growth stage or a growth stage before it is reached.

[0019] A regression model obtained by regression analysis with the accumulated temperature from the transplantation date before the previous year until the specific growth stage or a growth stage before it as an explanatory variable and the specific growth stage or a growth stage before it as an objective variable can be adopted as the prediction model. The irrigation schedule management unit can predict the time when the specific growth stage or a growth stage before it is reached by calculating the accumulated temperature at the time of calculation of the regression model from the transplantation date of the current year by adopting the daily average temperature of the current year, and calculating the accumulated temperature after the time of calculation by adopting the predicted temperature or the normal value.

[0020] The fifth characteristic configuration, in addition to the fourth characteristic configuration described above, is that the specific growth stage or a growth stage before it is the start time of the meiosis stage or the end time of the young panicle formation stage.

[0021] Even when there is a risk of cold damage, by appropriately predicting the start time of the meiosis stage or the end time of the young panicle formation stage, it becomes possible to take appropriate countermeasures.

[0022] The sixth characteristic configuration, in addition to the first characteristic configuration described above, is that the temperature index is obtained via the communication unit provided in the field water management device, and any one of the temperature information of the vicinity of each field provided by the weather information providing server, the temperature information of the vicinity of each field provided by the satellite positioning system, or the water temperature information or temperature information of the field detected by the temperature sensors installed in each field is adopted.

[0023] As the temperature index, any one of the temperature information of the vicinity of the field provided by the weather information providing server, the temperature information of the field provided by the satellite positioning system, or the water temperature information or temperature information of the field detected by the temperature sensors installed in each field can be adopted.

[0024] The seventh characteristic configuration, in addition to the first characteristic configuration described above, is that the irrigation schedule is individually set based on the variety information of the paddy rice cultivated in each field and the position information of the cultivation area.

[0025] Since the growth stage of rice is greatly affected by the variety of rice and the position information of the field where it is cultivated, the irrigation schedule needs to be set individually.

[0026] The first characteristic configuration of the field water management system according to the present invention includes a field water management device having any one of the first to seventh characteristic configurations described above, and a water level control device installed in each field, which is communicably connected to the field water management device. The water level control device adjusts the water level of the field based on the control command from the field water level control unit.

[0027] As a result of automatically adjusting the water level of each field in units of a group of fields, the paddy rice transplanted in each field will grow appropriately.

[0028] The first characteristic configuration of the paddy field water management method according to the present invention is a paddy field water management method executed by a paddy field water management device that manages water supply to the paddy field. The growth period of paddy rice from transplantation to harvest is divided into a plurality of growth stages, and a irrigation schedule is generated that determines the irrigation mode according to each growth stage. At the same time, an irrigation schedule management step is performed to update the irrigation schedule based on the accumulated temperature after transplantation. By remotely controlling the water level control devices provided in each paddy field based on the irrigation schedule, a paddy field water level control step is performed to adjust the water level of each paddy field so as to achieve the irrigation mode corresponding to the growth period. The paddy field water level control step is configured to select, based on the temperature index of each paddy field, whether to adjust the water level of each paddy field in the irrigation mode corresponding to the specific growth stage or to adjust the water level of each paddy field in a specific irrigation mode different from the irrigation mode when the paddy rice reaches a specific growth stage according to the irrigation schedule.

[0029] The second characteristic configuration is that, in addition to the first characteristic configuration described above, when the specific growth stage is the meiosis stage and it is determined based on the temperature index that there is a risk of being affected by cold damage, the paddy field water level control step selects deep water management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding paddy field.

[0030] The third characteristic configuration is that, in addition to the first characteristic configuration described above, when the specific growth stage is the heading and flowering stage and it is determined based on the temperature index that there is a risk of being affected by high temperature damage, the paddy field water level control step selects continuous irrigation management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding paddy field.

[0031] The fourth characteristic configuration is, in addition to the first characteristic configuration described above, the irrigation schedule management step is configured to update the irrigation schedule based on a prediction model that predicts the specific growth stage or the growth stage before it based on the accumulated temperature after transplantation, and the prediction model uses, as an explanatory variable, the accumulated temperature from the transplantation date before the previous year until the specific growth stage or the growth stage before it, and is a regression model obtained by regression analysis with the specific growth stage or the growth stage before it as the target variable. The accumulated temperature at the time of calculation of the regression model is calculated by adopting the daily average temperature of the current year from the transplantation date of the current year, and the accumulated temperature after the time of calculation is calculated by adopting the predicted temperature or the normal value, so as to predict the time when the specific growth stage or the growth stage before it is reached.

Advantages of the Invention

[0032] As described above, according to the present invention, it has become possible to provide a paddy field water management device, a paddy field water management system, and a paddy field water management method that can appropriately grow and manage paddy rice in response to environmental variations such as weather conditions without increasing the labor of the field manager.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0034] Hereinafter, a paddy field water management device, a paddy field water management system, and a paddy field water management method according to the present invention will be described. [Configuration of the field water management system] As shown in FIG. 1, in each field 1 where paddy rice cultivation is carried out, a water supply device 12 that guides the water flowing into the water supply pipe 10 to the field 1 through the water conduit 11, a drainage device 22 that drains the water in the field 1 to the drainage channel 20 through the drainage channel 21, and a water level gauge 2 that measures the water level of the field 1 are installed.

[0035] A water level control device for controlling the water level of the field 1 is constituted by the water supply device 12, the drainage device 22, and the water level gauge 2. In this specification, the term "field 1" means a paddy field, and a group of fields 1 supplied with irrigation water from a common water distribution system divided by a water diversion structure or the like from a water source is called a field group.

[0036] The water supply device 12 and the drainage device 22 are connected to the Internet 30 via a wireless router 32 arranged near the field 1, and are configured to be able to communicate with the field water management server 40 via the Internet 30. Further, the field water management server 40 is configured to be able to communicate with the weather information providing server 50 via the Internet 30, and is configured to be able to communicate with a terminal device 60 such as a smartphone owned by the administrator of each field 1.

[0037] The field water management server 40 functions as the field water management device of the present invention, and the field water management system 100 of the present invention is constituted by the water supply device 12 and the drainage device 22 connected via the Internet 30, the field water management server 40, the weather information providing server 50, and the terminal device 60. The field water management server 40 manages the stored water level of each field 1 in units of field groups.

[0038] The field water management server 40 is constituted by a cloud server provided with a CPU board, a memory board, a communication board, etc., and the desired field water management function is realized by executing a field water management program stored in a memory provided in the memory board by a CPU provided in the CPU board. Note that the field water management system 100 can also be configured using other known communication networks other than the Internet 30.

[0039] It is necessary to variably adjust the water storage level of the paddy field 1 according to each process and growth stage of rice cultivation, for example, harrowing, transplantation (rice planting), survival period, tillering stage (early stage, late stage), young panicle formation stage to heading and flowering stage, ripening stage, harvesting, etc.

[0040] For example, until survival after transplantation, adjust the water depth to about 5 - 7 cm so that the seedlings are not submerged, and protect the seedlings with the heat preservation effect of water. Then, when entering the tillering stage of increasing the stems, set the water depth to about 2 - 4 cm to raise the ground temperature and promote the occurrence of tillering. Intermittently irrigate in the late tillering stage, and drain the water when the tillering is about to end to dry the middle part, thereby supplying oxygen to the soil and promoting the growth of healthy roots.

[0041] After that, perform intermittent irrigation by repeating flooding and draining to promote the growth of roots and stems, and conduct shallow water management from the young panicle formation stage to the meiosis stage (early stage of panicle thinning). In cold regions, when the temperature becomes low during the meiosis stage (early stage of panicle thinning), the growth of panicles will be damaged by cold damage, so it is necessary to conduct deep water management to strive for heat preservation. Furthermore, conduct shallow water management during the heading to flowering stage to promote flowering, pollination, and fertilization. When it comes to the ripening stage, perform intermittent irrigation again to grow the rice grains, and drain the water 1 - 2 weeks before harvesting. In addition, for water management from the young panicle formation stage to the meiosis stage, in addition to the aforementioned shallow water management, there is a method of performing intermittent irrigation, and the paddy field manager appropriately judges according to the growth environment such as the growth status of rice and meteorological information.

[0042] Such a management water level of the paddy field 1 not only varies depending on the growth stage of rice, but also varies depending on the variety and whether the cultivation area is a warm region or a cold region. Therefore, the paddy field manager needs to perform the complicated task of monitoring the growth stage of rice, meteorological information such as the temperature at that time, and appropriately adjusting the water level of the paddy field 1. However, it requires a great deal of labor for a small number of paddy field managers to monitor the water storage level of the paddy field and the growth status of rice in a large - scale paddy field 1. Therefore, the paddy field water management system 100 of the present invention is utilized.

[0043] As shown in FIGS. 1 and 2, the water supply device 12 includes a water supply faucet 12A installed in the water supply trough 101 and a water supply control device 12B detachably attached to the water supply faucet 12A from above. The water supply control device 12B is housed in a waterproof casing and includes an actuator 120 that opens and closes the water supply faucet 12A, a water supply control unit 122 that controls the actuator 120, a communication unit 124, and a storage battery 126. A solar cell 128 for charging the storage battery 126 is attached to the top surface of the casing.

[0044] The water supply control unit 122 communicates with the field water management server 40 via the communication unit 124, and controls the actuator 120 in response to a control command from the field water management server 40, thereby controlling the valve provided in the water supply faucet 12A to a predetermined opening degree, and transmitting information such as the opening / closing state of the water supply faucet 12A and the stored water level of the field 1 measured by the water level gauge 2 to the field water management server 40.

[0045] The drainage device 22 includes a drainage weir 22A installed in the drainage trough 201 and a drainage control device 22B detachably attached to the drainage weir 22A from above. The drainage control device 22B is housed in a waterproof casing and includes an actuator 220 that raises and lowers the drainage weir 22A, a drainage water level control unit 222 that controls the actuator 220, a communication unit 224, and a storage battery 226. A solar cell 228 for charging the storage battery 226 is attached to the top surface of the casing.

[0046] The drainage water level control unit 222 communicates with the field water management server 40 via the communication unit 224, and controls the actuator 220 in response to a control command from the field water management server 40, thereby adjusting the raising and lowering height of the drainage weir 22A to the target water level. The stored water level of the field 1 is adjusted by the raising and lowering height of the drainage weir 22A.

[0047] The field water management server 40 includes a field water level control unit 42 and an irrigation schedule management unit 44, and manages the water supply to each field 1 in units of a field group composed of a plurality of fields 1. A field water management server 40 may be constructed for each field group, or one field water management server 40 that controls a plurality of field groups may be constructed.

[0048] The irrigation schedule management unit 44 divides the growth period of paddy rice from transplantation to harvest into a plurality of growth stages, initially generates an irrigation schedule that determines the irrigation mode for each field according to each growth stage, and stores and manages it in the memory on the memory board provided in the field water management server 40. Further, the irrigation schedule management unit 44 is provided with a prediction model 46 that predicts a specific growth stage based on the accumulated temperature after transplantation, and an irrigation schedule update unit 48 that updates the irrigation schedule based on the prediction model 46.

[0049] In addition to the field management information such as the unique identification information of each field 1 included in the field group, the administrator information, the unique identification information of the water supply device 12 and the drainage device 22 installed in each field, and the water level information, the memory on the memory board provided in the field water management server 40 stores a standard irrigation schedule corresponding to a plurality of types of rice grown in each field 1 and the like.

[0050] The irrigation schedule divides the growth period of paddy rice from transplantation to harvest into a plurality of growth stages, and determines the irrigation mode for each field according to each growth stage. For example, according to each growth stage such as transplantation, seedling establishment period, tillering period, young panicle formation period, meiosis period (early stage of panicle thinning), heading period, ripening period, and harvesting period, irrigation modes such as deep water, shallow water, intermittent irrigation, medium drying, and water drainage are determined. Each growth stage and irrigation mode are not limited to those described above. In addition, in deep water management and shallow water management, the water level may be individually set according to each growth stage, and even in deep water management, the water level may be set to different values.

[0051] Figure 3 shows an example of the irrigation schedule from transplantation to harvest. Starting from the transplantation date, growth periods such as establishment, tillering, young panicle formation, meiosis, heading and flowering, and ripening are set according to the predetermined number of elapsed days, and the water storage level, which is the irrigation mode of Field 1, is set according to each growth period. The transplantation date is set from May to June depending on the region where Field 1 is located, and the harvest period is set from September to October. When the temperature drops below 17°C during the meiosis period (pre-booting stage), cold damage occurs, which inhibits the growth of the panicles. Therefore, it is necessary to keep the rice warm by deep water management during such low-temperature periods.

[0052] In addition, during the heading and flowering period, etc., if the temperature during the day or at night exceeds about 35°C, there is a risk of "high-temperature damage" occurring, where the water absorption of the rice cannot keep up with transpiration, causing the rice to wilt and wither. When the stomata of the leaves close to prevent transpiration, photosynthesis also stops, growth halts, and eventually the rice will wither. To avoid such high-temperature damage, it is also necessary to flush the water for cooling.

[0053] The field water level control unit 42 manages the growth of rice while reducing the burden on the field manager by remotely controlling the water level control devices provided in each field 1 based on the field management information and the irrigation schedule to adjust the water level of each field 1.

[0054] However, the rice does not always grow according to the initially set irrigation schedule, and the growth situation may vary according to the meteorological conditions after transplantation. If there is a deviation between the actual growth stage and the timing of the irrigation mode specified in the irrigation schedule, it may actually hinder the growth of the rice. In such a case, it is very cumbersome for the field manager to access the field water management server 40 using the terminal device 60 to manually correct the irrigation schedule.

[0055] Therefore, it is configured to update the irrigation schedule based on the accumulated temperature after transplantation by the prediction model 46 provided in the irrigation schedule management unit 44 and the irrigation schedule update unit 48. The prediction model 46 is a model that predicts a specific growth stage or a growth stage before it based on the accumulated temperature after transplantation. The prediction model is a regression model obtained by regression analysis using, as explanatory variables, the accumulated temperature from the transplantation date before the previous year until a specific growth stage or a stage before it, and using, as the objective variable, the specific growth stage or a stage before it.

[0056] The irrigation schedule update unit 48 calculates the accumulated temperature at the time of calculating the regression model from the transplantation date of the current year by adopting the daily average temperature of the current year, and calculates the accumulated temperature after the calculation time by adopting the predicted temperature or the normal value, thereby predicting the time to reach a specific growth stage. The irrigation schedule update unit 48 updates the scheduled date of a specific growth stage or a growth stage before it in the irrigation schedule to the predicted date, and updates each subsequent growth stage based on the predicted date of the specific growth stage and the number of days elapsed thereafter. The field water level control unit 42 adjusts the water level of each field 1 based on the updated irrigation schedule.

[0057] As shown in FIG. 4(a), as the prediction model 46, a first-order regression model obtained by regression analysis using, as explanatory variables, the accumulated temperature from the transplantation date before the previous year until the panicle initiation stage, and using, as the objective variable, the panicle initiation stage can be adopted. In this case, the panicle initiation stage is a specific growth stage or a growth stage before it. For example, when it is necessary to grasp the start of the meiosis stage as a specific growth stage, the panicle initiation stage, which is the growth stage immediately before it, is predicted. Therefore, the start of the meiosis stage may be used as the objective variable.

[0058] The regression model is a regression equation obtained as a result of machine learning using, as teacher data, the accumulated temperature from the transplantation date in the past ten years until the panicle initiation stage. A first-order regression equation showing the accumulated temperature on the vertical axis and the transplantation date on the horizontal axis is indicated by a broken line. The regression equation is y = -2.5639x + 116459, coefficient of determination R 2It is 0.9832. In this example, the value on the horizontal axis is set with January 1, 1900 as "1", and the corresponding transplantation date is taken as the number of days elapsed from January 1, 1900. For example, when transplanting on May 24, it can be estimated that the point when the accumulated temperature reaches 905 °C arrives at the panicle initiation stage. Note that the coefficients of the regression equation change depending on the setting mode of the scale on the horizontal axis.

[0059] The irrigation schedule update unit 48 predicts the date when the end of the panicle initiation stage arrives using the prediction model 46 before reaching the meiosis stage (pre-heading stage). Therefore, as the daily average temperature for obtaining the accumulated temperature at the time of calculation of the prediction model 46 from the transplantation date of the current year, the measured value of the daily average temperature obtained from the meteorological information providing server 50 (the average value of 24 hours of the average temperature obtained from the meteorological information providing server 50 every 4 hours) is adopted, and the predicted temperature or normal year value obtained from the meteorological information providing server 50 is adopted as the daily average temperature for obtaining the accumulated temperature after the time of calculation. For example, the predicted temperature that can be obtained from the meteorological information providing server 50 can be adopted as the daily average temperature up to one week ahead, and the normal year value can be adopted as the daily average temperature after that when the daily average temperature cannot be obtained from the meteorological information providing server 50.

[0060] Based on the panicle initiation stage predicted by the irrigation schedule update unit 48 using the prediction model 46, the time of the panicle initiation stage defined in the irrigation schedule is corrected, and the times of subsequent growth stages such as the meiosis stage (pre-heading stage) are updated according to the number of days elapsed from the corrected panicle initiation stage.

[0061] The paddy field water level control unit 42 is configured to select, based on the temperature index of each paddy field 1, whether to adjust the water level of each paddy field 1 in an irrigation mode corresponding to a specific growth stage or to adjust the water level of each paddy field 1 in a specific irrigation mode different from the irrigation mode when the rice reaches a specific growth stage based on the updated irrigation schedule. The irrigation mode corresponding to a specific growth stage is the irrigation mode defined in the irrigation schedule.

[0062] Specifically, when the specific growth stage is the meiosis stage (pre-heading stage) and it is determined based on the temperature index that there is a risk of being affected by cold damage, the field water level control unit 42 selects deep water management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding field 1.

[0063] When the growth stage predicted in the irrigation schedule is from the end of the young panicle formation stage to the subsequent meiosis stage (early heading stage) and it is determined based on the temperature index that there is a risk of being affected by cold damage, the field water level control unit 42 remotely controls the water level control device of the corresponding field 1 to perform deep water management to a predetermined level, for example, about 15 cm, for a predetermined period.

[0064] When the growth stage is from the young panicle formation stage to the subsequent meiosis stage (early heading stage) and is affected by low temperature, cold damage that inhibits panicle formation occurs. When such a situation is predicted, by performing deep water management to keep the paddy rice warm, the occurrence of cold damage can be automatically and appropriately suppressed. That is, if the specific growth stage predicted by the prediction model 46 is the young panicle formation stage or the meiosis stage (early heading stage), the occurrence of cold damage in the meiosis stage (early heading stage) can be accurately and surely avoided.

[0065] In this embodiment, the predicted temperature, which is the temperature information near the field (weather information with a 1 km mesh size) obtained from the weather information providing server 50, is adopted as the temperature index. For example, when the predicted temperature is 17°C or lower, deep water management is performed for a predetermined period starting from the night before the predicted day of the meiosis stage (early heading stage). As the predetermined period, for example, the period of the meiosis stage (early heading stage) can be adopted, or the period until the predicted temperature becomes higher than a temperature without the risk of cold damage (for example, 20°C) can be adopted. Also, a predetermined number of days can be used as the predetermined period.

[0066] The above irrigation schedule is individually set based on at least variety information and the location information of the field, which is the cultivation area. This is because the growth stages vary depending on the variety and the cultivation area. In the field water management server 40, a basic irrigation schedule is pre-stored according to the type of rice grown in each field 1. When the transplanting date of each field 1 is input from the terminal device 60 of the field manager, an irrigation schedule is generated with the growth stage based on the transplanting date determined.

[0067] Fig. 5 shows the procedure for cold damage avoidance executed by the field water management device 40. When an irrigation schedule is generated in the field water management server 40 (S1), and after the seedlings are transplanted, the transplanting date is input to the field water management server 40 via the terminal device 60 of the field manager (S2, Y). Based on the number of days elapsed after the transplanting date, the arrival times of each growth stage are set and the irrigation schedule is finalized. Then, irrigation control is executed based on the finalized irrigation schedule (S3). Further, at a predetermined interval, the irrigation schedule update unit 48 predicts the arrival time of a specific growth stage based on the prediction model and updates the irrigation schedule (S4). The predetermined interval is set as appropriate and may be in units of one day or in units of several days.

[0068] When reaching the young panicle formation stage, which is a specific growth stage (S5, Y), the corresponding field 1 is intermittently irrigated by the field water level control unit 42 (S8). When ending the young panicle formation stage and entering the meiosis stage (early stage of panicle spreading) (S5, N), if it is determined that there is a risk of cold damage based on the temperature index of field 1 (S6, Y), the corresponding field 1 is managed with deep water by the field water level control unit 42 (S6). If it is determined that there is a risk of cold damage (S6, N), the corresponding field 1 is managed with shallow water by the field water level control unit 42 (S9).

[0069] Figure 4(b) shows another example of the prediction model 46. A first-order regression model obtained by regression analysis using the accumulated temperature from the transplanting date to the heading date before the previous year as an explanatory variable and the heading date as an objective variable is adopted. The heading date is a specific growth stage or a previous growth stage. The regression model is also a regression equation obtained as a result of machine learning using the accumulated temperature from the transplanting date to the heading date in the past ten years as teacher data. A first-order regression equation showing the accumulated temperature on the vertical axis and the transplanting date on the horizontal axis is indicated by a broken line. The regression equation is y = -3.3608x + 152940, and the coefficient of determination R 2 = 0.9885. In this example as well, the value on the horizontal axis is set with January 1, 1900 as "1", and the corresponding transplanting date is the number of days elapsed from January 1, 1900. For example, if transplanting is done on May 24, it can be estimated that the heading date is reached when the accumulated temperature reaches 1470 °C.

[0070] When the irrigation schedule is updated with the prediction model 46 shown in this example, the meiosis stage is predicted by going back a predetermined number of days from the predicted heading date. The more days are gone back, the worse the prediction accuracy becomes, but it becomes possible to cope with cold damage more appropriately than when using the initially generated irrigation schedule.

[0071] When the irrigation schedule is updated with the prediction model 46 shown in this example, countermeasures against "high-temperature damage" can be carried out well. When the field water level control unit 42 reaches the heading and flowering stage based on the prediction model 46 and the average temperature near the field obtained from the meteorological information providing server 50 exceeds about 35 °C, it is determined that there is a risk of "high-temperature damage" occurring, and the water level control device of the corresponding field 1 can be remotely controlled to perform high-temperature flushing control.

[0072] Figure 6 shows the control procedure for avoiding high-temperature damage. A watering schedule is generated in the field water management server 40 (S11). When the seedlings are transplanted, the transplantation date is input to the field water management server 40 via the terminal device 60 of the field manager (S12, Y). Based on the number of days elapsed since the transplantation date, the arrival times of each growth stage are set, and the watering schedule is finalized. Then, watering control is executed based on the finalized watering schedule (S13). Further, at a predetermined interval, the arrival time of a specific growth stage based on the prediction model is predicted by the watering schedule update unit 48, and the watering schedule is updated (S14).

[0073] When reaching the heading stage, which is a specific growth stage (S15), it is determined whether there is a risk of high-temperature damage based on the temperature index of field 1. If it is determined that there is a risk of high-temperature damage (S16, Y), the corresponding field 1 is managed by flushing by the field water level control unit 42 (S17). If it is determined that there is no risk of high-temperature damage (S16, N), the corresponding field 1 is managed with shallow water by the field water level control unit 42 (S18).

[0074] As described above, the field water management method according to the present invention is executed by the field water management server 40. The growth period of paddy rice from transplantation to harvest is divided into a plurality of growth stages, and a watering schedule is generated that defines the watering mode according to each growth stage. At the same time, a watering schedule management step is provided to update the watering schedule based on the accumulated temperature after transplantation. A field water level control step is provided to adjust the water level of each field so as to achieve a watering mode corresponding to the growth period by remotely controlling the water level control device provided in each field based on the watering schedule. The field water level control step is configured to select, based on the temperature index of each field, whether to adjust the water level of each field in a watering mode corresponding to a specific growth stage or to adjust the water level of each field in a specific watering mode different from the watering mode when the paddy rice reaches a specific growth stage based on the watering schedule.

[0075] When it is determined that a specific growth stage is the meiosis stage and there is a risk of being affected by cold damage based on the temperature index, the paddy field water level control step selects deep water management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding paddy field.

[0076] When it is determined that a specific growth stage is the heading and flowering stage and there is a risk of being affected by high temperature damage based on the temperature index, the paddy field water level control step selects continuous irrigation management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding paddy field.

[0077] The irrigation schedule management step is configured to update the irrigation schedule based on a prediction model that predicts a specific growth stage based on the accumulated temperature after transplantation. The prediction model is a regression model obtained by regression analysis with the accumulated temperature from the previous transplantation date to the specific growth stage as the explanatory variable and the specific growth stage as the target variable. The accumulated temperature from the transplantation date of the current year to the accumulated temperature at the time of calculating the regression model is calculated by adopting the daily average temperature of the current year, and the accumulated temperature after the calculation time is calculated by adopting the predicted temperature or the normal year value, so as to predict the time to reach a specific growth stage.

[0078] Hereinafter, another embodiment of the present invention will be described. In the above-described embodiment, the young panicle formation stage, meiosis stage, and heading stage are exemplified as the specific growth stages predicted by the prediction model 46, but other growth stages may also be predicted.

[0079] In the above-described embodiment, the case where the drainage device 22 in which the height of the drainage weir 22A can be remotely controlled by the field water management server 40 has been described. However, the present invention can also be applied to a drainage device 22 in which the height of the drainage weir 22A is manually adjusted. For example, when it is necessary to manage deep water, if the field manager adjusts the height of the drainage weir 22A to a height suitable for deep water management in advance, it is also possible to easily perform shallow water management by controlling the water supply amount based on the value of the water level gauge 2. Further, if the field manager adjusts the height of the drainage weir 22A to a height suitable for shallow water management in advance, intermittent irrigation is also possible by performing water supply control in consideration of the influence of the water depth reduction. In this case, a certain degree of load will be imposed on the field manager.

[0080] As the temperature index, in addition to the predicted air temperature which is the air temperature information near the field obtained from the weather information providing server 50, the temperature information near the field 1 provided by a satellite positioning system such as GPS, or the water temperature information or air temperature information of the field 1 detected by the temperature sensor installed in each field 1 may be adopted.

[0081] The detected temperature by the temperature sensor installed in the field 1 can be configured to be transmitted to the field water management server 40 via the water supply control device 12B or the drainage control device 22B, and the temperature sensor may be provided with a communication function.

[0082] In the above-described embodiment, the measured water level by the water level gauge 2 is configured to be transmitted to the field water management server 40 via the water supply device 12. However, the water level gauge 2 may be transmitted to the field water management server 40 via the drainage device 22, or the water level gauge 2 may be configured to be able to communicate directly with the field water management server 40.

[0083] The embodiments described above are merely examples of the present invention, and it is not intended that the technical scope of the present invention be limited by the description. Needless to say, the specific configuration of the field water management device can be appropriately changed and designed within the range in which the effects of the present invention are achieved.

Explanation of Reference Numerals

[0084] 1: Field 12: Water supply device 12A: Water tap 12B: Water supply control device 22: Drainage device 22A: Drainage weir 22B: Drainage control device 40: Field error management server 42: Field water level control unit 44: Irrigation schedule management unit 46: Prediction model 48: Irrigation schedule update unit 50: Weather information providing server 60: Mobile terminal 100: Field water management system

Claims

1. A paddy field water management device for managing water supply to a paddy field, which divides the growth period of paddy rice from transplantation to harvest into a plurality of growth stages, generates an irrigation schedule that defines an irrigation mode according to each growth stage, and updates the irrigation schedule based on the accumulated temperature after transplantation, an irrigation schedule management unit; a paddy field water level control unit that adjusts the water level of each paddy field so as to achieve the irrigation mode corresponding to the growth period by remotely controlling the water level control equipment provided in each paddy field based on the irrigation schedule; comprising: the paddy field water level control unit is configured to select, based on the temperature index of each paddy field, whether to adjust the water level of each paddy field in an irrigation mode corresponding to the specific growth stage or to adjust the water level of each paddy field in a specific irrigation mode different from the irrigation mode when the paddy rice reaches a specific growth stage based on the irrigation schedule. A paddy field water management device.

2. The paddy field water level control unit according to claim 1, wherein when the specific growth stage is the meiosis stage and it is determined that there is a risk of being affected by cold damage based on the temperature index, deep water management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding paddy field, is selected.

3. The paddy field water level control unit according to claim 1, wherein when the specific growth stage is the heading and flowering stage and it is determined that there is a risk of being affected by high temperature damage based on the temperature index, flowing water management, which is a specific irrigation mode different from the shallow water management that is the irrigation mode of the corresponding paddy field, is selected.

4. The irrigation schedule management unit is configured to update the irrigation schedule based on a prediction model that predicts the specific growth stage or the growth stage before it based on the accumulated temperature after transplantation. The prediction model is a regression model obtained by regression analysis using the accumulated temperature from the transplantation date before the previous year to the specific growth stage or the growth stage before it as an explanatory variable and the specific growth stage or the growth stage before it as an objective variable. The time when the specific growth stage or the growth stage before it is reached is predicted by calculating the accumulated temperature at the time of calculation of the regression model from the transplantation date of the current year by adopting the daily average temperature of the current year and calculating the accumulated temperature after the time of calculation by adopting the predicted temperature or the normal value. The paddy field water management device according to claim 1.

5. The field water management device according to claim 4, wherein the specific growth stage or the growth stage before that is the start time of meiosis or the end time of young panicle formation.

6. The temperature index is obtained through the communication unit provided in the field water management device, and any of the temperature information near each field provided by a meteorological information providing server, the temperature information near each field provided by a satellite positioning system, or the water temperature information or temperature information of the field detected by a temperature sensor installed in each field is adopted. The field water management device according to claim 1.

7. The irrigation schedule of the field water management device according to claim 1 is individually set based on the variety information of the paddy rice cultivated in each field and the position information of the cultivation area.

8. The field water management device according to any one of claims 1 to 7, A water level control device installed in each field, which is communicably connected to the field water management device, comprising The water level control device adjusts the water level of the field based on a control command from the field water level control unit. A field water management system.

9. A field water management method executed by a field water management device for managing water supply to a field, Dividing the growth period of paddy rice from transplanting to harvesting into a plurality of growth stages, generating an irrigation schedule that determines the irrigation mode according to each growth stage, and updating the irrigation schedule based on the accumulated temperature after transplanting. An irrigation schedule management step; A field water level control step of adjusting the water level of each field so as to achieve the irrigation mode corresponding to the growth period by remotely controlling the water level control device provided in each field based on the irrigation schedule. comprising The field water level control step is configured to select, based on the temperature index of each field, whether to adjust the water level of each field in an irrigation mode corresponding to the specific growth stage or in a specific irrigation mode different from the irrigation mode when the paddy rice reaches a specific growth stage according to the irrigation schedule. A field water management method.

10. When the specific growth stage is the meiosis stage and it is determined based on the temperature index that there is a risk of being affected by cold damage, the field water management method according to claim 9, which selects deep water management, which is a specific irrigation mode different from the shallow water management, which is the irrigation mode of the corresponding field.

11. The paddy field water level control step is the paddy field water management method according to claim 9, which selects continuous irrigation management, which is a specific irrigation mode different from shallow water management, which is the corresponding paddy field irrigation mode, when it is determined that the specific growth stage is the heading and flowering stage and there is a risk of being affected by high temperature damage based on the temperature index.

12. The irrigation schedule management step is configured to update the irrigation schedule based on a prediction model that predicts the specific growth stage based on the accumulated temperature after transplantation. The prediction model is a regression model obtained by regression analysis with the accumulated temperature from the transplantation date before the previous year to the specific growth stage as the explanatory variable and the specific growth stage as the target variable. The accumulated temperature at the time of calculation of the regression model from the transplantation date of the current year is calculated by adopting the daily average temperature of the current year, and the accumulated temperature after the time of calculation is calculated by adopting the predicted temperature or the normal year value, so as to predict the time when the specific growth stage is reached. The paddy field water management method according to claim 9.

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