Irrigation system

Abstract

To provide an irrigation system and control device capable of ensuring life and supplying liquid fertilizer.SOLUTION: An irrigation system 1 has a sub-path 17 including a passage that branches off upstream from a water supply pipe 130 through which irrigation water flows to be supplied to plants and merges further downstream. The system has a liquid fertilizer suction unit 16 that draws liquid fertilizer into the sub-path 17 using the suction force of the fluid flowing down the sub-path 17, and an automatic flow control valve 171 that controls the flow rate of the fluid flowing down the sub-path 17. The automatic flow control valve 171 is provided in the sub-path upstream of the mixing point where the liquid fertilizer sucked by the liquid fertilizer suction unit flows into the sub-path.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The disclosure in this specification relates to an irrigation system that controls the supply of liquid fertilizer to an irrigation path for growing plants. [Background technology]

[0002] Patent Document 1 discloses an irrigation system that controls the amount of liquid fertilizer supplied to an irrigation passage by turning a valve on and off. In addition, since highly acidic liquid fertilizer flows through the irrigation passage, parts such as pumps and valves come into direct contact with the liquid fertilizer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] European Patent Application Publication No. 3970469 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 has room for improvement in terms of suppressing deterioration of parts such as pumps that may come into contact with highly concentrated liquid fertilizer, and in terms of controlling the supply of liquid fertilizer with high precision.

[0005] An object of the disclosure in this specification is to provide an irrigation system that can ensure a long life and supply liquid fertilizer. [Means for solving the problem]

[0006] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference symbols in parentheses in the claims and in this section are merely examples showing the corresponding relationship with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope.

[0007] One of the disclosed irrigation systems comprises a main path (130) through which irrigation water flows to be supplied to plants, a secondary path (17) including a passage that branches off upstream from the main path and merges further downstream, a liquid fertilizer suction section (16) that draws liquid fertilizer into the secondary path using the suction force of the fluid flowing down the secondary path, and a flow rate adjustment mechanism section (171, 171A, 174) provided in the secondary path upstream of a mixing point where the liquid fertilizer sucked up by the liquid fertilizer suction section flows into the secondary path, and controls the flow rate of the fluid flowing down the secondary path.

[0008] According to this, the flow rate adjustment mechanism is provided upstream of the mixed flow area where the liquid fertilizer flows in the sub-path. This prevents the components of the flow rate adjustment mechanism from coming into direct contact with the liquid fertilizer. This provides an irrigation system that can ensure a long life and supply liquid fertilizer. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a configuration diagram of an irrigation system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing a liquid fertilizer supply section of the first embodiment. [Diagram 3] FIG. 2 is a block diagram showing a control unit. [Figure 4] FIG. 11 is a cross-sectional view showing a valve device applicable as a flow control valve of a second embodiment. [Diagram 5] 3 is a diagram showing a configuration of a drive unit included in the valve device. FIG. [Figure 6] FIG. 2 is a perspective view showing a valve provided in the valve device. [Figure 7] FIG. 4 is a diagram showing the relationship between the rotation angle and the flow rate in the valve device. [Figure 8] FIG. 11 is a diagram showing an example of a liquid fertilizer supplying section of the second embodiment. [Figure 9] FIG. 11 is a diagram showing an example of a liquid fertilizer supplying section of the second embodiment. [Figure 10] FIG. 2 is a block diagram showing a control unit. [Figure 11] 4 is a flowchart showing an example of the operation of the irrigation system. [Figure 12] FIG. 13 is a diagram showing an example of a liquid fertilizer supplying section of the third embodiment. [Figure 13] FIG. 13 is a diagram showing an example of a liquid fertilizer supplying section of the third embodiment. [Figure 14] FIG. 2 is a block diagram showing a control unit. [Figure 15] 4 is a flowchart showing an example of the operation of the irrigation system. [Figure 16] FIG. 13 is a diagram showing an example of an irrigation system according to a fourth embodiment. [Figure 17] FIG. 13 is a diagram showing an example of an irrigation system according to a fourth embodiment. [Figure 18] FIG. 2 is a block diagram showing a control unit. [Figure 19] 4 is a flowchart showing an example of the operation of the irrigation system. [Figure 20] FIG. 13 is a diagram showing an example of an irrigation system according to a fifth embodiment. [Figure 21] FIG. 13 is a diagram showing an example of an irrigation system according to a fifth embodiment. [Figure 22] FIG. 2 is a block diagram showing a control unit. [Figure 23] 4 is a flowchart showing an example of the operation of the irrigation system. [Figure 24] FIG. 13 is a diagram showing an example of an irrigation system according to a sixth embodiment. [Diagram 25] FIG. 13 is a diagram showing an example of an irrigation system according to a sixth embodiment. [Figure 26] FIG. 2 is a block diagram showing a control unit. [Figure 27] 4 is a flowchart showing an example of the operation of the irrigation system. [Figure 28] FIG. 13 is a diagram showing an example of an irrigation system according to a seventh embodiment. [Figure 29] FIG. 13 is a diagram showing an example of an irrigation system according to a seventh embodiment. [Diagram 30] FIG. 2 is a block diagram showing a control unit. [Diagram 31] 4 is a flowchart showing an example of the operation of the irrigation system. [Diagram 32] FIG. 23 is a diagram showing an example of a liquid fertilizer supplying section of the eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a number of embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, other embodiments described previously may be applied to other parts of the configuration. In addition to combinations of parts that are specifically indicated as being possible in each embodiment, it is also possible to partially combine embodiments even if not indicated, as long as there is no particular problem with the combination.

[0011] First embodiment A first embodiment disclosing an example of an irrigation system will be described with reference to Figs. 1 to 7. The irrigation system 1 includes a means for supplying liquid fertilizer to a main water supply pipe at the liquid fertilizer supply timing for carrying out fertilization. First, the irrigation operation carried out by the irrigation system 1 shown in Fig. 1 will be described, and a liquid fertilizer supplying unit 120 configured to supply liquid fertilizer to the water supply pipe will be described later. The liquid fertilizer supplying unit 120 will be described with reference to Figs. 2 and 3. In the following, three directions that are mutually orthogonal are referred to as the x-direction, the y-direction, and the z-direction. In this specification, the plane defined by the x-direction and the y-direction is along the horizontal plane. The z-direction is along the vertical direction.

[0012] <Field> The irrigation system 1 is applied to a field 20 cultivated outdoors on a hill or a plain. As shown in FIG. 1, an embodiment in which the irrigation system 1 is applied to a field 20 cultivated on a plain will be described. The field 20 has a plurality of growing areas such as ridges extending in the x direction. These growing areas extending in the x direction are spaced apart in the y direction. Plant seeds or seedlings are buried in each of these growing areas. The irrigation system 1 may be configured to be applied to a field 20 provided indoors, such as a greenhouse. Therefore, the field 20 in this specification can be applied to soil provided either outdoors or indoors.

[0013] A plurality of plants are grown in one growing area. A growing area is a furrow in which the plurality of plants are grown. The plurality of plants are lined up in a row in the x direction. In the following, the plurality of plants lined up in a row in the x direction will be referred to as a group of plants. In the field 20, the plurality of groups of plants are lined up at intervals in the y direction. The minimum distance between the plurality of groups of plants in the y direction is longer than the minimum distance between the plurality of plants included in one group of plants in the x direction. The distance between the plurality of groups of plants in the y direction is changed in various ways depending on the type of plants growing and the topography and climate of the field 20.

[0014] <Irrigation system> The irrigation system 1 includes a water supply device 100 and a control device 200. The water supply device 100 supplies irrigation water to plants in a field 20. The control device 200 determines the time and amount of irrigation water to be supplied from the water supply device 100 to the plants during a watering period. The control device 200 determines the irrigation schedule for the water supply device 100.

[0015] <Water supply device> The water supply device 100 includes a pump 110, a water supply pipe 130, etc. The pump 110 is a water supply source that causes irrigation water to flow down the water supply pipe 130.

[0016] <Pump> The pump 110 is in a constantly operating state. Alternatively, the pump 110 is in a daytime operating state. The operation and stopping of the pump 110 are controlled by the control device 200. The pump 110 pumps out irrigation water stored in a tank or a reservoir as a water source, and supplies it to the water supply pipe 130. The irrigation water is, for example, well water, river water, rainwater, city water, etc. The water supply pipe 130 is provided with a plurality of water supply valves 15 capable of controlling the flow rate of the irrigation water discharged to the field 20. When these water supply valves 15 are in a closed state and there is no leakage of irrigation water from the water supply pipe 130, the water supply pipe 130 is filled with irrigation water. At this time, the water pressure in the water supply pipe 130 becomes a value (hereinafter, pump pressure) that depends on the discharge capacity of the pump 110. When the water supply valve 15 changes from a closed state to an open state, irrigation water is discharged from the water supply pipe 130 to the field 20. When the amount of irrigation water discharged becomes stable on a time average, the water pressure in the water supply pipe 130 becomes a flow pressure that is lower than the pump pressure.

[0017] <Water supply piping> The water supply pipe 130 includes a main pipe. The main pipe is connected to a pump 110. The pump 110 supplies irrigation water to the main pipe. The irrigation water is supplied to the field 20 via the main pipe.

[0018] <Main piping> The main pipe includes a vertical pipe 131 and a first connecting pipe 132. The vertical pipe 131 extends in the y direction. The first connecting pipe 132 extends in the x direction. The vertical pipe 131 and the first connecting pipe 132 are connected to each other. Due to this configuration, irrigation water flows in the y direction and the x direction within the main pipe. In the example shown in FIG. 1, one vertical pipe 131 is connected to one pump 110. A plurality of first connecting pipes 132 extend from the vertical pipe 131 extending in the y direction.

[0019] 1 is merely one example of a passage configuration for irrigation. The number of pumps 110 and vertical pipes 131 provided in the field 20, the number of vertical pipes 131 connected to one pump 110, the number of vertical pipes 131 connected to one first connecting pipe 132, and the positions of the first connecting pipes 132 and the vertical pipes 131 in the z direction are not particularly limited.

[0020] The multiple first connecting pipes 132 are lined up at a distance in the y direction. The shortest distance between the multiple first connecting pipes 132 in the y direction is set to be equal to the shortest distance between the multiple plants in the y direction. One first connecting pipe 132 is provided corresponding to one of the plants. The first connecting pipe 132 extends along the direction in which the multiple plants included in the plants are lined up. A supply pipe is connected to this first connecting pipe 132.

[0021] The irrigation system 1 has a plurality of distribution tubes that discharge irrigation water downstream of the first connecting pipe 132 in the water supply path. Each distribution tube is an example of a supply pipe that supplies irrigation water to plants in the field 20. Each distribution tube is installed at a position where it can supply irrigation water to ridges provided in the field 20. The distribution tubes may be configured to have a pressure compensation mechanism that realizes a constant water discharge amount regardless of changes in water pressure, or may not be configured to have a pressure compensation mechanism.

[0022] The distribution tube is formed with a plurality of through holes that communicate the inside and outside of the tube through which irrigation water flows. The plurality of through holes are arranged in each tube at a predetermined interval in the axial direction of the tube. The through holes may also be arranged in each tube at a predetermined interval in the circumferential direction of the tube. The spacing between the plurality of through holes in the axial direction (e.g., x direction) is equal to the spacing between the plurality of plants in the x direction. The spacing between the plurality of through holes and the spacing between the plurality of plants may be different.

[0023] <Flow of irrigation water> The irrigation water supplied to the vertical pipe 131 by the pump 110 flows through the vertical pipe 131. This irrigation water is also supplied to each of the first connecting pipes 132 connected to the vertical pipe 131. The irrigation water flows through each of the first connecting pipes 132. The irrigation water flowing through the first connecting pipes 132 flows down to the distribution tubes. The irrigation water is discharged from each through hole in the distribution tube and supplied to the plants. The irrigation water supplied from each through hole in the distribution tube is mainly supplied to the trunks and roots of the plants. The through holes are provided, for example, at a position higher than the part of each distribution tube that faces the ground. In this case, the irrigation water discharged from the through holes spreads in a radial direction with respect to the central axis of the distribution tube, and can be sprayed at a position away from the tube.

[0024] <Water supply valve> The water supply valve 15 is provided upstream of the distribution tube in the water supply path. When the water supply valve 15 is controlled to an open state, the water supply pipe 130 communicates with each through-hole of the distribution tube. This allows irrigation water to be discharged from the through-holes. Conversely, when the water supply valve 15 is controlled to a closed state, communication between the water supply pipe 130 and each through-hole of the distribution tube is blocked. This stops the discharge of irrigation water from the through-holes.

[0025] The water supply valve 15 controls the flow rate of irrigation water discharged from the through hole of the distribution tube by controlling the valve opening degree with the control device 200. The control device 200 controls the valve opening degree of the water supply valve 15 to any value between a predetermined opening degree and fully open. The water supply valve 15 is a flow rate control valve or a pressure control valve that can precisely vary the flow rate passing through by adjusting the downstream or upstream pressure. The predetermined opening degree is set to a value including a slightly open opening degree or a 0% opening degree, that is, a fully closed position.

[0026] The control device 200 controls the valve opening of the water supply valve 15 to control the discharge flow rate or discharge flow velocity per unit time discharged from each through-hole of the distribution tube. The control device 200 can control the water flight distance, which is the distance that the irrigation water discharged from the distribution tube lands after moving away from the distribution tube, or the discharge amount. The water flight distance is the distance between the distribution tube and the soil landing point of the irrigation water that has flowed out of the distribution tube through the through-hole. This technology for controlling the water flight distance allows efficient irrigation to be performed in places that require irrigation, which also contributes to water conservation. The water supply valve 15 is an opening / closing valve that controls the flow down of the water supply and the cut-off of the water supply, and also functions as a flow rate adjustment valve that can control the water supply flow rate.

[0027] For example, the valve opening of the water supply valve 15 is controlled to increase the water jump distance when the plants have wide roots or the till layer is shallow and wide. Also, the valve opening of the water supply valve 15 is controlled to reduce the water jump distance when the plants have deep roots or the till layer is located close to the distribution tube. The water jump distance can be rephrased as the irrigation distance.

[0028] <Water pressure sensor> The water pressure sensor 14 is provided in a pipe included in the water supply pipe 130. The water pressure sensor 14 is a pressure sensor that detects the water pressure in the pipe. The water pressure detected by the water pressure sensor 14 is output to the control device 200. The water pressure sensor 14 is provided at a position upstream of the distribution tube in the water supply path. Furthermore, the water pressure sensor 14 may be configured to be provided at a position downstream of the distribution tube in the water supply path.

[0029] When the water supply valve 15 is closed and the piping is filled with irrigation water, the water pressure sensor 14 detects the pump pressure. When the water supply valve 15 changes from a closed state to an open state, irrigation water is discharged from the distribution tube. When the time-averaged amount of irrigation water discharge stabilizes, the water pressure sensor 14 detects the flow pressure. When the water supply valve 15 changes from an open state to a closed state, the discharge of irrigation water from the water supply piping 130 stops. The water pressure in the water supply piping 130 gradually recovers from the flow pressure to the pump pressure. The water pressure sensor 14 detects the water pressure during the transitional period when the flow pressure gradually recovers to the pump pressure. The irrigation system 1 may be configured to include a flow sensor that detects the flow rate of the fluid flowing through the passage, instead of the water pressure sensor 14. The irrigation system 1 feedback-controls the valve opening of the water supply valve 15 using the detection values ​​of the water pressure sensor 14 and the flow sensor.

[0030] <Control device> As shown in Fig. 1, the control device 200 includes a monitoring unit 300, an integrated communication unit 400, an information storage unit 500, and an integrated calculation unit 600. In the drawing, the integrated communication unit 400 is denoted as ICD. The control device 200 has a plurality of monitoring units 300. Each of the plurality of monitoring units 300 is configured to control irrigation for a predetermined divided area assigned to it in the field 20. To the divided area, for example, one or more ridges are assigned.

[0031] The water pressure detected by the water pressure sensor 14 is input to the monitoring unit 300. The monitoring unit 300 detects environmental values, which are physical quantities related to the environment of the farm field 20. Each monitoring unit 300 outputs the water pressure and the environmental values ​​to the integrated communication unit 400 by wireless communication.

[0032] The integrated communication unit 400 outputs the water pressure and environmental values ​​input from each monitoring unit 300 to the information storage unit 500 via wireless communication. The information storage unit 500 stores the water pressure and environmental values. An example of the information storage unit 500 is a so-called cloud. The integrated calculation unit 600 reads out various information such as the water pressure and environmental values ​​stored in the information storage unit 500. The integrated calculation unit 600 appropriately processes the read out information and displays the information and processing results on a monitor 700 of the user's smartphone or personal computer.

[0033] The integrated calculation unit 600 is included in a user's smartphone or personal computer. The integrated calculation unit 600 has an information processing calculation device 610, a memory 620, and a communication device 630. In the drawings, the information processing calculation device 610 is represented as IPCE, the memory 620 as MM, and the communication device 630 as CD. The information processing calculation device 610 includes a processor. The information processing calculation device 610 performs calculation processing related to irrigation operation control processing. This function is realized by downloading an irrigation application program to the information processing calculation device 610. The integrated calculation unit 600 may be a calculation device implemented on the cloud. In this case, the integrated calculation unit 600 and the information storage unit 500 may be configured to be implemented together on the cloud.

[0034] The memory 620 is a non-transient substantial storage medium that non-temporarily stores various programs and various information that can be read by a computer or a processor. The memory 620 has a volatile memory and a non-volatile memory. The memory 620 stores various information input to the communication device 630 and the processing results of the information processing device 610. The information processing device 610 executes various arithmetic processes using the information stored in the memory 620.

[0035] The communication device 630 has a wireless communication function. The communication device 630 converts a received wireless signal into an electric signal and outputs it to the information processing device 610. The communication device 630 outputs the processing result of the information processing device 610 as a wireless signal. Hereinafter, the technical content of this embodiment will be described using an integrated calculation unit 600, which collectively refers to the information processing device 610, the memory 620, and the communication device 630.

[0036] A user inputs user instructions related to the irrigation operation control process to the integrated calculation unit 600 using an input device 800 such as a touch panel or keyboard. The integrated calculation unit 600 outputs an irrigation operation control process command based on the user instructions and various information read from the information storage unit 500. If there are no instructions from the user, the integrated calculation unit 600 decides to start or stop irrigation based on various information. When an irrigation schedule arrives, the integrated calculation unit 600 decides to start irrigation when an irrigation start condition is met. The integrated calculation unit 600 decides to stop irrigation when an irrigation stop condition is met during irrigation.

[0037] When the integrated calculation unit 600 detects a forced irrigation operation control processing command or determines that an irrigation start condition has been met, it outputs an instruction signal for controlling the water supply valve 15 to the information storage unit 500. This instruction signal is input from the information storage unit 500 to the monitoring unit 300 via the integrated communication unit 400. The monitoring unit 300 controls whether to output a water supply signal to the water supply valve 15 based on the instruction signal. This controls the open / close state of the water supply valve 15. As a result, the supply of irrigation to the field 20 is controlled, or the stop of irrigation is controlled.

[0038] <Divided area> One monitoring unit 300 is provided for each distribution tube. The monitoring unit 300 may be provided in correspondence with a predetermined number of distribution tubes. The monitoring unit 300 may be provided in correspondence with each ridge. As shown in FIG. 1, the multiple monitoring units 300 are arranged in a matrix in the field 20 together with the water supply valves 15 and the water pressure sensors 14, with the x direction being the row direction and the y direction being the column direction. With this configuration, the monitoring units 300 individually monitor each divided area separated by the row direction and the column direction. The supply of irrigation water in each divided area is individually controlled by the corresponding monitoring unit 300.

[0039] <Monitoring section> The monitoring unit 300 has a control unit and the like. The water supply valve 15, the water pressure sensor 14, and the like are electrically connected to the control unit. In the drawings, the water supply valve 15 is represented as WV, and the water pressure sensor 14 is represented as WPS. The control unit may also be configured to be electrically connected to a soil sensor installed corresponding to a predetermined divided area in the field 20. In this case, the soil sensor detects an environmental value related to the soil condition of the corresponding divided area.

[0040] The monitoring unit 300 includes, for example, a microcomputer, a communication unit, an RTC, and a power generation unit. The microcomputer is an abbreviation for microcomputer. The RTC is an abbreviation for Real Time Clock. The microcomputer outputs soil environmental values ​​and water pressure to the integrated communication unit 400 via the communication unit. An instruction signal is input to the microcomputer from the integrated communication unit 400. The microcomputer outputs a water supply signal to the water supply valve 15 based on this instruction signal. The microcomputer is a control device that controls the operation of the water supply valve 15.

[0041] The communication unit performs wireless communication with the integrated communication unit 400. The communication unit outputs an electrical signal output from the microcomputer to the integrated communication unit 400 as a wireless signal. At the same time, the communication unit receives the wireless signal output from the integrated communication unit 400 and converts it into an electrical signal. The communication unit outputs the electrical signal to the microcomputer. The RTC has a clock function that keeps time and a timer function that measures time. The RTC outputs a wake-up signal to the microcomputer when a preset time is reached or when a preset time has elapsed. When this wake-up signal is input to a microcomputer in sleep mode, the microcomputer switches from sleep mode to normal mode.

[0042] The power generation unit converts light energy obtained by, for example, a solar cell into electrical energy. The power generation unit functions as a power supply source for the monitoring unit 300. Power is constantly supplied from the power generation unit to the RTC. This prevents the clock function and timer function of the RTC from being impaired. The solar cell may be replaced with a primary battery or a secondary battery. The power generation unit may be configured to convert natural energy other than light energy, such as wind power or hydraulic power, into electrical energy.

[0043] <Microcomputer> The microcomputer of the monitoring unit 300 includes an acquisition unit, a signal output unit, a storage unit, a processing unit, and a communication unit. The acquisition unit receives environmental values ​​related to the soil of the field 20 based on the detection values ​​of various sensors. The acquisition unit receives the water pressure detected by the water pressure sensor 14. The acquisition unit is electrically connected to each of the various sensors and the water pressure sensor 14. The signal output unit is electrically connected to the water supply valve 15. A control signal (water supply signal) for controlling the valve opening of the water supply valve 15 is output from the signal output unit to the water supply valve 15. When the water supply signal is not input, the water supply valve 15 is in a closed state. When the water supply signal is input, the water supply valve 15 is in an open state. The water supply valve 15 may be configured to maintain the current state when no water supply signal is input, and to open or close according to the input content when the water supply signal is input. For example, when no control signal is input, the valve opening of the water supply valve 15 is maintained, and the valve opening of the water supply valve 15 is adjusted according to the control signal of the opening instruction input at the time of input.

[0044] The memory unit is a non-transient, substantial storage medium that non-temporarily stores programs and data that can be read by a computer or a processor. The memory unit has a volatile memory and a non-volatile memory. The memory unit stores a program for the processing unit to execute arithmetic processing. This program includes at least a portion of the above-mentioned irrigation application program. The memory unit temporarily stores data when the processing unit executes arithmetic processing. The memory unit stores various data input to the acquisition unit and the communication unit, respectively, and the acquisition times of the various data.

[0045] When the processor receives a wake-up signal from the RTC, it goes from sleep mode to normal mode. In normal mode, the processor reads the programs and various data stored in the memory and executes arithmetic processing. This arithmetic processing includes calculating the valve opening required to allow the water splashed through the through-hole of the distribution tube to reach the desired irrigation position.

[0046] The processing unit reads out various sensor signals input to the acquisition unit, and reads out the acquisition time of the instruction signal input to the communication unit from the RTC. The processing unit stores the instruction signal and the acquisition time in the storage unit. The acquisition time may be read out by causing the integrated communication unit 400 to record the data acquisition time when the integrated communication unit 400 wirelessly receives data from each monitoring unit 300. Also, the information storage unit 500 may record the data acquisition time when the information storage unit 500 wirelessly receives data from the integrated communication unit 400.

[0047] The processing unit stores the environmental values ​​and water pressure input from the various sensors and the water pressure sensor 14, as well as the time of their acquisition, in the information storage unit 500 via the communication unit and the integrated communication unit 400. The processing unit 214 outputs a water supply signal to the water supply valve 15 via the signal output unit, based on an instruction signal input from the integrated calculation unit 600 via the information storage unit 500, the integrated communication unit 400, and the communication unit.

[0048] <Driving the irrigation system> In the irrigation system 1, signals are sent and received between the multiple monitoring units 300 and the integrated calculation unit 600, and various data are stored in the information storage unit 500. Each of the multiple monitoring units 300 and the integrated calculation unit 600 executes cycle tasks that are processed at each drive cycle and event tasks that are processed suddenly. As cycle tasks, each monitoring unit 300 executes sensor processing related to the acquisition of various sensor signals. The integrated calculation unit 600 executes update processing. As event tasks, each monitoring unit 300 executes monitoring processing and water supply processing. The integrated calculation unit 600 executes irrigation operation control processing, user update processing, and forced update processing.

[0049] <Monitoring process> When an instruction signal is input from the integrated calculation unit 600 to the microcomputer of the monitoring unit 300 via wireless communication, the monitoring unit 300 starts executing the monitoring process. The monitoring unit 300 first stores the input instruction signal and the time of acquisition of the signal. Next, the monitoring unit 300 judges whether or not the instruction signal includes a water supply instruction to change the water supply valve 15 from a closed state to an open state. If the instruction signal includes a water supply instruction, the monitoring unit 300 executes the water supply process. In the water supply process, the monitoring unit 300 outputs a water supply signal to the water supply valve 15 according to the water supply instruction. Furthermore, the monitoring unit 300 judges whether or not the water supply stop condition is satisfied. If the water supply stop condition is not satisfied, the monitoring unit 300 continues to output the water supply signal to the water supply valve 15. If the water supply stop condition is satisfied, the monitoring unit 300 stops outputting the water supply signal and ends the water supply process.

[0050] If the instruction signal does not include a water supply instruction, the water supply process is not executed, and it is determined whether the instruction signal includes an instruction to update the intermittent drive interval. The instruction to update the intermittent drive interval is output as an instruction signal from the integrated calculation unit 600 or the information storage unit 500 to each monitoring unit 300 periodically or irregularly.

[0051] If the instruction signal does not include an instruction to update the intermittent drive interval, sensor processing is performed. If water supply processing is performed, the environmental value after irrigation is supplied is detected in the sensor processing. If water supply processing is not performed, the environmental value when irrigation is not being supplied is detected in the sensor processing. This environmental value is stored in the information storage unit 500. Once the sensor processing has been completed, the monitoring processing is terminated. The condition for starting the monitoring processing is not limited to an instruction signal from the integrated calculation unit 600.

[0052] <Irrigation operation control process> The integrated calculation unit 600 executes the irrigation operation control process in each monitoring unit 300 whenever it is time to supply irrigation water. The timing for supplying irrigation water is when an irrigation start condition is met or when an irrigation command is issued by a user operation. The integrated calculation unit 600 first outputs a water supply signal including a water supply instruction to the monitoring unit 300 of the divided area to which irrigation water is to be supplied, among the multiple monitoring units 300. The water supply instruction includes the start of output of the water supply signal and the output time of the water supply signal (water supply time). The monitoring unit 300 that receives this water supply instruction executes the monitoring process described above. The integrated calculation unit 600 goes into a standby state until the monitoring process of the monitoring unit 300 is completed. When the monitoring process is completed, the update process is executed.

[0053] <User update process> The integrated calculation unit 600 executes the user update process when a user instruction relating to adjustment of the watering schedule or the intermittent drive interval is input from the input device 800. The integrated calculation unit 600 first stores the input user instruction in the information storage unit 500. Next, the integrated calculation unit 600 executes the update process described above. As a result, the watering schedule and the intermittent drive interval are updated based on the user instruction.

[0054] <Forced update process> The integrated calculation unit 600 executes the forced update process when a user instruction related to updating the watering schedule and the intermittent drive interval is input. The integrated calculation unit 600 first outputs a request signal including a request instruction requesting execution of sensor processing. This request signal is output to the monitoring unit 300 by wireless communication. Next, the update process goes into a standby state until the sensor processing of the monitoring unit 300 is completed.

[0055] When the sensor processing is completed, the update processing described above is executed. The determination as to whether the sensor processing is completed can be made, for example, based on whether the time expected for the sensor processing to be completed has elapsed. Alternatively, the determination as to whether the sensor processing is completed can be made by inquiring of the monitoring unit 300. There are no particular limitations on the method for determining whether the sensor processing is completed. The watering schedule and the intermittent drive interval are updated based on various data at the time of the user's update request.

[0056] <Individual irrigation operation control process> As described above, the integrated calculation unit 600 determines the irrigation schedule for each of the multiple divided areas. The integrated calculation unit 600 controls the supply of irrigation water based on each irrigation schedule. Although the irrigation schedule for each divided area is determined by the integrated calculation unit 600, a configuration may be adopted in which the supply of irrigation water based on each irrigation schedule is individually controlled by each monitoring unit 300. As a further example, a configuration may be adopted in which the irrigation schedule for each divided area is independently determined by the corresponding monitoring unit 300. In such a configuration, each monitoring unit 300 executes the update process described above.

[0057] <Liquid fertilizer supply section> Next, we will explain the liquid fertilizer supply unit 120 provided in the irrigation system 1. The liquid fertilizer supply unit 120 is a device that supplies a mixed nutrient solution, which is a mixture of irrigation water and liquid fertilizer, to soil and plants as irrigation water at the liquid fertilizer supply timing. The liquid fertilizer supply unit 120 has a function of promoting plant growth by mixing liquid fertilizer of an appropriate concentration into the water supply pipe 130.

[0058] As shown in Fig. 2, the liquid fertilizer supply unit 120 is provided upstream of the multiple distribution tubes. The liquid fertilizer supply unit 120 includes a part of the water supply pipe 130, which is the main path through which irrigation water flows, and a sub-path 17 including a passage that branches off from the main path upstream and joins with the main path downstream. The sub-path 17 is a liquid fertilizer mixing line through which a mixed fluid of liquid fertilizer and water flows. An automatic flow control valve 171 and a liquid fertilizer suction unit 16 provided downstream of the automatic flow control valve 171 are installed in the sub-path 17.

[0059] The automatic flow control valve 171 is a flow adjustment mechanism that can control the flow rate of the fluid in the sub-path 17 by itself without using a pressure sensor or the like. The automatic flow control valve 171 has, for example, a flow measurement function and a function of controlling the flow rate by controlling the passage opening degree according to the flow measurement value. The irrigation system 1 controls the operation and stop of the automatic flow control valve 171.

[0060] The liquid fertilizer suction section 16 includes a tank 161 in which liquid fertilizer is stored, a liquid fertilizer supply pipe 162 to which the tank 161 is connected, and a Venturi tube 163. The Venturi tube 163 has an inlet of the flow path, a narrowing section provided in the center of the flow path, and a widening section provided downstream of the narrowing section. The Venturi tube 163 further includes a suction port for mixing liquid fertilizer into the flow path, slightly downstream of the narrowing section. The suction port is connected to the tank 161 by a liquid fertilizer supply pipe 162. A mixer is provided downstream of the widening section to mix the liquid fertilizer flowing in from the suction port with the water in the flow path. An outlet is formed at the downstream end of the mixer.

[0061] The liquid fertilizer suction section 16 sucks liquid fertilizer into the sub-path 17 using the suction force of the fluid flowing down the sub-path 17. The liquid fertilizer suction section 16 mixes the water introduced into the narrowed section of the Venturi tube 163 under pressure at the expanding section downstream of the narrowed section, and accelerates the mixed flow rate at the outlet provided downstream of the narrowed section. The water flowing into the inlet section of the Venturi tube 163 is accelerated at the narrowed section, and the flow rate slows down at the expanding section, increasing the static pressure. At this time, the liquid fertilizer in the tank 161 is sucked through the liquid fertilizer supply pipe 162, flows from the suction port into the flow path in the Venturi tube 163, and mixes with the water. The mixed fluid of water and liquid fertilizer flows down the mixing section and reaches the outlet. The mixed fluid is accelerated again at the outlet, flows down the sub-path 17, and merges with the water flowing down the water supply pipe 130. The mixed nutrient solution thus supplied to the water supply pipe 130 is discharged from the distribution tube as irrigation water and supplied to the soil and plants. Also, the liquid fertilizer suction unit 16 may be configured to include a throttle unit such as an orifice or an ejector instead of the Venturi tube 163.

[0062] In the sub-path 17, an automatic flow control valve 171 that actively controls the passage opening degree by itself is provided upstream of the liquid fertilizer suction section 16. Therefore, the automatic flow control valve 171 is configured so that it is unlikely to come into contact with the liquid fertilizer sucked into the Venturi tube 163 unless a strong backflow occurs. The automatic flow control valve 171 may be configured to have a mechanism for suppressing backflow in the sub-path 17 upstream of the mixed flow section where the sucked liquid fertilizer flows into the sub-path 17.

[0063] As shown in FIG. 3, the irrigation system 1 includes a control unit 210 that controls the operation of the liquid fertilizer supply unit 120. The control unit 210 may be a part of the control device 200, or may be separate from the control device 200. The control unit 210 includes an acquisition unit 211, a signal output unit 212, a memory unit 213, and a processing unit 214. In the drawing, the acquisition unit 211 is represented as AD, the signal output unit 212 as SOU, the memory unit 213 as MU, and the processing unit 214 as PU. The acquisition unit 211 and the automatic flow control valve 171 are electrically connected. The passage opening degree controlled by the automatic flow control valve 171 itself is input to the acquisition unit 211. The signal output unit 212 is electrically connected to the pump 110. A control signal for controlling the operation of the pump 110 is output from the signal output unit 212 to the pump 110.

[0064] The storage unit 213 is a non-transient substantial storage medium that non-temporarily stores programs and data that can be read by a computer or a processor. The storage unit 213 has a volatile memory and a non-volatile memory. The storage unit 213 stores a program for the processing unit 214 to execute arithmetic processing. This program includes a control process for performing a suction amount of the Venturi tube 163 that can supply a recommended amount of liquid fertilizer described below at the liquid fertilizer supply timing when fertilization is performed.

[0065] The processing unit 214 reads the programs and various data stored in the memory unit 213 and executes calculation processing. This calculation processing includes calculation related to flow rate control by the pump 110 according to the passage opening degree of the automatic flow control valve 171 in order to supply the recommended amount of liquid fertilizer. The processing unit 214 outputs a control signal to the pump 110 via the signal output unit 212 based on an instruction signal according to the calculation result related to the flow rate driven by the pump 110.

[0066] The recommended amount of liquid fertilizer per day and the upper limit of the amount of liquid fertilizer per predetermined period for each type of plant are stored in the memory unit 213. The recommended amount of liquid fertilizer per day and the upper limit of the amount of liquid fertilizer per predetermined period may be stored in the memory unit in association with the type of liquid fertilizer and the month in which the fertilizer is applied.

[0067] When plant information including the type of plant is input to the input device 800 by the user's operation, the integrated calculation unit 600 receives the information and transmits it to the control unit 210. The control unit 210 determines the liquid fertilizer supply timing for controlling the automatic flow control valve 171 from a stopped state to an operating state based on the plant information. When the determined liquid fertilizer supply timing arrives and the automatic flow control valve 171 is controlled to an operating state, the automatic flow control valve 171 controls the passage opening degree by itself to control the flow rate of the fluid flowing through the sub-path 17. The automatic flow control valve 171 controls the flow rate of the fluid flowing into the Venturi tube 163 so as to satisfy the suction amount of the Venturi tube 163 that can supply the above-mentioned recommended amount of liquid fertilizer. The automatic flow control valve 171 stores the inflow flow rate into the Venturi tube 163 that can supply the recommended amount of liquid fertilizer, and controls the passage opening degree by itself to satisfy this inflow flow rate. The integrated calculation unit 600 may also be configured to determine the liquid fertilizer supply timing for controlling the automatic flow control valve 171 from a stopped state to an operating state based on the plant information. In this case, the integrated calculation unit 600 transmits the determined liquid fertilizer supply timing to the control unit 210.

[0068] The irrigation system 1 of the first embodiment is provided with a sub-path 17 including a passage that branches off upstream from a main path along which irrigation water flows to be supplied to plants and merges further downstream. The irrigation system 1 is provided with a liquid fertilizer suction unit 16 that draws liquid fertilizer into the sub-path 17 using the suction force of the fluid flowing down the sub-path 17. The irrigation system 1 is provided with a flow rate adjustment mechanism that controls the flow rate of the fluid flowing down the sub-path 17. The flow rate adjustment mechanism is provided in the sub-path 17 upstream of a mixing portion where the liquid fertilizer drawn by the liquid fertilizer suction unit 16 flows into the sub-path 17.

[0069] According to this, the irrigation system 1 is provided with a flow rate adjustment mechanism provided in the sub-path 17 upstream of the mixed flow portion where the liquid fertilizer flows in. This makes it possible to provide a sub-path 17 configured so that the flow rate adjustment mechanism does not come into direct contact with the liquid fertilizer. Since the components of the flow rate adjustment mechanism are not present in a flow path that comes into contact with highly acidic or alkaline liquid fertilizer, the frequency of maintenance of the components can be reduced. Furthermore, the irrigation system 1 makes it possible to expand the options for materials used for the flow rate adjustment mechanism. As described above, the irrigation system 1 can ensure the life of the flow rate adjustment mechanism and supply liquid fertilizer.

[0070] The flow rate adjustment mechanism includes an automatic flow rate control valve 171 that controls the flow rate of the fluid in the sub-path 17 by itself. The automatic flow rate control valve 171 has a function of controlling the passage opening degree in the sub-path 17 by itself without using the detection value of a separate sensor provided outside. This makes it possible to provide a sub-path 17 having a configuration in which the automatic flow rate control valve 171 does not directly come into contact with liquid fertilizer. Each part built into the automatic flow rate control valve 171 is not present in a flow path that comes into contact with liquid fertilizer that is highly acidic or alkaline. This makes it possible to reduce the frequency of maintenance of not only movable parts such as valves but also parts of the detection mechanism such as a sensor unit. It is also possible to expand the selection of materials to be used for each of these parts. As described above, the irrigation system 1 can ensure the life of the automatic flow rate control valve 171 and supply liquid fertilizer.

[0071] Second embodiment The second embodiment will be described with reference to Figures 4 to 11. The irrigation system 1 of the second embodiment differs from the first embodiment in the configuration of the liquid fertilizer supply unit 120. The configurations, actions, and effects of the second embodiment that are not specifically described are the same as those of the above-mentioned embodiments, and only the differences will be described below.

[0072] The liquid fertilizer supply unit 120 of the second embodiment includes a physical quantity sensor 173 that detects the flow state of the fluid, and a flow control valve 171A. The physical quantity sensor 173 detects the pressure value or flow rate value of the fluid as the flow state of the fluid. The control unit 210 shown in Fig. 10 controls the flow rate of the fluid flowing down the sub-path 17 by controlling the passage opening degree of the flow control valve 171A in accordance with the detection value of the physical quantity sensor 173. The physical quantity sensor 173 corresponds to a first physical quantity sensor.

[0073] Next, the configuration of an example of a valve device applicable to the flow control valve 171A will be described with reference to Figs. 4 to 6. The flow control valve 171A is a flow rate adjustment mechanism that can control the flow rate of the fluid in the sub-path 17 according to the detection value of the physical quantity sensor 173. This valve device is a so-called rotary type valve device. This valve device has one fluid inlet and three fluid outlets. This valve device is mounted on the irrigation system 1 by connecting the upstream piping in the sub-path 17 to the fluid inlet and connecting the downstream piping to any one of the fluid outlets. Furthermore, a blocking member may be attached to the fluid outlet that is not connected to the sub-path 17 to block the passage.

[0074] 4, the valve device includes a housing 9, a valve 90 as a valve body, a drive unit 70, a drive unit cover 80, etc. The valve device is configured as a ball valve in which the valve 90 rotates about the axis of a shaft 92 to open and close the valve device. In this specification, the direction along the axis of the shaft 92 is referred to as the axial direction DRa, and the direction perpendicular to the axial direction DRa and extending radially from the axial direction DRa is referred to as the radial direction DRr.

[0075] The housing 9 is an accommodating section that accommodates the valve 90. The housing 9 is formed, for example, from a resin member. The housing 9 includes a hollow housing main body 21 that accommodates the valve 90, a pipe member 50 that causes cooling water to flow out from the housing main body 21, and a partition wall section 60 that is attached to the housing main body 21. The housing main body 21 has an approximately rectangular parallelepiped appearance and is formed into a bottomed shape with an opening on the other side in the axial direction DRa. The housing main body 21 has a housing outer wall section 22 that constitutes the outer periphery of the housing main body 21. The housing outer wall section 22 forms a cylindrical valve accommodating space 23 inside the housing main body 21, the valve accommodating space 23 having an axis in the axial direction DRa.

[0076] An inlet port 251 for allowing fluid to flow into the valve accommodating space 23 is formed in the housing outer wall portion 22. The inlet port 251 is formed with a circular opening, and is connected to the connecting pipe 135. The inlet port 251 corresponds to a fluid inlet portion.

[0077] A pipe member 50 is attached to the housing outer wall portion 22. The housing outer wall portion 22 has a first outlet port 261, a second outlet port 262, and a third outlet port 263 for causing the fluid that has flowed into the valve accommodating space 23 via the inlet port 251 to flow out to the pipe member 50. The first outlet port 261, the second outlet port 262, and the third outlet port 263 correspond to a fluid outflow portion.

[0078] A partition wall portion 60 is attached to the housing opening surface 24 of the housing outer wall portion 22. The housing opening surface 24 is disposed on the other side of the housing main body portion 21 in the axial direction DRa. The housing opening surface 24 has a housing opening 241 that communicates between the valve accommodating space 23 and the outside of the housing main body portion 21. The housing opening 241 is closed by attaching the partition wall portion 60 to the housing opening surface 24.

[0079] The pipe member 50 includes a first pipe section 51, a second pipe section 52, and a third pipe section 53, each of which is formed into a cylindrical shape. The first pipe section 51, the second pipe section 52, and the third pipe section 53 are connected by a pipe connecting section 54. The pipe connecting section 54 connects the first pipe section 51, the second pipe section 52, and the third pipe section 53, and is a section for attaching the pipe member 50 to the housing outer wall section 22. The first pipe section 51 has an upstream side disposed inside the first outlet port 261. The second pipe section 52 has an upstream side disposed inside the second outlet port 262. The third pipe section 53 has an upstream side disposed inside the third outlet port 263.

[0080] The partition portion 60 closes the housing opening 241 and holds the valve 90 accommodated in the valve accommodating space 23. The partition portion 60 is disk-shaped with the axial direction DRa being the plate thickness direction, and is arranged so as to be fitted into the housing opening 241 from the other side toward one side in the axial direction DRa. When the partition portion 60 is fitted into the housing opening 241, the outer periphery of the partition portion 60 abuts against the inner circumferential surface of the housing, thereby closing the housing opening 241.

[0081] The drive unit cover 80 houses the drive unit 70. The drive unit cover 80 is made of resin and has a hollow shape, and a drive unit space for housing the drive unit 70 is formed inside. The drive unit cover 80 has a connector section 81 for connecting to the microcomputer of the monitoring section 300. The connector section 81 connects the valve device to the microcomputer, and has built-in terminals to which the drive unit 70 and the rotation angle sensor 73 are connected.

[0082] The drive unit 70 includes a motor 71 that outputs a rotational force for rotating the valve 90, a gear unit 72 that transmits the output of the motor 71 to the valve 90, and a rotation angle sensor 73 that detects the rotation angle of the gear unit 72. As shown in FIG. 4, the motor 71 includes a motor body, a motor shaft 711, a worm gear 712, and a motor side terminal. The motor 71 is configured so that the motor body can output power when power is supplied to the motor side terminal. The motor body is formed in a substantially cylindrical shape, and the motor shaft 711 protrudes from the other end of the motor body. The power output from the motor body is output to the gear unit 72 via the motor shaft 711 and the worm gear 712.

[0083] The gear portion 72 is composed of a reduction mechanism having a plurality of resin gears, and is configured to be able to transmit the power output from the worm gear 712 to the shaft 92. The gear portion 72 includes a first gear 721, a second gear 722 meshing with the first gear 721, and a third gear 723 meshing with the second gear 722. The shaft 92 is connected to the third gear 723. In the gear portion 72, the outer diameter of the second gear 722 is formed to be larger than the outer diameter of the first gear 721, and the outer diameter of the third gear 723 is formed to be larger than the outer diameter of the second gear 722.

[0084] The first gear 721, the second gear 722, and the third gear 723 are arranged so that their respective axes are perpendicular to the axis of the worm gear 712. The third gear 723 is arranged so that its axis is coaxial with the axis of the shaft 92. The third gear 723 is connected to the shaft 92. The drive unit 70 is configured so that the worm gear 712, the first gear 721, the second gear 722, and the third gear 723 rotate integrally with the valve 90, and the rotations of each are correlated with each other. The rotation angles of these gears and the shaft 92 are correlated with each other, and the rotation angle of any one of the components having the correlation can be calculated from the rotation angle of the other components.

[0085] A rotation angle sensor 73 for detecting the rotation angle of the third gear 723 is attached to the inner periphery of the drive unit cover 80 at a position facing the third gear 723. The rotation angle sensor 73 is a Hall type sensor with a built-in Hall element, and is configured to be able to detect the rotation angle of the third gear 723 in a non-contact manner. The rotation angle sensor 73 is connected to a microcomputer via a connector unit 81. The detected rotation angle of the third gear 723 is transmitted to the microcomputer. A processing unit of the microcomputer is configured to be able to calculate the rotation angle of the valve 90 based on the rotation angle of the third gear 723 transmitted from the rotation angle sensor 73.

[0086] The shaft 92 and the valve 90 will be described with reference to Figs. 5 and 6. The shaft 92 is configured to be rotatable about its axis by the rotational force output by the drive unit 70. The valve 90 is connected to the shaft 92, and is configured to be able to rotate the valve 90 integrally with the shaft 92 when the shaft 92 rotates. The shaft 92 is formed to extend in a cylindrical shape along the axis, and penetrates the valve 90 from one side to the other side. One side of the shaft 92 in the axial direction DRa is connected to the shaft support part of the housing main body 21, and the other side is connected to the gear part 72. The valve 90 is fixed to the outer periphery of the shaft.

[0087] The valve 90 is configured to be able to adjust the flow rate of the output fluid by rotating around the axis. The valve 90 has a shaft 92 inserted therein and is accommodated in the valve accommodation space 23 so as to be able to rotate together with the shaft 92. The valve 90 is cylindrical with an axis extending along the axial direction DRa. The valve 90 is formed by connecting a first valve 93, a second valve 94, and a third valve 95, each of which is cylindrical, a cylindrical connection part 914, and a cylindrical valve connection part 915. The valve 90 is arranged such that the first valve 93, the cylindrical connection part 914, the second valve 94, the cylindrical valve connection part 915, and the third valve 95 are arranged in this order from one side to the other side of the axial direction DRa. The first valve 93 and the second valve 94 are connected via the cylindrical connection part 914. The second valve 94 and the third valve 95 are connected via the cylindrical valve connection part 915.

[0088] In the valve accommodating space 23, the second valve 94 and the cylindrical connection portion 914 of the valve 90 face the inlet port 251 in the radial direction DRr. The valve 90 has a cylindrical shaft connection portion 916 in the center into which the shaft 92 is inserted. The valve 90 is connected to the shaft 92 by inserting the shaft 92 into the shaft connection portion 916. In the valve 90, for example, the first valve 93, the second valve 94, the third valve 95, the cylindrical connection portion 914, the cylindrical valve connection portion 915, and the shaft connection portion 916 are integrally molded by injection molding.

[0089] The valve 90 is a valve body for allowing the fluid that has flowed into the valve 90 to flow out to a first outlet port 261, a second outlet port 262, and a third outlet port 263. When the valve 90 rotates, the first valve 93 opens and closes the first outlet port 261, the second valve 94 opens and closes the second outlet port 262, and the third valve 95 opens and closes the third outlet port 263.

[0090] The first valve 93, the second valve 94, and the third valve 95 are arranged so that their respective axes are coaxial with the axis of the shaft 92. The first valve 93, the second valve 94, and the third valve 95 each have a central portion in the axial direction DRa that bulges outward in the radial direction DRr compared to both end sides. The first valve 93, the second valve 94, and the third valve 95 each are configured to allow fluid to flow inside.

[0091] 6, the first valve 93 has a first valve outer periphery 931 that forms an outer periphery, and a first flow path portion 961 is formed inside the first valve outer periphery 931. The first valve 93 is formed with a first inner opening 936 that allows fluid to flow into the first flow path portion 961. In the first valve 93, the fluid that has flowed into the valve accommodating space 23 flows into the first flow path portion 961 via the first inner opening 936. The first flow path portion 961 corresponds to a flow path portion in a valve device.

[0092] As shown in FIG. 6, the first valve outer periphery 931 is formed with a first outer periphery opening 934 that communicates the first flow passage 961 with the first outlet port 261 via the first seal opening 581 when the shaft 92 rotates. The first valve 93 allows the fluid that has flowed into the first flow passage 961 to flow out from the first outlet port 261 by communicating the first outer periphery opening 934 with the first outlet port 261. The first outer periphery opening 934 formed in the first valve outer periphery 931 corresponds to an outer periphery opening formed in the valve outer periphery. The first outer periphery opening 934 is formed in the first valve outer periphery 931, extending in the circumferential direction of the axis of the shaft 92. The flow rate of the fluid flowing out of the device from the first valve 93 is adjusted according to the area of ​​overlap between the first outer periphery opening 934 and the first seal opening 581 when the shaft 92 rotates. The first inner opening 936 functions as a communication passage that connects the outside of the first valve 93 with the first flow path portion 961 .

[0093] 6, the second valve 94 has a second valve outer periphery 941 forming an outer periphery, and a second flow path portion 962 is formed inside the second valve outer periphery 941. The second valve 94 is formed with a second inner opening 946 that allows the fluid to flow into the second flow path portion 962 on one side in the axial direction DRa. The second valve 94 is configured so that the fluid that flows into the valve accommodating space 23 via the inlet port 251 can flow through the second flow path portion 962 via the second inner opening 946. The second flow path portion 962 corresponds to a flow path portion in a valve device.

[0094] 6, a second outer circumferential opening 944 is formed in the second valve outer circumferential portion 941, which communicates the second flow path portion 962 with the second outlet port 262 via the second seal opening 582 when the shaft 92 rotates. The second valve 94 allows the fluid that has flowed into the second flow path portion 962 to flow out from the second outlet port 262 by communicating the second outer circumferential opening 944 with the second outlet port 262. The second outer circumferential opening 944 formed in the second valve outer circumferential portion 941 corresponds to an outer circumferential opening formed in the valve outer circumferential portion.

[0095] The second outer periphery opening 944 is formed to extend in the circumferential direction of the axis of the shaft 92. The flow rate of the fluid flowing out from the second valve 94 to the outside of the device is adjusted according to the area of ​​overlap between the second outer periphery opening 944 and the second seal opening 582 when the shaft 92 rotates. The second inner opening 946 functions as a communication passage that communicates the outside of the second valve 94 with the second flow path portion 962. The second inner opening 946 faces the first inner opening 936. The cylindrical connection portion 914 is for connecting the first valve 93 and the second valve 94. The cylindrical connection portion 914 forms a first inter-valve space 97 between the outer periphery of the cylindrical connection portion 914 and the inner periphery of the housing. The first flow path portion 961 and the second flow path portion 962 communicate with each other via the first inter-valve space 97.

[0096] The second valve 94 has a shaft connection part 916 disposed in approximately the center inside, the shaft connection part 916 covering the outer periphery of the shaft 92. The second valve 94 has a cylindrical valve connection part 915 connected to the other side in the axial direction DRa of the second valve outer periphery 941. The second valve 94 is configured to allow the fluid that has flowed into the second flow path part 962 to flow into the third valve 95 via the cylindrical valve connection part 915.

[0097] The cylindrical valve connection part 915 has a second inter-valve space 98 formed on the inside. The second inter-valve space 98 is in communication with the second flow path part 962 and the third flow path part 963. The cylindrical valve connection part 915 has an outer diameter on one side in the axial direction DRa that is the same as the outer diameter of the portion of the second valve 94 on the other side in the axial direction DRa. The cylindrical valve connection part 915 has an outer diameter on the other side in the axial direction DRa that is the same as the outer diameter of the portion of the third valve 95 on one side in the axial direction DRa. The cylindrical valve connection part 915 is formed to be continuous with the second valve outer periphery part 941 and the third valve outer periphery part 951.

[0098] 6, the third valve 95 has a third valve outer periphery 951 that forms the outer periphery of the third valve 95, and a third flow path portion 963 is formed inside the third valve outer periphery 951. One side of the third valve outer periphery 951 in the axial direction DRa of the third valve 95 is connected to the cylindrical valve connection portion 915. In the third valve 95, the fluid that has flowed into the second flow path portion 962 flows into the third flow path portion 963 via the second inter-valve space 98. The third flow path portion 963 corresponds to a flow path portion in a valve device.

[0099] 6, a third outer periphery opening 954 is formed in the third valve outer periphery portion 951, which connects the third flow path portion 963 to the third outlet port 263 via the third seal opening 583 when the shaft 92 rotates. The third valve 95 allows the fluid that has flowed into the third flow path portion 963 to flow out of the device from the third outlet port 263 by connecting the third outer periphery opening 954 to the third outlet port 263. The third outer periphery opening 954 formed in the third valve outer periphery portion 951 corresponds to the outer periphery opening formed in the valve outer periphery.

[0100] The third outer periphery opening 954 is formed in the third valve outer periphery 951, extending in the circumferential direction of the axis. The flow rate of the fluid flowing out from the third valve 95 to the outside of the device is adjusted according to the area of ​​overlap between the third outer periphery opening 954 and the third seal opening 583 when the shaft 92 rotates. The shaft connection part 916 is cylindrical, and connects the valve 90 and the shaft 92 by fixing the inserted shaft 92. When the shaft 92 rotates, the shaft connection part 916 transmits the rotational force of the shaft 92 to the valve 90 via the shaft connection part 916. The shaft connection part 916 is formed extending from the second valve 94 to the third valve 95 toward the other side of the axial direction DRa.

[0101] The operation of the flow control valve 171A will be described. The control unit 210 calculates the rotation angle of the valve 90 for ensuring a necessary flow rate for the Venturi tube 163, i.e., the rotation angle of the motor 71. The control unit 210 transmits information on the calculated rotation angle of the motor 71 to the flow control valve 171A. At this time, blocking members are attached to the two fluid outlets that are not connected to the sub-path 17. The calculation of the rotation angle of the motor 71 may be configured to be executed by the information processing calculation device 610 of the integrated calculation unit 600.

[0102] The flow control valve 171A rotates the motor 71 based on information on the rotation angle received from the control unit 210. By rotating the motor 71, the flow control valve 171A rotates the valve 90 via the gear unit 72 and the shaft 92, and causes a required flow rate of fluid to flow out from the first outer circumferential opening 934, the second outer circumferential opening 944, and the third outer circumferential opening 954.

[0103] For example, a case where the first outlet port 261 is adopted as a fluid outflow portion that communicates with the Venturi tube 163 will be described. The flow control valve 171A communicates the first outer circumferential opening 934 of the first valve 93 with the first outlet port 261 by rotating the valve 90. The flow control valve 171A adjusts the overlapping area between the first outer circumferential opening 934 and the first seal opening 581 by adjusting the rotational position of the valve 90. The flow control valve 171A causes the fluid that has flowed into the valve accommodating space 23 from the inlet port 251 to flow into the first flow passage portion 961 via the first inner opening 936, and causes the fluid to flow out from the first outer circumferential opening 934 to the first outlet port 261. The control unit 210 controls the valve opening degree, which is the overlapping area between the first outer circumferential opening 934 and the first seal opening 581, to control the flow rate of the fluid.

[0104] For example, a case where the second outlet port 262 is adopted as a fluid outflow portion that communicates with the Venturi tube 163 will be described. The flow control valve 171A communicates the second outer periphery opening 944 of the second valve 94 with the second outlet port 262 by rotating the valve 90. The flow control valve 171A adjusts the overlapping area between the second outer periphery opening 944 and the second seal opening 582 by adjusting the rotational position of the valve 90. The flow control valve 171A causes the fluid that has flowed into the valve accommodating space 23 from the inlet port 251 to flow into the second flow passage portion 962 via the second inner opening 946, and causes the fluid to flow out from the second outer periphery opening 944 to the second outlet port 262. The control unit 210 controls the valve opening degree, which is the overlapping area between the second outer periphery opening 944 and the second seal opening 582, to control the flow rate of the fluid.

[0105] For example, a case where the third outlet port 263 is adopted as a fluid outflow portion that communicates with the Venturi tube 163 will be described. The flow control valve 171A communicates the third outer periphery opening 954 of the third valve 95 with the third outlet port 263 by rotating the valve 90. The flow control valve 171A adjusts the overlapping area between the third outer periphery opening 954 and the third seal opening 583 by adjusting the rotational position of the valve 90. The flow control valve 171A causes the fluid that has flowed into the valve accommodating space 23 from the inlet port 251 to flow into the third flow path portion 963 via the second flow path portion 962 of the second valve 94, and causes the fluid to flow out from the third outer periphery opening 954 to the third outlet port 263. The control unit 210 controls the flow rate of the fluid by controlling the valve opening degree, which is the overlapping area between the third outer periphery opening 954 and the third seal opening 583. The control of these valve opening degrees may be configured to be executed by the information processing calculation device 610 of the integrated calculation unit 600.

[0106] In the flow rate control valve 171A, the rotation angle sensor 73 detects the rotation angle of the third gear 723. The flow rate control valve 171A adjusts the rotation angle of the motor 71 by feeding back information on the detected rotation angle to the control unit 210.

[0107] The relationship between the rotation angle of the shaft 92 and the flow rate of the valve device will be described with reference to the graph of FIG. 7. In FIG. 7, the horizontal axis represents the rotation angle RA of the motor 71, and the vertical axis represents the flow rate FR of the fluid flowing out of the valve device. In FIG. 7, FO1 is the first valve 93, FO2 is the second valve 94, and FO3 is the third valve 95. In FIG. 7, FS indicates that the valve opening is fully open, FC indicates that the valve opening is fully closed, and MO indicates that the valve opening is intermediate. The intermediate opening is an opening between the fully closed state and the fully open state. The solid line graph in FIG. 7 shows the relationship between the flow rate of the fluid flowing out of the third valve 95 and the rotation angle. The dashed line graph in FIG. 7 shows the relationship between the flow rate of the fluid flowing out of the second valve 94 and the rotation angle. The dashed line graph in FIG. 7 shows the relationship between the flow rate of the fluid flowing out of the first valve 93 and the rotation angle.

[0108] 7, when the rotation angle is near 0 degrees, third valve 95 is fully open and the other valves are fully closed, and fluid flows out of the device only through third valve 95. When the rotation angle is increased from this state, third valve 95 transitions to an intermediate opening, and when the rotation angle is further increased, all three valves are fully closed.

[0109] When the rotation angle of all three valves is increased from a fully closed state, only the second valve 94 transitions to a fully open state via an intermediate opening. When the rotation angle is further increased, the first valve 93 transitions to a fully open state via an intermediate opening, and the first valve 93 and the second valve 94 are in a fully open state. When the rotation angle is increased from this state, the second valve 94 transitions to a fully closed state via an intermediate opening, and the second valve 94 and the third valve 95 are in a fully closed state. When the rotation angle is further increased, the first valve 93 transitions to a fully closed state via an intermediate opening, and all valves are in a fully closed state.

[0110] As described above, the opening degree of each valve changes according to the rotation angle, and the flow rate of the fluid flowing out of each valve changes. The flow control valve 171A controls the flow rate of the fluid according to the rotation angle by supplying the fluid from only one of the three valves.

[0111] <Liquid fertilizer supply section> Next, the liquid fertilizer supplying section 120 of the second embodiment will be described. The liquid fertilizer supplying section 120 of the second embodiment has the same function as the liquid fertilizer supplying section 120 of the first embodiment. Here, only the differences from the first embodiment will be described.

[0112] As shown in FIG. 8, the liquid fertilizer supplying unit 120 of the second embodiment includes a flow control valve 171A and a check valve 172 in the sub-path 17. The check valve 172 is provided upstream of the Venturi tube 163 and downstream of the flow control valve 171A, and is a device for suppressing backflow of the fluid. The liquid fertilizer supplying unit 120 includes a physical quantity sensor 173 for detecting the flow state of the fluid upstream of the flow control valve 171A in the sub-path 17. The physical quantity sensor 173 may be a pressure sensor for detecting the pressure value of the fluid flowing down the sub-path 17, a flow sensor for detecting the flow value of the fluid flowing down the sub-path 17, or the like. In addition, the physical quantity sensor 173 may be a device for detecting the flow state of the fluid downstream of the flow control valve 171A in the sub-path 17, as shown in FIG. 9.

[0113] As shown in FIG. 10, the acquisition unit 211 is electrically connected to each of the physical quantity sensor 173 and the flow control valve 171A. In the drawing, the physical quantity sensor 173 is denoted as S1, and the flow control valve 171A is denoted as WV. A physical quantity indicating the flow state of the fluid detected by the physical quantity sensor 173 is input to the acquisition unit 211. A passage opening amount indicating the opening information of the flow control valve 171A is input to the acquisition unit 211. The signal output unit 212 is electrically connected to the flow control valve 171A. A control signal for controlling the valve opening of the flow control valve 171A is output from the signal output unit 212 to the flow control valve 171A. The signal output unit 212 outputs the valve opening to the flow control valve 171A in response to the input control signal of the opening instruction.

[0114] The memory unit 213 stores the inflow flow rate into the Venturi tube 163 that can supply the recommended amount of liquid fertilizer, and outputs this inflow flow rate to the processing unit 214. When the control unit 210 receives the above-mentioned plant information acquired from the integrated calculation unit 600, it executes control of the flow control valve 171A based on the plant information at the liquid fertilizer supply timing. In this way, the control unit 210 controls the passage opening amount of the flow control valve 171A according to the detection value of the physical quantity sensor 173.

[0115] The irrigation system 1 executes liquid fertilizer supply control according to the flowchart shown in Fig. 11. Fig. 11 is a flowchart showing an example of operation at liquid fertilizer supply timing. A liquid fertilizer supply command is executed when the liquid fertilizer supply timing arrives, when a liquid fertilizer supply command is issued by a user, when the liquid fertilizer supply time set by a timer arrives, etc. The control unit 210 executes each process shown in Fig. 11.

[0116] The control unit 210 controls the pump 110 to be in operation in step S110. If the pump 110 is already in operation, the control unit 210 maintains the pump 110 in operation in step S110. Furthermore, the control unit 210 controls the flow control valve 171A so that the passage opening degree satisfies the predetermined opening degree in step S120. The processing unit 214 determines the passage opening degree of the flow control valve 171A that satisfies the predetermined opening degree. The signal output unit 212 outputs a control signal indicating the determined passage opening degree to the flow control valve 171A. By this process, the water flowing down the water supply pipe 130 is diverted to the sub-path 17. The liquid fertilizer in the tank 161 is sucked by the suction force of the Venturi tube 163, mixed into the Venturi tube 163, and flows down the sub-path 17.

[0117] Next, the acquisition unit 211 acquires physical quantities such as a pressure value and a flow rate detected by the physical quantity sensor 173 in order to detect the flow state of the fluid flowing through the sub-path 17. In step S130, the processing unit 214 compares the detected physical quantity with a threshold value and judges the magnitude relationship between the two. Step S130 is a judgment process for determining the passage opening degree by the flow control valve 171A. The threshold value used in the judgment process of step S130 is stored in advance in the memory unit 213 or the information storage unit 500. This threshold value is a value set according to the type of crop and / or the type of soil. In addition, this threshold value may be a value that is updated according to the season, temperature, and / or the amount of solar radiation. In addition, this threshold value may be configured to be updated by an instruction value input by a user to the integrated calculation unit 600 using the input device 800. The processing unit 214 executes the judgment process of step S130 using the updated threshold value as necessary.

[0118] When the processing unit 214 judges that the detected physical quantity exceeds the threshold, it decides to reduce the passage opening of the flow control valve 171A by the reduced opening in step S140. The value of the reduced opening used in the judgment process of step S140 is stored in advance in the memory unit 213 or the information storage unit 500. The signal output unit 212 outputs a control signal that reduces the current passage opening by the reduced opening to the flow control valve 171A. By the process of step S140, the water that branches off from the water supply pipe 130 and flows down the sub-path 17 is controlled to decrease. Therefore, the suction force by the Venturi tube 163 is reduced, and the amount of liquid fertilizer that is sucked from the tank 161 and mixed into the Venturi tube 163 is reduced. Therefore, the amount of liquid fertilizer contained in the mixed fluid flowing down the sub-path 17 is reduced, so the control unit 210 controls to reduce the liquid fertilizer concentration of the mixed nutrient solution flowing down the water supply pipe 130.

[0119] When the processing unit 214 judges that the detected physical quantity is less than the threshold value, in step S145, it decides to reduce the passage opening of the flow control valve 171A by the increased opening. The value of the increased opening used in the judgment process of step S145 is stored in advance in the memory unit 213 or the information storage unit 500. The signal output unit 212 outputs a control signal to the flow control valve 171A, which is increased by the increased opening from the current passage opening. By this process, the water that is diverted from the water supply pipe 130 and flows down the sub-path 17 is controlled to increase. Therefore, the suction force by the Venturi tube 163 increases, and the amount of liquid fertilizer that is sucked from the tank 161 and mixed into the Venturi tube 163 increases. Therefore, the amount of liquid fertilizer contained in the mixed fluid flowing down the sub-path 17 increases, so the control unit 210 controls to increase the liquid fertilizer concentration of the mixed nutrient solution flowing down the water supply pipe 130.

[0120] The processing from steps S130 to S145 is executed until it is determined in step S150 that a predetermined time has elapsed. The predetermined time used in the determination processing in step S150 is stored in advance in the memory unit 213 or the information storage unit 500. When it is determined in step S150 that a predetermined time has elapsed, the control unit 210 controls the pump 110 to a stopped state in step S160. Furthermore, the control unit 210 controls the flow control valve 171A so that the passage opening degree becomes zero in step S170. After executing step S170, the flow chart shown in FIG. 11 is ended and the liquid fertilizer supply control is ended. When the next liquid fertilizer supply timing arrives, the processing in step S110 is executed again, and the subsequent processing is continued.

[0121] The flow rate adjustment mechanism of the second embodiment includes a flow rate control valve 171A that controls the passage opening degree of the sub-path 17 according to the detection value of the physical quantity sensor 173 upstream of the mixed flow portion. This makes it possible to provide a sub-path 17 having a configuration in which the flow rate control valve 171A does not directly contact the liquid fertilizer. Each part built into the flow rate control valve 171A is not present in a flow path that contacts the liquid fertilizer that is highly acidic or alkaline. This makes it possible to reduce the frequency of maintenance of parts such as movable parts such as valves. Furthermore, it is possible to expand the selection of materials used for each of these parts. Since the detection value of the physical quantity sensor 173 changes according to the fluctuation of the fluid flow in the main path, the accuracy of liquid fertilizer mixing can be achieved by adjusting the opening degree of the control valve according to the fluctuation of the fluid flow in the main path.

[0122] The flow control valve 171A of the third embodiment is configured to set the valve 90 to an open state or a closed state depending on the rotational position of the valve 90 as a valve body. The flow control valve 171A includes a rotation angle sensor 73 that detects the rotation angle of a gear portion 72 that transmits a rotational force to the valve 90. This configuration makes it possible to provide a flow control valve 171A that is capable of detecting a malfunction based on the detection value of the rotation angle sensor 73, and improves the detection accuracy of functional deterioration or malfunction of the liquid fertilizer supply unit.

[0123] The flow control valve 171A includes a motor 71 that outputs a torque for rotating the valve 90, and a gear unit 72 that transmits the output of the motor 71 to the valve 90 via a worm gear 712. With this configuration, since it is not essential to maintain electrical current in the open valve state, it is possible to provide a flow adjustment function unit that can reduce power consumption, thereby reducing the labor required for the liquid fertilizer supply unit.

[0124] Third embodiment The third embodiment will be described with reference to Figures 12 to 15. The irrigation system 1 of the third embodiment differs from the second embodiment in the configuration of the liquid fertilizer supply unit 120. The configurations, actions, and effects of the third embodiment that are not specifically described are the same as those of the above-mentioned embodiments, and only the differences will be described below.

[0125] The liquid fertilizer supplying unit 120 of the third embodiment differs from the liquid fertilizer supplying unit 120 of the second embodiment in that it includes an auxiliary pump 174 instead of a flow control valve 171A. As shown in Figures 12 and 13, the liquid fertilizer supplying unit 120 of the third embodiment has the same configuration as the liquid fertilizer supplying unit 120 of the second embodiment, except that it includes the auxiliary pump 174.

[0126] The auxiliary pump 174 functions as a flow rate adjustment mechanism that can control the flow rate of the fluid in the secondary path 17 in accordance with the detection value of the physical quantity sensor 173. The auxiliary pump 174 is a pump having a smaller discharge capacity than the pump 110, which is the main pump. For example, a booster pump can be used as the auxiliary pump 174. As shown in FIG. 14 , the signal output unit 212 is electrically connected to the auxiliary pump 174. A control signal for controlling the operation of the auxiliary pump 174 is output from the signal output unit 212 to the auxiliary pump 174. The control unit 210 can control the flow rate of the fluid flowing through the secondary path 17 by controlling the discharge capacity of the auxiliary pump 174.

[0127] The irrigation system 1 executes liquid fertilizer supply control according to the flowchart shown in Fig. 15. Fig. 15 is a flowchart showing an example of operation at the liquid fertilizer supply timing. The control unit 210 executes each process shown in Fig. 15. In Fig. 15, steps having the same reference numbers as those shown in Fig. 11 execute the same processes as in the second embodiment.

[0128] The control unit 210 controls the pump 110 to an operating state in step S110, and controls the auxiliary pump 174 to have a predetermined rotation speed in step S120A. The predetermined rotation speed used in the judgment process in step S120A is stored in advance in the memory unit 213 or the information storage unit 500. The signal output unit 212 outputs a control signal that satisfies the predetermined rotation speed to the auxiliary pump 174. By this process, the water flowing down the water supply pipe 130 is drawn into the sub-path 17 and diverted. The liquid fertilizer in the tank 161 is sucked into the Venturi tube 163 according to the fluid flow rate by the auxiliary pump 174, mixed with the water, and flows down the sub-path 17.

[0129] When the processing unit 214 determines that the detection value of the sensor exceeds the threshold value, it decides to reduce the rotation speed of the auxiliary pump 174 by the reduced rotation number in step S140A. The value of the reduced rotation speed used in the determination process of step S140A is stored in advance in the memory unit 213 or the information storage unit 500. The signal output unit 212 outputs a control signal that reduces the current rotation speed by the reduced rotation number to the auxiliary pump 174. By this process, similar to S140 described in the second embodiment, the control unit 210 controls so as to reduce the liquid fertilizer concentration of the mixed nutrient solution flowing down the water supply pipe 130.

[0130] When the processing unit 214 determines that the detection value of the sensor is less than the threshold value, it decides to increase the rotation speed of the auxiliary pump 174 by the increased rotation number in step S145A. The value of the increased rotation speed used in the determination process of step S145A is stored in advance in the memory unit 213 or the information storage unit 500. The signal output unit 212 outputs a control signal that is increased by the increased rotation number with respect to the current rotation speed to the auxiliary pump 174. By this process, similar to S145 described in the second embodiment, the control unit 210 controls so as to increase the liquid fertilizer concentration of the mixed nutrient solution flowing down the water supply pipe 130.

[0131] The processing from steps S130 to S145A is executed until it is determined in step S150 that a predetermined time has elapsed. When the predetermined time has elapsed, the control unit 210 controls the pump 110 to a stopped state in step S160, and stops the operation of the auxiliary pump 174 in step S170A. After execution of step S170A, the flow chart shown in Fig. 15 is ended, and the liquid fertilizer supply control is terminated. When the next liquid fertilizer supply timing arrives, the processing shown in Fig. 15 is resumed, and the processing from step S110 onwards is executed.

[0132] The flow rate adjustment mechanism of the third embodiment includes an auxiliary pump 174 that controls the flow rate of the fluid flowing down the auxiliary path 17 according to the detection value of the physical quantity sensor upstream of the mixed flow area. This makes it possible to provide the auxiliary path 17 having a configuration in which the auxiliary pump 174 does not directly come into contact with the liquid fertilizer. Each part of the auxiliary pump 174 is not present in a flow path that comes into contact with the liquid fertilizer that is highly acidic or alkaline. This makes it possible to reduce the frequency of maintenance of the parts of the auxiliary pump 174. Furthermore, it is possible to expand the selection of materials to be used for each part of the auxiliary pump 174. In addition, since the detection value of the physical quantity sensor 173 varies according to the fluctuation of the fluid flow in the main path, the accuracy of liquid fertilizer mixing can be improved by adjusting the pump rotation speed according to the fluctuation of the fluid flow in the main path.

[0133] Fourth embodiment The fourth embodiment will be described with reference to Figs. 16 to 19. The irrigation system 1 of the fourth embodiment differs from the second embodiment in that liquid fertilizer supply control is executed using the detection value of the soil sensor 18. The liquid fertilizer supply control of the fourth embodiment determines the timing to end liquid fertilizer supply based on the detection value of the soil sensor 18. The configurations, actions, and effects of the fourth embodiment that are not specifically described are the same as those of the above-mentioned embodiments, and only the differences will be described below.

[0134] As shown in Figs. 16 and 17, the liquid fertilizer supplying unit 120 of the fourth embodiment has the same configuration as the liquid fertilizer supplying unit 120 of the second embodiment. The irrigation system 1 of the fourth embodiment detects the soil condition of the field using a soil sensor 18. Physical quantities related to the soil condition detected by the soil sensor 18 indicate the soil moisture condition, such as soil water tension (pF value) and soil dielectric constant (ε). The irrigation system 1 can individually control the soil condition of each divided area based on the detection value of the soil sensor 18, and further control the concentration of liquid fertilizer contained in the soil.

[0135] 18, the acquisition unit 211 is electrically connected to each of the physical quantity sensor 173, the soil sensor 18, and the flow control valve 171A. In the drawing, the soil sensor 18 is denoted as S2. The acquisition unit 211 receives input of a physical quantity indicating the soil condition detected by the soil sensor 18.

[0136] The irrigation system 1 executes liquid fertilizer supply control according to the flowchart shown in Fig. 19. Fig. 19 is a flowchart showing an example of operation at the liquid fertilizer supply timing. The control unit 210 executes each process shown in Fig. 19. In Fig. 19, steps having the same reference numbers as those shown in Fig. 11 execute the same processes as in the second embodiment.

[0137] The processing from step S130 to S145 is executed until it is determined in step S150A that the detection value of the soil sensor 18 is equal to or greater than a predetermined value. When the detection value of the soil sensor 18 is equal to or greater than a predetermined value, it can be determined that the amount of liquid fertilizer in the soil has reached, for example, the above-mentioned recommended amount of liquid fertilizer. The predetermined value used in the determination processing in step S150A is stored in advance in the memory unit 213 or the information storage unit 500. When it is determined that the detection value of the soil sensor 18 is equal to or greater than a predetermined value, the control unit 210 controls the pump 110 to a stopped state and controls the flow control valve 171A to a fully closed state. After the execution of step S170, the flow chart shown in FIG. 19 is ended and the liquid fertilizer supply control is ended. When the next liquid fertilizer supply timing arrives, the processing shown in FIG. 19 is resumed and the processing from step S110 onward is executed. The liquid supply control shown in FIG. 19 determines whether or not to perform the determination processing in step S130 based on the detection value of the soil sensor 18. The liquid supply control shown in FIG. 19 executes steps S140 or S145 based on the detection value of the soil sensor 18, and therefore executes flow rate control by the flow rate control valve 171A.

[0138] The irrigation system 1 of the fourth embodiment includes a soil sensor 18 that detects the soil condition of the field. The flow control valve 171A controls the flow rate of the fluid flowing down the sub-path 17 based on the detection value of the soil sensor 18. This makes it possible to prevent an excessive amount of liquid fertilizer from being supplied based on the soil condition, thereby suppressing the amount of liquid fertilizer used and suppressing inappropriate loading of the soil.

[0139] The irrigation system 1 of the fourth embodiment includes a control unit 210 that controls the operation of the flow rate adjustment mechanism unit. The control unit 210 determines whether to end the flow rate control of the sub-path 17 in accordance with the detection value of the first physical quantity sensor using the flow rate control valve 171A, based on the detection value of the soil sensor 18. The control unit 210 determines whether to end the control of the flow rate of the fluid flowing down the sub-path 17 in accordance with the detection value of the first physical quantity sensor, based on the detection value of the soil sensor 18. In this way, the timing to end the control of the flow rate control valve is determined based on the state of the soil, so that liquid fertilizer supply control can be performed that ensures that the soil contains an appropriate amount of liquid fertilizer.

[0140] Fifth embodiment The fifth embodiment will be described with reference to Figures 20 to 23. The irrigation system 1 of the fifth embodiment differs from the fourth embodiment in that it includes an auxiliary pump 174 instead of the flow control valve 171A. As shown in Figures 20, 21 and 22, the liquid fertilizer supplying section 120 of the fifth embodiment has the same configuration as the liquid fertilizer supplying section 120 of the third embodiment, except that it includes the auxiliary pump 174.

[0141] The liquid fertilizer supply control of the fifth embodiment determines the timing of liquid fertilizer supply termination based on the detection value of the soil sensor 18, similarly to the liquid fertilizer supply control of the fourth embodiment. The irrigation system 1 executes liquid fertilizer supply control according to the flowchart shown in FIG. 23. FIG. 23 is a flowchart showing an example of operation at the liquid fertilizer supply timing. The control unit 210 executes each process shown in FIG. 23. In FIG. 23, the steps with the same reference numbers as those shown in FIG. 19 execute the same processes as in the fourth embodiment. In steps S120A, S140A, S145A, and S170A in FIG. 23, the same processes as in the third embodiment are executed. The liquid supply control shown in FIG. 23 determines whether or not to execute the determination process of step S130 based on the detection value of the soil sensor 18. The liquid supply control shown in FIG. 23 executes step S140A or S145A based on the detection value of the soil sensor 18, so that the flow rate control by the auxiliary pump 174 is executed.

[0142] The irrigation system 1 of the fifth embodiment includes a soil sensor 18 that detects the soil condition of the field. The auxiliary pump 174 controls the flow rate of the fluid flowing down the sub-path 17 based on the detection value of the soil sensor 18. This makes it possible to prevent an excessive amount of liquid fertilizer from being supplied based on the soil condition, thereby suppressing the amount of liquid fertilizer used and suppressing inappropriate load on the soil.

[0143] The irrigation system 1 of the fifth embodiment includes a control unit 210 that controls the operation of the flow rate adjustment mechanism. The control unit 210 determines whether to end the flow rate control of the sub-pathway 17 in accordance with the detection value of the first physical quantity sensor using the auxiliary pump 174, based on the detection value of the soil sensor 18. In this way, the timing to end the auxiliary pump control is determined based on the state of the soil, so that liquid fertilizer supply control can be performed that ensures that the soil contains an appropriate amount of liquid fertilizer.

[0144] Sixth embodiment The sixth embodiment will be described with reference to Figs. 24 to 27. The irrigation system 1 of the sixth embodiment differs from the second embodiment in that liquid fertilizer supply control is performed using detected values ​​such as the EC value of irrigation water. The liquid fertilizer supply control of the sixth embodiment includes controlling the passage opening degree of the flow control valve 171A based on the detected value of a physical quantity sensor 19 that detects the physical quantity of irrigation water. The configurations, actions, and effects of the sixth embodiment that are not specifically described are the same as those of the above-mentioned embodiments, and only the differences will be described below.

[0145] As shown in Figs. 24 and 25, the liquid fertilizer supply unit 120 of the sixth embodiment is different from the liquid fertilizer supply unit 120 of the second embodiment in that it further includes a physical quantity sensor 19. The physical quantity sensor 19 is a sensor that detects a physical quantity indicating the state of irrigation in the water supply pipe 130. The physical quantity sensor 19 is, for example, a pH sensor that detects the pH value of the irrigation water, an EC sensor that detects the EC value that indicates the ion concentration of the irrigation water, or the like. The pH value and EC value of the irrigation water need to be controlled so as to satisfy an appropriate range or a recommended amount of liquid fertilizer for the growth of plants. The physical quantity sensor 19 detects the state of irrigation downstream of the mixing portion where the liquid fertilizer sucked by the liquid fertilizer suction unit 16 mixes with the sub-path 17. The irrigation system 1 can control the amount of liquid fertilizer contained in the irrigation water supplied to the field based on the detection value of the physical quantity sensor 19. The physical quantity sensor 19 corresponds to a second physical quantity sensor.

[0146] 26, the acquisition unit 211 is electrically connected to each of the physical quantity sensor 173, the physical quantity sensor 19, and the flow control valve 171A. In the drawing, the physical quantity sensor 19 is denoted as S3. The acquisition unit 211 receives an input of a physical quantity that indicates the state of irrigation detected by the physical quantity sensor 19.

[0147] The irrigation system 1 executes liquid fertilizer supply control according to the flowchart shown in Fig. 27. Fig. 27 is a flowchart showing an example of operation at the liquid fertilizer supply timing. The control unit 210 executes each process shown in Fig. 27. In Fig. 27, steps with the same reference numbers as those shown in Fig. 11 execute the same processes as in the second embodiment. Only the processes that differ from the second embodiment will be explained below.

[0148] In step S130, the control unit 210 compares the detected physical quantity with a threshold value, determines whether the two are larger or smaller, and executes the processes of steps S140 and S145, and then executes S200. The acquisition unit 211 acquires the physical quantity detected by the physical quantity sensor 19 in order to detect the amount of liquid fertilizer during irrigation. In step S200, the processing unit 214 compares the detected physical quantity with a threshold value and determines whether the two are larger or smaller. Step S200 is a determination process for determining the passage opening degree by the flow control valve 171A. The liquid fertilizer concentration threshold used in the determination process of step S200 is stored in advance in the memory unit 213 or the information storage unit 500. The liquid fertilizer concentration threshold is a value set according to the type of crop, the type of soil, and the like. The liquid fertilizer concentration threshold may be a value that is updated according to the season, temperature, the amount of solar radiation, and the like. The liquid fertilizer concentration threshold may be configured to be updated by an instruction value input by a user to the integrated calculation unit 600 using the input device 800. The processing unit 214 executes the determination process of step S200 using the liquid fertilizer concentration threshold value updated as necessary.

[0149] When the processing unit 214 judges that the detected physical quantity exceeds the liquid fertilizer concentration threshold, it decides to reduce the passage opening of the flow control valve 171A by the reduced opening in step S210. The value of the reduced opening used in the process of step S210 is stored in advance in the memory unit 213 or the information storage unit 500. The signal output unit 212 outputs a control signal that reduces the current passage opening by the reduced opening to control the flow control valve 171A. By the process of step S210, the water that is diverted from the water supply pipe 130 and flows down the sub-path 17 is controlled to decrease. By the process of step S210, the control unit 210 controls the liquid fertilizer concentration of the mixed nutrient solution flowing down the water supply pipe 130 to decrease, similar to S140 described in the second embodiment.

[0150] When the processing unit 214 judges that the detected physical quantity is less than the liquid fertilizer concentration threshold, in step S215, it decides to reduce the passage opening of the flow control valve 171A by the increased opening. The value of the increased opening used in the process of step S215 is stored in advance in the memory unit 213 or the information storage unit 500. The signal output unit 212 outputs a control signal that is increased by the increased opening from the current passage opening to control the flow control valve 171A. By the process of step S215, the water that is diverted from the water supply pipe 130 and flows down the sub-path 17 is controlled to increase. By the process of step S210, the control unit 210 controls the liquid fertilizer concentration of the mixed nutrient solution flowing down the water supply pipe 130 to increase, similar to S140 described in the second embodiment.

[0151] The processing from steps S130 to S215 is executed until it is determined in step S220 that a predetermined time has elapsed. In steps S220, S230, and S240 shown in Fig. 27, the same processing as in steps S150, S160, and S170 shown in Fig. 11 is executed. After execution of step S240, the flow chart shown in Fig. 27 is ended, and the liquid fertilizer supply control is terminated. When the next liquid fertilizer supply timing arrives, the processing shown in Fig. 27 is resumed, and the processing from step S110 onwards is executed.

[0152] The irrigation system 1 of the sixth embodiment includes a second physical quantity sensor that detects the pH value or EC value of the irrigation water flowing downstream of the mixed flow portion. The flow control valve 171A controls the flow rate of the fluid flowing down the sub-path 17 based on the detection value of the second physical quantity sensor in addition to controlling the flow rate of the fluid flowing down the sub-path 17 according to the detection value of the first physical quantity sensor. This allows the flow control valve 171A to be controlled so as to appropriately adjust the amount of liquid fertilizer suctioned by the liquid fertilizer suction unit 16, and further allows the flow control valve 171A to be controlled based on a physical quantity indicating the amount of liquid fertilizer contained in the irrigation water immediately before it is supplied to the field. The sixth embodiment provides an irrigation system 1 that can generate highly accurate irrigation water containing an appropriate amount of liquid fertilizer by combining these controls of the amount of liquid fertilizer.

[0153] Seventh embodiment The seventh embodiment will be described with reference to Figures 28 to 31. The irrigation system 1 of the seventh embodiment differs from the sixth embodiment in that it includes an auxiliary pump 174 instead of the flow control valve 171A. As shown in Figures 28, 29 and 30, the liquid fertilizer supplying section 120 of the seventh embodiment has the same configuration as the liquid fertilizer supplying section 120 of the sixth embodiment, except that it includes the auxiliary pump 174.

[0154] In the liquid fertilizer supply control of the seventh embodiment, the fluid driving force of the auxiliary pump 174 is controlled based on the detection value of the physical quantity sensor 19. The irrigation system 1 executes liquid fertilizer supply control according to the flowchart shown in FIG. 31. FIG. 31 is a flowchart showing an example of operation at the liquid fertilizer supply timing. The control unit 210 executes each process shown in FIG. 31. In FIG. 31, the steps having the same reference numbers as those shown in FIG. 27 execute the same processes as in the sixth embodiment. In steps S120A, S140A, and S145A in FIG. 31, the same processes as in the steps having the same reference numbers in FIG. 23 are executed. In steps S210A, S215A, and S240A in FIG. 31, processes different from those in the sixth embodiment are executed.

[0155] When the processing unit 214 determines that the detection value of the physical quantity sensor 19 exceeds the liquid fertilizer concentration threshold, it decides to reduce the rotation speed of the auxiliary pump 174 by the reduced rotation number in step S210A. The value of the reduced rotation number used in the processing of step S210A is stored in advance in the memory unit 213 or the information storage unit 500. By the processing of step S210A, similar to S210 described in the sixth embodiment, the control unit 210 controls so as to reduce the liquid fertilizer concentration of the mixed nutrient solution flowing down the water supply pipe 130.

[0156] When the processing unit 214 determines that the detection value of the physical quantity sensor 19 is less than the liquid fertilizer concentration threshold value, it decides to increase the rotation speed of the auxiliary pump 174 by an increased number of rotations in step S215A. The value of the increased rotation speed used in the processing of step S215A is stored in advance in the memory unit 213 or the information storage unit 500. By the processing of step S215A, similar to S215 described in the sixth embodiment, the control unit 210 controls so as to increase the liquid fertilizer concentration of the mixed nutrient solution flowing down the water supply pipe 130.

[0157] The processing from steps S130 to S215A is executed until it is determined in step S220 that a predetermined time has elapsed. When the predetermined time has elapsed, the control unit 210 controls the pump 110 to a stopped state in step S230, and stops the operation of the auxiliary pump 174 in step S240A. After execution of step S240A, the flow chart shown in Fig. 31 is ended, and the liquid fertilizer supply control is terminated. When the next liquid fertilizer supply timing arrives, the processing shown in Fig. 31 is resumed, and the processing from step S110 onwards is executed.

[0158] The irrigation system 1 of the seventh embodiment includes a second physical quantity sensor that detects the pH value or EC value of the irrigation water flowing downstream of the mixed flow portion. The auxiliary pump 174 controls the flow rate of the fluid flowing down the sub-path 17 based on the detection value of the second physical quantity sensor, in addition to controlling the flow rate of the fluid flowing down the sub-path 17 according to the detection value of the first physical quantity sensor. This makes it possible to control the auxiliary pump 174 so as to appropriately adjust the amount of liquid fertilizer suctioned by the liquid fertilizer suction unit 16, and further control the auxiliary pump 174 based on a physical quantity indicating the amount of liquid fertilizer contained in the irrigation water immediately before it is supplied to the field. The seventh embodiment provides an irrigation system 1 that can generate highly accurate irrigation water containing an appropriate amount of liquid fertilizer by combining these controls of the amount of liquid fertilizer.

[0159] Eighth embodiment The eighth embodiment will be described with reference to Fig. 32. The irrigation system 1 of the eighth embodiment differs from each of the above-mentioned embodiments in that it includes a liquid fertilizer supplying unit 120A including a plurality of liquid fertilizer suction units 16. As shown in Fig. 32, the liquid fertilizer supplying unit 120A of the eighth embodiment has a plurality of sub-pathways 17 in which a plurality of the liquid fertilizer supplying units 120 in each of the above-mentioned embodiments are connected in parallel. Fig. 32 discloses, as a representative example, a liquid fertilizer supplying unit 120A having a plurality of sub-pathways 17 in which a plurality of the liquid fertilizer supplying units 120 of the second embodiment shown in Fig. 8 are connected in parallel.

[0160] The liquid fertilizer supply unit 120A includes an integrated pump 175 that drives a fluid downstream of a junction where a plurality of liquid fertilizer supply units 120 described in each of the above-described embodiments are connected in parallel. The integrated pump 175 has a smaller discharge capacity than the pump 110, which is the main pump. For example, a booster pump can be used as the integrated pump 175. The integrated pump 175 is a pump that draws the mixed fluid containing liquid fertilizer flowing down each of the plurality of sub-paths 17 into the water supply pipe 130. The integrated pump 175 may also be configured to be provided upstream of a branching portion that branches into the plurality of sub-paths 17.

[0161] The irrigation system 1 of the eighth embodiment includes a plurality of sub-paths 17. The plurality of sub-paths 17 are connected in parallel to the main path. With this configuration, it is possible to provide an irrigation system 1 that can improve the amount of liquid fertilizer supplied to irrigation water. With this configuration, it is possible to provide an irrigation system 1 that can ensure the supply of liquid fertilizer even if a problem occurs in any of the plurality of sub-paths 17.

[0162] An integrated pump 175 that controls the flow rate of the fluid is provided in the passage connecting the multiple sub-paths 17 and the main path. With this configuration, the flow rate is controlled by each flow rate adjustment mechanism provided in each sub-path 17, so the capacity and size of the integrated pump 175 can be reduced. Therefore, an irrigation system 1 can be provided that can reduce product costs and save labor.

[0163] <Other embodiments> The disclosure of this specification is not limited to the exemplified embodiments. The disclosure includes the exemplified embodiments and modifications by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of parts and elements shown in the embodiments, and can be implemented in various modifications. The disclosure can be implemented by various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure includes those in which parts and elements of the embodiments are omitted. The disclosure includes the replacement or combination of parts and elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is indicated by the description of the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the description of the claims.

[0164] Each component of the irrigation system and liquid fertilizer supply unit shown in each drawing is a functional concept, and does not necessarily have to be physically configured as shown in the drawings. For example, the specific form of distribution and integration of each functional block is not limited to that shown in the drawings, and all or part of it can be functionally or physically distributed and integrated in any unit depending on various loads and usage conditions.

[0165] The apparatus and methods described herein may be implemented by a special purpose computer having a processor programmed to perform one or more functions embodied in a computer program. Alternatively, the apparatus and methods described herein may be implemented by special purpose hardware logic circuitry. Alternatively, the apparatus and methods described herein may be implemented by one or more special purpose computers comprising a processor that executes a computer program in combination with one or more hardware logic circuits. The computer program may also be stored on a computer-readable non-transitory tangible recording medium as instructions that are executed by the computer.

[0166] The irrigation system disclosed herein may also be used for indoor cultivation or for soil-free cultivation such as hydroponics.

[0167] Disclosure of technical ideas This specification discloses a number of technical ideas described in the following paragraphs. Some paragraphs may be described in a multiple dependent form, in which the subsequent paragraph alternatively refers to the preceding paragraph. The paragraphs described in the multiple dependent form define a number of technical ideas.

[0168] (Technical thought 1) a main channel (130) through which irrigation water flows to supply to plants; A secondary path (17) including a passage that branches off upstream from the main path and joins the secondary path downstream; a liquid fertilizer suction section (16) that draws liquid fertilizer into the secondary passage using a suction force caused by a fluid flowing down the secondary passage; a flow rate adjusting mechanism (171, 171A, 174) provided in the sub-path upstream of a mixed flow portion where the liquid fertilizer sucked by the liquid fertilizer suction unit flows into the sub-path, and configured to control the flow rate of a fluid flowing down the sub-path; An irrigation system comprising:

[0169] (Technical thought 2) The irrigation system described in Technical Idea 1 is equipped with an automatic flow control valve (171) that has the function of controlling the passage opening degree by itself without using the detection value of a separate sensor installed externally, and controls the flow rate of fluid in the secondary path by itself.

[0170] (Technical Thought 3) a first physical quantity sensor (173) for detecting a flow state of a fluid flowing down the secondary passage; and a check valve (172) for preventing a backflow in the secondary passage upstream of the mixed flow portion, The irrigation system described in Technical Idea 1, wherein the flow control mechanism unit is provided with a flow control valve (171A) upstream of the mixing area that controls the passage opening degree of the secondary path in accordance with the detection value of the first physical quantity sensor.

[0171] (Technical Thought 4) a first physical quantity sensor (173) for detecting a flow state of a fluid flowing down the secondary passage; and a check valve (172) for preventing a backflow in the secondary passage upstream of the mixed flow portion, The irrigation system described in Technical Idea 1, wherein the flow control mechanism unit is provided with an auxiliary pump (174) upstream of the mixing area that controls the flow rate of fluid flowing down the secondary path in accordance with the detection value of the first physical quantity sensor.

[0172] (Technical Thought 5) A soil sensor (18) is provided for detecting a soil condition of a field, The irrigation system according to Technical Idea 3 or Technical Idea 4, wherein the flow rate adjustment mechanism controls the flow rate of the fluid flowing down the secondary path based on the detection value of the soil sensor.

[0173] (Technical Thought 6) A control unit (210) for controlling the operation of the flow rate adjustment mechanism unit, The control unit (210) of the irrigation system according to technical idea 5 determines whether or not to terminate control of the flow rate of the fluid flowing down the secondary path in accordance with the detection value of the first physical quantity sensor, based on the detection value of the soil sensor.

[0174] (Technical Thought 7) a second physical quantity sensor (19) for detecting a pH value or an EC value of the irrigation water flowing downstream of the mixed flow portion; The flow rate control mechanism of the irrigation system described in Technical Idea 3 or Technical Idea 4 controls the flow rate of fluid flowing down the secondary route based on the detection value of the second physical quantity sensor, in addition to controlling the flow rate of fluid flowing down the secondary route in accordance with the detection value of the first physical quantity sensor.

[0175] (Technical Thought 8) A plurality of the sub-paths are provided, The plurality of sub-paths are connected in parallel to the main path, An irrigation system according to any one of technical ideas 1 to 7, wherein an integrated pump (175) for controlling the flow rate of fluid is provided in a passage connecting the multiple sub-paths and the main path. [Explanation of symbols]

[0176] 16...Liquid fertilizer suction section, 17...Sub-path, 18...Soil sensor, 19...Physical quantity sensor (second physical quantity sensor), 130...Water supply pipe (main path), 171...Automatic flow control valve (flow adjustment mechanism section), 171A...Flow control valve (flow adjustment mechanism section), 172...Check valve, 173...Physical quantity sensor (first physical quantity sensor), 174...Auxiliary pump (flow adjustment mechanism section), 175...Integrated pump

Claims

1. A main channel (130) through which irrigation water flows to supply to plants; A secondary route (17) including a passage that branches off upstream from the main route and joins further downstream; A liquid fertilizer suction section (16) that sucks liquid fertilizer into the secondary passage using a suction force caused by a fluid flowing down the secondary passage; A flow rate control mechanism (171, 171A, 174) is provided in the sub-path upstream of a mixed flow portion where the liquid fertilizer sucked by the liquid fertilizer suction unit flows into the sub-path, and controls the flow rate of the fluid flowing down the sub-path; An irrigation system comprising:

2. The irrigation system of claim 1, wherein the flow control mechanism unit is provided with an automatic flow control valve (171) that has the function of controlling the passage opening degree by itself without using the detection value of a separate sensor installed externally, and controls the flow rate of fluid in the secondary path by itself.

3. a first physical quantity sensor (173) for detecting a flow state of a fluid flowing down the secondary path, and a check valve (172) for suppressing a backflow in the secondary path upstream of the mixed flow portion, The irrigation system of claim 1, wherein the flow rate adjustment mechanism is provided with a flow rate control valve (171A) upstream of the mixing area that controls the passage opening degree of the secondary path in accordance with the detection value of the first physical quantity sensor.

4. a first physical quantity sensor (173) for detecting a flow state of a fluid flowing down the secondary path, and a check valve (172) for suppressing a backflow in the secondary path upstream of the mixed flow portion, The irrigation system of claim 1, wherein the flow control mechanism includes an auxiliary pump (174) upstream of the mixing area that controls the flow rate of fluid flowing down the secondary path in accordance with the detection value of the first physical quantity sensor.

5. A soil sensor (18) is provided for detecting the soil condition of a field; 5. The irrigation system according to claim 3, wherein the flow rate adjustment mechanism controls the flow rate of the fluid flowing down the sub-path based on a detection value of the soil sensor.

6. A control unit (210) for controlling the operation of the flow rate adjustment mechanism unit, The irrigation system of claim 5, wherein the control unit (210) determines whether or not to terminate control of the flow rate of the fluid flowing down the secondary path in accordance with the detection value of the first physical quantity sensor, based on the detection value of the soil sensor.

7. a second physical quantity sensor (19) for detecting a pH value or an EC value of the irrigation water flowing downstream of the mixed flow portion; The irrigation system of claim 3 or claim 4, wherein the flow rate control mechanism controls the flow rate of fluid flowing down the secondary route based on the detection value of the second physical quantity sensor, in addition to controlling the flow rate of fluid flowing down the secondary route in accordance with the detection value of the first physical quantity sensor.

8. A plurality of the sub-paths are provided, The plurality of sub-paths are connected in parallel to the main path, The irrigation system according to any one of claims 1 to 4, wherein a passage connecting the plurality of sub-paths and the main path is provided with an integrated pump (175) for controlling a flow rate of fluid.

9. The flow control valve is configured to set the valve to an open state or a closed state depending on a rotational position of a valve (90) serving as a valve body, The irrigation system according to claim 3, wherein the flow control valve is provided with a rotation angle sensor (73) that detects a rotation angle of a gear portion (72) that transmits a rotational force to the valve.

10. The flow control valve of the irrigation system described in claim 3 comprises a motor (71) that outputs rotational force to rotate a valve (90) serving as a valve body, and a gear portion (72) that transmits the output of the motor to the valve via a worm gear (712).

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