Patent Description:
Conventionally, in large-scale agricultural fields, irrigation has been performed in order to appropriately maintain the soil moisture content in the entire agricultural fields. Furrow irrigation, sprinkler irrigation, and drip irrigation as shown in <FIG> are known as examples of a main irrigation method. <FIG> is an explanatory diagram for explaining conventional irrigation methods. <FIG> shows features of the irrigation methods.

From among these, the furrow irrigation is rudimentary irrigation, and is not suitable for a large-scale agricultural field in terms of the use efficiency of irrigation water. On the other hand, sprinkler irrigation refers to a method for scattering irrigation water using a sprinkler, and is suitable for a large-scale agricultural field. In addition, with sprinkler irrigation, the equipment cost can be reduced in a large amount, compared with drip irrigation to be described later.

On the other hand, drip irrigation refers to a method in which drip tubes for irrigation are laid in an agricultural field, and irrigation water is supplied and dripped from drippers provided on the drip tubes, to agricultural crops. Commonly, in cultivation of agricultural crops, it is important to supply appropriate amounts of water and fertilizer in accordance with a growth stage. The importance is significant for vegetables such as tomatoes for which more delicate water and fertilizer management is required. Also, in drip irrigation, irrigation can be performed at the bases of crops in a pinpoint manner, and thus more delicate water management is enabled. Moreover, in drip irrigation, water with fertilizer mixed therein can also be used as irrigation water, and, in this case, delicate fertilizer management is also enabled. Therefore, drip irrigation is suitable for crops such as tomatoes for which delicate water and fertilizer management is required.

The equipment cost for drip irrigation is high, but an appropriate amount of water can be efficiently supplied to agricultural crops in this manner. Therefore, in drip irrigation, it is possible to reliably supply water to agricultural crops, compared with sprinkler irrigation, and it is possible to reduce the use amount of water in a large amount. Therefore, when agricultural crops, for which there is demand for strict management of a soil moisture content, are cultivated, drip irrigation is mainly adopted.

Incidentally, in an actual agricultural field in which drip irrigation is adopted, the amount of irrigation water that is supplied is manually managed in most cases. Specifically, a worker opens a supply valve at a start time and closes the supply valve at an end time in accordance with a plan made by a manager. The flow amount of irrigation water that is discharged from the supply valve is constant, and thus the amount of irrigation water that is supplied is managed by appropriately setting the start time and the end time.

However, in actuality, there are cases where times when a worker opens and closes a valve are respectively different from a start time and an end time that have been set in a plan. There is also the possibility that the degree of this difference will change depending on a worker. As a result, it may be difficult to strictly manage the amount of irrigation water that is supplied.

In view of this, Patent Document <NUM> discloses a system that mechanically controls a supply amount of irrigation water in irrigation. Specifically, the system disclosed in Patent Document <NUM> manages a supply amount of irrigation water by opening a valve if it is determined that the amount of moisture in soil reaches a lower limit, and closing the valve if it is determined that the moisture content reaches an upper limit, based on data output from a sensor and estimated data of climate and moisture in soil.

<CIT> and <CIT> illustrate alternative irrigation water amount measurement apparatus and associated methods.

Incidentally, usually, if drip irrigation is adopted, an agricultural field is divided into several sections, and supply lines that include drip tubes are constructed for the respective sections. Supply valves are installed between a water source and the respective supply lines, and a worker opens/closes the supply valves according to an established plan, for the respective supply lines.

Accordingly, in drip irrigation, a moisture content in soil differs for each of the sections, and is not uniform. Therefore, the system disclosed in Patent Document <NUM> is not based on the assumption that a moisture content is measured for each section, and thus, if this system is applied to drip irrigation without any change, there is the possibility that an error in the supply amount of irrigation water will be too large.

On the other hand, it is conceivable that the above problem is solved if the system disclosed in Patent Document <NUM> is introduced with estimation of data and control of supply valves being enabled for each section, but, in this case, the equipment cost will be very high.

An example object of the invention is to provide an irrigation water amount measurement apparatus, an irrigation water amount measurement method, and a computer program that solve the foregoing problem, and that can enable strict management of the amount of irrigation water that is supplied to an agricultural field in which drip irrigation is adopted, while suppressing an increase in the equipment cost.

The foregoing object is achieved by the features of the independent claims.

As described above, according to the invention, it is possible to perform strict management of the amount of irrigation water that is supplied to an agricultural field in which a drip irrigation is adopted.

An irrigation water amount measurement apparatus, an irrigation water amount measurement method, and a program according to an example embodiment of the invention will be described below with reference to <FIG>.

First, the configuration of the irrigation water amount measurement apparatus according to the example embodiment will be described with reference to <FIG> is a configuration diagram showing the configuration of the irrigation water amount measurement apparatus according to the example embodiment of the invention.

An irrigation water amount measurement apparatus <NUM> according to the example embodiment shown in <FIG> is an apparatus for measuring a supply amount of irrigation water, in an agricultural field in which a drip irrigation system is installed. As shown in <FIG>, the irrigation water amount measurement apparatus <NUM> includes a sensor data obtaining unit <NUM>, an irrigation water amount measurement unit <NUM>, an irrigation time specifying unit <NUM>, and a calculation processing unit <NUM>.

The sensor data obtaining unit <NUM> obtains sensor data for specifying soil moisture contents in respective sections resulting from dividing the agricultural field into a plurality of pieces, from moisture sensors installed in the respective sections. The irrigation water amount measurement unit <NUM> measures a supply amount of irrigation water supplied from a drip irrigation system <NUM> (hereinafter, referred to as a "total irrigation water amount"), in the entire agricultural field, during a period from start to end of irrigation.

The irrigation time specifying unit <NUM> specifies, for each of the sections, a period of time during which irrigation water was supplied to the section, based on a change state of the soil moisture content of the section specified by the sensor data. The calculation processing unit <NUM> calculates, for each of the sections, a supply amount of irrigation water supplied to the section, based on the total irrigation water amount and the period of time specified for the section.

As described above, according to the example embodiment, a supply amount of irrigation water is calculated for each section, based on the feature, in the drip irrigation system, of supplying irrigation water to each section. Therefore, according to the example embodiment, it is possible to strictly manage the amount of irrigation water that is supplied to an agricultural field in which drip irrigation is adopted. Also, according to the example embodiment, it is not necessary to automatically control a valve for each section, and thus an increase in the equipment cost is suppressed. Furthermore, the example embodiment can be applied to an existing drip irrigation system without any change, and thus an increase in the equipment cost is suppressed in this regard as well.

Next, functions of the irrigation water amount measurement apparatus according to the example embodiment will be described in detail with reference to <FIG> is a configuration diagram showing an example where an irrigation water amount measurement apparatus according to an example embodiment of the invention is applied to an irrigation system.

<FIG> shows the drip irrigation system <NUM> and an agricultural field <NUM> to which the irrigation water amount measurement apparatus <NUM> according to the example embodiment is applied. As shown in <FIG>, a plurality of ridges are provided in the agricultural field <NUM>, and crops <NUM> are planted along such ridges. Also, in the example in <FIG>, the agricultural field <NUM> is divided into four sections <NUM> along the ridges. Reference numerals A to D in <FIG> denote identifiers assigned to the respective sections <NUM> to facilitate description.

As shown in <FIG>, the drip irrigation system <NUM> includes supply lines 21a to 21d provided for the respective sections, drip lines 22a to 22d that branch from the respective supply lines, valves 25a to 25d provided for the respective supply lines, a flow meter <NUM>, and a supply tank <NUM>.

The supply lines 21a to 21d are lines for guiding irrigation water of the supply tank <NUM>, which is a water source, to corresponding sections. When one of the valves corresponding to the supply lines 21a to 21d is opened, irrigation water of the supply tank <NUM> is guided to the corresponding section <NUM> via the supply line.

In addition, in the drip irrigation system <NUM> shown in <FIG>, the valves 25a to 25d are opened/closed by a worker sequentially. Specifically, the worker opens, for example, the valve 25a, 25b, 25c, and 25d in the stated order, each for a certain period of time, in accordance with a plan established in advance, and supplies irrigation water to the sections. Note that, in the drip irrigation system <NUM>, only one valve is set to an open state, and, after the valve in the open state is closed, another valve is opened.

The flow meter <NUM> measures a supply amount of irrigation water supplied from the supply tank <NUM> to the agricultural field <NUM> via one of the supply lines. In addition, in the example in <FIG>, the flow meter <NUM> is a pulse-transmitting flow meter, and outputs a pulse signal every time a set amount of fluid flows. According to the example embodiment, an output pulse signal is sent to the irrigation water amount measurement apparatus <NUM>. Note that, according to the example embodiment, the flow meter <NUM> is not limited to the pulse-transmitting type. A case will be described later in which a flow meter <NUM> of another type is used.

The drip lines 22a to 22d are lines that respectively branch from the corresponding supply lines, and are each made of a general agricultural drip tube. Also, the drip lines 22a to 22d are respectively arranged along ridges of the corresponding sections. In the example in <FIG>, the drip line 22a branches from the supply line 21a, the drip line 22b branches from the supply line 21b, the drip line 22c branches from the supply line 21c, and the drip line 22d branches from the supply line 21d.

In addition, as described above, the drip lines 22a to 22d are each made of a drip tube, and thus drippers (not illustrated in <FIG>) are provided at a certain interval in the longitudinal direction on the tube wall of each of the drip lines. The drippers are configured to be capable of irrigating a certain amount of irrigation water as in a drip, and supply an optimum amount of irrigation water to the crops <NUM>.

With such a configuration, the drip irrigation system <NUM> enables pinpoint irrigation at the roots of the crops <NUM>, and thus more delicate water management can be performed. Also, in drip irrigation, fertilizer is supplied in a state of being mixed with water, and thus delicate fertilizer management is also enabled.

Moisture sensors <NUM> are installed in the respective sections <NUM>. Also, each of the moisture sensors <NUM> transmits sensor data for specifying a soil moisture content of the section in which that moisture sensor <NUM> is installed, to the irrigation water amount measurement apparatus <NUM> at a certain interval. The moisture sensor <NUM> outputs an analog signal as sensor data, but, according to the example embodiment, includes a digital/analog conversion circuit, and converts sensor data into a digital signal, and then transmits the digital signal to the irrigation water amount measurement apparatus <NUM>. In addition, in the example in <FIG>, the moisture sensors <NUM> convert sensor data into a digital signal, and transmit the digital signal to the irrigation water amount measurement apparatus <NUM> through wireless communication. Sensor data may also be transmitted in a wired manner.

When sensor data is transmitted, the sensor data obtaining unit <NUM> obtains the sensor data. In addition, according to the example embodiment, the sensor data obtaining unit <NUM> specifies, based on the sensor data, a soil moisture content in the section in which the moisture sensor <NUM> that transmitted the sensor data is arranged, and outputs the specified soil moisture content to the irrigation time specifying unit <NUM>.

According to the example embodiment, the irrigation water amount measurement unit <NUM> obtains a pulse signal output by the flow meter <NUM>, and measures a total irrigation water amount based on the number of times a pulse signal was obtained. Specifically, the irrigation water amount measurement unit <NUM> measures a total irrigation water amount by multiplying a preset flow amount per pulse by the number of times a pulse signal was obtained.

The irrigation time specifying unit <NUM> first specifies, for each section, a time when a soil moisture content of the section started to rise and a time when a soil moisture content in another section started to rise. The irrigation time specifying unit <NUM> then specifies a period from the former specified time until the latter specified time, as a period during which irrigation water was supplied to that section (hereinafter, referred to as an "irrigation implementation period").

Here, the functions of the irrigation time specifying unit <NUM> will be described in more detail with reference to <FIG> are a diagram showing a soil moisture content measured according to the example embodiment of the invention, and <FIG> shows a case of the section A, and <FIG> shows a case of the section B.

First, as shown in <FIG>, the section A and the section B are adjacent to each other, but the drip lines of the respective sections are respectively connected to the separate supply lines. Assume that, in the examples in <FIG>, supply to the section A is performed, and supply to the section B is then performed. In other words, assume that a worker opens the valve 25a for a predetermined period of time, then closes the value, and then opens the valve 25b.

In this case, as shown in <FIG>, when the valve 25a is opened, the soil moisture content rises in the section A, and, after that, when the valve 25a is closed, the soil moisture content gradually lowers. Also, when the valve 25b is opened, the soil moisture content rises in the section B.

At this time, the irrigation time specifying unit <NUM> specifies, as an irrigation implementation period in the section A, a period from when the soil moisture content in the section A started to rise until when the soil moisture content in the section B started to rise. The irrigation time specifying unit <NUM> also calculates irrigation implementation periods of the sections B to D similarly. In addition, the irrigation time specifying unit <NUM> can define a time when a valve corresponding to a section where irrigation water is lastly supplied was closed, as an end time of the irrigation implementation period.

In addition, according to the example embodiment, the calculation processing unit <NUM> calculates a supply amount per unit time by first dividing the total irrigation water amount measured by the irrigation water amount measurement unit <NUM>, by a period during which irrigation water was supplied through irrigation, in other words the total of periods during which the valves 25a to 25d were respectively open (from opening until closing). The calculation processing unit <NUM> then calculates, for each section, a supply amount of irrigation water supplied to the section using Expression <NUM> below.

In addition, according to the example embodiment, assume that times when a worker or the manager of the drip irrigation system <NUM> opened and closed each of the valves 25a to 25d are directly input to the irrigation water amount measurement apparatus <NUM>. In this case, the calculation processing unit <NUM> calculates, based on the input times, a period during which irrigation water was suppled through irrigation. Furthermore, when a signal indicating open/close of a valve is transmitted from each of the valves 25a to 25d to the irrigation water amount measurement apparatus <NUM>, the calculation processing unit <NUM> specifies, based on this signal, times when each of the valves 25a to 25d was opened and closed, and calculates a period during which irrigation water was supplied through irrigation.

Next, operations of the irrigation water amount measurement apparatus <NUM> according to the example embodiment will be described with reference to <FIG> is a flowchart showing operations of the irrigation water amount measurement apparatus according to an example embodiment of the invention. In the following description, <FIG> will be referred to as appropriate. In addition, according to the example embodiment, the irrigation water amount measurement method is implemented by causing the irrigation water amount measurement apparatus <NUM> to operate. Thus, a description of the irrigation water amount measurement method according to the example embodiment is replaced with the following description of operations of the irrigation water amount measurement apparatus <NUM>.

As shown in <FIG>, first, the sensor data obtaining unit <NUM> obtains sensor data transmitted from the moisture sensors <NUM> arranged in the respective sections <NUM> (step A1). Also, in step A1, the sensor data obtaining unit <NUM> specifies, based on the obtained sensor data, soil moisture contents of the respective sections where the moisture sensors <NUM> that transmitted the sensor data are arranged respectively.

Next, the irrigation time specifying unit <NUM> specifies irrigation implementation periods of the respective sections based on the change states of the soil moisture contents specified by the sensor data in step A1 (step A2).

Specifically, in step A2, as shown in <FIG>, a period from when a soil moisture content started to rise in a specific section <NUM> until when a soil moisture content started to rise in another section <NUM> is specified, and that period is defined as an irrigation implementation period of the specific section <NUM>.

Next, the irrigation time specifying unit <NUM> determines whether or not irrigation implementation periods could be specified for all of the sections <NUM> (step A3). As a result of the determination in step A3, if irrigation implementation periods could not be specified for all of the sections <NUM>, the irrigation time specifying unit <NUM> causes the sensor data obtaining unit <NUM> to execute step A1 again.

On the other hand, as a result of the determination in step A3, if irrigation implementation periods could be specified for all of the sections <NUM>, the irrigation time specifying unit <NUM> notifies the irrigation water amount measurement unit <NUM> of that result. Accordingly, the irrigation water amount measurement unit <NUM> measures a total irrigation water amount (step A4).

Specifically, in step A4, the irrigation water amount measurement unit <NUM> obtains pulse signals output by the flow meter <NUM> while irrigation is performed, and measures the number of times a pulse signal was obtained. Accordingly, the irrigation water amount measurement unit <NUM> measures a total irrigation water amount by multiplying the number of times by a preset flow amount per pulse.

Next, the calculation processing unit <NUM> calculates supply amounts of irrigation water supplied to the respective sections, based on the irrigation implementation periods specified in step A2, the period from start to end of irrigation in the entire agricultural field, and the total irrigation water amount measured in step A4 (step A5).

Specifically, in step A5, the calculation processing unit <NUM> calculates a supply amount per unit time by first dividing the total irrigation water amount measured in step A4, by the total of periods during which the valves 25a to 25d were respectively open (from opening until closing). The calculation processing unit <NUM> then calculates, for each of the sections, a supply amount of irrigation water supplied to the section using Expression <NUM> above.

After executing step A5, the irrigation water amount measurement apparatus <NUM> can transmit data for specifying the calculated supply amount of irrigation water of each section, to a terminal apparatus or the like of the manager of the drip irrigation system <NUM>. In this case, the manager can confirm an accurate supply amount of irrigation water of each section, on the terminal apparatus or the like, and can strictly manage a supply amount of irrigation water.

As described above, according to the example embodiment, the amount of supplied irrigation water can be accurately measured for each section using the feature of the drip irrigation system. According to the example embodiment, it is possible to strictly manage a supply amount of irrigation water that is supplied to an agricultural field in which drip irrigation is adopted. In addition, according to the example embodiment, an existing drip irrigation system can be used without any change, and an increase in the equipment cost is suppressed.

Next, Modified Example <NUM> of the irrigation water amount measurement apparatus <NUM> according to the example embodiment will be described with reference to <FIG> is a configuration diagram showing an irrigation water amount measurement apparatus according to Modified Example <NUM> of the example embodiment of the invention.

In this Modified Example <NUM>, the flow meter <NUM> is a type of flow meter that displays, through meter display, a flow amount of irrigation water that has passed through the flow meter. In addition, a digital camera <NUM> is arranged near the flow meter <NUM> such that the meter portion can be shot. The digital camera <NUM> performs shooting at a set interval, and transmits image data obtained through shooting to the irrigation water amount measurement apparatus <NUM> in time series. Note that shooting that is performed by the digital camera <NUM> at the set interval may be performed by the manager, or may also be automatically performed.

Therefore, according to this Modified Example <NUM>, the irrigation water amount measurement unit <NUM> obtains image data of the flow meter <NUM> from the digital camera <NUM> in time series, and measures a total irrigation water amount based on the obtained image data.

Specifically, for example, if the flow meter <NUM> is an analog meter, the irrigation water amount measurement unit <NUM> extracts a needle portion on the meter from image data through image processing, and specifies, from the extracted needle portion, the flow amount of irrigation water that has passed through the flow meter <NUM>. Also, if the flow meter <NUM> is a digital meter that displays a numerical value, the irrigation water amount measurement unit <NUM> extracts a number portion through image processing, and specifies, from the extracted number portion, the flow amount of irrigation water that has passed through the flow meter <NUM>. The irrigation water amount measurement unit <NUM> then calculates a total irrigation water amount based on the specified flow amount.

Next, Modified Example <NUM> will be described. According to the above-described example embodiment, a case has been described in which irrigation water is supplied through drip irrigation, but, according to this Modified Example <NUM>, irrigation is performed using irrigation water with fertilizer mixed therein. Accordingly, an irrigation water amount measurement apparatus in this Modified Example <NUM> can be applied when the drip irrigation system <NUM> supplies, to the agricultural field <NUM>, irrigation water with fertilizer mixed therein at a specific mixing rate.

Specifically, according to this Modified Example <NUM>, the calculation processing unit <NUM> calculates not only a supply amount of irrigation water for each section, but also a supply amount of fertilizer for each section. Letting the mixing rate of fertilizer to water be α, the calculation processing unit <NUM> calculates, for each section, a supply amount of fertilizer supplied to the section using Expression <NUM> below.

According to this Modified Example <NUM>, it is also possible to strictly perform fertilizer management in drip irrigation. This Modified Example <NUM> is also useful for crops for which fertilizer management is important. In addition, in Modified Example <NUM>, fertilizer is dissolved in irrigation water, and thus, instead of the moisture sensors <NUM>, an EC sensor that can detect fertilizer in soil may also be used as the sensor.

The program according to the example embodiment need only be a program that causes a computer to execute steps A1 to A5 shown in <FIG>. The irrigation water amount measurement apparatus <NUM> and the irrigation water amount measurement method according to the example embodiment can be realized, by this program being installed on a computer and executed. In this case, the processor of the computer performs processing, while functioning as the sensor data obtaining unit <NUM>, the irrigation water amount measurement unit <NUM>, the irrigation time specifying unit <NUM>, and the calculation processing unit <NUM>.

Also, the program according to the example embodiment may be executed by a computer system constituted by a plurality of computers. In this case, for example, each of the computers may function as one of the sensor data obtaining unit <NUM>, the irrigation water amount measurement unit <NUM>, the irrigation time specifying unit <NUM>, and the calculation processing unit <NUM>.

Here, a computer that realizes an irrigation water amount measurement apparatus by executing the program according to the example embodiment will be described with reference to <FIG> is a block diagram showing an example of a computer that realizes an irrigation water amount measurement apparatus according to example embodiment of the invention.

As shown in <FIG>, a computer <NUM> includes a CPU <NUM>, a main memory <NUM>, a storage device <NUM>, an input interface <NUM>, a display controller <NUM>, a data reader/writer <NUM>, and a communication interface <NUM>. These units are connected in a manner that enables data communication therebetween, via a bus <NUM>. Note that the computer <NUM> may also include a GPU (Graphics Processing Unit) or an FPGA (Field-Programmable Gate Array) in addition to or instead of the CPU <NUM>.

The CPU <NUM> implements various computational operations, by deploying, to the main memory <NUM>, program (codes) according to the example embodiment that are stored in the storage device <NUM>, and executing these codes in predetermined order. The main memory <NUM>, typically, is a volatile storage device such as a DRAM (Dynamic Random Access Memory). Also, programs according to the example embodiment are provided in a state of being stored on a computer-readable recording medium <NUM>. Note that programs according to the example embodiment may be distributed over the Internet connected via the communication interface <NUM>.

Also, a semiconductor storage device such as a flash memory is given as a specific example of the storage device <NUM>, other than a hard disk drive. The input interface <NUM> mediates data transmission between the CPU <NUM> and input devices <NUM> such as a keyboard and a mouse. The display controller <NUM> is connected to a display device <NUM>, and controls display by the display device <NUM>.

The data reader/writer <NUM> mediates data transmission between the CPU <NUM><NUM> and the recording medium <NUM>, and executes readout of programs from the recording medium <NUM> and writing of processing results of the computer <NUM> to the recording medium <NUM>. The communication interface <NUM> mediates data transmission between the CPU <NUM> and other computers.

Also, a general-purpose semiconductor storage device such as a CF (Compact Flash (registered trademark)) card or an SD (Secure Digital) card, a magnetic recording medium such as a flexible disk, and an optical recording medium such as a CD-ROM (Compact Disk Read Only Memory) are given as specific examples of the recording medium <NUM>.

Note that the irrigation water amount measurement apparatus <NUM> according to the example embodiment is also realizable by using hardware corresponding to the respective units, rather than by a computer on which programs are installed. Furthermore, the irrigation water amount measurement apparatus <NUM> may be realized in part by programs, and the remaining portion may be realized by hardware.

Although the present invention has been described above with reference to the example embodiments above, the invention is not limited to the above example embodiments. Various modifications understandable to a person skilled in the art can be made in configurations and details of the invention, within the scope of the claims.

Claim 1:
An irrigation water amount measurement apparatus for measuring a supply amount of irrigation water in an agricultural field in which a drip irrigation system (<NUM>) is installed, the apparatus comprising:
a sensor data obtaining unit (<NUM>) configured to obtain sensor data for specifying soil moisture contents in respective sections (<NUM>) resulting from dividing the agricultural field into a plurality of pieces, from moisture sensors (<NUM>) installed in the respective sections (<NUM>);
an irrigation water amount measurement unit (<NUM>) configured to measure a supply amount of irrigation water supplied from the drip irrigation system (<NUM>), in the entire agricultural field, during a period from start to end of irrigation;
an irrigation time specifying unit (<NUM>) configured to specify, for each of the sections (<NUM>), a period of time during which irrigation water was supplied to the section (<NUM>), based on a change state of a soil moisture content of the section (<NUM>) specified by the sensor data; and
a calculation processing unit (<NUM>) configured to calculate, for each of the sections (<NUM>), a supply amount of irrigation water supplied to the section (<NUM>), based on a period of time specified for the section (<NUM>), the period from start to end of irrigation in the entire agricultural field, and the measured supply amount,
wherein the irrigation time specifying unit (<NUM>) is configured to specify, as a period of time during which irrigation water was supplied to the section (<NUM>), a period from a time when the soil moisture content started to rise in the section until a time when a moisture content started to rise in a section (<NUM>) other than the section (<NUM>).