JPH0525447B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a plant cultivation nutrient solution control device used for cultivation of plants planted in a culture medium.

[Conventional technology]

Conventionally, when cultivating plants using an artificial medium such as Rotsuwool (trademark), growth control of the plants has been based on controlling the moisture content of the medium.

[Problem that the invention seeks to solve]

In order to control the moisture content of such a medium, it is necessary to establish a correlation between the amount of transpiration and weather conditions such as solar radiation, temperature, and humidity, as well as to establish a correlation between the number of days of plant growth and transpiration. It is necessary to understand complex parameters, such as knowing the relationship between quantities, but it is extremely difficult to accurately understand these relationships.

In this type of control, it is necessary to accurately detect the amount of water in the culture medium, but there are many problems such as the lack of appropriate detection equipment and the fact that the amount of water required by plants is not understood. If the moisture content is incorrectly controlled, there is a risk of root rot or death due to lack of moisture. For this reason, such control requires increased control accuracy, requires safety measures, and requires expensive sensors, making the control system complex and expensive.

Therefore, an object of the present invention is to provide a plant cultivation nutrient solution control device that can optimize the supply of nutrient solution to plants planted in a culture medium according to the growth state of the plants and environmental conditions such as weather.

[Means for solving problems]

The plant cultivation nutrient solution control device of the present invention accommodates a nutrient solution supply means (nutrient solution supply device 2) that supplies a nutrient solution to a plant 16 to be cultivated, and a water-permeable medium 14 in which the plant is planted. At the same time, a discharge pipe 2 is provided at the bottom of the nutrient solution, which receives the nutrient solution from the nutrient solution supply means and collects the nutrient solution that has passed through the culture medium.
A container 18 for discharging the nutrient solution from the container 2 is provided with an opening/closing means (bottom plate 26) on the bottom. a detection tank 24 that overflows when the nutrient solution exceeds a certain amount; and a nutrient solution that is installed in the detection tank and generates a detection output indicating that the nutrient solution in the detection tank has reached a certain amount when the opening/closing means is closed. A liquid detection means (water level detector 34) detects the supply of the nutrient solution from the nutrient solution supply means, closes the opening/closing means when the nutrient solution is supplied, and closes the opening/closing means when the supply of the nutrient solution is cut off. an opening/closing control means (a nutrient solution supply detector 30, an opening/closing control section 32, and an opening/closing drive section 28) that opens the means to discharge the nutrient solution from the detection tank; and a time point at which the nutrient solution starts to be supplied to the nutrient solution supply means. and controlling the supply of the nutrient solution by setting a supply end time, and calculating the replenishment time of the nutrient solution according to the time from the start of supply of the nutrient solution until the nutrient solution detection means generates the detection output. The present invention is characterized in that it includes a control means (cultivation control section 4) that extends the supply of the nutrient solution by the replenishment time from the supply end time.

[Effect]

The amount of nutrient solution required for plants planted in a medium can be roughly calculated based on the plant, its growth rate, weather conditions, etc. Furthermore, it is also possible to calculate the necessary and optimal supply time based on the amount of the nutrient solution in accordance with weather conditions such as the amount of solar radiation.

Therefore, this calculated supply time is measured, and the nutrient solution W _Q is applied to the culture medium according to the arrival of the supply time.
supply, monitor the nutrient solution W _Q that has passed through the medium,
Continuation and stop of supply of the nutrient solution _WQ is controlled based on its presence or absence.

When the nutrient solution _WQ is supplied, the opening/closing means on the bottom side of the detection tank 24 is closed, so the nutrient solution _WQ discharged from the container is stored in the detection tank. While this nutrient solution _WQ is being supplied, the nutrient solution detection means installed in the detection tank generates a detection output indicating that a certain amount has been reached. Further, when the supply of the nutrient solution W _Q continues and exceeds a certain water level in the detection tank, the nutrient solution W _Q is discharged to the outside from the detection tank.

The control unit calculates the time from the start of supply of the nutrient solution W _Q until the nutrient solution detection means generates a detection output, and controls the amount of the nutrient solution W _Q supplied by the nutrient solution supply means in accordance with this time.

In other words, if the supply amount of the nutrient solution _WQ is constant, the time from the start of supply of the nutrient solution _WQ to the generation of the detection output of the nutrient solution detection means depends on retention of the culture medium, evaporation, and absorption by the plants. This reflects environmental conditions such as weather and the growth state of plants, so controlling the addition of replenishment time to the supply time of nutrient solution _WQ according to this relationship is necessary for the growth of plants 16. The aim is to optimize the amount of nutrient solution.

〔Example〕

FIG. 1 shows an embodiment of the plant cultivation nutrient solution control device of the present invention.

The nutrient solution supply device 2 as a nutrient solution supply means is controlled by a cultivation control section 4 that constitutes a control means,
Water Wr such as agricultural water and fertilizer concentrate Q are mixed to create a nutrient solution _WQ necessary for plant cultivation, and the nutrient solution _WQ is supplied to a pipe in accordance with a supply control signal Vw from the cultivation control unit 4. 8 into the drip side piping 10 and dripped into the culture medium 14 through the drip nozzle 12.

The culture medium 14 is made of rock wool or the like, and a specific plant 16 is planted therein and housed in a container 18. The container 18 contains the culture medium 14
The nutrient solution supplied to the culture medium 14
It is installed as a means for receiving _WQ , and a protrusion 20 is provided on the bottom surface to form a space between it and the culture medium 14.
is provided, and the culture medium 14 is supported by this protrusion 20.

A discharge pipe 22 for the nutrient solution _WQ is provided at the bottom of the container 18, and as shown by arrow a, the nutrient solution _WQ discharged through the discharge pipe 22 is guided to a detection tank 24 for detecting the nutrient solution. . The detection tank 24 has a bottom plate 26 that can be opened and closed as shown by arrow b, and is opened and closed by an opening and closing drive unit 28. Opening/closing drive unit 2
8 uses a hydraulic cylinder device, a pneumatic cylinder device, a diaphragm mechanism, an electromagnetic drive device, or the like to open and close the opening and closing according to the supply of the nutrient solution _WQ .

The nutrient solution supply detector 30 detects the supply of the nutrient _{solution WQ} for controlling the opening/closing drive unit 28,
The arrival of the nutrient solution _WQ to the drip side piping 10 is confirmed by
It is detected mechanically, chemically, or electrically, and the detection signal is applied to the opening/closing control section 32. The opening/closing control means is the detection result of the nutrient solution supply detector 30 indicating that the nutrient solution W _Q has arrived at the drip side pipe 10, or the detection result of the nutrient solution supply detector 30 indicating that the supply of the nutrient solution W _Q has been canceled. The drive of the opening/closing drive unit 28 is controlled based on the detection result of the detector 30, and thereby,
The bottom plate 26 is controlled to be closed when the nutrient solution _WQ is supplied, and opened when the nutrient solution _WQ is stopped being supplied. For example, by detecting the pressure of the nutrient solution _WQ arriving at the drip side pipe 10,
The pressure signal is converted into a drive signal to open and close the bottom plate 26. When the bottom plate 26 is opened, the nutrient solution _WQ accumulated in the detection tank 24 is discharged as shown by arrow c.

When the nutrient solution _WQ is supplied, the nutrient solution _WQ that seeps out from the culture medium 14 and accumulates in the detection tank 24 represents a certain amount of the nutrient solution _WQ discharged from the container 18,
When the height reaches _h1 , the detection electrode 3 of the water level detector 34, which serves as a nutrient solution detection means, detects a certain amount of nutrient solution.
4a and 34b, a water level detection signal Sw indicating that the height of the nutrient solution _WQ has reached _h1 is output from the water level detector 34 according to the change in electrical resistance, and is sent to the cultivation control unit 4 as well. It will be done. In this case, the nutrient solution
Nutrient solution W _Q accumulated in the detection tank 24 when W _Q is supplied
When the height exceeds h ₂ , it is naturally discharged to the outside from the discharge hole 36 as shown by arrow d.

The cultivation control section 4 is equipped with an input section 40 that takes in various signals such as a water level detection signal Sw and a replenishment time signal S _T as condition setting data. The data is then added to the arithmetic unit 42. The calculation unit 42 is composed of a calculation circuit that performs digital calculations or a calculation circuit that performs analog calculations, and performs calculation processing according to the cultivation program stored in the storage unit 44. In this case, a timer 46 is used to set and measure the time limit for controlling the supply time of the nutrient solution _WQ .
is installed, and the timer 46 sets the nutrient solution supply time calculated from the amount of nutrient solution required for cultivating the plants 16, and measures the arrival time. Therefore, the calculation unit 42 adjusts the nutrient solution according to the arrival of the supply time.
The supply start time of _WQ and the supply release time based on the arrival of the water level detection signal Sw are calculated, and as a result of the calculation, the nutrient solution supply control signal Vw is applied to the nutrient solution supply device 2 through the output section 48. In other words, the nutrient solution supply control signal Vw is a signal representing information on both the start time of the nutrient solution _WQ and the continuous supply time from that time.

Regarding the supply of such a nutrient solution _WQ , the supply time of the nutrient solution _WQ can be determined by adding a replenishment time signal S _T to the input section 40 in advance, and then inputting the replenishment time to the water level detection signal.
It is set by adding based on the arrival time of Sw. For example, in Figure 2, the nth nutrient solution
It shows the supply of W _Q and the (n+1)th supply of the nutrient solution W _Q , where t ₁ is the start time of the nth nutrient solution supply,
t ₂ is the supply stop reference time due to the arrival of the nth water level detection signal Sw, t ₃ is the replenishment end time, and t ₄ is (n+
1) The nutrient solution supply start time, _t5 , is the supply stop reference time when the (n+1)th water level detection signal Sw arrives, and _t6 is the replenishment end time. Therefore,
The nth supply time T _o is the time T ₁ and the replenishment time 0.1T ₁
The conversion time of (n+1)th supply time T _o+1 is,
This is the conversion time of time T ₂ and replenishment time 0.1T ₂ .

FIG. 3 shows a control program for a plant cultivation nutrient solution by the plant cultivation nutrient solution control device of the present invention.

Prior to the start of control, in step _S1 , the number of times of supply per day and the supply time (interval) are calculated in advance according to the growth and environmental conditions such as the number of growing days of the plant 16, amount of sunlight, seasonal changes, temperature, and humidity. The supply start time is set in the timer 46, and the replenishment time is also set as necessary.

After such settings, a control operation is performed, and in step _S2 , the time to start supplying the nutrient solution _WQ is measured.
As a result of this time measurement, it is determined in step _S3 whether or not the supply start time has arrived. If the supply start time has not arrived, time measurement is continued in step _S2 , and if the supply start time has arrived, the process moves to step _S4 to start supplying the nutrient _{solution WQ} . I do.

The supply of this nutrient solution _WQ is controlled by the nutrient solution supply control signal Vw.
is output from the calculation unit 42, and starts based on the nutrient solution supply control signal Vw.

The nutrient solution W _Q is passed through the pipe line 8 to the drip side pipe 1.
medium 1 through the drip nozzle 12.
4. Irrigation (dropping or spraying) is applied. At this time,
When the nutrient solution _WQ passes through the drip side piping 10, the nutrient solution supply detector 30 detects the supply of the nutrient solution _{WQ based on the pressure of the nutrient solution WQ} in step _S5 , and detects the supply of the nutrient solution _WQ based on the detection signal. The opening/closing control section 32 is operated. This operation causes the opening/closing drive section 28 to operate, and as shown in step _S6 , the bottom plate 28 of the detection tank 24
occlude.

The nutrient solution W _Q dripped onto the culture medium 14 permeates (absorbs) into the culture medium 14 , and the nutrient solution W _Q is supplied to the plants 16 . In this case, the nutrient solution _WQ that has passed through the medium 14 is
It is received by the container 18, flows into the detection tank 24 from the discharge pipe 22 as shown by the arrow a, and accumulates therein.

Then, in step _S7 , the presence or absence of the nutrient solution _WQ is detected, and the nutrient solution _WQ accumulated in the detection tank 24 is detected.
If the amount of water is small, the water is not detected, so the process moves to step _S4 , and the supply of the nutrient solution _WQ is continued. In addition, the nutrient solution accumulated in the detection tank 24
When the amount of W _Q exceeds a predetermined amount (its height is h ₁ ),
The water level detector 34 generates a water level detection signal Sw indicating that the nutrient solution _WQ has reached a predetermined amount, and the water level detection signal Sw is input to the input section 40 of the cultivation control section 4.

Next, in step _S8 , it is determined whether or not there is a replenishment time. If the replenishment time is not set, the process moves to step _S11 upon arrival of the water level detection signal Sw, and the nutrient solution _{WQ is}
The nutrient solution supply control signal Vw is canceled as a stop signal indicating the end of the supply time of the nutrient solution WQ, and the supply of the nutrient solution _WQ is ended. If it is determined in step _S8 that a replenishment time is set, the process moves to step _S9 to continue supplying the nutrient solution _WQ and measure the replenishment time. At this time, the bottom plate 26 of the detection tank 24 is maintained in a closed state.

Next, in step _S10 , it is determined whether the replenishment time has arrived, and if the replenishment time has not come, the nutrient solution _WQ is supplied and the replenishment time is measured in step _S9 . If it is determined in step _S10 that the replenishment time has come, the process moves to step _S11 and the supply of the nutrient solution _WQ is ended.

Then, in step _S12 , the nutrient solution supply detector 30 detects that the supply of the nutrient _{solution WQ} has been released, and based on the detection signal, the opening/closing control section 3
2, the drive of the opening/closing drive unit 28 is released and the bottom plate 26 is released as shown by the broken line. As a result, the nutrient solution _WQ accumulated in the detection tank 24 is discharged to the outside as shown by arrow c.

In this way, the supply start time of the nutrient solution _WQ is set according to the required amount determined by the growth situation of the plants 16, weather conditions, etc., but the supply end time is
Since it is based on the detection of the nutrient solution _WQ flowing out from the medium 14, the amount of the nutrient _{solution WQ} supplied to the plants 16 can be arbitrarily controlled and quantified depending on the dryness of the medium 14 and the absorption rate of the plants 16. It has not been.

As a result, in this kind of control, it is only necessary to program the supply start time depending on individual differences in the plants 16, weather conditions, etc., and the supply time can be set to A in FIG. 4 on a clear day, B in FIG. 4 on a cloudy day, etc. During rainy weather, the system is controlled arbitrarily according to the weather conditions, as shown in C in FIG. In Figure 4, T _A , T _B , T _C (T _A > T _B
>T _C ) represents the supply time. In addition, the nutrient solution for the daily solar radiation amount Sn as shown in Fig. 5 D
The supply time t of _WQ and the supplied amount L are:
As shown in E of FIG. 5, supply times ta, tb, tc...
...is proportional to the amount of solar radiation. Here, the supplied amount of the nutrient solution _WQ is the value obtained by subtracting the amount discharged to the detection tank 24 from the amount supplied from the nutrient solution supply device 2. In Fig. 5, tr is the sunrise time, tn is noon, ts is the sunset time, and La, Lb, Lc... are the amounts of the nutrient solution W _Q supplied at each time ta, tb, tc... represent

Next, looking at the supply time of the nutrient solution _WQ in terms of the number of growth days,
As shown in F in Figure 6 at the fixed value, G in Figure 6 in January after planting, and H in Figure 6 in February after planting, it was confirmed that the length increases as the growth progresses. In addition,
In FIG. 6, T _F , T _G , T _H (T _F <T _G <T _H ) represent supply times.

In such a control method, since the moisture content of the medium 14 is set high, the water content of the medium 14 is set high.
Materials with good breathability and high water absorption are suitable for this purpose.
Further, the fertilizer concentration of the nutrient solution _WQ is changed depending on the growth conditions of the plants 16 and the like.

As shown in FIG. 7, the cultivation control unit 4 is provided with a timer 401 that can arbitrarily set the supply time of the nutrient solution _WQ . At the same time, the water level detection signal Sw from the water level detector 34 is output.
A controller 402 configured with a switching circuit that cancels the nutrient solution supply control signal Vw may also be used. In this way, in the case of complex control in which various cultivation conditions are set, the cultivation control unit 4 shown in FIG. 1 is used, and in the case of simple control, the cultivation control unit 4 shown in FIG. 7 is used. , efficient control can be performed.

Furthermore, for opening and closing the bottom plate 26 of the detection tank 24, an opening/closing mechanism 280 may be used that opens and closes the bottom plate 26 by directly utilizing the increase in water pressure when the nutrient solution _WQ is supplied in the drip side pipe 10.

〔Effect of the invention〕

According to this invention, the supply time is set based on the supply amount of the nutrient solution calculated from the growth situation of the plants and the weather conditions such as the amount of sunlight, humidity, and temperature, and the nutrient solution is supplied according to the arrival of the time. Since the supply is stopped in accordance with the nutrient solution that has passed through the culture medium, the nutrient solution can be supplied in a way that is suitable for the plants and the culture medium, and the nutrient solution supply can be optimized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the plant cultivation nutrient solution control device of the present invention, FIG. 2 is a diagram showing nutrient solution supply control, and FIG. 3 is a block diagram showing an embodiment of the plant cultivation nutrient solution control device of the present invention. Figure 4 shows the program. Figure 4 shows the supply time of nutrient solution depending on the weather conditions. Figure 5
The figure shows the supply time of nutrient solution and the supplied amount in relation to the amount of solar radiation, Figure 6 shows the supply time of nutrient solution corresponding to the number of days of plant growth, and Figure 7 is the same as shown in Figure 1. FIG. 7 is a block diagram showing a modification of the cultivation control unit and the detection tank opening/closing means of the embodiment. W _Q ... Nutrient solution, 2... Nutrient solution supply device (nutrient solution supply means), 4... Cultivation control section (control means), 14...
Culture medium, 16... Plant, 18... Container, 22... Discharge pipe, 24... Detection tank, 26... Bottom plate (opening/closing means), 28... Opening/closing drive unit (opening/closing control means), 3
0... Nutrient solution supply detector (opening/closing control means), 32...
...Opening/closing control section (opening/closing control means), 34... Water level detector (discharge amount detection means).

Claims (1)

[Scope of Claims] 1. A nutrient solution supply means for supplying a nutrient solution to plants to be cultivated, and a means for accommodating a water-permeable medium in which the plants are planted, and receiving the nutrient solution from the nutrient solution supply means. A container that collects the nutrient solution that has passed through the culture medium and discharges the nutrient solution from a discharge pipe provided at the bottom of the container; and an opening/closing means is provided at the bottom of the container, and when the opening/closing means is closed, the nutrient solution is discharged from the container. a detection tank that stores the nutrient solution to be discharged and causes the nutrient solution to overflow when the nutrient solution exceeds a certain water level; and a detection tank that detects the supply of the nutrient solution from the nutrient solution supply means and controls the opening and closing when the nutrient solution is supplied. an opening/closing control means for opening and closing the opening/closing means to supply the nutrient solution from the detection tank when the supply of the nutrient solution is cut off; A nutrient solution detection means that generates a detection output indicating that a certain amount of the nutrient solution has been reached in the detection tank; and a nutrient solution supply means that sets a supply start time and a supply end time of the nutrient solution to In addition to controlling the supply of the nutrient solution, the replenishment time of the nutrient solution is calculated according to the time from the start of the nutrient solution supply until the nutrient solution detection means generates the detection output, and the supply end time is set as the replenishment time. A control device for controlling a nutrient solution for cultivating plants, comprising: a control means for extending the supply of the nutrient solution.