JPH0347808B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to culture medium management in a system for cultivating plants for food, ornamental use, etc. in a medium such as soil, sand, peat moss, rock wool, etc. It is about the method.

(Prior Art) In a system for cultivating plants by using a culture medium and supplying a culture solution such as water or an aqueous fertilizer solution, management of the culture solution of the culture medium is important. However, in the past, there was no suitable detection method that could directly detect the amount of culture solution in the culture medium, so the amount of culture solution supplied was calculated using an indirect method, and the amount increased by 30 to 50 times this value. management. In other words, the amount of water required by plants varies greatly depending on conditions such as the amount of sunlight, temperature, humidity, number of growing days, etc., so the amount of culture solution supplied should be calculated taking these factors into account, and the amount of water needed by plants should be 1.3 to 1.5 times this value. It supplies quantity.

(Problem to be Solved by the Invention) When implementing the above method, if one attempts to constantly monitor the above-mentioned conditions and perform calculations to calculate the supply amount, expensive solar radiation sensors, humidity sensors, temperature sensors, etc. are required. Not only are sensors required, but also complex calculation software is required, and even if these are used, it is extremely difficult to perform calculations that satisfy all conditions. cannot be prevented. There is also a method that uses a timer to supply electricity for a certain amount of time at a certain time of the day, without using sensors that automatically monitor the above conditions. Based on the estimated amount calculated in advance, the amount supplied is 1.3 to 1.5 times the maximum required amount as described above, so on rainy days, for example, there will be an excess supply, which may cause too much moisture for plant growth. Otherwise, the culture solution will be wasted.

The purpose of the present invention is to solve the above-mentioned conventional problems, namely, to make it possible to directly detect the amount of culture solution in a culture medium without being affected by changes in the temperature of the culture solution or fertilizer concentration. The purpose of this invention is to enable good control of the amount of culture solution in the culture medium by controlling the supply of culture solution based on the detected amount of culture solution.

(Means for Solving the Problems) Means for solving the above-mentioned problems will be explained with reference to the drawings corresponding to the examples. First, the culture solution management method of the first invention uses the medium 2, Alternatively, in a system for cultivating plants 6 by supplying a culture solution such as an aqueous fertilizer solution, a pair of electrodes 7 and 8 are attached to the medium 2 so that the culture solution can be energized, and the electrodes 7 and 8 A detection unit 9 is provided to detect the electrical conductivity between the electrodes 7 and 8, and a temperature sensor S1 is provided at an appropriate location to detect the temperature of the culture solution in the culture medium 2. The detection unit 9 corresponds to the electrical conductivity between the electrodes 7 and 8. At the same time, the temperature of the culture solution is detected by the temperature sensor S1, and the electrical conductivity between the electrodes 7 and 8 detected by the detection unit 9 is determined based on the correspondence between the culture solution temperature and the electrical conductivity. The gist of this method is to detect the amount of culture solution in the medium 2 by correcting the corresponding amount, and to control the supply of the culture solution based on the detected amount of culture solution.

Further, the culture solution management method of the second invention is based on the culture medium 2.
In a system for cultivating plants 6 by supplying water or a culture solution such as an aqueous fertilizer solution, the medium 2
A pair of electrodes 7 and 8 are attached to the culture medium 2 so that electricity can be freely applied to the culture medium, and a detecting section 9 is provided to detect the electrical conductivity between the electrodes 7 and 8. A fertilizer concentration sensor S2 for detecting is provided at a suitable location, the detection unit 9 detects an amount corresponding to the electrical conductivity between the electrodes 7 and 8, and the fertilizer concentration sensor S2 detects the fertilizer concentration of the culture solution,
Based on the correspondence between the fertilizer concentration and the electrical conductivity of the culture solution, the amount of culture solution in the medium 2 is detected by correcting the amount corresponding to the electrical conductivity between the electrodes 7 and 8 detected by the detection unit 9. However, the gist of the present invention is to control the supply of the culture solution based on the detected amount of culture solution.

(Function) Therefore, the pair of electrodes 7 attached to the medium 2,
When a constant voltage is applied between 8 and 8, a current flows through the culture solution in medium 2. When the amount of culture solution in the medium 2 is changed in this state, the current corresponding to the electrical conductivity changes as shown in FIG. 2 with respect to the amount of culture solution. When this is illustrated with respect to the passage of time during plant cultivation, the current corresponding to the electrical conductivity decreases as the amount of culture solution decreases with the passage of time, as shown in FIG. The decrease in electrical conductivity with respect to the amount of culture solution is due to the fact that the medium 2 is not physically continuous and has gaps, so as the amount of culture solution decreases, electrical connection gradually becomes impossible to maintain. . In this way, the electrical conductivity changes in response to changes in the amount of culture solution in the medium 2, so the electrical conductivity or its corresponding amount, such as current, is detected by the detection unit 9, and the electrical conductivity is detected by measuring in advance. From the corresponding relationship between the obtained electrical conductivity and the culture solution amount, the culture solution amount can be detected from the electrical conductivity corresponding amount detected by the detection unit 9. The electrical conductivity of medium 2
In addition to the amount of culture solution in the medium, for example, Fig. 4 a, b,
As shown in c, it changes even if the temperature, pH, and fertilizer concentration of the culture solution change, so it is not always possible to accurately detect the amount of culture solution by simply detecting the corresponding amount of electrical conductivity with the detection unit 9. is not limited.

However, among the properties of the above-mentioned culture solution, the change in electrical conductivity due to PH change is small and can be ignored, and the correspondence between the above-mentioned culture solution temperature or fertilizer concentration and electric current can be obtained by prior measurement. can.

Therefore, the detecting section 9 detects the corresponding amount of electrical conductivity between the electrodes 7 and 8, and the temperature sensor S1 or the fertilizer concentration sensor S2 detects the temperature or fertilizer concentration of the culture solution. Due to the correspondence between the fertilizer concentration and the corresponding amount of electrical conductivity,
By correcting the corresponding amount of electrical conductivity between the electrodes 7 and 8 detected by the detection unit 9, the amount of culture solution in the medium 2 can be adjusted without being affected by changes in the temperature or fertilizer concentration of the culture solution. The amount of culture solution detected can thus be used to appropriately control the supply of culture solution based on the detected amount of culture solution.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a system explanatory diagram corresponding to an embodiment of the present invention, in which reference numeral 1 indicates a plant cultivation container and 2 indicates a culture medium. The medium 2 may be soil, sand, peat moss, rock wool, etc. as appropriate. Reference numeral 3 indicates a culture solution tank for water or fertilizer aqueous solution, 4 indicates a culture solution supply device such as a pump or a solenoid valve, and 5 indicates a culture solution supply section. The culture solution supply section 5 can be configured to supply the culture solution in the vicinity of the plants 6 in a drip manner, or any other suitable supply method can be applied.

In the above configuration, a pair of electrodes 7 and 8 are attached to the culture medium 2 so that electricity can be freely applied to the culture solution.
The pair of electrodes 7 and 8 are connected to a detection unit 9, and the detection unit 9 applies a voltage between the electrodes 7 and 8 to detect an amount corresponding to the electrical conductivity of the culture solution, for example, a current. composition. The applied voltage is preferably an alternating current voltage in consideration of the influence of polarization, but may be a direct current voltage depending on the case. In addition, as will be explained later, the detection unit 9 applies a constant voltage to each electrode 7, 8, and directly uses the current flowing between the electrodes 7, 8 as a corresponding amount of electrical conductivity. Of course, it is also possible to change the applied voltage and calculate the electrical conductivity from the applied voltage and current, that is, use the electrical conductivity itself as a corresponding quantity of the electrical conductivity.
Further, each of the electrodes 7 and 8 may be composed of a single electrode member or may be composed of a plurality of electrode members.

Next, reference numeral S1 denotes a temperature sensor for the culture solution, which is installed in the culture medium 2 and is configured to directly detect the temperature of the culture solution in the culture medium 2. Also, the code S
Reference numeral 2 denotes a fertilizer concentration sensor for the culture solution, which is installed in the culture solution tank 3 and configured to indirectly detect the fertilizer concentration of the culture solution in the culture medium 2 by the culture solution supplied to the culture medium 2. There is. These sensors S1,
S2 may be installed when there is a possibility that the detectable properties of the culture fluid may change due to these, and either one or both can be installed.

Reference numeral 10 denotes a control unit, and this control unit 10 has the following information: the correspondence between the electrical conductivity detected by the detection unit 9 and the amount of the culture solution, and the correspondence between the temperature of the culture solution or the fertilizer concentration and the electrical conductivity. Correcting the corresponding amount of electrical conductivity between the electrodes 7 and 8 detected by the detecting section 9 based on the storage means of the corresponding relationship between the temperature of the culture solution or the fertilizer concentration and the corresponding amount of the electrical conductivity. and a means for controlling the culture solution supply device 4 based on the amount of culture solution detected by these calculation means. As the storage means, any suitable means for storing each correspondence relationship as a function formula or a table can be applied.

With the above configuration, the detection unit 9 detects the corresponding amount of electrical conductivity between the electrodes 7 and 8, and the temperature sensor S1 or fertilizer concentration sensor S2 detects the temperature or fertilizer concentration of the culture solution. If the corresponding amount of electrical conductivity between the electrodes 7 and 8 detected by the detection unit 9 is corrected based on the correspondence between the temperature or fertilizer concentration and the corresponding amount of electrical conductivity, the temperature of the culture solution or the fertilizer The amount of culture solution in the medium 2 can be detected without being affected by changes in concentration, and the supply of the culture solution can be appropriately controlled based on the detected amount of culture solution. The above-mentioned culture solution amount can be derived as an absolute value, or can be controlled without deriving an absolute value.

A method for supplying a culture solution based on the amount of culture solution detected as described above includes, for example, activating the culture solution supply device 4 to start supplying the culture solution when the amount of culture solution decreases to a predetermined value. The amount of culture solution in the culture medium 2 increases due to the supply, and when it reaches a predetermined value, the operation of the culture solution supply device 4 is stopped, and the amount of culture solution in the culture medium 2 is kept within a certain range. How to control the culture solution supply device 4 as well as
After activating, a predetermined amount of culture solution is supplied using a timer, flow meter, etc., and the lower limit of the amount of culture solution is controlled based on the above-mentioned electrical conductivity, but the upper limit is controlled by the timer, etc. Appropriate methods such as these can be applied, and the range of the amount of culture solution to be controlled and the range of electrical conductivity depend on various conditions such as the type of medium 2, the type of plant 6, the number of growing days, and the season. It can be set as appropriate. for example,
Under these various conditions, the plants 6 can be cultivated well with the amount of culture solution corresponding to the rapidly changing portion of the curve showing the current, which is the amount corresponding to the electrical conductivity shown in FIGS. 2 and 3. In some cases, it is possible to perform highly sensitive control.

The control section 10 that performs the above-mentioned control may have any specific configuration, such as a device using a microcomputer or the like.

The present invention described above is based on attaching a pair of electrodes 7, 8 to the electrically integrated culture medium 2 via a culture solution, but it is possible to attach a plurality of pairs of electrodes 7, 8 to the culture medium 2, which is electrically integrated with the culture medium. It is also possible to make it possible to detect the amount of culture solution for each of the electrodes 7 and 8. However, even if multiple pairs of electrodes 7 and 8 are simply attached to the electrically integrated culture medium 2, they will interfere with each other, so in order to prevent this interference, the detection unit 9 , the voltage applied to each of the eight pairs is an insulated AC voltage. For example, as shown in the figure, such a configuration includes an isolation transformer 11.
, or by providing independent oscillators for each. By attaching multiple pairs of electrodes 7 and 8 in this way, it is possible to detect the average amount of culture solution in the medium 2 over a wide range, and it is also possible to detect the amount of culture solution for each plant. This has advantages such as being able to perform fine-grained moisture management. In addition, when multiple pairs of electrodes 7 and 8 are attached in this way, the method of supplying the culture solution is appropriate.
A plurality of culture solution supply devices 4 can be provided for the electrically integrated culture medium 2. In addition, one pair or multiple pairs of electrodes 7,
8 can be installed to control these in an integrated manner, and the specific control method is appropriate.

(Effects of the Invention) Since the present invention is as described above, the conventional control method, that is, estimation of the amount of culture solution supplied in consideration of various conditions without directly detecting the amount of culture solution in the culture medium. Compared to methods that control based on values, it is possible to appropriately control the supply of culture solution to the culture medium according to the plant cultivation conditions without being affected by fluctuations in the temperature of the culture solution or fertilizer concentration. Therefore, it is possible to prevent the culture solution in the medium from becoming too much or too little, so that plant cultivation conditions can always be maintained appropriately, and waste of the culture solution can be minimized. There is an effect. In addition, although the present invention can perform such appropriate control, the configuration can be simplified in terms of both hardware and software, and an inexpensive and efficient plant cultivation system can be constructed. There is an effect.

[Brief explanation of drawings]

Fig. 1 is a system explanatory diagram showing an example of a plant cultivation system to which the present invention is applied, Fig. 2 is an explanatory diagram showing the relationship between the amount of culture solution and the corresponding amount of electric conductivity, and Fig. 3 is Explanatory diagram showing the relationship between the amount of culture solution and the current of the corresponding amount of electrical conductivity with respect to the elapsed time, 4th
Figures a, b, and c are explanatory diagrams showing the relationship between electrical conductivity, culture solution temperature, fertilizer concentration, and fertilizer concentration, respectively;
FIG. 5 is a system explanatory diagram showing the configuration of an embodiment equipped with a plurality of electrode pairs. Code 1... Plant cultivation container, 2... Medium, 3...
Culture solution tank, 4... Culture solution supply device, 5... Culture solution supply unit, 6... Plant, 7, 8... Electrode, 9...
...Detection section, 10...Control section, 11...Isolation transformer.

Claims (1)

[Scope of Claims] 1. A system for cultivating plants by using a culture medium and supplying a culture solution such as water or an aqueous fertilizer solution, wherein a pair of electrodes is attached to the culture medium so that electricity can be freely applied to the culture solution. A detection unit for detecting the electrical conductivity between the electrodes is provided, and a temperature sensor for detecting the temperature of the culture solution in the medium is provided at an appropriate location, and the detection unit detects an amount corresponding to the electrical conductivity between the electrodes. detecting the temperature of the culture solution using the temperature sensor;
Based on the correspondence between culture solution temperature and electrical conductivity, the amount of culture solution in the medium is detected by correcting the amount corresponding to the electrical conductivity between the electrodes detected by the detection unit, and the detected culture solution is A method for managing a culture medium in a plant cultivation system, the method comprising controlling the supply of culture solution based on the amount. 2. In a system for cultivating plants using a culture medium and supplying a culture solution such as water or an aqueous fertilizer solution, a pair of electrodes are attached to the medium so that electricity can be freely applied to the culture solution, and the connection between the electrodes is A detection unit for detecting electrical conductivity is provided, and a fertilizer concentration sensor for detecting the fertilizer concentration of the culture solution in the culture medium is provided at an appropriate location, and the detection unit detects an amount corresponding to the electrical conductivity between the electrodes, and the The fertilizer concentration in the culture solution is detected by a fertilizer concentration sensor, and based on the correspondence between the fertilizer concentration in the culture solution and the electrical conductivity, an amount corresponding to the electrical conductivity between the electrodes detected by the detection section is corrected. A method for managing a culture medium in a plant cultivation system, which comprises detecting the amount of culture solution in the medium and controlling the supply of the culture solution based on the detected amount of culture solution. 3. A patent characterized in that a plurality of pairs of electrodes are electrically attached to a single culture medium via a culture medium, and the voltage applied to each pair of electrodes by the detection unit is an insulated alternating current voltage. A method for managing a culture medium in a plant cultivation system according to claim 1 or 2.