JPS62226A - System for controlling nutrient solutin culture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to automation of nutrient solution supply management in hydroponic cultivation of plants.

<Conventional technology> In hydroponic cultivation, nutrient solution supply management is based on its pH (III and EC).
We have relied on the measurement of (electrical conductivity), but its essential components,
In particular, N and P are said to be the third components of fertilizer.

A percentage of 100% cannot be managed using this method. In order to know the proportions of each element, conventional methods require troublesome analysis using absorption or flame photometry, which is not practical, and it is difficult to measure pH and EC not only in the field but also in research experiments. The current situation was to do it.

<Problems to be Solved by the Invention> FIGS. 4 and 5 are examples of measuring the ion concentration of each element when nutrient solution is replenished by conventional management means.

FIG. 4 shows the change in nitrate ion NOx-'a degree, and the dotted line shows the replenishment of components. Figure 5 shows Rinshun ion PO4-,
The graph shows changes in potassium ion + and ammonia ion NH4+ concentrations, and the dotted line also shows component replenishment.

Nutrient absorption varies depending on the type of plant, growth stage, and environmental conditions, and in some cases, important elements that were thought to be still present may be completely absorbed and remain at zero. There was found.

It can be seen from FIG. 5 that this tendency is strong for potassium ions and ammonia ions.

In other words, managing the nutrient solution using only pH and EC may be a guideline, but it is insufficient for managing the third component of fertilizer.
Each component must be analyzed and the results reflected in nutrient solution management.

For this purpose, an analyzer that satisfies the following conditions is required.

a) Continuous measurement and automatic operation (does not use fire or unstable reaction reagents for analysis) b) Small size of the device (can simultaneously measure N, P, and other components with one analyzer) C) Can be analyzed in a short time without complicated pretreatments However, with the conventional method of analyzing N and P, spectrophotometry,
Reagents vary depending on the component you want to measure, or pretreatment is required. Additionally, the tip photometer, which is K's analytical means, uses fire, making automatic operation difficult. Furthermore, both methods have the disadvantage of requiring large-sized devices.

The present invention aims to provide a control system that solves this problem by using a recently developed ion chromato analyzer.

<Means for solving the problems> The structural feature of the present invention is that in cultivation using a nutrient solution,
The present invention includes an analysis means for measuring the ion concentration of essential components of the nutrient solution, and a means for replenishing each of the components to the nutrient solution based on the output of the analysis means.

<Example> An example of the present invention will be described with reference to FIG. 1 is a cultivation tank, 2 is a culture solution, 3 is a pipe for supplying the culture solution to the cultivation tank 1, 48 to 4e are tanks containing essential components, 5a to
Reference numeral 5e indicates a control valve for supplying the components in each tank to the pipe line 3, and Va to Ve indicate operation signals to these control valves.

Reference numeral 6 denotes an introduction pipe for introducing a 3 m sample of the culture solution, 7 an ion chromato analyzer for analyzing the ion concentration of a specific component in the sample solution, and Ea the analysis output thereof.

8 is a controller that sends operation signals Va to ■e to the control valves 5a to 5e, and based on the deviation between the analytical output lea of each component and the set value 5a to 8e of each component, an ON signal for a certain period of time or a deviation proportional Sends on/off operation signals.

The analysis time of an ion chromato analyzer is usually about 10 degrees, while the analysis interval for growing plants is once every 1 to 2 days.
Since one analyzer is sufficient, it is possible to analyze the culture solution of many cultivation tanks by switching one analyzer.

Regarding the configuration and operation of the ion chromato analyzer,
For example, this is disclosed in Japanese Patent Application Laid-open No. 135156/1983 and is well known, but the principle structure will be briefly explained with reference to FIG. 9 is a sample injector that collects a certain amount of culture solution; 10 is an eluent pump that pumps eluent Wa (for example, NaHCOa, etc.) to the sample injector; 11 is a separation column; 12 is a suppressor; 13 is a device that controls ion concentration by conductivity. The measuring detector 14 is a removal liquid pump that supplies the removal liquid Wb (for example, DBS-H) to the suppressor 12 in a direction opposite to that of the eluent. The sample injector 9 is equipped with a loop having a predetermined content 1 (for example, 100 μl), and is adapted to collect a sample Sm injected into this loop.

The separation column 11 is filled with ion exchange resin, and is capable of separating the target ion species in the sample being carried in. The suppressor 12 has a double structure consisting of an ion exchange membrane tube and an outer tube, with the eluent flowing inside and the removal liquid flowing outside. The detector 13 is capable of quantifying the target ion species by detecting the conductivity of the eluent introduced from inside the suppressor.

The ion chromato analyzer with such a configuration can perform simultaneous analysis of multiple components at high speed without complicated pretreatment. FIG. 3 is an example of a recorded output showing an example of an analysis result, and (Δ) is PO48I-.

This is an example of measurement of NO3- and (B) is an example of measurement of NO3-, and Isuri can also be measured in an analysis time of about 10 minutes.

<Effects of the Invention> As explained above, according to the present invention, the following effects can be expected.

(a) Since the amount of absorption of each fertilizer component by plants can be determined, the growth status can be constantly checked.

(b)! Since you can see which fertilizer components are deficient in the liquid, you only need to replenish that amount, which is different from conventional EC,
This is much more rational than managing only pH.

(C) It becomes possible to use fertilizers rationally and save money.

(d) Since the relationship between plant growth and fertilizer absorption, which has not been very clear until now, will be clarified, it will become possible to realize optimal culture solution management to promote growth.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram explaining the principle of an ion chromato analyzer, Fig. 3 is an example of output recording of analysis results, and Figs. 4 and 5 are It is an explanatory view showing an example of changes in each component in a nutrient solution when conventional management means are used. 1...Cultivation tank 2...Culture solution 3...Component supply pipe lines 4a to 4e...Component storage tank 5a to 5e
...Control valve 6...Sample introduction pipe 7.
...Ion chromato analyzer 8...Control Figure 1 Figure 2 (A) □1C1 (B)

Claims (1)

[Claims] In cultivation using a nutrient solution, a hydroponic cultivation control comprising an analysis means for measuring the ion concentration of essential components of the nutrient solution, and a means for replenishing each of the above components to the nutrient solution based on the output of the analysis means. system.