JP2005278587A - Improvement of method for open field hydroponics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve method for open field hydroponics protecting plants from heat in summer. <P>SOLUTION: A heat damage preventing method in open field hydroponics comprising supporting a transplanting panel having planted vegetables on a culture fluid in a cultivation tank, and soaking roots of the vegetables in the culture fluid, wherein the liquid temperature of the culture fluid is cooled down to 15-25°C and the concentration of the culture fluid is regulated between a little higher than the concentration of the vegetable cell liquid and close to zero concentration, and cooling the vegetables by soaking in the culture fluid in hot summer time and then lifting up the vegetables from the culture fluid and cooling the vegetables by the heat of evaporation of the water adhered on the vegetables and repeating the short time soaking and lifting up cooling some necessary times. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to an improvement for preventing summer heat damage, strong wind damage, and acid rain damage that plants suffer from open field cultivation in an open field hydroponics method.

  Conventionally, in outdoor hydroponic cultivation, the photosynthesis of plants is not performed sufficiently due to long heat in the summer, so the leaves, stems, etc. are wilted, and the growth is significantly delayed. A method of stretching a heat shield screen such as cold chill on the cultivation tank is used, but the shield screen is damaged during strong winds, especially when the typhoon is blown away, and the screen support frame collapses. .

  Also, depending on the strong wind, in addition to the damage and collapse of the shielding screen, the leaves of the plant may be blown off, the stem may be broken, and the entire plant may be detached from the planting panel. The fact is that no effective measures have been taken.

  In addition, depending on the acid rain, there may be spots on the leaves of the plants or there are holes that reduce the value of the product, eventually causing the whole to die, and as a countermeasure, a waterproof sheet is placed on the cultivation tank. Although a means for stretching is adopted, there is a problem that a complicated work of attaching / detaching the waterproof sheet is required every rain.

1st invention of this application makes it a subject to protect a plant effectively from the heat-and-heat damage of a summer in outdoor hydroponics,
The second invention of the present application aims to effectively protect plants from strong wind damage,
It is an object of the third invention of the present application to effectively protect plants from damage caused by acid rain.

  In order to solve the above-mentioned problems, the present inventor has conceived that a plant is immersed in a culture solution in a cultivation tank as a basic means common to the first, second, and third inventions.

Therefore, first, the safety of the plant when the plant is immersed in the culture solution is examined.
In general, when a plant is immersed in an aqueous solution, in terms of plant physiology, as long as the cells of the plant remain alive during the immersion, the plant taken out from the aqueous solution after the immersion grows healthy without leaving any sequelae. In this case, it is known that what influences the life and death of plant cells during immersion is the level of the osmotic pressure between the plant cell solution and the aqueous solution, in other words, the level that determines the osmotic pressure. Therefore, we will consider both of them. In addition, although the osmotic pressure of the cell fluid of a plant changes with kinds of plant, it is 5-10 atm and the density | concentration are 0.2-0.8M (molar concentration) at normal temperature.

(1) When a plant is immersed in an aqueous solution having the same concentration as the plant cell solution.
There is no water in and out of plant cells, and the cells continue to survive while maintaining their shape.

(2) When a plant is immersed in an aqueous solution having a lower concentration than the cell solution.
The cells absorb water from the outer aqueous solution through the semipermeable cell membrane and expand the protoplasm. By the way, since the plant cell has a cell wall made of a completely permeable elastic tissue outside the cell membrane, the bulging protoplasm exerts a bulging pressure that tries to push the cell wall and expands the cell wall as a reaction. It receives the wall pressure to return to the protoplasm. As the cell swells, its concentration in the cell decreases, its osmotic pressure decreases, and the swell pressure increases, and when the wall pressure equal to that is equal to the osmotic pressure in the cell, the outside of the cell Automatically stops water absorption from and continues to survive in a bulging tension.

(3) When a plant is immersed in a zero concentration aqueous solution (that is, water).
Same as (2) above.

(4) When a plant is immersed in an aqueous solution having a higher concentration than the cell solution.
Intracellular water leaches out and the protoplasm contracts, eventually causing protoplasm separation. Here, if the concentration of the aqueous solution is slightly higher than the plant cell fluid, the cells that have undergone protoplast separation will return to protoplasm when immersed in water again, but when the concentration of the aqueous solution is higher than that, Many plants die because protoplasmic reversion is impossible.
In this case, the concentration of the aqueous solution that enables protoplast reversion varies depending on the type of plant according to experiments, but is about 0.1 to 0.3 M higher than the concentration of plant cell fluid.

As a means for solving the above problems based on the above examination, the first invention of the present application is:
In the plant hydroponics where the roots of the plant are immersed in the culture solution while supporting the fixed planting panel in which the plant is planted on the culture solution put in the cultivation tank,
The temperature of the culture solution is cooled to about 15 ° C. to 25 ° C., and the concentration of the culture solution is adjusted between a concentration slightly higher than the concentration of plant cell fluid and a concentration close to zero.
During the summer heat, the plant is immersed in the culture solution for a short time and cooled, and then the plant is pulled out of the culture solution and cooled by the heat of vaporization of water adhering to the plant. Repeat as many times as necessary,
Proposes heat damage prevention methods in outdoor hydroponics,

The second invention of the present application is
In the plant hydroponics where the roots of the plant are immersed in the culture solution while supporting the fixed planting panel in which the plant is planted on the culture solution put in the cultivation tank,
Adjust the concentration of the above-mentioned culture solution to a concentration close to zero from the concentration of plant cell fluid,
During the strong wind, the plant is immersed in the culture solution for the duration of the strong wind to avoid the strong wind.
Proposed methods to prevent strong wind damage in open-air hydroponics,

The third invention of the present application is
In the hydroponic cultivation of the plant in which the roots of the plant are immersed in the culture solution while supporting the fixed planting panel in which the plant is planted on the culture solution put in the cultivation tank,
Adjust the concentration of the culture solution to a concentration close to zero from the concentration of plant cell fluid,
During the acid rain, the plant is immersed in the culture solution for the required time to wash away the acid rain adhering to the plant, and the required time immersion washing is repeated at short intervals during the duration of the acid rain,
After raining, the pH of the culture solution is adjusted normally.
We propose a method for preventing acid rain damage in hydroponics in open ground.

  According to the first invention of the present application, a plant is immersed in a medium of about 15 ° C. to 25 ° C. in midsummer heat and cooled, then pulled up and cooled by heat of vaporization. It keeps cool, thereby preventing damage from hot heat and maintaining healthy growth, as well as making it possible to grow winter vegetables such as spinach and lettuce in the summer.

  According to the second invention of the present application, a plant can be immersed in a culture solution during a strong wind, and can be maintained in a calm state without any influence of the strong wind, thereby sufficiently preventing damage caused by the strong wind, particularly during a typhoon. It is.

  According to the third invention of the present application, acid rain damage can be prevented by repeatedly washing the acid rain adhering to the plant by immersing the plant in the culture solution during the acid rain.

In the first invention of the present application, the “short-time soaking” is performed when the concentration of the culture solution is adjusted to be 0.1 to 0.3 M higher than the concentration of the plant cell solution. For safety, it is desirable that the immersion time is 3 to 5 minutes and the interval is 10 to 15 minutes. However, when the concentration of the culture solution is adjusted below the concentration of the plant cell solution, the immersion time can be freely selected as 10 to 20 minutes.
In addition, for the low-temperature adjustment of the culture solution, a method is preferred in which a cooling pipe is provided in the cultivation tank, and cooling is performed through the pipe through ground water, cooling water from a cooling machine, or the like.

  In the second invention of the present application, the term “soaked during continuous strong wind” means that the plant continues to be immersed for 2 to 3 hours while continuing strong wind for 1 to 2 days.

In the third invention of the present application, the “short time interval” between the immersion and the next immersion is such that when the acidity of acid rain is strong, the short time interval is about 1 to 5 so that the plant is not damaged. If the acidity is weak, about 5 to 10 minutes is preferable.
Also, since the rain that has fallen is not always acid rain, it is better to detect the acidity of the rain with a PH meter, litmus paper, etc., and to start dipping immediately when the pH is 5.0 or less.
The “pH adjustment of the culture solution” after the rain is adjusted to a pH of 5.5 to 6.5 (normal value) preferable for plant cultivation by adding a pH adjusting agent such as sodium hydroxide or sodium carbonate.

(Example 1 of the first invention)
Komatsuna is planted on the fixed planting panel, and the concentration of the cell fluid is 0.3M.
The basic composition and concentration of the fertilizer contained in the culture solution were 1.77 mM (mmol) of calcium nitrate, 2.37 mM of potassium nitrate, 1.25 mM of magnesium sulfate, 0.435 mM of ammonium dihydrogen phosphate, and a total of 5.825 mM (= 0.005825M), EDTA iron, copper sulfate, zinc sulfate, and ammonium molybdate are added in small amounts, and an appropriate amount of organic fertilizer is added to make the concentration of the whole culture broth about 11.7 mM (= 0.117M). It is adjusted to be lower than the cell fluid concentration of Komatsuna.

  The culture solution was cooled to 23 ° C. through ground water through a cooling pipe provided in the cultivation tank. The temperature is 36 ° C. The planted panel in which the komatsuna is planted is immersed in the culture solution for about 15 minutes by appropriate means to cool the komatsuna to 23 ° C, and then the panel is pulled up from the culture solution to bring it back to the original hydroponics state. Then, cooling was carried out for about 20 minutes by the heat of vaporization of the water adhering to the komatsuna. This 15-minute immersion cooling and 20-minute vaporization heat cooling were repeated during a hot summer time of 36 ° C. (from 2 pm to 4 pm).

  By the immersion for 15 minutes, Komatsuna cells absorb water from the culture medium to expand the protoplasm, and as the cells expand, the concentration and osmotic pressure in the cells decrease and the expansion pressure increases. When the equal wall pressure and intracellular osmotic pressure become equal, the absorption of water stops and the cells continue to live in the swollen state. The expanded cells gradually return to normal within 20 minutes after being pulled out of the culture.

  Komatsuna was not affected by heat and heat due to repeated immersion cooling and vaporization heat cooling.

(Embodiment 2 of the first invention)
Komatsuna was planted in the same manner as in Example 1, and the concentration of the culture solution was further increased to 0.4M by adding a large amount of fertilizer, and the concentration of the cell solution of Komatsuna exceeded 0.3M. This is an example in which the immersion time is further shortened.

  Air temperature 36 ° C, culture solution 22 ° C. The planting panel was immersed in the culture solution for about 5 minutes and cooled, and then the panel was pulled up from the culture solution and cooled by evaporation for about 20 minutes. This immersion cooling for 5 minutes and vaporization heat cooling for 20 minutes were repeated during hot and hot hours.

  During the short-time immersion, the moisture in the plant cell is leached to the outside, the protoplasm contracts and finally the initial protoplast separation occurs. However, since the concentration of the culture solution is only slightly higher (0.1 M) than the concentration of the cell solution, but the immersion time is shortened to 5 minutes, the protoplast separation does not proceed further. During 20 minutes after returning to the original hydroponics, Komatsuna restores protoplast separation to normal by the moisture absorbed from the roots.

  Komatsuna is not damaged by heat due to the above immersion cooling and pull-up cooling.

(Embodiment of the second invention)
Lettuce is planted on a fixed planting panel, and the concentration of the cell solution is 0.4M.
To the culture solution, EDTA iron, copper sulfate, zinc sulfate and ammonium molybdate are added in small amounts to the basic composition substantially the same as the basic composition and its concentration in Example 1 of the first invention, and the total concentration is about 11.2 mM (= 0.0112 M), which was lower than the cell fluid concentration of lettuce.

  Under a temperature of 25 ° C. and a culture solution temperature of 18 ° C., a panel in which lettuce was planted along with the typhoon attacked was immersed in the culture solution and continued for 23 hours until the strong wind left in that state.

  The above-mentioned long-time immersion causes the lettuce cells to absorb water and expand the protoplasm, and when the cell wall pressure and intracellular osmotic pressure are equal, the water absorption stops and the cells live in the expanded state. to continue. When lettuce is lifted from the culture and returned to the original hydroponics, the cells gradually return to normal.

  Lettuce immersed in the culture is kept in a calm state with no wind and is not damaged at all by the strong wind.

(Embodiment 1 of the third invention)
Saladana is planted on a fixed planting panel, and the concentration of the cell solution is 0.5M.
The culture solution had the same composition as that of the example of the second invention, and the total concentration was about 10.6 mM (= 0.0106 M), which was lower than the cell solution concentration of Sardana.

  When rain occurred at an air temperature of 27 ° C. and a culture solution temperature of 20 ° C., the pH of the rain was measured with a PH meter. Therefore, the fixed planting plant in which Saladana is planted is immersed in the culture solution for 10 minutes, and the attached acid rain is washed away with the culture solution. In this case, it is better to lightly shake the plant. Next, the panel is pulled out of the culture solution, and an interval of 5 minutes is set. Thereafter, the measurement of rain PH is continued and the immersion for 10 minutes and the interval of 5 minutes are repeated.

  In general, acid rain is the most acidic at the beginning and tends to decrease thereafter. When the pH of rain becomes as high as 5.0, switch to 10 minutes immersion and 10 minutes interval.

  Thereafter, the immersion is repeated for 10 to 20 minutes and the interval for 5 to 10 minutes, and the immersion is terminated when the pH of the rain reaches or approaches 5.5.

  After raining, the pH of the culture solution is measured, and the pH of the culture solution is adjusted to 5.5 to 6.5 by adding 4% sodium hydroxide to the pH adjusting agent.

  When the acid rain adhered to Saladana is washed away by the above immersion and pulled out from the culture solution, the acid rain that falls by the culture solution adhering to Saladana is diluted, thereby sufficiently preventing acid rain damage.

(Embodiment 2 of the third invention)
In Example 1 above, when the pH of the initial rainfall was measured and showed a strong acidity of, for example, 3.0, the panel in which the saladna was planted was immersed in the culture solution, and the acidity of the rain decreased. Wait for. After 1 hour, when the pH of the rain increased to 4.5, the 10 minute immersion and the 5 minute interval were repeated as in Example 1, and then the 10 minute immersion and the 10 minute interval were repeated. The immersion is terminated when the pH becomes 5.5 or a value close thereto.

After raining, the pH of the culture is adjusted to 5.5-6.5 by adding 10% sodium carbonate. This example also sufficiently prevents acid rain damage.

Claims (3)

In the plant hydroponics where the roots of the plant are immersed in the culture solution while supporting the fixed planting panel in which the plant is planted on the culture solution put in the cultivation tank,
The temperature of the culture solution is cooled to about 15 ° C. to 25 ° C., and the concentration of the culture solution is adjusted between a concentration slightly higher than the concentration of the plant cell solution and a concentration close to zero.
During the summer heat, the plant is immersed in the culture solution for a short time to cool, then the plant is pulled up from the culture solution and cooled by the heat of vaporization of water adhering to the plant. Repeat as many times as necessary,
How to prevent heat and heat damage in outdoor hydroponics. In the plant hydroponics where the roots of the plant are immersed in the culture solution while supporting the fixed planting panel in which the plant is planted on the culture solution put in the cultivation tank,
Adjust the concentration of the culture solution to a concentration close to zero from the concentration of plant cell fluid,
During the strong wind, the plant is immersed in the culture solution for the duration of the strong wind to avoid the strong wind.
A method to prevent strong wind damage in open-sea hydroponics. In the hydroponic cultivation of the plant in which the roots of the plant are immersed in the culture solution while supporting the fixed planting panel in which the plant is planted on the culture solution put in the cultivation tank,
Adjust the concentration of the culture solution to a concentration close to zero from the concentration of plant cell fluid,
During acid rain, the plant is immersed in the culture solution for a required time to wash away the acid rain adhering to the plant, and this required time immersion washing is repeated at short intervals during the duration of the acid rain,
After raining, the pH of the culture solution is adjusted normally.
Acid rain damage prevention method in the hydroponics of the open field.