JP2009055871A - Method of spraying hydroponics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an epoch-making method of spraying hydroponics which has solved the problematic points of method of spraying hydroponics by using culturing soil as a supporting material, and has been developed further. <P>SOLUTION: This method of spraying hydroponics is provided by installing a cultivation floor installed with a cultivation medium containers having bottom surfaces from which the roots of plants downwardly freely elongate, on a rack in a green house, dividing the space in the house up and down to separate it as an upper layer and a lower layer, installing an air-circulation device to be able to perform three-dimensional ventilation, laying the cultivation medium having been subjected to sterilization treatment including the cultivation soil in the cultivation medium container, covering the opened up surface of the lower space of the rack with a light-shading material to make it a dry mist chamber and spraying liquid fertilizer in a dry mist state to the roots of the plants in the dry mist chamber. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement of spray hydroponics that supplies mist-like liquid fertilizer (nutrient) directly to plant roots, and more particularly, to a spray hydroponics that does not use agricultural chemicals or chemical fertilizers.

The current agriculture is in a vicious cycle where the vitality of the soil has been lost due to the use of pesticides and chemical fertilizers for many years, and so the vitality of plants has declined, and more and more pesticides and chemical fertilizers are required. As a result of comparing the nutritional value of crops between the 1950s and the recent period, surprising data have been reported that, although there is a difference depending on the production area, it is generally reduced to about 1/2 to 1/10. In addition, pesticides can cause environmental pollution, direct phytotoxicity to farmers, and decreased immunity caused by eating crops containing residual pesticides, which may be one of the causes of cancer and allergic diseases. Cannot be denied. Therefore, the spread of agricultural chemical-free and dechemical fertilizer agriculture as soon as possible is desired.
Hydroponics is known as a plant cultivation method that can cope with soil degradation (for example, Patent Documents 1 and 2). Hydroponics is also called hydroponics, and it is also called “soilless cultivation” because it cultivates crops without using soil. It is a field different from soil cultivation as one of the plant cultivation methods of the 21st century. In the spotlight. Today, in crop production, the decrease in the population engaged in and the aging of the population are a problem. In the field horticulture, soil degradation due to salt accumulation failure is serious, and hydroponics has been studied as a countermeasure. Hydroponics is also attracting attention in the area of corporate plant production, especially biotechnology. Furthermore, regarding the quality of crops (desiring high nutritional value), it has been found that hydroponic cultivation can easily carry out high-quality and high-nutrient cultivation, and is becoming increasingly important. It can be said that hydroponics has already entered the diffusion stage, depending on how it is viewed.
FIG. 10 shows currently known types of hydroponics.

Hydroponics supports plants using various supports instead of soil. Each has advantages and disadvantages, and must be selected according to the characteristics of the crop. In addition, hydroponic cultivation always involves root respiratory disturbance, and thus various ideas have been made. However, as long as the root is in solution, it cannot be completely solved. Therefore, in recent years, a method called spray hydroponics has attracted attention and research has been conducted. The spray hydroponic cultivation method is a method in which liquid fertilizer (nutrient solution) is misted with a spray pump and sprayed onto the roots, and the roots are supported in the air without being immersed in the solution, so that respiratory problems can be avoided.
However, the conventional spray hydroponic cultivation method has a problem because the soil is not used for the culture medium, and the present inventor has first applied for an invention relating to the spray hydroponic cultivation method using soil (see Patent Document 3). Furthermore, an application for an improved invention was filed (see Patent Document 4, hereinafter referred to as a prior invention). And it has been cultivated in the fields throughout the country. However, it has been found by subsequent examinations that the invention of the prior application has further improvements.

JP 11-46577 A JP-A-9-275831 JP 2003-274774 A JP 2006-67999 A

  An object of the present invention is to provide an innovative spray hydroponic cultivation method that solves and further develops the problems of the spray hydroponic cultivation method using culture soil as a support material.

The above problems are solved by the following inventions 1) to 2).
1) In the house, a cultivation floor with a cultivation medium container with a bottom that allows the roots of the plants to freely extend downwards is installed on a gantry, and the space inside the house is divided into upper and lower layers. In addition to separation, an air circulation device is provided to enable three-dimensional ventilation, and the cultivation medium container is laid with a sterilized cultivation medium containing culture soil, and the open surface of the space below the gantry can be shielded from light A spray hydroponic cultivation method, characterized in that it is covered with a material to form a dry mist chamber, and liquid fertilizer is sprayed in the form of dry mist on the roots of plants in the dry mist chamber.
2) The spray hydroponics method according to 1), wherein a non-woven fabric that has been subjected to a hydrophilic treatment is laid on the bottom of a cultivation medium container having a mesh-like bottom, and the cultivation medium is spread on the nonwoven fabric.

Hereinafter, the present invention will be described in detail.
In the above-mentioned prior application, various improvements have been made. However, it has been found that there are points that should be further improved by subsequent studies, and the present invention has solved these problems.
In FIG. 1, the image figure of the nutrient solution supply system in the spray hydroponics method of invention of a prior application is shown.
For facility management, it is not easy to make the mist droplets sprayed by spray hydroponic cultivation smaller than 50 μm, and in the invention of the prior application, we inevitably made efforts at this limit level. Since the root surface gets wet with mist, the nature of the root becomes an underwater root.
Also, when the temperature is high, the nutrient solution evaporates and fertilizer salt is deposited on the surface of the roots, and salt damage reduces the activity of the roots and weakens the vigor. In some cases, salt causes reverse osmosis and the roots die.
Furthermore, when the roots get wet, excess mist liquefies and returns to the nutrient solution recovery pit through the drain. The collected nutrient solution is returned to the nutrient solution storage tank through a high-precision filter for recycling. However, the concentration balance of each fertilizer salt is incorrect in the nutrient solution storage tank compared to the concentration of each fertilizer salt at the time of spraying. Therefore, it is necessary to perform simple fertilizer correction, and it will take a large cost for nutrient solution management.

Therefore, a new cultivation method that solves the above problems was developed. In FIG. 2, the image figure of the nutrient solution supply system using the dry mist of this invention is shown. The main improvements are the following (1) to (3).
(1) The nutrient solution is sprayed in the form of an extremely fine dry mist that does not wet the roots.
Dry mist is a dry mist that will not get wet even if you put your hand in it, and will remain in the air for a long time because the mass of the droplet is extremely small, and will gradually change to moisture. That is, by making the nutrient solution into droplets of 10 μm or less, the nutrient solution becomes moisture, and roots in the moisture are rooted to absorb the fertilizer salt and moisture contained in the moisture. The dry mist can be obtained by using a two-fluid nozzle (fog nozzle) that can atomize the nutrient solution on the same principle as spraying. Specific examples thereof include a spray fogger manufactured by Spraying Japan.
The rough particle size of rain and fog is as shown in FIG. * In the figure indicates that it becomes floating in the air by Brownian motion when it becomes 0.1 μm or less. MVD is a method of displaying the particle diameter by the volume (mass) of the spray liquid, and 50% of the total sprayed volume consists of particles larger than the average value, and the remaining 50% is smaller than the average value. Refers to the value consisting of particles.

Here, the roots in moisture will be explained. In the invention of the prior application, the roots are cultivated in the state of underwater roots. An underwater root is a root in a wet state, and a wet root is a root in a moisture but dry state like the root in the dry mist described above.
As a cultivation method using a root in moisture, a capillary hydroponics method (Nagano agricultural test method) and passive cultivation are known. However, none of them is a spray hydroponics method and is not a reference for the present invention.
In the present invention, dry mist is sprayed to form a root in moisture. Although there are differences in many physical and chemical conditions such as moisture, temperature, oxygen, etc. in moisture and water, their effects on root function and morphology are not clear. Therefore, we compared “underwater roots”, which are roots that have been developed by dipping in a nutrient solution, and “humidity roots”, which are roots that have been developed on a wet sheet and exposed to the air. The results are shown in FIG. In the figure, the horizontal axis represents the distance (cm) from the root tip, and the vertical axis represents the number of root hairs generated on the primary root axis (the number of hair roots growing in the range of 250 μm).
There is no particular difference in the growth of the above-ground part when comparing the plants with the roots in the water and the plants with the roots in the water, but as for the root growth, the roots in the moisture are more so as to be understood from the number of root hairs generated. Plants that are more vigorous than underwater roots and have a moisture-borne root have a lower “overground weight / underground weight”.
In addition, the fractal dimension of the side roots (a measure representing the visual complexity of the structure) is higher for the roots in the moisture than in the roots in the water, and branch roots are developed in the roots in the humidity.
However, since the nutrient solution absorbability per unit weight of the roots in the moisture is smaller than the roots in the water, it is considered that the nutrient solution absorbability is compensated by the large amount of roots in the roots in the moisture.

(2) Do not collect nutrient solution.
In the prior invention, since a part of the sprayed nutrient solution mist becomes droplets, a system for recovering excess nutrient solution is necessary. In the present invention, the droplets are used to spray the nutrient solution in the form of dry mist. No nutrient solution recovery system is required. As a result, nutrient solution management for recycling the collected nutrient solution becomes unnecessary, and a significant cost reduction can be achieved.
FIG. 5 shows comparison data of facility costs when the cultivation facilities of FIG. 1 (the invention of the prior application) and FIG. 2 (the present invention) are installed in a house having a size of 20a. In the invention of the prior application, a mist with a droplet of 50 μm was used, and in the present invention, a dry mist of 8 μm was used. From FIG. 5, it can be seen that the cost of the present invention is reduced by about 22% due to the reduction of the nutrient solution mixing system and nutrient solution circulation system costs.
The two-fluid nozzle for spraying the dry mist-like nutrient solution on the roots is usually arranged at intervals of about 10 m. A humidity sensor is provided at an intermediate point between the nozzles, and spraying is stopped when the humidity reaches 90%, and spraying is performed when the humidity drops to 70% to maintain a high humidity environment.

(3) Although there are viral diseases and mold diseases in crop diseases, seeds and pests are the vectors of viral diseases. Seeds can be obtained by obtaining virus-free reliable seedling manufacturers. In addition, pests use a high-precision insect-proof net (mesh size 0.4 mm) to cut off the approach path, and provide a room at the entrance of the house to make the pressure in the room higher than the outside. If the door between the room and the room is not closed, the door between the room and the house can be opened (double door). These were also implemented in the prior invention.
On the other hand, mold disease generally develops when indoor humidity exceeds about 90%. If the leaf surface temperature is lower than the air temperature, condensation occurs on the leaf surface, and mold tends to propagate. However, if there is an airflow on the leaf surface, condensation does not occur, so the airflow fan is activated to generate airflow in the house. However, when the leaves overgrow, the airflow fan gives airflow to the leaf surface. I can't.
Therefore, in the present invention, the space in the house is divided into upper and lower layers by dividing the space in the upper and lower sides, and for example, an air circulation device such as a large ventilation fan is provided near one end of the house to send the upper layer air to the lower layer. In the vicinity of the other end of the house, a gap is provided in the upper and lower partitions so that the air in the lower layer flows to the upper layer. As a result, three-dimensional ventilation is possible in the house, and airflow can be given to the overgrown foliage, thereby preventing the occurrence of mold disease.

FIG. 6 shows an image of a house that enables air circulation by three-dimensional ventilation. (A) is the schematic diagram seen from the side, (b) is a perspective view. In the figure, the space is divided up and down by a heat insulating sheet.
When this three-dimensional ventilation is performed, there is also an advantage that heating costs can be significantly reduced.
Referring to FIG. 13, heat input and output in the house will be described. Heat is supplied by sunlight to warm the house in the daytime, and at the same time, about 20% of the supplied heat is stored in the ground by underground heat transfer. . Moreover, about 20% of the supplied heat goes out of the gap of the house by the gap ventilation heat transfer. Conversely, at night, the heat stored in the ground by underground heat transfer returns to the house. However, the heat generated by the gap ventilation heat transfer does not return to the house.
Furthermore, since the temperature in the house is usually set to about 15 ° C., it is necessary to perform night heating according to the season and installation location. At that time, heat is released from the roof surface or the like due to heat flow in the house, and the amount of released heat increases as the temperature of the upper part of the house increases.
On the other hand, when the set temperature is 15 ° C., in the house of the invention of the prior application, the temperature at the top of the house is higher by about 7-9 ° C. than the temperature near the cultivation floor, whereas in the present invention, it is only about 1-2 ° C. higher. It is. At this time, the amount of heat released due to the through-flow heat transfer is about 80% of the amount of heat supplied by heating in the prior invention, whereas it is about 60% in the present invention. That is, in the present invention, since the temperature rise at the upper part of the house can be suppressed, the amount of heat released at night becomes very small, and the cost is reduced by about 20%. The house with a size of 20a can save about 80,000 kcal / day of heat regardless of the outside air temperature.

By the above (1) to (3), the following effects (a) to (f) are obtained.
(I) Highly active moisture roots grow vigorously and can maintain a high vigor.
(B) The occurrence of mold disease can be prevented.
(C) A nutrient solution circulation system consisting of nutrient solution recovery pits, nutrient solution return pumps, high precision filters, etc. is no longer required.
(D) Since there is no deviation in nutrient solution concentration, frequent analysis and simple fertilizer correction are not required, and the nutrient solution mixing system can be simplified.
(E) Temperature unevenness in the house can be eliminated by three-dimensional ventilation, and heating costs can be reduced.
(F) Since the foliar boundary layer cannot be created by three-dimensional ventilation, photosynthesis is promoted and the vigor is enhanced.
Many plants grow while exchanging gases such as carbon dioxide and water vapor in an air stream. Gas exchange between the leaves and the surrounding atmosphere is carried out through an air layer with a small air flow called the leaf boundary layer formed near the leaf surface, and the “thickness of the leaf boundary layer” is the gas diffusion resistance. As a dominant effect on the gas exchange rate. Moreover, on the conditions with a small air velocity like a cultivation house, the diffusion of carbon dioxide on the leaf surface is suppressed. Therefore, in order to promote photosynthesis, airflow control for supplying carbon dioxide into the leaves is important.

Furthermore, it is preferable to shield the dry mist chamber from light in order to prevent browning of the roots.
As described in the specification of the previous application, in the conventional method in which the dry mist chamber is not shielded from light, the roots are browned, the vitality is reduced, the root elongation rate is slowed, and the growth of the foliage is slow. If the shielding sheet in the mist chamber is made light-shielding so that light does not enter, the roots do not turn brown and become pure white, and the extension becomes vigorous and vigorous. It is desirable to block out light as completely as possible because it will turn brown when light enters. Moreover, generation | occurrence | production of the algae of a dry mist chamber can also be prevented by light-shielding.
In addition to this, it is also possible to appropriately adopt the opening and closing of the cover of the dry mist chamber disclosed in the invention of the prior application and the cultivating floor being movable.

Here, the outline of the facility for carrying out the spray hydroponics of the present invention will be briefly described with reference to the drawings, but the embodiment of the present invention is not limited thereto.
As shown in FIG. 2 and FIG. 6, an elevated dry mist cultivation floor on which a cultivation medium container is placed on a frame made of galvanized steel pipe for agriculture is installed in the house, and plants are placed in the lower space of the cultivation floor. Equipment for spraying dry mist nutrient solution on the roots will be provided. In addition, the space in the house is divided up and down by an agricultural heat insulation sheet (commercially available product) and a large ventilation fan is provided at the end of the house. Furthermore, it is preferable to provide a side window for ventilation and a roll-up type skylight.
The shape, structure, and material of the culture medium container are not particularly limited as long as the roots of the plant pass through the bottom surface and can be freely extended downward, and those having a known bottom surface in a mesh shape are used. Usually, it is made of a lightweight plastic with a length of 60 to 70 cm, which is convenient for one person. However, since the cultivation medium is spread, it is preferable to have a side wall having an appropriate height (about 6 to 8 cm) at the end so that the cultivation medium does not spill from the container.

In addition, it is desirable to spread a sheet made of a hydrophilic nonwoven fabric or the like on the mesh bottom of the container to prevent the culture medium from flowing out and improve water retention (see FIG. 7). The opening of the sheet is preferably 1 mm or less and the thickness is preferably about 3 to 10 mm. Nonwoven fabrics have a high degree of openness and can be used freely even when the roots grow and become thicker. The degree of spillage is also greatly reduced.
The depth of the culture medium spread in the container is usually 4 to 6 cm. If it is too shallow, the function as a support material cannot be exhibited, and the merit of combining hydroponics and soil cultivation is lost, which is not preferable, and if it is too deep, the advantages of hydroponics are lost. However, since it varies depending on the type of plant and the nature of the cultivation medium, it is not limited to the above range. The gantry has a height of about 70 to 80 cm and a width of about 60 to 100 cm, but can be appropriately changed depending on the working environment. The length is arbitrary because it varies depending on the size of the house, the number and arrangement of the houses. In the lower space of the cultivation floor, a spray device for dry mist nutrient solution (for example, a PVC pipe having fog nozzles at regular intervals) is provided. Cover both sides of the cultivation floor with a light-shielding vinyl sheet and make the lower space a simple dry mist room.
FIG. 8 shows a detailed assembly diagram (front view) of an example of an elevated dry mist cultivation floor comprising a gantry and a cultivation medium container. The unit of the dimension in the figure is mm. In this figure, a drain pan for collecting washing water is provided at the bottom of the gantry, and a net shelf is provided at the top of the drain pan to prevent plant roots extending down to the drain pan. Moreover, it has the baseplate for respond | corresponding to rough terrain in the lower part of a mount.

One of the features of the present invention and the prior invention is that a culture medium is used for spray hydroponics.
The role of the medium is a) to compensate for the independence of crops, b) to have water retention because there is a fine space corresponding to capillary pores, c) to have a high gas phase rate and high air permeability, and d) organic matter And a living space for symbiotic rhizosphere microorganisms, and e) a rich source of minerals.
As materials for the culture medium, akadama soil (a core material for rich soils with rich water retention), peat moss (water moss deposits with high water retention acidity), pearlite (baked pearlite, used to improve air permeability. ), Vermiculite (baked meteorite and used for water retention improvement), cattle manure compost, chicken manure compost (organic material), and humus (composted hardwood fallen leaves).
In the cultivation method using the dry mist of the present invention, it is preferable to use a medium in which soil is mixed with a material having a high effect of improving water retention and air permeability and organic fertilizer (cow manure compost, chicken manure compost). An example is shown in FIG.
Furthermore, it is preferable to use mineral water in order to replenish trace minerals that are lacking in recent soil. Extraction of finely ground basalt, rhyolite, granite and serpentinite with 30% sulfuric acid heated to 100 ° C. over 1 hour gives a mineral stock solution. The analysis result of the elements contained in the mineral stock solution extracted by changing the mixing weight ratio of the four kinds of rocks is shown in FIG. The mineral stock solution is diluted and adjusted to PH6 to obtain mineral water, which is used as raw water for nutrient solution or raw water for irrigation.

The present invention can be applied to any plant that can be spray hydroponically cultivated, and representative examples include large leaf perilla, tomato, honey beet, lettuce, strawberry, melon, spinach and the like.
Because it is a cultivation method that does not use agricultural chemicals or chemical fertilizers, safe crops can be obtained, and it has a longer shelf life and higher nutritional value than commercial ones. For tomatoes, strawberries, melons, etc., extremely high quality crops can be obtained, such as a drastic increase in sugar content. Especially for large leaf perilla, the amount of residual nitrate nitrogen can be greatly reduced, the value of allyl aldehyde, a perfume component of perilla, increases, and it is larger than normal large leaf perilla while maintaining its softness and taste. Is easily obtained.

  According to the present invention, it has the merits of spray hydroponics and soil cultivation, and the plant looks like a tree with roots down to the ground, has a forcing effect, extends the harvest period, is amazing Can provide a groundbreaking cultivation method that can produce high-quality crops with high nutritional value and good shelf life while preventing the occurrence of diseases without using agricultural chemicals or chemical fertilizers.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples.

Example 1
Large leaf perilla was cultivated using the cultivation house outlined in FIGS.
Commercially available thermal insulation sheets are used to partition the upper and lower spaces in the house, and a large ventilation fan (Matsushita Nabek belt-driven ventilation fan, NK-17WA-50, ventilation air volume 445 m ² / min, power consumption 630 W is used for the air circulation device. ) Was used.
7 and 8 using an approximately 30 m long dry mist cultivation bed and a cultivation medium container, and a light-shielding sheet (manufactured by Mikado Chemical Co., Ltd.) on the lower release surface (side surface, etc.) of the gantry. Silver / black double multi-sheet). The bottom of the culture medium container was laid with a hydrophilic treated nonwoven fabric (manufactured by Oji Kinocross Co., Ltd., TDS nonwoven fabric, thickness 3 mm). For the culture medium, soil having the composition shown in FIG. 9 was sterilized with high-temperature steam at 95 ° C. and used.
Twenty days after sowing, the plants were planted on the cultivation floor, and a dry mist nutrient solution (see FIG. 12) was sprayed on the roots from the stage where the roots extended below the cultivation medium. The fog nozzle has a spraying Japan quick fogger (YB1 / 8 MFJ-SU-EA-001-SS, spray liquid amount: 2.2 liter / hour, air amount per nozzle: 39 liter / minute, average particle size : 8μm, spraying distance: 4m), arranged at 10m intervals, provided a humidity sensor at the midpoint of two adjacent nozzles, spraying was stopped when the humidity reached 90%, and sprayed when it decreased to 70% Control was performed. In addition, spraying distance is distance which can confirm fog visually.
As a result of cultivation as described above, large leaf perilla was able to be harvested without using pesticides and chemical fertilizers, without causing viral diseases and mold diseases.
In addition, compared with the system of the prior invention of FIG. 1, the facility cost could be reduced by about 22%, and the heating cost could be reduced by about 20%.
In addition, large leaf perilla cannot be harvested with good quality by hydroponics, so it has been tested in Toyohashi and Oita, but none of them continue. The fact is that it cannot be harvested unless a large amount of pesticide is applied.

The image figure of the nutrient solution circulation system in the spray hydroponic cultivation method of prior invention. The image figure of the nutrient solution supply system using the dry mist of this invention. The figure which shows the standard of the particle diameter of rain or fog. The figure which shows the number of root hair generation | occurrence | production on the primary side root axis of an underwater root and a root in moisture. The figure which compared the installation expense of this invention and prior application invention. The image figure of the house which enables the air circulation by three-dimensional ventilation, (a) The schematic diagram seen from the side, (b) Perspective view. The figure which shows an example of the culture medium container and the culture medium outflow prevention and water retention sheet | seat of a bottom part. (A) A cultivation medium container having a mesh-like bottom, (b) a hydrophilically treated sheet placed on the mesh-like bottom, and (c) a state in which a sheet is spread on the bottom of the cultivation medium container. The detailed assembly figure (front view) of an example of the elevated dry mist cultivation floor which consists of a mount frame and a cultivation culture medium container. The figure which shows an example of the culture medium used by this invention. The figure which shows the analysis result of the content element of a mineral stock solution. The figure which shows the classification | category of hydroponics. The figure which shows the composition of the nutrient solution used in the Example. (A) Assurance component based on law, (b) Compounding component, (c) Composition of amino acids contained in CS shiso amino. The figure explaining the entrance and exit of the heat of the house at daytime and at night.

Claims (2)

  In the house, set up a cultivation floor with a cultivation medium container with a bottom that allows the roots of the plants to extend freely downwards, and divide the space in the house into upper and lower layers and separate it into upper and lower layers At the same time, an air circulation device is provided so that three-dimensional ventilation is possible, and the cultivation medium container is laid with a culture medium that has been subjected to sterilization treatment containing culture soil. A spray hydroponic cultivation method characterized in that a dry mist chamber is covered, and liquid fertilizer is sprayed in the form of dry mist on the roots of plants in the dry mist chamber.   2. The spray hydroponic cultivation method according to claim 1, wherein a non-woven fabric subjected to hydrophilic treatment is laid on the bottom of a cultivation medium container having a mesh bottom and the cultivation medium is spread thereon.

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