JPH06335323A - Artificial soil structure and method for raising plant using the same - Google Patents

Abstract

PURPOSE:To make even a dried area unsuitable for agriculture to a soil environment suitable for plant culture by securing water required for soil, efficiently supplying necessary water to an upper layer of soil for cultivating an agricultural product. CONSTITUTION:An artificial soil structure consists of a water permeating layer in soil, a gravel layer existing on the water permeating layer, a hydrophobic layer composed of hydrophobic particles existing on the gravel layer and an upper layer existing on the hydrophobia layer. The hydrophobic particles are obtained by treating particles of sand and/or soil with a water repellent. The water permeating layer is a layer for sending sea water and air. In production of a plant, dried ground or desert is dug in an limited area and depth, space formed in the ground is provided with a water permeating layer to supply sea water and air, a gravel layer is laid on the water permeating layer, a water repellent sand layer treated with a water repellent is made on the gravel layer and an upper layer is formed on the water repellent sand layer to grow plant on the upper layer. The upper layer is a hydrophilic soil composed of a water-- retaining agent-containing sand or soil.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a new and improved artificial soil structure. More specifically, the present invention relates to an artificial soil structure capable of supplying water necessary for growing a plant in soil in a dry region, particularly in a desert, and a plant growing method using the same.

[0002]

[Related Technology] The ratio of deserts occupying the land of the world is currently about 3
It is around 0%, but the area continues to increase. There are various causes for this, but human production activities such as environmental pollution such as tree felling and acid rain, large intake of groundwater, abnormal weather that is thought to be caused by ozone layer depletion and carbon dioxide gas increase, etc. There are many things that are based on the environmentally destructive factors that accompany.

On the other hand, the world population is increasing year by year, and it is necessary to prevent desertification of the soil and to revive the dead and dead soil in order to avoid the food crisis in the future due to this population increase. is there.

For the purpose of avoiding the food crisis, efforts have been made to improve the production efficiency by improving the crops themselves by the recent biotechnology. However, in order to improve the production efficiency of agricultural products, it is necessary to improve the soil on which the agricultural products are grown to a soil suitable for various agricultural products.

Conventionally, in actual agricultural production, soil improvement such as tilling the soil surface or applying fertilizer has been carried out on a daily basis, but fundamental improvement of soil environment based on soil structure. For the purpose, the method of artificially assembling the strata that make up the soil for actual agricultural production has not been commonly used.

As described above, at present, it is necessary to improve the soil structure in order to make the environmental properties of the soil desirable for human beings at the global environmental level. Often determined by the water content. Therefore, it is first necessary to improve the soil structure so that the water content in the soil can be artificially controlled.

[0007] In order to perform agriculture in soil in arid regions, especially in deserts or dunes, it is necessary to constantly supply the water necessary for the soil layer in which agricultural crops are planted, and an artificial soil structure capable of always supplying water. You need your body.

Conventionally, as means for controlling the water content in the soil, for example, the soil and the water-retaining polymer compound are mixed, or as disclosed in JP-A-1-319585.
Means have been proposed for treating the surface of soil with high molecular weight hydrogen siloxanes.

On the other hand, in arid areas such as deserts and dunes, how to secure fresh water and supply it to the soil of agricultural products becomes a problem. For example, a method of converting seawater into a large amount by using a desalination apparatus and performing irrigated agriculture using the desalination apparatus is conceivable, but a large-scale desalination apparatus is required, which causes a cost problem.

[0010]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive research from the above viewpoint, and as a result, a dry soil structure such as a desert where agriculture cannot be performed is formed into a water layer. Gravel layer present on it, a hydrophobic layer consisting of hydrophobic particles present on the gravel layer, and a structure having an upper layer present on the hydrophobic layer, when seawater is circulated in the water-passing layer, Surprisingly, they have found that the necessary water can be efficiently supplied to the upper layer on which the crop grows, and have completed the present invention.

The main object of the present invention is not to merely improve the surface of the soil as in the prior art, but to provide a water-permeable layer and a hydrophobic layer consisting of a specific combination in the structure of the strata forming the soil. As a result, by securing the necessary water and efficiently supplying the necessary water to the upper layers of the soil for cultivating agricultural products, it is possible to provide a soil environment suitable for plant cultivation in arid areas such as deserts where agriculture is not possible. is there.

[0012]

That is, according to the present invention, as described in claim 1 of the claims, a water-passing layer in soil and a gravel layer existing on or surrounding the water-passing layer. And a hydrophobic layer composed of hydrophobic particles existing on the gravel layer, and an upper layer existing on the hydrophobic layer.

Further, according to the present invention, as described in claim 2 of the claims, the hydrophobic particles are sand and / or soil particles treated with a water repellent. The artificial soil structure described in 1.

Further, the present invention is the artificial soil structure according to claim 2, wherein the water repellent agent is a silicone-based or fluorine-based water repellent agent as described in claim 3 of the appended claims. .

Further, according to the present invention, as described in claim 4 of the appended claims, the water-passing layer is a layer for feeding water such as seawater and air, and any one of claims 1 to 3. The artificial soil structure described in 1.

Further, according to the present invention, as described in claim 5 of the appended claims, dry ground or a desert is excavated to a finite area and depth to form a space formed in the ground. A water-permeable layer for circulating water such as seawater and air is provided, a gravel layer is provided on or around the water-permeable layer, and a water-repellent sand layer treated with a water-repellent agent is provided on the gravel layer. A method for growing a plant is provided, wherein an upper layer is provided on the water-repellent sand layer, and a plant is grown on the upper layer.

Further, according to the present invention, as described in claim 6 of the claims, the upper layer is a hydrophilic soil consisting of sand or sand containing a substance having a water retention property. It is the method for growing the plant described.

Further, the present invention is the method for growing a plant according to claim 5 or 6, wherein water such as seawater is heated by solar heat and then passed through water as described in claim 7 of the appended claims. .

The present invention will be described below with reference to embodiments. The water-passing layer of the present invention is set in soil, and water is supplied to this water-passing layer. It is sufficient that the aquifer has a structure capable of supplying water and allowing water to flow through the entire aquifer. It is a layer that functions as a so-called underground waterway. The water supplied to the aquifer may be seawater.

The water supplied to the aeration layer can be circulated from the sea or a water source to the aeration layer by using, for example, potential energy or a pump. It is also possible to pass natural running water. It is also preferable to heat the water supplied to the water-passing layer using solar heat.

The water-passing layer can artificially use a compressor to send in air to aerate the water flowing through the water-passing layer. Sufficient water is supplied from the water-permeable layer to the upper layer by sending in air, which is preferable.

A gravel layer is set on the water passage layer. Further, the gravel layer may be set in a state of surrounding the water passage layer. For example, as a water-passing layer, a pipe having holes at regular intervals for discharging water may be embedded below or in the gravel layer. Further, water may be directly passed through the gravel layer, and the gravel layer may function as a water passing layer. This gravel layer can be of any thickness.
In order to allow this gravel layer to exist above the water-permeable layer, for example, the bottom surface and side surfaces of the water-permeable layer can hold water to some extent, and the top surface of the water-permeable layer allows water to penetrate into the gravel layer and the gravel layer. The structure must prevent water from falling into the aquifer.
For example, it is also possible to cover a U-shaped concrete drainage channel with a metal or resin net, supply water to this to form a water-permeable layer, and provide a gravel layer thereon.

The hydrophobic layer composed of hydrophobic particles is a particle-like layer which is present on the gravel layer and has a hydrophobic property, and is made of an inorganic or organic material. It doesn't matter. The term “above the gravel layer” means that the layer is facing the surface of the earth, and does not necessarily have to be in contact with the gravel layer. For example, a hydrophobic layer may be present via the sand layer above the gravel layer. . That is, the hydrophobic layer may be present between the gravel layer and the upper layer.

It suffices that the hydrophobic layer is substantially composed of hydrophobic particles, and within the scope of the present invention, the hydrophobic property is not lost as a whole layer even if particles having other properties are mixed. is there.

Hydrophobicity is a concept including so-called water repellency, and is specifically obtained by treating sand and / or soil particles with a water repellent. In particular, water-repellent sand obtained by treating sand with a water-repellent agent is preferable.

The particle size of the hydrophobic particles constituting the hydrophobic layer of the present invention is not particularly limited as long as the object of the present invention can be achieved, but preferably, it is easy to control the water content. The average particle diameter is preferably 4000 μm or less. Particularly preferably, it is 2000 μm or less.

The water-repellent agent used is not particularly limited as long as it is generally used as a water-repellent agent, but silicone-based and fluorine-based agents are particularly preferable.

Examples of the silicone water repellent include silicone compounds represented by the following general formula (Formula 1), which are directly (without solvent) or diluted with a solvent such as toluene, xylene and trichlene, Alternatively, it is used as an emulsion type. Further, a curing catalyst such as dibutyltin dilaurate, dibutyltin diacetate, dioctyltin laurate, iron octate may be used.

[0029]

Embedded image R ¹ aR ² bSiOx [R ¹ is the same or different, unsubstituted or substituted monovalent hydrocarbon group; R ² is the same or different group selected from a hydrolyzable group, —OH or —H A and b are 0 ≦ a <4 and 0 ≦ b
A number represented by ≤4, 0 <a + b≤4; x = (4-a-b) / 2. ] For example, in the general formula (Formula 1), R ¹ is an alkyl group having 1 to 15 carbon atoms such as a methyl group, an ethyl group, a propyl group, a decyl group, an alkenyl group such as a vinyl group or an allyl group, a phenyl group, etc. Aryl group, cycloalkyl group, CH ₃ C
It is a group in which some or all of the hydrogen atoms bonded to the carbon atoms of the above groups such as H ₂ CH ₂ — are substituted with halogen atoms or cyano groups. Further, R ² is a hydrolyzable group such as an alkoxy group, an acyloxy group, a ketoxime group, an amino group, an aminoxy group, an amide group, an enoxy group or an alkenyloxy group, a halogen group such as chlorine, —OR ³ (R ³ Is Na
Or K), -OH, -H and the like.

As specific silicone compounds, the following compounds represented by (Chemical formula 2) to (Chemical formula 5) are used.

Embedded image HO-Si (ONa) (CH ₃ )-[OSi (ONa) CH
₃ ] n-OH (n: 0, 1, 2)

Embedded image CH _3- [SiO (CH ₃ ) ₂ ] _m- [SiO (H) (C
H ₃ )] _l -Si (CH ₃ ) ₃ (l, m: 0 or integer)

Embedded image _{^{R 4 - [SiO (CH 3}} ) 2] k-Si (CH 3) 2 R 4 (K: ^{integer, R 4: -OH, -CH =} CH 2, OCH 3)

Embedded image CH ₃ SiCl ₃ , C ₁₀ H ₂₁ SiCl ₃ , CF ₃ CH
₂ CH ₂ SiCl ₃ , CH ₃ Si (OCH ₃ ) ₃ or a partial hydrolyzate thereof

In addition,

Embedded image A silazane compound of (CH ₃ ) ₃ SiNH—Si (CH ₃ ) ₃ is also useful as the water repellent used in the present invention.

As a surface treatment method for sand or soil particles with a water repellent, a method generally used for surface treatment of powder may be used. For example, it is possible to produce hydrophobic particles by mixing various silicone oils and sand by a mechanochemical method and performing surface treatment.

As the hydrophobic particles, the above-mentioned water repellent sand and the like are preferable, but it is also conceivable to use fine particles of a polymer (plastic) having a hydrophobic surface. Of these, organosilicone-based compounds are preferable, and polymethylsilsesquioxane is particularly preferable.

Further, it is also possible to use, for example, waste plastics pulverized into particles, whereby the waste plastics are effectively used and the waste disposal problem of the waste plastics is solved. It is also possible to use these high molecular weight polymers after water repellent treatment.

Besides the above-mentioned hydrophobic particles as specific examples, for example, hydrophobic granular metal oxides such as silica, alumina, titania, zirconia, vanadium acetate, iron oxide, glass beads, crushed oil shells, Needless to say, hydrophobic particles such as oil sand can be used, but in particular, those whose surface is treated with a silicone water repellent are more preferable. However, the oil shell and the oil sand can be effectively used even if they are not treated with silicone.

The hydrophobicity of the hydrophobic layer can be arbitrarily adjusted, for example, by changing the type of hydrophobic particles or the thickness of the hydrophobic layer.

That is, the hydrophobic layer composed of hydrophobic particles in the soil of the present invention, depending on the type, size and shape of the hydrophobic particles constituting the soil, the depth from the soil surface, the control rate of water, etc. It may be selected as needed. For example, the hydrophobic strength can be adjusted by appropriately mixing water-repellent sand that is a hydrophobic particle and ordinary sand that is not treated with a water-repellent agent and that is a non-hydrophobic particle.

The upper layer of the present invention is a layer existing on the hydrophobic layer, which is the uppermost layer of the soil structure having the three-dimensional structure of the present invention and which forms the surface layer. Is. Usually a surface layer of the soil structure to be improved can be used, for example in the case of a desert a layer of sand.

In the present invention, this upper layer is present on the hydrophobic layer to protect the hydrophobic layer, and there is no loss due to the wind of the hydrophobic particles, and there is no deterioration due to sunlight, etc. There is an advantage that the hydrophobic particles constituting the are excellent in durability. This advantage is extremely effective in arid areas with strong sunlight and wind.

The present invention is a soil structure having the above-mentioned three-dimensional structure. Soil is a concept that includes sand. in particular,
The artificial soil structure of the present invention can be formed in a desert area and can be used effectively for plant cultivation such as agriculture. That is, the dry ground or desert is excavated to a finite area and depth, a water layer for circulating seawater and air is provided in the space formed in the ground, and the water layer on or above the water layer is removed. Providing a gravel layer surrounding it, providing a water repellent sand layer treated with a water repellent agent on the gravel layer,
An upper layer is provided on the water-repellent sand layer, and it is positively utilized in a method for growing a plant in which a plant is grown on the upper layer. The artificial soil structure can be produced in a large container to grow a plant, for example.

The upper layer is a layer in which plants are planted and their roots are present. In this case, the upper layer is preferably a hydrophilic soil composed of sand, sand containing a water-retaining substance, or soil.

The material having water retention property is, for example, PVA,
A water-retaining polymer such as MC or CMC, an acrylic polymer water-absorbing polymer, peat moss, inorganic pearlite, montmorillonite, vermiculite, or a mixture thereof is used.

The water-retaining substance is preferably a natural water-retaining substance such as peat moss and viscosity.

When the water-retaining substance to be used is a polymer such as a polymer amylase, a polymer having durability against enzymes such as cellnase and peptalase is preferable. Furthermore, those that generate toxic substances by decomposition are not preferable, and those that do not destroy the soil environment used are preferable. In this respect, cellulose derivatives, gums, PVA and the like are preferable.

Particularly when the present invention is used in a desert area where the dryness is severe, an artificial soil structure containing a so-called water-absorbing polymer having a good water-retaining property and capable of absorbing several hundred times its own weight of water as a water-retaining agent. Is preferred.

In the desert area, it is difficult to secure so-called fresh water. The most preferable mode when the present invention is actually used in a desert is a mode in which seawater is secured from the coast and circulated in the aquifer.

It is impossible to directly supply the seawater to the plants because of the damage caused by so-called salt damage. Further, the method of converting seawater into fresh water by using a desalination apparatus requires an extremely large apparatus and is extremely expensive in cost.

However, the artificial soil structure of the present invention is extremely practical in that it can supply fresh water necessary for the upper layer for cultivating plants without causing damage by salt damage even if seawater is used for the water-permeable layer. Have a positive effect.

Seawater can be circulated in the water passage directly from the sea by using a pump, for example. Further, it is preferable to send air to the water-passing layer using a compressor to apply pressure, because water is supplied to the upper layer more efficiently than when air is not sent. Before passing water, by heating water such as seawater to be used to 5 to 30 ° C. with solar heat, the amount of evaporated water can be increased and the amount of air used can be decreased.

In order to carry out the present invention, for example, a desert is excavated, a water-permeable layer for supplying seawater is made of concrete, and a resin net is covered thereover, and gravel is fixed on the mesh. To the thickness of. Next, spread water-repellent sand treated with a water-repellent agent.
For example, sand and a silicone water repellent can be mixed on site using a mixing stirrer of the same type as a concrete mixer and laid on a gravel layer, or sand can be laid from a factory of silicone oil using a mixer truck. It is also possible to work on the site while water repellent treatment is being performed.

[0051]

EXAMPLE The present invention was tested at a laboratory level to confirm its effect. The present invention is not limited to this.

[Production of water-repellent sand] Asano silica sand No. 3 (average particle size of about 1.2 mm) and Asano silica sand No. 7 (average particle size of about 0.
1 mm) 0.3% C ₁₀ H ₂₁ Si for each 10 kg
2.5 kg of (Cl) ₃ / n-hexane solution was poured, and after stirring, the mixture was left at room temperature for about 12 hours, filtered, washed with water, and then at 100 ° C.
Then, it was dried in a vacuum to obtain silicone-treated water-repellent silica sand which is hydrophobic particles.

[Preparation of Artificial Soil Structure] A hole was set at a position of about 15 mm from the bottom of a glass cylinder having an inner diameter of 75 mm and a height of 200 mm. First, 600 g of silica sand No. 7 and 140 g of 3% salt water were put into this cylindrical container to form a water-permeable layer. A gravel layer having an average diameter of 3 to 5 mm was put on it so that the thickness was about 10 mm, and the water-repellent sand of Asano silica sand No. 7 produced above was put on it so that the thickness was 17 mm. Asano quartz sand No. 7 was placed as the upper layer on the top, and an artificial soil structure was created at the laboratory level.

[Effect test] A compressor is connected to a cylindrical container through silica gel and a flow meter, and when air is not passed through the water-passing layer, when water of about 10 L / HR or about 20 L / HR is passed, water is passed through. The weight loss of the layer was measured, and the amount of water supplied to the upper layer was measured. In addition, precipitation of salt in the upper layer was observed. In the effect test, the atmospheric temperature was set to about 30 ° C. and the sample was allowed to stand and the water loss in the aquifer was measured.

As a result, precipitation of salt on the upper layer does not occur,
The water loss in the aquifer gradually increased with time in proportion to the air flow rate, and water was supplied from the aquifer to the upper layer.
When a similar test was performed using asanosilica sand which had not been treated with water repellent instead of water repellent sand, salt precipitation was observed in the upper layer. Without air flow and about 10L / HR
In this case, the artificial soil structure of the present invention has a smaller reduction in the water-permeable layer as compared with the soil structure having no layer made of water-repellent sand. Therefore, in a dry area such as a desert where the temperature is high, it is possible to suppress water loss due to rapid evaporation, and it is possible to supply an appropriate amount of water to the upper layer by adjusting the air flow rate. Also, when the same test was performed using the water-repellent sand of Asano silica sand No. 3, the same effect as above was observed.

Acryhope (manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.), which is a water retention agent containing polymeric sodium acrylate as a main component, was mixed in the upper layer of the artificial soil structure described above at a ratio of 0.1% by weight to Asano silica sand No. 7. For example, a hydrophilic soil containing a water retention agent is obtained, and plants such as crops can be cultivated in the upper layer.

[Solar artificial soil structure for passing seawater heated by solar heat] A pipe for sprinkling seawater with holes at regular intervals on the bottom of a large container having drainage holes at the bottom.
And a pipe B for air diffusion are penetrated, and a solar water heater is connected to the pipe A to pass seawater. Pipe B connects a compressor to allow air to flow. Gravel is laid on the bottom of the container and pipes A and B are embedded in the gravel layer. This gravel layer is laid on 10 cm, Asano silica sand No. 7 is laid on it for 2 cm, and the water repellent sand of Asano silica sand No. 7 produced above is laid on it for 1 cm.
% Asahi quartz sand No. 8 containing 30% was laid to make an artificial soil structure. When this artificial soil structure is allowed to pass through seawater heated by a solar water heater at a rate of 2.8 L / HR and air is ventilated at a rate of 2.2 m ³ / HR, it is left at 37 ° C. The water content of the upper layer was 5.6%, which shows that the water content is sufficient to grow plants.
Even when operated for 2000 hours under these conditions, accumulation of salt in the upper layer was not observed at all. For comparison, in the same experiment, precipitation of salt was observed in an artificial soil structure using Asano silica sand No. 8 which was not subjected to water repellent treatment in place of water repellent sand, which was not suitable for plant growth. It was soil.

[0058]

EFFECTS OF THE INVENTION According to the present invention, the water required for soil for cultivating agricultural crops is improved by not only improving the surface of the soil as in the prior art but by improving the structure of the stratum zone that constitutes the soil. Can be efficiently supplied to provide a soil environment suitable for plant cultivation in a dry area such as a desert where agriculture cannot be performed. Further, by using seawater, it becomes possible to stably supply fresh water to agricultural products without using a desalination device or the like.

Claims (7)

[Claims] 1. A water-permeable layer in soil, a gravel layer existing on or surrounding the water-permeable layer, a hydrophobic layer composed of hydrophobic particles existing on the gravel layer, and a hydrophobic layer Soil structure with upper layer existing in 2. The artificial soil structure according to claim 1, wherein the hydrophobic particles are sand and / or soil particles treated with a water repellent. 3. The artificial soil structure according to claim 2, wherein the water repellent agent is a silicone-based or fluorine-based water repellent agent. 4. The artificial soil structure according to claim 1, wherein the water-passing layer is a layer for feeding water such as seawater and air. 5. A dry ground or desert is excavated to a finite area and depth, and a space formed in the ground is provided with a water passage for circulating water such as seawater and air, and the water passage layer. A gravel layer on or around the gravel layer, a water repellent sand layer treated with a water repellent agent is provided on the gravel layer, an upper layer is provided on the water repellent sand layer, and a plant is grown on the upper layer. How to grow plants 6. The method for growing a plant according to claim 5, wherein the upper layer is a hydrophilic soil made of sand or sand containing a substance having a water retention property. 7. The method for growing a plant according to claim 5, wherein water such as seawater is heated by solar heat and then passed through.