JPH0928179A - Culture soil for gardening - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a horticultural culture soil having good air permeability and water retention. SOLUTION: Expanded polyurethane granules are mixed in a volume ratio of 50.
% Or more of horticultural culture soil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horticultural culture soil excellent in air permeability and water retention.

[0002]

2. Description of the Related Art Commercially available culture soil for planters is a mixture of natural mulch soil, which is the main material, with red balls, hydrating soil, peat moss, oil dregs, natural fertilizers, chemical fertilizers and the like. However, in recent years, it has become difficult to secure good humus, and the price has risen. Also, when conducting research on plant culture, it may not be possible to supplement the reports published in papers, etc., because the growth state of plants varies depending on the type of soil used. Therefore, there is a demand for a culture soil that can be stably supplied and that is suitable for studies on plant culture.

On the other hand, in order to improve the air permeability and water retention of commercially available culture soil for planters, conventionally, ceramic balls, vermiculite, pumice stone, etc. have been mixed. However, ceramic balls are disadvantageous in that they are expensive and brittle. Clay minerals such as vermiculite are
It has the drawback of affecting various chemical properties such as ion exchange capacity, adsorption capacity, precipitation capacity and binding capacity. Pumice stone is becoming difficult to collect year after year. As an alternative to vermiculite or the like having such a defect, Japanese Patent Application Laid-Open No. 51-27535
No. 4, pp. 187-242 proposes a horticultural culture soil composed of expanded polymer material particles. Further, in this publication, foamed polyurethane or the like is mentioned as the foamed polymer material (the publication, page 1, right column, lines 15 to 19). However, this publication only describes that the foamed polymer material is crushed to form a granular body having a size of several mm or less, and is mixed with a soil culture soil such as upland soil in an amount of 10 to 40% by volume. No mention is made of the case where the foamed polymer material is contained in a high content.

On the other hand, at present, in order to green the desert, a method of spraying sodium polyacrylate on the soil surface to form a water impermeable layer in the soil is being studied. However, this method 1) depends on the amount of base such as Ca contained in the soil,
A difficult-to-permeable layer may not be formed. 2) It is difficult to adjust the position of the difficult-to-permeable layer in soil. 3) A difficult-to-permeable layer will not be formed unless sodium polyacrylate is continuously sprayed. However, there is a drawback that 4) the price is expensive.
Further, the method of forming a water impermeable layer in the soil layer by burying a vinyl sheet in the underground about 40 to 50 cm to green the desert is not widely used because it requires a lot of labor. Furthermore, AMB (Asphalt Moisture) laying an impermeable layer while pressurizing molten asphalt into a place 40 to 50 cm underground
Regarding the Barrier method, 1) the press-fitting device is too large, 2) the laid layer completely blocks the permeation of water, and stagnant water containing salt exists in the shallow part of the soil layer, leading to the accumulation of salt in the surface soil. It has the drawback of being easy. Therefore, there is a demand for a method of forming a soil having good air permeability and water retention without labor, in order to green the desert.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a cultivating soil for horticulture which is excellent in air permeability and water retention and has stable chemical properties. The present invention also provides a horticultural soil suitable for greening the desert.

[0006]

In order to solve the above-mentioned problems, the cultivating soil for horticulture according to claim 1 is characterized by containing expanded polyurethane granules in a volume ratio of 50% or more. The horticultural soil of claim 2 is characterized by comprising an upper layer made of soil not containing expanded polyurethane particles and a lower layer made of the horticultural culture soil of claim 1.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The expanded polyurethane granules are produced from isocyanate and polyol as raw materials and have moisture retention and air permeability themselves. The diameter of the expanded polyurethane granules is appropriately determined within a range of several cm or less depending on the sand or clay used. Further, the foamed polyurethane granules may have any shape such as a sphere or a sheet. An example of a surface view of polyurethane foam (25 times magnification) is shown in FIG. 1, and an example of polyurethane foam granules (50 times magnification) is shown in FIG.

The reasons for using the expanded polyurethane granules in the present invention are as follows. (1) The foamed polyurethane powder is resistant to acids, alkalis and various organic solvents and does not react with them. It also does not chemically react with fertilizers or pesticides. Even if it is buried in the soil for a long time, it does not leak toxic substances. Therefore, microorganisms in the soil, plants,
Harmless to animals. (2) Since the foamed polyurethane powder is not charged, it does not adsorb or bind to surrounding ions even if it is mixed in the soil, and does not change the chemical properties of the soil. (3) Since foamed polyurethane has various color variations, it becomes a culture soil for gardening of various colors. For example,
Only colored polyurethane foam granules soaked with fertilizer or the like can be put in a glass container for use as an ornamental product. (4) Since the foamed polyurethane expands to several ten times the volume of the raw material, it is lightweight when transported as a measure against desertification. (5) Improving soil properties using expanded polyurethane granules
This is possible for both sand and clay. Traditional ceramic balls, vermiculite, and sodium polyacrylate can only be used with either sand or clay. (6) Natural products such as vermiculite, pumice, and mulch
Although collection has become difficult year by year, polyurethane can be stably supplied because it is a chemically synthesized substance. (7) Since polyurethane is a thermosetting resin, it is originally difficult to recycle, but it can be recycled by pulverizing it for reuse. For example, polyurethane, which is a material for automobile parts, can be recycled.

The foamed polyurethane can also be used after absorbing fertilizer or the like. If you pulverize polyurethane foam that has absorbed fertilizers, pesticides, and pH adjusters in advance, or let the pulverized product of polyurethane foam absorb fertilizer, etc., and then mix them with sand or clay, a good soil for plants will be obtained. Gives a similar effect. By arranging this foamed polyurethane pulverized product in a concentrated manner around the seeds and around the roots of young trees, the roots are well-balanced and the germination rate and growth rate are increased. Agricultural chemicals and the like are rarely leaked to others, and young trees susceptible to disease can be protected from disease.

Explaining the case where the expanded polyurethane granules are mixed with sand and used, the sand has a single particle structure and water and nutrients flow out. Are formed, and it becomes possible to retain water and nutrients. In addition, the case where the expanded polyurethane granules are mixed with clay and used will be explained. Clay has poor air permeability and tends to be over-humidified. However, due to the inclusion of expanded polyurethane granules, the air permeability is improved and an appropriate moisture content is obtained. Will hold.

When using the horticultural culture soil containing expanded polyurethane granules, it is desirable to arrange them in layers under the soil not containing expanded polyurethane granules. The reason is as follows. (1) If only the culture soil containing the expanded polyurethane particles is used, the polyurethane particles may be scattered by the wind during drying, which may cause dust pollution. (2) When the culture soil containing the expanded polyurethane granules is used outdoors, such as in a field, the expanded polyurethane granules are deteriorated or discolored by the sunlight, thus impairing the landscape. (3) By forming a layer of culture soil containing expanded polyurethane particles under the sand of the desert, a water retention layer is provided, which can be utilized for preventing desertification.

The thickness of the soil layer containing no foamed polyurethane and the layer of the horticultural culture soil containing the foamed polyurethane granules are appropriately set depending on the soil used and the purpose. Generally, when soil is added to a height of 18 cm using a planter, the layer of soil that does not contain expanded polyurethane is about 3 to 15 cm, and the amount of culture soil containing expanded polyurethane particles is 15 to 3 cm. It is a degree.
Outdoors, it is desirable to form a layer of soil containing no polyurethane foam on the soil surface with a thickness of 5 cm or more in order to prevent the polyurethane foam particles from being scattered by the wind.

[0013]

Example 1 The following attempts were made to increase the water retention capacity and delay the passage time of water by incorporating expanded polyurethane particles into sand. The sand washed with running water and the foamed polyurethane crushed to 200 μm or less were dried at 80 ° C. for 24 hours. Next, sand and polyurethane foam granules, mixing ratio (volume ratio)
Is 100: 0, 80:20, 60:40, 40:60,
Mix so that the ratio becomes 20:80 and 0: 100, and the total amount is 2
It was adjusted to 0 ml. Nylon mesh (5
They were placed in a cylinder with a diameter of 20 mm with a 5 μm gap). Then, 25 ml of distilled water was poured from the upper part of the cylinder, and the time for dropping 10 ml was measured. further,
After the water stopped dripping, the total amount of water that passed through the cylinder was measured, and the amount subtracted from 25 ml was taken as the water retention amount. 1
Table 1 shows the dropping time and water retention amount of 0 ml of water.

[0014]

[Table 1]

As shown in Table 1, when the foamed polyurethane granules are mixed in a volume ratio of 50% or more, water retention (water retention amount) is obtained.
Will be good.

Example 2 An attempt was made to improve a mudland (clay) which has a small gap between soil grains and retains water but lacks air permeability. 80% of the clay collected from the rice field, with clay and other contaminants removed, and foamed polyurethane cut into 5 mm squares or less
Dry at 24 ° C. for 24 hours. After that, clay and foamed polyurethane were mixed at a mixing ratio (volume ratio) of 100: 80 and 80: 2.
0, 60:40, 40:60, 20:80, 0: 100
Were mixed so that the total amount was 10 ml. Nylon mesh (55μm gap) on the bottom
It was placed in a cylinder with a diameter of 20 mm. 25 ml of distilled water was poured from the top of the cylinder, and the time taken for 10 ml to drop was measured. Furthermore, after the water stopped dripping, the total amount of water that passed through the cylinder was measured, and the amount subtracted from 25 ml was taken as the water retention amount. Table 1 shows the dropping time and water retention amount of 10 ml of water.

[0017]

[Table 2]

As shown in Table 2, when the foamed polyurethane granules are mixed in a volume ratio of 50% or more, the drainage is improved and the water retention amount is appropriately maintained. In addition, when the soil of the field was tested by the same method, the dropping time of water was 141 seconds,
The water retention amount was 4.5 ml.

[0019]

Industrial Applicability According to the present invention, it is possible to obtain a horticultural culture soil having good air permeability and water retention. Further, the soil in which the horticultural culture soil is arranged in the lower layer has a high water retention property and is suitable for plant growth.

[Brief description of drawings]

FIG. 1 is an enlarged view of a surface of polyurethane foam (magnification: 25 times).

FIG. 2 is an enlarged view (magnification: 50 times) showing an example of expanded polyurethane granules.

[Explanation of symbols]

 1 hole 2 foamed polyurethane

Claims (2)

[Claims] 1. The expanded polyurethane granules are contained in a volume ratio of 50.
% Or more of horticultural culture soil. 2. A horticultural soil comprising an upper layer made of soil containing no expanded polyurethane granules and a lower layer made of the horticultural culture soil according to claim 1.