JP3479505B2 - Soil revegetation and stabilization material and its construction method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces the alkalinity exhibited by lime or cement-based solidifying material added and mixed as a strength-retaining material to vegetation base materials such as soil, chemical fertilizer, park compost, peat moss, etc. The present invention relates to a soil greening / stabilizing material capable of forming a soil base suitable for growth and a construction method thereof.

[0002]

2. Description of the Related Art The slope of cut or embankment is stable when the slope is created, but becomes unstable with the passage of time.
The scale may gradually increase due to erosion, rockfall, and collapse. Therefore, slope protection is necessary.
In the case of general soil with high surface strength, simple seed spraying is performed, but when surface strength is weak, a legal framework is constructed or mortar is sprayed over the entire slope.

[0003]

However, spraying mortar is not very preferable from the viewpoint of landscape because the slope surface becomes gray. As an inexpensive and strong coating material for the ground surface, there is no substitute for the cement-based solidifying material. This is because the cement-based solidifying material has an advantage that it is stable in an early stage, is strong against water, and is hard to be washed away by rain. However, its strong alkalinity is not suitable for the growth of most plants and is not preferable from the viewpoint of nature protection.

As a countermeasure against this, the pH of lime superphosphate, etc.
A measure for reducing alkalinity by adding an acidic substance such as a buffer or aluminum sulfate has been proposed. However, the conflict between the strength of cement and the reduction of alkalinity has not yet been overcome.

In order to create a slope in harmony with the environment,
It is desirable to increase the strength of the vegetation base material laid on the slope, improve the vegetation base material so that it is suitable for plant growth, and introduce plants into the base material to protect the slope. A cement-based solidifying material may be used for strengthening the vegetation base material, but in that case, a problem with plant growth is alkali damage caused by cement.

Therefore, in the present invention, it was attempted to improve the alkali damage caused by the cement-based solidifying material which is a problem for the growth of plants by utilizing the ecology of microorganisms. For the test strains, it was decided to select bacteria that grow in an alkaline environment. Many bacteria have a resistance mechanism against alkalinity with a pH of about 9. However, most of these bacteria grow in a neutral environment.

However, there are bacteria that grow best at pH 10 or higher and grow even at pH 11.5, and they are called alkalophilic bacteria. When an alkalophilic bacterium is cultivated in a medium having a neutral pH or an extremely high pH, the medium becomes alkaline or acidified,
It has been observed that eventually it will settle to a value near pH 9.

The present invention has been made under such a technical background, and particularly, by utilizing alkalophilic bacteria,
The purpose of the present invention is to propose a soil revegetation / stabilization material that can lower the pH of lime or cement-based solidifying material that is added to and mixed with the vegetation base material, and create a soil base on which plants can grow easily, and its enforcement method.

[0009]

Means for Solving the Problems] Soil greening and stabilization material to which this invention provides is soil, fertilizer, bar click compost, with a mixture of vegetation base material and the lime or cement solidifying material such as peat moss It consists of a certain greening material and an alkaliphilic bacterium that inoculates this greening material (hereinafter referred to as the first
Of materials).

Alkaliphilic bacteria in the first material are
Aeromonas hydrophila, Baci
llus alcalophilus, Bacillu
s thuringiensis, Cla v ibact
er michiganense, Bacillus
subtilis, or at least one of them.

Further, the method for constructing a soil greening / stabilizing material provided by the present invention is to add water to the greening material to form a slurry,
This is a construction method in which a coagulant and alkalophilic bacteria are added to and mixed with this slurry.

Alkaliphilic bacteria used in this procedure are Aeromonas hydrophila,
Bacillus alcalophilus, Bac
illus thuringiensis, Cla v i
Bacter Michiganense, Bacil
at least one of L. subtilis.

The cement-based solidifying material contains at least cement among cement, ash, sulphate and soil as a main component.

[0014]

The mechanism for reducing the alkalinity of the lime-based or cement-based solidifying material by the alkali-philic bacteria of the present invention, that is, the mechanism for reducing the free alkali generated as the solidification of the lime-based or cement-based solidifying material progresses I have to wait for research. However, it is considered that the reduction of free alkali is probably due to the neutralizing effect of the organic acid generated by the ecological action of the above microorganisms.

The conventional inorganic acidic substances used for reducing alkalinity are strongly acidic, and their neutralizing action is also consumed for the neutralization of the cement itself and, in some cases, inhibits the strength development of the cement. There are difficulties. In contrast, weakly acidic organic acids which are considered to be generated by the ecological effects of alkalophilic bacteria of the present invention, the calcium silicate hydrate gel is strength development material cement without intends harm the cement original function It is considered to neutralize the alkali of free lime that accompanies the formation.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to examples.

Example 1 In Example 1, a greening material obtained by adding and mixing a cement-based solidifying material to a plant base material composed of bark compost, peat moss, and chemical fertilizer was inoculated with an alkaliphilic bacterium for preparation. Explain the soil greening / stabilizing materials to be used.

This material is effective in lowering the pH of the solidifying material and making a soil base on which plants can easily grow, especially a soil base suitable for protecting the slope of cut soil or embankment.

As a method of preventing soil erosion and greening on the slope, a method of forming the surface layer with soil cement in which cement is mixed with soil, or a cement-based solidification method for soil containing dredged soil or sludge from an Ikenuma There is a method of forming a mixture of materials.

However, either method is not suitable for plant growth because of its strong alkalinity. Therefore, first, the alkali-philic bacteria were screened for the purpose of lowering the pH of the strongly alkaline cement-based material by utilizing the alkali-philic bacteria and creating a soil base on which plants can easily grow.

Although there are very few alkaline soils in Japan, we decided to screen the soils in those areas for alkalophilic bacteria. The sampling location of the test soil is
There are three locations, S city in Yamaguchi prefecture, Y city in Yamaguchi prefecture, and M city in Shimane prefecture.
After that, the strains were screened using the eight samples collected at the above-mentioned three places. The pH of each sample is 6.3.
It was in the range of ˜8.7. In the screening, 34 kinds of alkalophilic bacteria were isolated from the above-mentioned three soils. Of these, 15 strains of alkalophilic bacteria that had a fast growth period (1 to 3 days) were subjected to an inoculation test using an agar medium.

In the inoculation test, it was found that the pH of the bacterial culture medium was lowered by about 1 to 3 in all cases. From this, it was considered that when the cement-based solidifying material was inoculated with these strains, the pH in the solidifying material was lowered with the growth of the strains.

(1) Selection of alkalophilic bacteria to inoculate greening material A basal medium having the composition shown in Table 1 used for the isolation of alkalophilic bacteria, which is obtained by removing agar and sodium carbonate, is
It was dissolved in 0 ml of ion-exchanged water, dispensed in 20 ml portions into 16 100 ml Erlenmeyer flasks, sodium carbonate was dissolved in 100 ml of ion-exchanged water, and each was separately sterilized in an autoclave at 120 ° C. for 20 minutes. Then, aseptically in a clean bench, 5 ml of a solution of sodium carbonate was dispensed into each of the 16 Erlenmeyer flasks and mixed.

[0024]

[Table 1] The above-mentioned fast-growing 15 strains were inoculated into the liquid medium for alkalophilic bacteria. This was shake-cultured at 25 ° C., and changes in pH and absorbance were measured.

Based on the results, the following five species were selected as alkalophilic bacteria to be inoculated on the greening material described later. In the liquid cultures having an initial pH value of 10, these bacteria A to E showed rapid growth of the bacteria after the culture, the pH value thereof decreased correspondingly, and the final pH value showed a desirable value of about 7.5.

A: Aeromnas hydrohpi
la (hereinafter, referred to as bacterium A) B: Bacillus alcalohpilus (hereinafter, referred to as bacterium B) C: Bacillus thuringiensis
(Hereinafter referred to as the bacteria C) D: Cla v ibacter michiganens
e (hereinafter referred to as Bacteria D) E: Bacillus subtilis (hereinafter referred to as Bacteria E) (2) pH of the liquid medium by the selected alkalophilic bacteria
And change in absorbance About 1 × 10 ⁵ cells of alkaliphilic bacteria A to D to be inoculated into a greening material described later in a liquid medium of pH ^5, 7, 10
Each of the cells was inoculated into a liquid medium having a pH of 10 so that the volume became ml ⁻¹ . This was shake-cultured at 25 ° C., and changes in pH and absorbance were measured with time.

It has been found that there are two patterns of pH decrease associated with the growth of alkalophilic bacteria in a liquid medium having a pH of 10. One is a pattern in which the bacteria gradually grow and the pH decreases with it, but then it rises again, and the other is a pattern in which the bacteria grow rapidly after culturing and the pH also decreases with it. Is. Also, for each strain, p in liquid medium of pH 5, 7, 10
As a result of measuring changes in H and absorbance, bacteria A grew fastest at pH 7, but settled to around pH 9 when the initial medium pH was 5, 7, or 10. Bacteria B has a pH
Growth at 10 was fastest. Bacterium C grows fastest at pH 7 and decreases to around pH 5, but those that started culturing at pH 5 and 10 settled at around pH 9. Bacteria D and E grow fastest at pH 7 and at pH 5
The cultures started at 7 and 7 lowered to around pH 4, but those started at pH 10 settled at around pH 9.

[0028] (3) inoculation vegetation base material of alkalophilic bacteria were selected to greening materials (bar click compost, a mixture of peat moss) 15 g
And put fertilizer 0.11g flask, after the silicone stopper, 120 ° C. in an autoclave, and sterilized 20 min. 0.15 g of the cement-based solidifying material (solidifying material in Table 5) was wrapped in medicine packing paper, put in a petri dish, and sterilized at 170 ° C. for 1 hour. These were aseptically mixed in a clean bench to obtain a greening material.

On the other hand, the number of bacteria A to E grown in a liquid medium was measured, 1 ml of each strain was taken with a pipette and added to 9 ml of sterile water to make a primary dilution (dilution ratio 10 ^-1). ), Further add each primary dilution to 2 x 10
^It was adjusted to ⁴ cellml ^-1 . 0.5 ml of each of the obtained diluted solutions was inoculated into the greening material contained in 10 Erlenmeyer flasks.

This operation was performed aseptically in a clean bench. The pH of the greening material was measured with a pH meter by adding 50 ml of sterile water to 25 g of the same material. The viable cell count in the greening material was measured by the dilution plate method (basic medium: Table 1).

As a result, bacteria A to E selected as greening materials
When inoculated with, most of the strains lowered the pH value of the greening material by about 0.5 to 1 on the 7th day of culture. From this,
It was found that alkaline damage at the early stage of plant growth, which was the original purpose, could be improved early.

It is generally said that a pH value of 8.5 or less and a hardness of 20 or less in terms of Nakayama's hardness index value are desirable as soil conditions required for germination and growth of plants. According to the experience of the present inventor, the change in soil pH value due to the cement-based solidifying material indicates whether free lime generated along with the progress of strength expression is neutralized by rainwater or acidic substances in the soil, or flows out as it is. Then, the pH value reaches 8.5 or less at a relatively early time. However, the pH value is further lowered by 0.5 to 1.0, and the pH value range desirable for germination and growth of plants is:
It takes a considerable number of days to reach 7.0 to 7.5 or less.

In this respect, the pH value of the greening material of Example 3 is
In the early stage of one week, it decreased by 0.5 to 1.0.
This fact is considered to enable the practical use of the soil greening / stabilizing material of the examples.

Example 2 100 g of the vegetation base material shown in Example 1 and 0.7 of chemical fertilizer.
5 g, cement-based solidifying material 2 g (equivalent to 20 kg / m ³ ),
As seeds, tall fescue falcon 0.1 g (30 g
Granules) were mixed well to make a greening material.

On the other hand, the same 2 × 10 ⁴ cellm as used in Example 1 was used for the bacterium A showing a desired reduction in pH value in liquid culture.
A diluted solution of l ⁻¹ was added, and 3.3 ml of this diluted solution was added to the above-mentioned greening material and mixed well, then filled in a 200 ml No. 3 pot with a mesh net on the bottom, and well pressed down to vegetate. It was a pot. Four vegetation pots were prepared by adding each bacterium A. Four vegetation pots containing blank samples to which no strain was added were also prepared in the same manner.

The vegetation pot thus obtained was placed in a greenhouse under temperature conditions of 20 to 25 ° C. Table 2 shows the number of germinated growth after 3 weeks, the pH value of the greening material in the pot, and the hardness index. From the test results shown in Table 2, the germination growth rate was 1.5 times higher, the pH value was 0.5 lower, and the hardness index was the same without change, with the presence of the strain.

[0037]

[Table 2] (Example 3) In Example 3, first, a mixture of 932 g of the vegetation base material shown in Table 3 and 20 g of the cementitious solidifying material of Example 1 was mixed with water 260.
g was added to obtain a transferable slurry, and the properties when a coagulant was added were examined. Originally, a coagulant was added to the outlet of the spray nozzle of this slurry, and the slurry after spraying was instantly solidified to produce a composite without sagging, but in this example, as a model experiment thereof, 20 g of each coagulant shown in Table 4 was added to the slurry, and the properties of the slurry before and after the addition were examined. Table 4 shows the properties.

In any case, the quasi-slump value decreases,
It had changed to a composite that was difficult to sag.

[0039]

[Table 3]

[0040]

[Table 4] Quickly gutter type water sprinkling resistance test equipment (own work)
The filling box (125 × 125 × 45 mm) was packed into 3 pieces and left outdoors, and a test piece for a water resistance test was prepared. 1
After a lapse of days, the test pieces (composite) taken out from each filling box were placed on a wooden box type gutter which was set individually to have a gradient of 8 minutes, and each test piece was sprayed with a fully automatic sprayer at about 100 mm / hr. Intense, water sprayed.

Table 5 shows the results of measuring the amount of runoff soil one day after the composite. The amount of soil runoff is the average value of three composite specimens. Spray sprinkling strength: The amount of runoff soil around 100 mm / hr is less than any blank case (without adding the cement-based solidifying material and the solidifying agent) in any of the cement-based solidifying material to the solidifying agent, which is a significant improvement. Was recognized.

[0042]

[Table 5] Next, to 932 g of the vegetation base material shown in Table 3, 5 g of chemical fertilizer (Sumika Ace), and the cementitious solidifying material 20 of Example 1 were used.
g, as seed, tall fescue falcon 1.0 (3
(00 grains) was added and mixed well to obtain a greening material. Then, 260 g of water was added to this material to form a slurry, and as a coagulant, No. 3 silica (manufactured by Tokuyama Corp.) (1
+1) 20 g of the diluted aqueous solution and 33 ml of the 2 × 10 ⁴ cell ml ⁻¹ diluted solution of the bacterium A shown in Example 1 were added and mixed well.

The obtained soil greening / stabilizing material was filled in 5 pots for vegetation test, 150 ml each. In addition, 5 pots were prepared in the same manner for blank samples to which no strain was added. The vegetation pot thus obtained was installed outdoors.

Table 6 shows the number of germinated seedlings after 3 weeks, the pH value of the greening material in the pot and the hardness index. From the test results in Table 6, the germination growth rate was 1.3 times higher and the pH was higher with the strain.
It was found that the value was 0.5 lower and the hardness index was 2 lower, indicating a preferable value.

[0045]

[Table 6]

[0046]

As described above, according to the present invention, since it has the above-mentioned constitution, the free alkali generated by the solidification of the lime-based or cement-based solidifying material added to and mixed with the vegetation base material. Can be reduced and a soil base on which plants can grow easily can be created.

─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Shunji Mizoue 1007-14 Tokuyama, Tokuyama City, Yamaguchi Prefecture (72) Inventor Takuya Marumoto 702-2 Nakao, Yamaguchi City, Yamaguchi Prefecture (72) Toshihiro Fukunaga Shimomatsu City, Yamaguchi Prefecture Suetake Kaneda 1337 (56) Reference JP-A-10-98938 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) A01G 1/00 303 E02D 17/20 102

Claims (4)

(57) [Claims] 1. A soil, the more chemical fertilizers, bar click compost, and planting material is a mixture of vegetation base material and the lime or cement solidifying material such as peat moss, and alkalophilic bacteria inoculated into the planting material Soil greening and stabilizing material. Wherein said alkalophilic bacteria, Aeromonas hydrophila, Bacillus alcalophilus, Bacillus thuringiensis, Cla v ibacter michiganense, Bacillus subtilis, according to claim 1 soil greening and stabilization material according at least one. 3. The method for constructing a soil greening / stabilizing material according to claim 1, wherein water is added to the greening material to form a slurry, and a coagulant and an alkaliphilic bacterium are added to and mixed with the slurry. Construction method of soil greening and stabilizing materials. Wherein said alkalophilic bacteria, Aeromonas hydrophila, Bacillus alcalophilus, Bacillus thuringiensis, Cla v ibacter michiganense, Bacillus subtilis, at least one kind Enforcement Act soil greening and stabilization material according to claim 3, wherein one of .