JPH0352990A - Methdo for controlling soil - Google Patents

Abstract

PURPOSE: To form stable fine aggregates in especially surface hardened soil or compressed soil by applying a product derived from a coal such as an oxyhumic acid (salt) gel to soil.

CONSTITUTION: A product derived from coal selected from a group consisting of oxyhumic acid gel, a gel of oxyhumate (e.g; alkali metal salt or ammonium salt), oxyhumate capable of forming a gel in water and a mixture of them is applied to soil such as surface hardened soil or compressed soil by a mixing method to regulate soil. The addition amt. of the product to soil is usually 0.02 below 2 wt.% (pref. below 1 wt.%).

COPYRIGHT: (C)1991,JPO

Description

[Detailed description of the invention] (Technical field) The present invention relates to soil conditioning.

(Background technology) In soil where the surface has become extremely hard, micro water supply (micro water supply) is necessary.
-irrigation), water does not penetrate,
Therefore, a large amount of water will flow away. Also, highly compacted soil is impermeable to plant root tissue.

Therefore, the roots of plants are unable to extend into the soil and utilize the nutrients and moisture available in the soil.

These problems are best solved by adding conditioning agents to create stable microaggregates of soil.

Such modifiers are often polymeric or polymeric products that are significantly more expensive.

As is well known, humic products obtained by the decomposition of plant materials in soil are the most effective stabilizers for stabilizing soil tissue. However, there is not enough plant material available. Furthermore, in the case of humic acids obtained from plant sources, relatively large amounts of humic acids are required, for example 1% by weight or more, to significantly increase the stability of soil aggregates. Regarding this point, “Phil Science (
Soil Science) J 146, No. 47~
Picco entitled ``Effect of humic acids and surfactants on the stability of soil aggregates'' published on page 54.
olo and Mbagwu.

DISCLOSURE OF THE INVENTION In the present invention, certain oxidation products containing humic acid or its salts derived from coal (hereinafter referred to as oxyhumic acid and oxyhumates) are excellent soil conditioners, especially for surface It has been found to be a suitable conditioning agent for creating aggregates and microaggregates in compacted or compacted soils.

Accordingly, in one aspect, the present invention provides oxyhumic acid gels, gels of oxyhumic acid salts,
A soil conditioning method is provided, which comprises applying to the soil a raw material derived from coal selected from the group consisting of oxyhumates and mixtures thereof that can form gels in water.

Essential to the invention is the use of gels that are oxyhumic acid gels or oxyhumate gels, or the use of oxyhumates that are capable of forming gels in water. In the latter case, when added to the soil, the oxyhumate forms a gel with the water present in the soil or added to the soil. Furthermore, it is essential that the oxyhumic acid is derived from coal.

In the present invention, products derived from coal are compared with similar products obtained by decomposition of plant materials.
It has been found that it can be used in significantly smaller amounts.

Oxyhumic acid or its salt typically has the following elemental and functional group analysis values on an air-dried basis: Carbon Hydrogen Nitrogen Sulfur Oxygen 30-7055.5 2-62.7 0.1-51.5 0.1 -10 0.320~45
32. l Total acidity 3-13 6,45 Carboxyl groups 0.5-12 3.38 Phenol groups 0.5-9 4.07 Oxyhumates are typically alkali metal salts such as sodium or potassium; Or an alkali metal salt.

The coal-derived bioactive substance added to the soil is typically added in an amount of 0.02% by weight or more. Usually the amount of said product added is less than 2% by weight, preferably 1% by weight.
less than % by weight.

It is common for raw wood derived from coal to be added to the soil and then thoroughly mixed with the soil. The product is particularly useful in hard-surfaced soils and compacted soils.
It has the effect of forming stable aggregates and microaggregates. This allows water to penetrate better into such soils. Additionally, the roots of plants are better able to extend into the soil and utilize the available nutrients and moisture in the soil.

In a first preferred embodiment of the invention, the coal-derived product is an oxyhumic acid gel prepared in the following manner. Oxidized coal (hereinafter referred to as "Xyxycol J") is mixed with an aqueous alkaline solution and the mixture is heated to temperatures above 90°C < 180°C under sufficient pressure to prevent water evaporation.
Heat to a lower temperature and maintain this elevated temperature for a time sufficient to extract substantially all of the available oxyhumic acid from the oxycol. After cooling, the resulting mixture is filtered, the filtrate is acidified to precipitate the coal-derived oxyhumic acid, and the precipitate is collected by centrifugation;
The inorganic acid is removed by washing with water and then the gel is obtained by centrifugation. Oxycols are typically produced by the wet oxidation process disclosed in US Pat. No. 4,912,256.

In a second preferred embodiment of the invention, the oxycol is mixed with an aqueous alkaline solution and the mixture is heated to a temperature above 90° C. and below 180° C. under pressure sufficient to prevent evaporation of the water; A gel of coal-derived oxyhumate is produced by maintaining this elevated temperature for a period sufficient to extract substantially all of the available oxyhumic acid from the coal. The solution containing water-soluble oxyhumic acid is filtered to remove solids. The filtrate is then concentrated until a gel forms. Alternatively, concentration can continue until a powder is produced.

This powder is oxifumate (oxyfumate).
). This salt forms a gel when water is added.

In the first and second preferred embodiments of the present invention described above, the elemental analysis values and functional group analysis values are as described above.

The resulting gel may contain other substances that do not adversely affect the growth of the gel. For example, some residual solids from oxycol may be present in the gel.

(Example) Next, the present invention will be explained with reference to examples.

Waterberg charcoal (400g)
) and water (700 roI!) were slurried in a 2 l reactor with a stirrer. 8. Oxygen was added to the reactor. 0MP
The mixture was supplied to a pressure of 1, and heated to 160°C. Do not stir this slurry! 41! A flow of oxygen was passed at a flow rate of /min.

After a reaction period of 1 hour, the oxygen flow was stopped, the reactor was cooled to room temperature, and the pressure was returned to atmospheric pressure.

The slurry was removed from the reactor and filtered to obtain the xycol and filtrate.

This oxycol (log) was converted into potassium hydroxide (14
g) was refluxed for 7 hours in an aqueous solution of potassium hydroxide dissolved in water (300 van). The extraction mixture was centrifuged to remove insoluble residue containing ash and unreacted coal. The supernatant was acidified with sulfuric acid, and then the insoluble oxyhumic acid gel was collected by centrifugation.

The oxyhumic acid gel was washed twice with distilled water to remove excess sulfuric acid.

(2) Application method Different amounts of oxyhumic acid gel were added to 500 g samples of soil with a significantly hardened surface. Each mixture was formulated with distilled water and then thoroughly mixed. Each sub-sample was then maintained at a constant temperature of 27°C for 5 weeks in a glass beaker in a dark dryer indoors. After 5 weeks, the sample dried in the dryer was
．． Mechanically wet sieved through a 25am sieve. The soil remaining on the sieve sank into water during the sieving process. Sieving was performed for 4 minutes while vibrating 75 times/min. After sieving, the material remaining on the sieve was transferred to a glass beaker and dried in an oven at 105° C. before determining the weight of the material.

As a control, oxyhumic acid gel was not added.
It was treated exactly like the other samples.

For comparison, a commercially available soil conditioner (PVM/
5, trade name) was used. A similar procedure was performed except that PVM/5 was used instead of oxyhumic acid gel.

Each measurement was performed twice. The results obtained are shown in Table 1.

Table 1: Effect of Waterberg Oxyhumic Acid Gel, a Coal-Derived Oxyhumic Product, and Commercially Available Synthetic Soil Conditioners in Creating Stable Microaggregates in Surface Significantly Hardened Soils* *WVM/5? ＆*n4”A.NitrogenT a XJ@
FJ; ci Crystal DI'J Le Inukoukai Yuoxyhumic acid gel was produced in the same manner as in Example 1.

Potassium oxyhumate gel was prepared as described for the preparation of oxyhumate gel in Example 1, except that the supernatant was not acidified.

A sodium oxyhumate gel was similarly produced by using sodium hydroxide instead of potassium hydroxide. Ammonium oxyhumate gel was similarly produced by using ammonium hydroxide instead of potassium hydroxide. Note that the reaction with oxycol was performed under ambient conditions.

As two types of light gray topsoil of alluvium,
Ltlckho f f (7)
) soil and Addo soil were used. All of these soils were characterized by extremely high proportions of fine substances, ie, fine sand and fine silt. The effect of the above-mentioned coal-derived oxyhumin material on the stability of these topsoils was investigated.

Weigh out 250g of air-dried soil, add the exact weight of oxyhumin product to a specific weight percent, and add the optimal amount of water for crumbling while mixing. Then, by thoroughly mixing these, soil for mixed sieving was prepared. The optimum amount of water was determined empirically in advance for each soil. The soil was then maintained for one week at 27''C in a controlled thermostatic chamber. An alternating 21711 and drying system was used.

Initial tests have shown that a system of alternating wetting and drying is significantly better than a system in which tissue stabilization by xyfumin products or the soil is maintained in a continuous fieldable condition.

After one week, the soil was dried in a dryer at 105°C for 24 hours. Two samples of 50 g each of the soil dried in this dryer were then used for wet sieving.

Wet sieving is carried out in a mechanical wet sieving machine with vertical dipping action. Passed through a 25+nm sieve.

Sieving was performed for 4 minutes while vibrating 60 times/min. The soil remaining on the sieve is transferred to a glass beaker and heated to 105 ml in a dryer.
It was dried for 24 hours at °C and weighed.

The results obtained are shown in Tables 2 and 3.

Table 2 Results of the effects of selected coal-derived oxyhumin compounds on the stability of soil aggregates in Lückhoff soils as determined by wet sieving Control O t + Schifmic acid Genore 0.
0170,083 0.330 Ammonium xyhumate Genore o. t
oo0.200 years old + sodium sifmate powder 0.01
30.025 0,050 0,125 years old + sodium cimate genore 0.0
130.025 0,050 0.125 33.4 68.9 72.4 79.8 46, 0 43.9 36, 0 45.6 46, 6 43.7 36, 9 40.0 43.9 55. 9 Table 3 Results of the effects of oxyhumic products derived from selected coals on the stability of soil aggregates in soils of Ato, determined by hot sieving Control 0 23.3 From Tables 2 and 3 It can be seen that in case of soil treated with oxyhumin derivatives derived from coal, the proportion of soil remaining on the sieve is significantly higher than the control. In other words, coal-derived oxyhumin products improved the soil aggregate stability of soils even at small application rates.

Rainfall simulation test Soil for the rainfall simulation test was prepared in the same manner as the soil for the wet sieving test. A specially made perforated polyethylene tray with a width of about 300 mm and a length of about 500 mm was used. I spread the tissue paper over the bottom of the tray. On top of this was placed 101101 of coarse grained quartz sand, and on top of this was added 8 kg of pulverized soil (ie about 20 m thick).

The soil was then maintained at a constant temperature in the laboratory.

At this time, drying was performed using a fan type heater.

An alternating wetting and drying system was used.

In the case of Lückhof soil, a constant temperature was maintained for one month. The Ado soil was maintained at a constant temperature for one week.

After maintaining a constant temperature, the tray was transferred to a laboratory scale rainfall simulation device. A slope with a slope of 5% was used. The soil was pre-wetted by a zero-energy drizzle and then exposed to a rainstorm with a rainfall of 42 mm/h for 2 hours. Infiltration rate and soil loss (erosion) were measured.

The results obtained are shown in Table 4.

Star 1 ± 1 Table Effect of selected coal-derived oxyhumic products on final infiltration rate (FIR) in laboratory-scale rainfall simulation tests
Lückhoff's soil control 03.0 Add's soil control 03.4 tAmmonium xyhumate 0.
125 3.4t + Potassium Schifmate Gel 1,000 5.4 The infiltration rate in the case of soils treated with coal-derived oxyhumin products was greater than in the control, especially when Lückhoff soil was used. Ta. Ammonium oxyhumate did not improve the final infiltration rate of Ado soil.

Claims (1)

[Claims] 1. For soil conditioning, a coal derived from coal selected from the group consisting of oxyhumic acid gel, oxyhumate gel, oxyhumic acid salt capable of forming a gel in water, and mixtures thereof. A soil conditioning method characterized by applying a product to soil. 2. The method according to claim 1, wherein the soil is surface hardened soil or compacted soil. 3. A method according to claim 2, characterized in that the product derived from coal is applied to the soil by mixing it with the soil. 4. The product derived from coal has the following elemental analysis values and functional group analysis values on an air-dried basis: @Elemental analysis value @ Element @ Range (%) @ Carbon 30-70 Hydrogen 2-6 Nitrogen 0.1 ~5 Sulfur 0.1-10 Oxygen 20-45 @Functional group analysis @Functional group @Amount (%) @ Total acidity 3-13 Carboxyl group 0.5-12 Phenol group 0.5-9 4. A method according to any one of claims 1 to 3, characterized in that: 5. Products derived from coal have the following elemental analysis values and functional group analysis values on an air-dried basis: @Elemental analysis value @Element @Amount (%) @ Carbon 55.5 Hydrogen 2.7 Nitrogen 1.5 Any one of claims 1 to 3, characterized in that it has 0.3 sulfur, 32.1 oxygen, functional group analysis amount (%), total acidity 7.45, carboxyl group 3.38, and phenol group 4.07. A method described in one section. 6. The method according to any one of claims 1 to 5, wherein the oxyhumate is an alkali metal salt. 7. The method according to any one of claims 1 to 5, wherein the oxyhumate is an ammonium salt.