JPH04258225A - Soil improver and soil-improving method - Google Patents

Abstract

PURPOSE:To improve the soil properties and the germination percentage and promote the growth of plant by adding a water-absorbing resin and a humic acid salt to soil. CONSTITUTION:Soil properties are improved by adding a water-absorbing resin and a humic acid salt (e.g. potassium humate and ammonium humate) to soil. The weight ratio of the water-absorbing resin to the humic acid salt is preferably 100:(1-200), more preferably 100:(5-50). The germination percentage and the initial growth of plant seed can be improved and moderate air-diffusibility, water-retainability and fertilizer-retainability can be imparted to the soil.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a novel soil conditioner and soil conditioner comprising a water-absorbing resin and a humic acid salt. Furthermore, it is possible to impart appropriate air permeability, water retention, and fertilizer retention to the soil, and it is highly effective in prolonging plant life and promoting growth even under poor irrigation conditions, making it suitable for agricultural and greening projects. It is widely used in the civil engineering and construction industry.

0002

[Prior Art] In recent years, various methods and agents have been reported in the agricultural field for improving soil performance by increasing soil water retention and fertilizer retention, as well as improving aeration, by using water-absorbing resins. has been

[0003] Soil improvement methods using water-absorbing resins can manage moisture in the soil through the appropriate water-holding capacity of water-absorbing resins and their ability to release water when the surrounding area is dry, as well as their ability to adsorb fertilizer components. This method is attracting attention as a method that can effectively utilize fertilizers that have been washed away due to irrigation, rainfall, etc., and can also solve the problem of environmental pollution caused by fertilizers (Japanese Patent Laid-Open No. 50-29340).

[0004] Furthermore, since the water-absorbing resin itself does not contain fertilizers, pesticides, etc. necessary for growing crops, it may be mixed or combined with these fertilizers, pesticides, or other soil conditioners in advance. A method of adding it to the soil by mixing it or adding it in layers (hereinafter referred to as layer addition) has been proposed (Japanese Patent Laid-Open No. 59-10288).
8).

[0005]

[Problems to be Solved by the Invention] However, in conventional methods and chemicals, water-absorbing resins simply improve water retention conditions in soil areas with poor irrigation conditions, making the soil suitable for growing crops. In other cases, the role of water-absorbing resin was merely to prevent fertilizer from flowing away, and there was nothing particularly noteworthy in terms of improving plant growth.

That is, when water-absorbing resin-based soil conditioners are used under good irrigation and fertilizer conditions, improvements in plant growth and yield can be expected; however, when used in areas with poor irrigation and fertilizer conditions, In this case, it was only possible to improve the soil to the extent that it would not cause the plants to wither. For this reason, concerns remain about its use in dry areas, etc., where the use of water-absorbent resins is truly required.

[0007] The present inventors have proposed an improvement in the germination rate of plant seeds;
We provide soil conditioners and soil conditioners that can promote early growth, as well as impart appropriate air permeability, water retention, and fertilizer retention to the soil, and have excellent effects on prolonging plant life and promoting growth under poor irrigation conditions. In order to find this, we conducted various studies.

[0008]

[Means for Solving the Problems] As a result of various studies on the above-mentioned problems by the present inventors, the present inventors have found that soils with poor irrigation and fertilizer conditions can be improved by applying a soil conditioner consisting of a water-absorbing resin and humic acid salts to the soil. The present invention was completed by discovering that it is possible to significantly improve plant germination rate and growth.

That is, the present invention is characterized by a soil conditioner comprising a water-absorbing resin and a humic acid salt, and a soil improving agent characterized in that the water-absorbing resin and humic acid salt are mixed into soil to improve the properties of the soil. This relates to methods for improving soil quality.

〇Water-absorbing resin The water-absorbing resin used in the present invention is made of a polymer compound that has water-swelling ability due to its crosslinked structure, and has a water-absorbing resin that is at least several tens of times its own weight. It is preferable for the present invention to use a material that absorbs water of
Water-absorbing and water-stopping agents in the construction field, cold storage and water-stopping agents in the food and logistics fields
Known water-absorbing resins used as freshness-preserving agents and the like can also be used in the present invention.

Specific examples of water-absorbing resins include polyvinyl alcohol, polyethylene oxide, sodium poly(meth)acrylate, sodium polysulfonate, poly(
meth)acrylamide, carboxymethyl cellulose,
Synthetic polymer compounds whose main components are vinyl alcohol/sodium acrylate copolymer, sodium acrylate/acrylamide copolymer, etc., natural polymers such as agar, konjac mannan, latin, alginic acid, carrageenan, etc. Examples include those that have been graft polymerized.

[0012] Among these polymer compounds, preferred for the present invention are polyacrylate crosslinked products and acrylamide/acrylate co-polymer compounds from the viewpoint of drug stability, durability, swelling degree, etc. in soil. It is a crosslinked polymer.

[0013] In the present invention, as the water-absorbing resin, one type of the above-mentioned polymer compounds can be used alone or two or more types can be used in combination.

[0014] The water-absorbing resin used in the present invention is
It can be produced by a conventionally known method, by reacting a polyfunctional group-containing crosslinking agent in the polymerization process of synthetic polymers,
It can be produced by a method in which a water-absorbing resin has a crosslinked structure at the same time as a polymer, or a method in which a non-crosslinkable polymer compound is treated with a reactive crosslinking agent to give a crosslinked structure to form a water-absorbing resin.

The water-absorbing resin used in the present invention has a particle size of 75 to 5000 μm in dry powder form.
Preferably, the range is m, and more preferably,
It is in the range of 300 to 1500 μm.

If the particle size of the water-absorbing resin is smaller than 75 μm, the effect of improving air permeability in soil due to repeated swelling/contraction of the water-absorbing resin will be reduced, and if the particle size is larger than 5000 μm, the surface area of the water-absorbing resin will decrease. Since the water absorption rate is small, the rate of water absorption is slow, and there is a risk that water and fertilizer cannot be sufficiently captured when watered, which is undesirable.

〇Humic acid salt The humic acid salt used in the present invention is an acidic organic substance generally referred to as (nitro)humic acid in the chemical field, and is also used as a soil conditioner to neutralize humic acid. It is a thing.

Specific examples of humic acid salts include alkali metal salts such as potassium humic acid, alkaline earth metal salts such as magnesium humic acid, ammonium humic acid, etc. Potassium can be used as a fertilizer component for plant growth. Or potassium humic acid and ammonium humic acid containing nitrogen are preferred compounds for the present invention.

[0019] As the humic acid salt in the present invention, the above-mentioned specific compounds may be used alone or in combination of two or more.

[0020] In the present invention, humic acid salts are present in the soil or dissolved in water that has been sprayed, and the water in which the humic acid salts are dissolved is absorbed by a water-absorbing resin, and the water-absorbing resin supplies water to plant roots. This is probably because they are simultaneously released at the same time, but powders that are easily soluble in water are preferred, and powders with a diameter of 300 μm are particularly preferred.

〇Combined ratio In the present invention, the combined ratio of water absorbent resin and humic acid salt is preferably 100:1 to 100:200 in weight ratio, more preferably 100:5 to 100:50.

[0022] If the amount of humic acid salt per 100 parts of water-absorbing resin is less than 1 (weight ratio), the effect of humic acid salt on promoting plant growth and germination will be insufficient, and the amount will be more than twice that of the water-absorbing resin. If a large amount is used, there is a risk that cations such as potassium ions and ammonium ions generated when the humic acid salt is dissolved in water may inhibit the swelling property of the water-absorbing resin.

〇 Method for preparing soil conditioner A soil conditioner consisting of a water-absorbing resin and a humic acid salt is prepared by the following method. First of all, the method is prepared by simply mixing the water-absorbing resin and the humic acid salt in suitable equipment under dry conditions.

[0024] Next, there is also a method of mixing humic acid salts in the production (polymerization) stage of the water-absorbing resin to use it as a soil conditioner.
By adding and dissolving humic acid salts in the aqueous solution of the raw material for water-absorbent resin, or by adding humic acid salt solution already dissolved in water and then going through the normal manufacturing (polymerization) process of water-absorbing resins, this product can be produced. The soil conditioner of the invention is obtained.

Furthermore, by utilizing the water-absorbing resin's ability to absorb water-soluble ions, a humic acid salt aqueous solution is added to the water-absorbing resin powder.
There is also a method of making the resin absorb humic acid salt and then drying it to make a soil conditioner.This method is more complicated in terms of process, but the method described above is also similar, but the water-absorbing resin and humic acid are This is an excellent method that has a synergistic effect with acid salts.

[0026] The soil conditioner of the present invention may contain, if necessary,
water glasses such as bentonite, diatomaceous earth, and sodium silicate;
It is also possible to use binders such as various adhesives, fertilizers, agricultural chemicals, and other soil conditioners.

〇 Soil improvement method The soil improvement method of the present invention includes a method in which the soil conditioner prepared by the above method is simply mixed into the soil, and a method in which the water-absorbing resin and humic acid salt are mixed separately. Examples include a method of adding it to soil and mixing it, and a method of separately providing a mixed layer of water-absorbing resin and soil and a mixed layer of humic acid salt and soil in the soil.

[0028] When the water-absorbing resin mixed layer and the humic acid salt mixed layer are provided separately, the humic acid salt dissolved when water is applied can be absorbed by the water-absorbing resin. It is preferable to provide it on the mixed resin layer.

In the present invention, the amount of the soil conditioner applied to the soil varies depending on the local weather conditions, plant types, soil conditions, etc., but preferably the total amount of the water-absorbing resin and humic acid salts to the soil is It is 0.05 to 5 wt%, more preferably 0.1 to 2 wt%. If the mixing amount is less than 0.05wt%, the effect of increasing soil moisture by the water absorbent resin will be insufficient, and if the mixing amount exceeds 5wt%, there will be phytotoxicity due to humic acid salts and absorption by the water absorbent resin. Adverse effects such as root rot due to moisture may occur.

[0030] The water-absorbing resin used in the present invention is
If it is exposed to sunlight for a long time in a swollen state, some of the resin may decompose and lose its water insolubility, making it impossible to swell again, so it is mixed into the soil for improvement. If this is desired, it is preferable to cover the water-absorbent resin with at least several centimeters of soil so that it does not come out onto the soil surface.

[0031] When carrying out the method of the present invention, it is also possible to use agricultural chemicals such as insecticides and herbicides, fertilizers, and soil improvers such as park compost, bentonite, ligninsulfonic acid, and lime, if necessary. be.

The present invention is mainly applied to areas with insufficient irrigation such as drylands and mountains, but it can also be applied to fields and fields in Japan and abroad.
It can be fully used for golf courses, home gardens, afforestation, etc., and can also be used for transplanting and transporting seedlings and adult trees.

When applying the present invention to areas with very good irrigation conditions, it is necessary to control the number of irrigations and the amount of watering, otherwise plant root rot may occur. need to be managed.

[0034]

[Function] Although it is not clear what the reason for the excellent effects of the present invention and the excellent effects shown in promoting germination and growth of plants are, it is thought to be based on the following effects.

[0035] Since a water-absorbing resin is used, the water content in the soil is increased, and moisture evaporation from the soil surface is suppressed, thereby extending the time that the soil retains water.

[0036] When the plant roots that extend toward the soil conditioner existing in the soil come into contact with the soil conditioner, they are held by or penetrated by the hairy roots, and the water absorbed in the water-absorbing resin is absorbed. , humic acid salts, fertilizers, etc. are directly ingested.

(2) The humic acid salt absorbed by the water-absorbing resin is gradually released into the soil (sustained release).

(2) Although the water-absorbing resin repeatedly swells and contracts while in contact with plant roots, it does not absorb water from the plant roots themselves or compete with plant roots when absorbing water from the soil.

[0039]

[Examples] Examples carried out by the present inventors will be shown below in order to explain the present invention more specifically.

Example 1 Sodium acrylate 70 mol%, acrylic acid 30
After adding 0.1 wt% of ethylene glycol diacrylate as a crosslinking agent to a mol% aqueous solution and carrying out copolymerization in the presence of a polymerization initiator, this was dried at 140°C and pulverized to obtain particles with an average particle size of 500 μm. A water absorbent resin (a) was obtained. The water absorbent resin (a) had the ability to absorb approximately 700 cc of distilled water per gram. Water absorbent resin (a) 1
20 parts by weight of fine powder ammonium humic acid salt was added to 00 parts by weight and mixed for about 20 minutes under dry conditions to obtain a soil conditioner (A).

Example 2 0.2 wt% of N,N'-methylenebisacrylamide was added as a crosslinking agent to an aqueous solution of 65 mol% of acrylamide and 35 mol% of sodium acrylate, and copolymerization was carried out in the presence of a polymerization initiator. After that, this was dried at 140°C and pulverized to obtain a water absorbent resin (b) with an average particle size of 500 μm.
) was obtained. The water-absorbing resin (b) has a content of approximately 50 per gram.
It had the ability to absorb 0 cc of distilled water. 100 parts by weight of the water-absorbing resin (b) was added to 200 parts by weight of an aqueous solution of 10 wt % potassium humic acid salt, allowed to swell, completely absorbed, and then dried to obtain a soil conditioner (B).

Comparative Example 1 To 100 parts by weight of the water-absorbent resin (a) obtained in Example 1, 200 parts by weight of finely powdered nitrofumic acid was added to give approximately 20 parts by weight.
The mixture was mixed for a minute to obtain comparative agent (1).

Comparative Example 2 100 parts by weight of the water absorbent resin (b) obtained in Example 2,
The mixture was added to 200 parts by weight of an aqueous solution containing a chemical fertilizer (N:P:K=1:1:1), completely absorbed, and then dried to obtain a comparative agent (2).

Evaluation test of soil conditioner The water-absorbent resins (a) and (b) obtained in Examples 1 and 2 and the soil conditioner (A) and (B), as well as those obtained in Comparative Examples 1 and 2. Germination tests were conducted on comparative agents (1) and (2). Add 30 g of gel of the above six drugs, each swollen 150 times, to a sterilized φ9 cm glass petri dish, and add Common Bermuda grass (Cynodon dacty) on top of it.
lon P) seeds were evenly sown, each completely sealed and stored in an incubator adjusted to 25°C, and the number of germinated seeds was investigated. In addition, as a control, 10 g of filter paper was used in the same manner as 30 cc of distilled water. In addition, in this test, three repeated experiments were conducted for each drug. Table 1 shows the number of germinated seeds from the day after the start of the test to 14 days later.

[0045]

[Table 1]

The soil improvers (A) and (B) of the present invention germinated more than 28 seeds in about 3 days, showing a better germination rate than the control plot and other test plots.

Example 3 Water absorbent resins (a) and (b) obtained in Examples 1 and 2, soil conditioner (A) and (B), and comparative agent (1) obtained in Comparative Examples 1 and 2. ) and (2) were used to improve the soil quality, and the effect was confirmed in a plant growth test. Pre-mix 2 of the above chemicals in the weight amount shown in Table 2 in dry sandy soil.
Add 000g to 1/2000 are pot, and
300 g of sandy soil mixed with 3 g of chemical fertilizer (N:P:K=1:1:1) was added. Here is Kentucky 31F (
Festuca elatio var. arud
inacea) seeds were uniformly sown, 200
The soil was covered with g of sand. Immediately after seeding, water was supplied to each pot until gravity water began to drip from the bottom, and then watering was performed at a rate of 3 mm every day. Two months later, the Kentucky 31F plants in each pot were harvested, and the number of plants, plant height, above-ground fresh weight, and underground dry weight were investigated. As control plots, we established a humic acid ammonium salt mixed plot, a bark compost mixed plot, and an untreated plot. Table 2 shows the test results and water retention rates for each pot. The water retention rate was calculated using the following formula.

[0048]

[Table 2]

When the soil conditioners (A) and (B) of the present invention were used, extremely good plant growth was shown compared to other test plots, indicating that the present invention is superior. ing.

Example 4 Water absorbent resins (a) and (b) obtained in Examples 1, 2, and 3
, soil conditioners (A), (B) and comparative agents (1), (2) obtained in Comparative Examples 1 and 2 were used to improve the soil condition, and the effects were evaluated through rooting tests by transplanting plants and This was confirmed in a life extension test under non-irrigated conditions after establishment. In a 1/2000 are pot adjusted using the same ratio and method as in Example 2, Medhagi (Hespo japonica) was seeded separately and grew to a height of 20 cm.
leza cuneata G. Don. ) seedlings were transplanted into each pot, three at a time. Immediately after transplanting, the plants were sufficiently watered until the gravity water drained from the bottom of the pot, and then watered 3 mm every day, and the condition of the leaves of the plants was observed for one month to determine the state of rooting. Thereafter, irrigation was completely stopped and leaf growth was observed to continue to extend the life of the plants. In this study, three repeated experiments were conducted for each drug. As a control plot, humic acid ammonium salt mixed plot,
A bark compost mixed area and an untreated area were established. The results of the survival test for each pot are shown in Table 3, and the results of the life extension test are shown in Table 4. In addition, in Table 3, △ indicates that it is a clump, and × indicates that it has died.In Table 4, the number in the first row of the results column indicates the number of clumps; The number indicates the number of dead peaches. Soil conditioner of the present invention (A
) and (B) showed an extremely good survival rate and life extension effect compared to other test plots, indicating that the present invention is excellent.

[0051]

[Table 3]

[0052]

[Table 4]

[0053]

[Effects of the Invention] According to the present invention, the excellent effects described below are achieved, so that it is possible to improve the soil quality in areas with insufficient irrigation such as dry areas and mountains, and it is possible to improve the environment. It is widely used in the agricultural and horticultural fields.

■ It has excellent ability to capture and maintain moisture, making it possible to improve the soil quality so that plants can grow even in areas with poor irrigation conditions such as drylands, or to save on irrigation water.Furthermore, it can retain fertilizer along with moisture, thereby reducing fertilizer runoff. It is possible to save fertilizer and prevent environmental pollution. ■ Promote plant germination and improve germination rate. ■ Improves the survival rate of transplanted plants and significantly promotes early growth immediately after transplanting. ■ Promotes the growth of above-ground and underground parts of plants,
Crop yields can be increased. ■ It has a life-extending effect that prevents plants from dying over a long period of time even without irrigation. ■ It is equally effective in promoting plant germination and growth even under extremely poor irrigation conditions.

Claims (2)

[Claims] 1. A soil conditioner comprising a water-absorbing resin and a humic acid salt. 2. A method for improving soil quality, comprising mixing a water-absorbing resin and a humic acid salt into the soil.