JPH03217485A - Soil treating material - Google Patents

Abstract

PURPOSE:To obtain a soil treating agent preventing blight of soil borne disease and damage of soil insect pests, comprising a structural isomer of aminobenozic acid or an ester compound thereof. CONSTITUTION:The objective soil improving agent comprising a structural isomer of aminobenozic acid such as p-aminobenzoic acid or an ester thereof only or the structural isomer blended with chitin such as crab shell or prawn shell and/or clay minerals such as illite base or montmorillonite base of 2:1 type.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a soil improvement material for imparting to soil the ability to suppress the onset of soil-borne diseases or damage caused by soil pests.

[Prior Art] In recent years, with the increase in the cultivation of vegetables, flowers, etc., damage caused by soil-borne diseases or soil pests has increased. This tends to increase rapidly when certain crops are continuously cultivated, and is a major cause of continuous cropping failure, posing a serious threat to agricultural management. Moreover, since soil-borne pathogens and soil pests live in the complex environment of soil, pesticides are less likely to act on them compared to airborne pathogens and pests.

To prevent damage from soil-borne disease bacteria or soil pests, soil is disinfected.

[Problems to be solved by the invention] Soil can be disinfected by steam disinfection, methyl bromide,
Fumigation treatment using a gas agent such as chloropicrin is performed, but the efficacy is not only short compared to the cost, but also pesticides that can be treated and controlled during the growing period of crops, or pesticides whose medicinal efficacy lasts effectively. There is no. Furthermore, treatment with fumigants reduces the number of antagonistic microorganisms that inhibit the growth of soil-borne pathogens, making the risk of disease outbreak greater than before.

Therefore, once the disease occurs, there is no effective control method, so
This not only causes great damage such as reduced yields and quality, but also causes serious damage such as having to abandon acquired crop cultivation techniques and switch to new crops, resulting in great damage to agricultural management. causing damage.

However, there are some types of soil where soil-borne diseases or soil pests easily occur, and there are also soils where the onset of soil-borne diseases or damage from pests does not occur even if continuous cropping is continued. Soil that does not cause disease even after continuous cropping is called disease-preventing soil, and in recent years, the mechanism of disease-preventing soil has progressed in elucidation. Furthermore, although a similar phenomenon is observed with respect to the occurrence of damage caused by soil pests, there has been little research on how to prevent damage caused by soil pests.

An overview of the research results to date shows that, in general, millions to tens of millions of microorganisms live in 1 gram of agriculturally cultivated soil. The soil-borne pathogens in question are members of soil microorganisms, but there are few obligate parasitic bacteria, and they correspond to rhizosphere microorganisms, which are not inherently pathogenic. It parasitizes and infects crops due to changes in environmental conditions, causing disease.

The most important problem with changes in environmental conditions that accompany disease development is the abnormal increase in soil-borne pathogens. 1g of soil with no signs of disease
Dozens of soil-borne disease bacteria live inside. The disease occurs when the number of animals increases from several thousand to several hundred thousand.

Disease prevention soil is characterized by the fact that the density of pathogenic bacteria is always kept low. The reason why the density of pathogenic bacteria is kept low is that many microorganisms living in the soil interact with each other, and as the number of certain microorganisms increases, the number of microorganisms that suppress it increases, resulting in a kind of biological equilibrium. is maintained.

Therefore, in soil where this biological equilibrium is disrupted, the number of pathogenic bacteria increases significantly, resulting in the onset of soil-borne diseases. Soils that can maintain this biological equilibrium are soils that inhibit disease development. Actinomycetes, amoeba, and the like are known as microorganisms that are useful for killing pathogenic bacteria and reducing the density of pathogenic bacteria, and the effects of actinomycetes have been particularly well studied.

It has been known for a long time that actinomycetes not only have gauchial effects, but also have the ability to feed on nematodes, which are major soil pests. That is, it is noteworthy that actinomycetes have not only gauchial action but also gauchial action.

In order to maintain biological equilibrium with soil microorganisms, attempts have been made to inoculate various microorganisms and take measures that take into account the nutritional characteristics of the microorganisms. For example, many pathogenic bacteria have cell membranes made of chitin, so
Focusing on the existence of actinomycetes that reproduce using chitin as nutrients, inoculation of actinomycetes and application of chitin were investigated. As chitinous materials, crab shells, chitosan obtained by treating shrimp shells with alkali, crab shells, shrimp shells, mold cells, etc. were used.

Chitin is chemically a high polymer of N-cetylglucosamine, and as mentioned above, it forms the outer skin of arthropods, insects, and filamentous fungi. When these natural chitin-containing substances are treated with a strong alkali, acetyl groups are partially removed to produce chitosan.

What is generally called chitin includes chitin, natural chitin-containing substances, chitosan, and the like.

It is known that the effects of these various bovine tin substances are proportional to the glucosamine content, and similar results have been obtained with all of them.

When only conventional chitin is used as a soil improvement material, the effective application amount is 200 kg or more as chitosan per 10 are, and when converted to crab shell or shrimp shell, a large amount of several thousand kg is required per 10 are. becomes. Furthermore, even if chitin has been shown to have a deterrent effect on soil-borne diseases, there is a problem with its economic effectiveness, and there are concerns that excessive lime contained in crab and shrimp shells may be harmful.

[Means for Solving the Problems] Therefore, the present inventor has intensively investigated a method that can be highly effective in suppressing soil-borne diseases and soil pests even if the amount of chitin such as crab shell is used is small. This invention has been achieved.

From the perspective of clay mineralogy, non-suppressing soils have the following characteristics:
Although it does not contain type 1 clay minerals, it has been confirmed that all deterrent soils contain type 2:1 clay minerals, and in such 2:1 clay minerals, microorganisms that feed on pathogens are It is also recognized that there is an increase in

On the other hand, it has been known for a long time that when 2:1 type clay minerals are cultivated, they easily decompose depending on the environment and decompose into 1-11 type clay minerals, and the amount decomposed per year is about 10 are. It is said that each fish can weigh up to 500 kg. From this, it is thought that the decomposition of 2:1 type clay minerals due to cultivation is the cause of continuous cropping failure and a decrease in the ability to deter soil infectious diseases and soil pest damage.

The present inventor attempted to suppress the onset of soil-borne diseases by adding a 2:1 type clay mineral to soil affected by the disease, but discovered that the problem was that it took some time for the effects to appear. The reason for this is that if crops are planted soon after applying 2:1 type clay minerals, the microflora in the soil has not yet been improved and infection with soil-borne disease bacteria may occur. In particular, this tendency was strongly observed in the ability to prevent damage caused by soil pests and nematodes.

Furthermore, as a result of intensive studies to elucidate the mechanism by which 2:1 type clay minerals exert their deterrent effect, it was found that actinomycetes, which are said to be bacteria that feed on soil-borne pathogens, are sterilized by the ammonia excreted by the bacteria. However, the base substitution ability of 2:1 type clay minerals adsorbs and detoxifies ammonia, and helps the growth of glucoscopic microorganisms.
It was discovered that the effect of promoting the growth of glucobacterial microorganisms such as actinomycetes is low. Therefore, soils that are deficient in 2:1 type clay minerals and whose effects are delayed contain substances that act as food for actinomycetes, that is,
I thought that there might be a deficiency in chitin, etc.
When chitin was added to a 2:1 type clay mineral, actinomycetes increased and it was confirmed that the density could be stably maintained.

However, when applying a mixture of 2:1 type clay mineral and chitin, the amount of each applied is enormous and the economic burden is too large, so it is not practical to consider reducing the amount used. It is considered difficult to On the other hand, all of the materials conventionally known as organic materials that are effective for the growth of actinomycetes not only require a large amount of application, several tons per 10 ares, but even if actinomycetes multiply, the soil It is recognized that this does not necessarily lead to the prevention of infectious diseases or damage caused by soil pests.

Bacteria classified as actinomycetes vary in their characteristics and functions, and even if a competent strain is isolated, it is likely to mutate during passage, resulting in strains with different characteristics and functions. This is well known from research on antibiotic-producing bacteria.

Based on these facts, it appears that strains of actinomycetes, which have poor ability to feed on pathogenic bacteria, are increasing in soils that have poor ability to suppress the onset of disease. Therefore, as a result of repeated research into changing the functions of actinomycetes to a more favorable strain, the present invention was completed.

That is, the present inventor has found that by using a substance containing a structural isomer of aminobenzoic acid such as para-aminobenzoic acid or an ester thereof as a soil conditioner, the number of actinomycetes that fight against soil-borne disease bacteria can be effectively increased. It was discovered that this is possible.

Barraminobenzoic acid is known to be given as a therapeutic agent for cows suffering from vitamin B12 deficiency, such as quail disease and mistletoe disease. This is thought to be due to the recovery of the production activity of vitamin B12-producing bacteria such as actinomycetes, which are intestinal microorganisms in cows. unknown.

In the present invention, structural isomers of aminobenzoic acid such as para-aminobenzoic acid or esters thereof can be used alone, but chitin such as crab shell or 2:1 type clay, which is a nutrient for microorganisms, can be used alone. Either mineral or a mixture of both can be used and can also be applied in addition to commonly used fertilizers.

Regarding the amount of application of the mixture of 2:1 type clay mineral, crab shell, and para-aminobenzoic acid, based on the above results, the base replacement capacity is practically 10% per 107-L.
120 milligram equivalent per 0g (hereinafter, 1.20me.
2: 500 kg of L-type clay mineral, 5 crab shells
0 kg, and 250 g of paraaminobenzoic acid are appropriate amounts.

It is found that it is more effective to use a mixture of type 21 clay mineral, crabshell, and para-aminobenzoic acid, or at least a mixture of crabshell and para-aminobenzoic acid, than to apply each of these materials alone. Approved. The effect of the combination of crab shell and para-aminobenzoic acid is higher than that of the combination of para-aminobenzoic acid and 2:1 type clay minerals. This is thought to be caused by benzoic acid.

Typical 2:1 type clay minerals include illite clay minerals and montmorillonite clay minerals, and montmorillonite clay minerals are generally sold under the trade name of bentonite. However, since there are differences in type and quality of bentonite, its selection is important. The selection criteria is that the base substitution capacity is 60me. It is preferably at least 100 me, more preferably at least 100 me.

Furthermore, the particle size is preferably 0.2 mm or less, and 0.05 mm
The following are more preferable. In addition, products with high sodium content require treatment with a salt remover.

The inventors of the present invention have made extensive studies on the method for selecting 2:1 type clay minerals, and have discovered an easy and simple method for determining the content of 2:1 type clay minerals.

This method measures the replaceable potassium in soil and determines that the content of replaceable potassium is 30 mg per 100 g of dry soil.
It was discovered that the deterrent power was inferior in the following cases. The substitutable potassium content of 30 mg has a base substitution capacity of about 0. 6
Corresponds to me. And this is the base substitution capacity of 120
It was found that it corresponds to about 500 kg per 10 are as a 2:1 type clay mineral of me.

For crab shells and shrimp shells, the total nitrogen content is generally 4.
-6%, and the chitin content is about 4-5%, and the particle size varies, but particles with a particle size of several mm or less are highly effective. In addition, as a pure chitinous material, chitosan obtained by alkali treatment of crab shell, shrimp shell, etc. is generally used.

Aminobenzoic acid has ortho, meta, and rose structural isomers. Both have relatively similar chemical properties. It is also relatively sparingly soluble in water, with a melting point of 145 to 186°C. The methyl or ethyl ester of para-aminobenzoic acid is used as a local anesthetic.

Furthermore, three isomers of amine benzoic acid and their esters were found to be effective in restoring the function of actinomycetes.

The method for producing the soil improvement material of the present invention is based on the mixing efficiency of the materials, in which a small amount of materials, that is, crab shells and baraminobenzoic acid, are preliminarily mixed and then mixed with 2:1 type clay mineral. Although it is the most ideal to look at, it is of course possible to mix the champion at the same time. The mixing method is
Although it is possible to do this by hand, it is convenient to use a mixer for compound fertilizer production, a screw type stirrer, or a ribbon type stirrer.

It is also possible to mix it with other materials, such as various fertilizers, compost, and various soil improvement materials. Furthermore, it is also possible to add a gelatinizing agent such as waste molasses, carboxymethyl cellulose, or polyvinyl alcohol in an amount of 3% or less and granulate it using a granulator.

[Function] The soil improvement material of the present invention contains only a structural isomer of aminobenzoic acid such as para-aminobenzoic acid or its ester, or it contains chitinous material such as crab shell or two which is nutrient for mold organisms. : By using either type 1 clay mineral or a mixture of both, it increases the growth of actinomycetes that resist soil-borne pathogens and also removes ammonium ions, etc. that inhibit the growth of actinomycetes. Extremely large effects can be obtained with a much smaller application amount than when using chitin or 2:1 type clay minerals such as crab shell alone as a soil conditioner.

EXAMPLES The present invention will be explained in more detail by showing examples of the present invention below.

[Example 1] The test soil is black volcanic ash soil in Ueki-cho, Kamoto-gun, Kumamoto Prefecture, which is often damaged by nematodes during tomato cultivation, and contains crab shells and 2:
We used soil in which the functional recovery ability of actinomycetes was delayed even when type 1 clay minerals were used, and the soil with low functional recovery ability of actinomycetes was sandy alluvial soil in Tosa City, Kochi Prefecture. , cultivated melons in greenhouses using soil from a field suffering from vine crack disease. In melon cultivation, melons were grafted onto disease-resistant rootstocks to prevent the onset of soil-borne diseases, but as new pathogens have appeared, disease resistance has disappeared, raising concerns about the future prospects of melon cultivation.

The test area was set up as follows.

(1) Untreated area (2) Crab shell single use area (3) Crab shell and 2:1 type clay mineral combined area (4) Varaminobenzoic acid single use area (5) Varaminobenzoic acid and crab shell combined area (6) ) Para-aminobenzoic acid, crab shell, and 2:1 type clay mineral combined test method (7) Para-aminobenzoic acid and 2:1 type clay mineral combined test method: 400 g of the above test soil was placed in a seedling pot with a diameter of 10 cm. Crab shell to be filled and mixed into soil, 2:
Type 1 clay mineral and paraamine benzoic acid are each 4 g per pot for crab shell, and 1 pot for type 2:1 clay mineral.
40g per piece 1 rose aminobenzoic acid is 0 per pot
, 1 g was used.

In addition, before filling the pot with soil, each component was thoroughly mixed with the weighed soil and then filled into the pot.

Tomato and melon seeds were sown in each pot and their growth status was observed. The number of pots was 5 for each crop, the seedling amount was 5 seeds per pot, and after germination, the seedlings were thinned out so that only one seedling per pot. In addition, the sown pots were moved into a greenhouse and seedlings were raised and managed using conventional methods. In addition, in order to prevent the onset of seedling damping off, water was absorbed from the bottom of the pot.

To investigate the test results, melon seedlings were taken out of the pot along with the soil 20 days after sowing, the soil was washed off with tap water, and the onset of vine crack disease was investigated.

Seedling damping-off caused by Pythium fungus, a soil-borne disease, occurred in untreated plots and crab shell-only plots.
There were no survivors on day 0.

On the other hand, tomato seedlings were removed from the pot along with the soil on the 30th day after sowing, and the soil was washed off with tap water before being investigated. Regarding tomatoes, we investigated the number of root-knot nematode parasitism.

The occurrence of galls on the roots was investigated using a magnifying glass, and plants with one or more galls were regarded as infected plants, and the percentage of plants that developed was determined.

The experimental results are shown in Tables 1 and 2 below.

(Margins below) From the above experimental results, para-aminobenzoic acid is judged to be effective in restoring the function of actinomycetes, but it seems to lack the ability of actinomycetes to proliferate, which chitinous substances like crab shells have. Therefore, para-aminobenzoic acid appears to be effective when used in combination with materials such as crab shells that are effective in propagating actinomycetes. In particular, the combination of 2:1 type clay mineral, crab shell, and para-aminobenzoic acid produced a remarkable effect.

[Example 2] Next, the appropriate amount of chitin such as crab shell to be used when para-aminobenzoic acid was used was investigated. The test soil, test crops, and test method were the same as in Example 1. In the soil,
5 parts of 2:1 type clay mineral was added to 95 parts of soil by weight. Next, a mixture was prepared in which rose aminobenzoic acid was added at a weight ratio of 1 part to 400 parts of soil. Further, as a mixture of para-aminobenzoic acid and crab shell, a mixture was prepared in which para-aminobenzoic acid was added at a weight ratio of 0.5 part to 100 parts of crab shell.

The treatment areas were created as follows. In addition, the amount of crab shell, crab shell, rose aminobenzoic acid, and their mixture added is as follows:
The weight ratio is based on 100 parts of soil.

(1) After mixing clay mineral and para-aminobenzoic acid, crab shell 5
Part addition area (2) After mixing clay mineral and para-aminobenzoic acid, crab shell,
0.5 part added area (3) After mixing clay minerals and para-aminobenzoic acid, crab shell, 0
．． 05 parts added area (4) After mixing clay minerals, para-aminobenzoic acid/crab shell mixture, 5 parts added area (5) After clay minerals mixed, para-aminobenzoic acid/crab shell mixture, 0.5 parts added area (6) Clay After mineral mixing, 0.05 parts of para-aminobenzoic acid/crab shell mixture was added (7) The experimental results regarding melon vine crack disease and tomato nematode parasitism rate for each treatment area above the untreated area are as follows. It is shown in Table 3.

From the above results, it can be seen that by applying a mixture of para-aminobenzoic acid and crab shell, it is possible to significantly reduce the amount of crab shell applied. In addition, it is possible to reduce the amount of crab shell applied to the order of tens of kg, whereas conventionally, when using only crab shell as a soil improvement material, several tons were required per 10 are. It has become clear that the amount of crab shell applied can be reduced to 1/100 or less.

[Example 3] We investigated the appropriate amount of para-aminobenzoic acid to add.

According to Examples 1 and 2, a synergistic effect was observed when para-aminobenzoic acid and crab shell were applied in combination, and it was found that the amount of crab shell applied could be significantly reduced.

The test soil, test crops, and test method were the same as in Example 1. Then, 2:1 type clay mineral was uniformly added to the test soil in advance according to Example 2. The amount of crab shell applied was 0.05 part by weight per 100 parts of the test soil according to the results of Example 2, and the crab shell and baraminobenzoic acid were mixed according to the test area before being added to the soil.

Test plots were prepared in which 5 parts, 0.5 parts, 0.05 parts of para-aminobenzoic acid were added to 100 parts of crab shell, and those without additives were prepared in terms of weight ratio. The test results are shown in Table 4, and the names of the test plots are indicated by the addition ratio of baraminobenzoic acid to crab shell.

From the above test results, the amount of baraminobenzoic acid added to crab shell is effective at 0.005 parts by weight per 100 parts of crab shell. In practical terms, 1 for general cultivated land.
It is effective to apply 50 kg of para-aminobenzoic acid added to 100 parts of crab shell at a weight ratio of 0.0 are.

[Example 4] Aminobenzoic acid has ortho, meta, and rose structural isomers, and esters of rose aminobenzoic acid include methyl ester and ethyl ester, which are used as local anesthetics. Therefore, we conducted a comparative study of the effects of these compounds on modifying actinomycetes and suppressing soil-borne diseases and soil pests. The experimental method was conducted according to Example 1.

The test plot was prepared by adding 0.5 parts of various aminobenzoic acids to 100 parts of crab shell by weight, and adding 2:1 type clay minerals to 95 parts of test soil in advance by weight. On the other hand, crab shells to which various aminobenzoic acids had been added in advance according to the test plots were mixed into the soil to which 0.5 parts had been added.

The types of crops, sowing methods, and test results were investigated in accordance with Example 1.

The relationship between the test plot name and the test compound name is shown below.

(1) Ortho: Ortho-aminobenzoic acid (2) Meta: Meta-aminobenzoic acid (3) Para: Para-aminobenzoic acid (4) Methyl: Para-aminobenzoic acid methyl ester (5
) Ethyl: para-aminobenzoic acid ethyl ester (6) Untreated: 2:1 type clay mineral, crab shell, aminobenzoic acids, no additives.

The experimental results are shown in Table 5.

[Example 5] Crab shell 100k containing 5.2% total nitrogen and having a particle size of 5 degrees or less
A product was prepared by mixing 500 g of para-aminobenzoic acid per g with a small ribbon mixer for laboratory use.

Then, 5 parts by weight of crab shell mixed with para-aminobenzoic acid was added to 100 parts of the bed for raising melon seedlings, which had been left unattended due to the occurrence of melon vine cracking disease, to raise melon seedlings. As a result, no disease was observed. For comparison, when the seedling beds that had been left unused were used as they were, seedling damping-off and vine cracking occurred frequently.

[Example 6] A 2:1 type clay mineral was added to the product obtained in Example 5 immediately before the bagging process. The addition method used a small screw conveyor whose rotation speed was linked so that the amount of addition was adjusted according to the amount of 2:1 type clay mineral obtained by sieving to a particle size of 0.05 mm or less.

The amount added is based on 95 parts of 2:1 type clay mineral by weight.
The product obtained in Example 5 was made into 5 parts.

The product thus produced was filled into paper bags in an amount of 20 kg each. After transporting about 700km by truck,
When 100 g of the product was extracted from each of the 10 bags and the total nitrogen content was analyzed and measured, it was found to be 0.25%±0.05.

Therefore, it was determined that the mixing was uniform and there was little separation.

When this product was used together with starter fertilizer at a rate of 500 kg per 10 ares for growing tomatoes in greenhouses, where root-knot nematodes are common, an earthy odor was observed to occur in the greenhouse in about 10 days. In the post-harvest survey,
There was almost no damage caused by root-knot nematodes.

[Example 7] A soil-borne disease that occurs on golf courses is called "red scorch disease" of western grass caused by infection with Pythium fungus. In addition, Japanese turf is also affected by Pythium and Rhizoctonia fungi.
There are diseases called "Shizumi" and "Large Patch."

All of these are very serious obstacles to golf course management. Therefore, improvements to the green floor and appearance are desired. Floor and top floors can be manufactured according to almost the same specifications. This example relates to the formulation, and the formulation specifications for the formulation are as follows. Note that the blending ratio is based on weight ratio.

(1) Burnt sand...900 parts (
2) 2:1 type clay mineral... 80 parts (3)
Salt removal agent (trade name "Enrei" manufactured by Nitto Gypsum Board Co., Ltd.) ... 5 parts (4) Redox buffer agent (iron oxide, manganese oxide) ... 3 parts (5) Organic fertilizer ... 5 parts (6)
Peat moss... 1 part (7) Chemical fertilizer... 2 parts (8) Crab shell
... 4 parts (9) para-aminobenzoic acid ...0. 045 parts (10) water
... To mix one part, first, put para-aminobenzoic acid dissolved in water and spray it on the crab shell in a ribbon mixer while stirring. Next, organic fertilizer, beet moss, and chemical fertilizer are added to the ribbon mixer and stirred and mixed. Separately, the 2:1 type clay mineral, salt remover, and redox buffer are mixed in the 2:1 type clay mineral manufacturing process.

Next, while feeding the baked sand from the hopper to the ribbon mixer using a belt conveyor, the two types of mixture are mixed.
It is fed from a screw-type conveyor whose rotation speed changes according to the amount of baked sand, and is stirred and mixed by a ribbon mixer to form a product. The products are stored in hoppers and packed into resin bags before being shipped.

The chemical analysis values of the product are as follows.

Units: *': mg/100g*2: Millimo/CID2 *3: As a result of a sampling survey of 50 milligram equivalents, the error was within a range of ±5%. Therefore, the uniformity of the product is high and there is no problem in practical use.

In addition, when I applied it in October of the previous year to the green grass of Korai grass where ``Shizumi'' had appeared, ``Shizumi'' did not appear in the spring of the following year.

[Example 8] In strawberry cultivation, yellowing disease caused by Fusarium fungi has become a problem. Therefore, we added para-aminobenzoic acid to chitosan and used it in an organic compound fertilizer.

The organic compound fertilizer used has a fertilizer component content of nitrogen = 5.
%. Phosphoric acid: 7%. Kari: 5%. is guaranteed. As chitosan, a commercially available product obtained by finely pulverizing the material obtained by treating crab shell with caustic soda was used.

Moreover, a commercially available chemical agent was used as para-aminobenzoic acid.

The manufacturing method involved adding 50 parts of paraminobenzoic acid to 100 parts of chitosan by weight, and since the amount was small, the mixture was mixed in an appropriate manner.

100 kg of the organic compound fertilizer was placed in a mixer, and 200 g of the previously prepared mixture of chitosan and paraaminobenzoic acid was added thereto, followed by thorough stirring and mixing. Mixing time was approximately 1 hour. As a result of chemical analysis of the fertilizer components, it was found that the added amount of chitosan etc. was small, so there was no effect on the guaranteed fertilizer components. This compounded fertilizer was applied as a base fertilizer to a strawberry field where yellow wilt had developed in the previous year at a rate of 700 kg per 10 are. On the other hand, we also prepared a site where 700 kg of compounded fertilizer using raw materials that did not contain chitosan and para-aminobenzoic acid was applied per 10 ares, and compared the degree of onset of yellowing disease.

As a result, disease onset was observed in more than 30% of the plants where ordinary fertilizer was applied, but almost no disease onset was observed in the mixed fertilizer group containing chitosan and para-aminobenzoic acid according to the present invention.

[Comparative Example 1] The test soil is the same black volcanic ash soil used in Example 1 from Ueki-cho, Kamoto-gun, Kumamoto Prefecture. Regarding the soil in a field where watermelons and melons are continuously cultivated, and where damage from hanging rot and root-knot nematodes is habitual, no deterrent effect was observed even when applying 2:1 type clay minerals. The following treatments were performed to measure the density of actinomycetes.

Using Erlenmeyer flasks with a capacity of 500 ml, each
Filled with 200g of soil and without application of 2:1 type clay minerals, and 2
: Type 1 clay mineral application area and 2:1 type clay mineral application area have a base displacement capacity of 12 Qme, particle size of 0.05 mm.
Thereafter, 2 g of montmorillonite clay mineral having a sodium content of 0.01% was applied to each flask.

In addition, in order to see the effects of crab shells, 0.2 g, 2 g, 10 g, and 20 g of crab shells were added to each soil.

The soil, clay mineral, and crab shell were placed in a vat in advance and thoroughly stirred and mixed, and then filled into a flask.

Thereafter, 50 ml of water was added to each flask, and each flask was covered with a cotton plug and placed in an incubator maintained at 30° C. to replenish the water that evaporated during the test period.

To measure the density of bacteria, the density of actinomycetes and Fusarium bacteria was measured using the plate method on soil without additives of clay minerals and crab shells on the day of the start of the test. The number of Actinobacteria and Fusarium fungi is 1
They were 102 and 105 cows per gram, respectively.

On the other hand, 1 gram of soil was collected from each test plot every week, the density of actinomycetes and 7.
Shown in Table and Table 8.

The numerical values in the table are an index expressing the number of actinomycetes and Fusarium bacteria per gram of soil as a multiple of the number of bacteria in the soil at the start of the test.

(Left below) Table 7 Density of actinomycetes due to differences in soil treatment (Left below) Table 8 When removing the cotton stopper from the flask and taking out the soil sample, the flasks with the highest growth rate of actinomycetes were
It had a so-called earthy smell.

This earthy smell is said to be a unique odor emitted by actinomycetes, and can be used as a means of determining the degree of proliferation of actinomycetes.

Single application of crab shell promotes an increase in the number of actinomycetes, but as the amount of application increases and the number of days after application increases, the number of actinomycetes decreases. On the other hand, when crab shell and 2:1 clay minerals were used in combination, the number of actinomycetes increased as the amount of crab shell applied increased. As the number of actinomycetes increases, the number of Fusarium bacteria decreases.

From the above results, it is determined that the increase in the number of Fusarium bacteria is also due to a lack of actinomycetes, which act like their natural enemies. The increase in the number of actinomycetes is presumed to be due to a lack of chitin-containing substances such as crab shells, which serve as food for actinomycetes.

The number of actinomycetes increases with the increase in the amount of crab shell applied, but 2
:With no addition of type 1 clay minerals, it is highest in the 2nd to 3rd week and then tends to decrease.

On the other hand, with the addition of 2:1 type clay minerals, the high number of actinomycetes was
It was found that it lasted for a relatively long time. This indicates that as actinomycetes ingest crab shells, the metabolites inhibit the growth of actinomycetes, and a typical example is ammonia derived from amino groups contained in chitin. it is conceivable that.

Since the negative charge of the 2:1 type clay mineral has a high affinity for ammonia, it can be concluded that the addition of the 2:1 type clay mineral stabilizes the number of actinomycetes.

However, the large amounts of crab shells and 2:1 type clay minerals that are effective are considered to be an obstacle in applying this method to the improvement of soil in actual fields. In particular, based on the results of this experiment, the effective amount of crab shell added is 1 ton or more per 10 are, and it is judged that 10 ton is required if a sufficient effect is expected.

(Effects of the Invention) The present invention uses aminobenzoic acid, which has the effect of multiplying antagonistic microorganisms that inhibit the growth of soil-borne disease bacteria in the soil, to prevent soil-borne diseases or soil pests without using conventional agricultural chemicals. By applying a soil improvement agent mixed with chitinous and 2:1 type clay minerals to the soil, soil-borne diseases and soil pests can be controlled even during the growing period of crops, and the medicinal effects are also effective. Since it can be sustained, it has a great effect on crop growth.

Claims (6)

[Claims] (1) A soil improvement material containing a structural isomer of aminobenzoic acid or an ester compound thereof. (2) The soil improvement material according to claim 1, wherein 0.5 to 3 parts by weight of a structural isomer of aminobenzoic acid or an ester compound thereof is added to 100 parts by weight of crushed crab shells of 5 mm or less. (3) The soil improvement material according to claim 1, wherein 10 to 60 parts by weight of a structural isomer of aminobenzoic acid or an ester compound thereof is added to 100 parts by weight of chitosan. (4) Base substitution capacity is 60me. The particle size is 0.2m or more.
3. The soil improvement material according to claim 2, wherein a 2:1 type clay mineral having a sodium content of 1% or less is added in an amount of 6 to 20 times by weight. (5) Base substitution capacity is 60me. Above, the particle size is 0.2
4. The soil improvement material according to claim 3, wherein a 2:1 type clay mineral having a sodium content of 1% or less is mixed in a weight ratio of 4000 to 1000 times that of chitosan. (6) Claim 1: Mixed with fertilizer or other soil conditioner
The soil improvement material according to any one of 5 to 5.