JP2516963B2 - PH adjuster for soil - Google Patents

Description

TECHNICAL FIELD The present invention relates to a so-called pH adjusting agent which adjusts the pH of soil to be suitable for the growth of crops, and particularly without any danger in handling. However, it is an attempt to effectively reduce the pH of soil with a small amount.

(Prior Art) Soil pH has a great influence on many factors in soil that are involved in the growth of crops. For example, the solubility of nutrient elements varies depending on the pH, so the availability to crops varies, and the activity of soil microorganisms also varies. The crop itself also has a pH range suitable for its growth.

By the way, arable land in Japan originally has a lot of volcanic ash soil,
Moreover, acid soil is widely distributed due to the weather condition of warm and heavy rain, but since the growth of crops is generally extremely poor in acid soil, such acid correction is one of the important items for soil improvement. For that purpose, about 1 million tons of calcareous fertilizer is used every year, and about 1.5 million tons of basic fertilizer is used every year.

However, recently, it has been pointed out that the pH of cultivated soil in Japan is gradually increasing due to such a large amount of basic fertilizer being thrown. Alkalinization has become a problem.

However, as mentioned above, although there are many kinds and amounts of materials that increase pH, there are few materials that lower pH.

However, regarding the bed soil for raising seedlings of paddy rice, the applicant company proposed in JP-A-49-91853 a method of adjusting pH using nitrohumic acid obtained by oxidative decomposition of lignite with nitric acid. There is.

After that, methods using acidic gypsum and sulfuric acid, ferrous sulfate, sulfur flower, etc. have also been proposed, but these applications are limited to pH adjustment of nursery bed soil,
If the area is large like a general field and the soil volume is huge in the whole soil layer, use such a material.
It is difficult to lower the pH. Therefore, conventionally the actual pH of the soil
The only way to lower the pH was to use civil engineering methods such as soil with low pH soil or deep plowing, but the reality is that these are difficult to implement.

(Problems to be solved by the invention) In order to lower the pH of the soil, an acidic substance may be mixed, and particularly in the case of limited soil such as bed soil for nursery, mineral acids such as sulfuric acid are used. By diluting with water and mixing
As described above, the pH can be lowered. However, this is due to the danger of handling sulfuric acid and excessive addition.
It has been pointed out that practical problems such as too low pH.
On the other hand, in the case of white sulphate, the pH does not decrease until a long time has passed after the addition and mixing, so it is extremely difficult to adjust the pH to an appropriate pH, and it is difficult to put it to practical use. In addition, in the case of facility soil such as greenhouses and general upland soil where an increase in pH has been pointed out, there is no material that lowers the pH simply by spraying and cultivating. Since it is laborious, time-consuming, and expensive to carry out, the advent of suitable pH-lowering materials has been long-awaited.

The present invention advantageously responds to the above-mentioned demands, and it is not only possible to effectively lower the pH with a small amount of application, but in some cases, even if it is sprayed on the surface layer, it permeates the pH.
The purpose of the present invention is to propose a pH adjusting agent for soil, which can reduce the amount of water and does not harm plants even when applied in a large amount, and which is not dangerous in handling.

(Means for Solving Problems) Now, the present inventors considered that a mineral acid, which is a strong acid, is effective for lowering the pH with a small amount, and first examined the use of various mineral acids. However, again, it was recognized again that mineral acid is not only extremely dangerous in handling, but it is difficult to mix an appropriate amount into soil as it is. Therefore, next, it was attempted to dilute them appropriately with water and impregnate them with the organic powder.

As a result, i) coals such as coal, lignite, lignite, peat and grass peat are most suitable as the organic matter, and ii) nitric acid reacts with the above-mentioned organic matter and humic acid as a mineral acid to be impregnated. While generating an acid, it decomposes itself into nitrogen gas and volatilizes, and it cannot be expected that the pH will be lowered by nitric acid.
(Weaker than mineral acid) Not suitable for purpose, sulfuric acid and phosphoric acid are suitable, iii) and when both are mixed, the mineral acid is uniformly impregnated in the organic matter, and the mixture is well mixed with soil. We obtained the knowledge that the pH of soil can be effectively lowered.

 The present invention is based on the above findings.

That is, the present invention is a soil pH adjuster obtained by impregnating pulverized coals with sulfuric acid or phosphoric acid.

In the present invention, coals refer to one or more selected from coal, lignite, lignite, peat and grass peat.

Further, in the present invention, when impregnated with sulfuric acid or phosphoric acid, it is difficult to handle such a mineral acid at a high concentration, and it is difficult to uniformly mix it with an organic powder, so that the concentration is 10 to 50%, preferably Is preferably diluted with water to about 10 to 30%, and the impregnation ratio of the mineral acid to the organic powder is 5 to 60% by weight, preferably 10 to
It is desirable to set it to about 30 wt%.

Furthermore, especially when using sulfuric acid, if water is added to concentrated sulfuric acid, hot dilute sulfuric acid is generated due to intense heat of dissolution, so it is immediately mixed and kneaded with the organic powder to react, and when this is heated for drying, it is added. A part of the sulfuric acid added becomes a sulphone group and is added to organic matter.However, as will be described later, such sulphonated carbon not only excels in pH lowering action, but also functions to increase soil buffering capacity and cation exchange capacity. It is particularly advantageous because it is also present. In addition, it is more effective to use a pressure treatment at the time of heating for the formation of a sulfone.

The mineral acid-containing organic substance powder containing sulfonated carbon prepared as described above (hereinafter simply referred to as acidic carbon) can be granulated so that it can be easily handled during use. It is desirable that such a granular product be one that absorbs water and disintegrates after spraying and returns to the original powder.Also, at the time of granulation, it is possible to add a granulation accelerator, and further to adjust the water content. Therefore, it is also possible to mix an inorganic substance that does not react with the mineral acid.

(Operation) After being sprayed on soil, the above-mentioned acidic carbon dissolves the contained sulfuric acid and phosphoric acid and reacts with basic components such as coal, magnesia, and potassium in the soil to lower the pH. In particular, the sulfuric acid and phosphoric acid in the aqueous solution penetrate into the lower layer and also function to lower the pH of the lower layer soil. Regarding phosphoric acid, the phosphoric acid is effective as a fertilizer.

In the case of sulfonation charcoal using sulfuric acid here, free sulfuric acid impregnated in the organic powder immediately contributes to the pH decrease, but the one that has become a salt by the neutralization reaction reacts further. No, and unreacted free sulfuric acid is washed away by rainfall and irrigation water, but the sulfone groups added to organic matter remain in the soil as ion exchangers,
It not only keeps the soil pH low, but also enhances the soil buffering capacity and cation exchange capacity. In the case of phosphoric acid, since it does not react with organic matter, it is possible to adjust the pH of the former only. On the other hand, phosphoric acid is absorbed as a nutrient for crops and improves its growth.

Such acidic charcoal can be sprayed easily if it is granulated into granules.It can be hand-spreaded or mechanically sprayed, and it can be permeated by rainfall or irrigation water to lower the pH simply by spraying it on the soil surface. However, after spraying, it can be cultivated and mixed well with soil to correct the pH even faster. Therefore, it is effective even in the soil such as greenhouses and general fields.

It goes without saying that this material can also be used to lower the pH of the bed soil for raising rice seedlings. Also recently
When composting livestock manure, which has been a problem as livestock pollution, adding ammonia to this suppresses the generation of ammonia, keeps pH at an appropriate level, and adjusts the water content to facilitate fermentation and accelerate composting. Can also be used.

〔Example〕

Example-1 Coal and powder obtained by crushing lignite each had a concentration of 15
-30% phosphoric acid was added at various proportions from 5 wt% to 50 wt%, kneaded with a kneader, granulated with a granulator and dried to obtain a product.

Table 1 below shows the results of examining the pH and the state of commercialization of the product thus obtained.

As is clear from the table, all the products obtained according to the present invention were acidic carbon having a low pH, and were easily granulated.

Example-2 Grass charcoal powder produced in Sarobetsu, Hokkaido and peat powder produced in Bibai were used as organic raw materials, and 10 to 30% sulfuric acid and phosphoric acid were added thereto in the range of 10 to 30 wt% to obtain a product.

The results of pH measurement of the acidic carbon thus obtained are shown in Table 2 below.

Example 3 A pulverized product of lignite was used as a raw material, concentrated sulfuric acid was added to this to dilute it by adding water to a concentration of 15 to 30%, and this diluted sulfuric acid was mixed with pulverized coal while it was hot by the heat of dissolution. , Kneaded well with a kneader. Then, after granulating with a granulator, the product was dried with hot air. Table 3 shows the results of examining the pH and the sulfonation rate of the product thus obtained. In the measurement of the sulfonation rate, the sulfonation carbon was washed with 50 times the amount of water and the sulfur in the residue was analyzed to determine the sulfonation rate as the sulfone group added with the difference from the raw coal.

As is clear from the table, about 36% of the added sulfuric acid was added to the lignite powder as a sulfone group.

Next, the inventions Nos. 1 to 3 obtained as described above were investigated for their ability to lower the pH of soil. As the soil, alluvial soil sand loam soil with a pH of 6.18 was used, and 0.5% of each of the products of the present invention (No. 1 to 3) was used.
%, 1%, 2%, 4% and 6% were added, and then the pH was measured.

 The results obtained are shown in Table 4.

In addition, the pH of the soil whose pH has been lowered is adjusted to 6.5 with calcium carbonate.
Then, seeds of Japanese mustard spinach were sown in the soil, the germination rate was measured, and the presence or absence of harmful effects of the product of the present invention on plants was examined. As a result, as shown in Table 5 below, it was confirmed that the germination rate was high in all the soils without addition, and the safety was high.

Table 6 below shows the results of cultivating Chinese cabbage (cultivar: 1,000 units) by applying the product of the present invention (No. 1) and lowering the pH to 6.5.

As is clear from the table, the area in which the pH was adjusted by the product of the present invention was significantly superior in both the growth investigation and the yield investigation as compared to the non-application area.

(Effect of the invention) Thus, according to the present invention, the pH of the soil can be lowered safely and accurately with a relatively small amount.

In addition, since it can be easily made into a granular product, it can be easily sprayed, and when it is mixed with soil, the pH can be lowered and a soil environment suitable for growing crops can be provided.

Claims (2)

(57) [Claims] 1. A crushed product of coal has a concentration of 10 to 50, respectively.
% Of the sulfuric acid or phosphoric acid in an amount of 5 to 60 wt% of the pulverized product, which is a pH adjuster for soil. 2. The pH adjusting agent according to claim 1, wherein the coal is one or more selected from coal, lignite, lignite, peat and grass peat.