JPH0260709B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field to which the invention pertains] The present invention relates to a soil conditioner that improves the alkalinity of soil. [Description of Prior Art] Agricultural land in Japan generally has a lot of acidic soil, but as the frequency of use increases, the PH value exceeds 6.5, the PH value exceeds 7.0, and sometimes even higher. Soil is emerging. Soil improvers that improve acidic soil are well known, such as slaked lime and magnesia, and these can easily solve the problem. However, in cases where the soil is alkaline, there have been proposals to improve the soil using sulfuric acid, but this is not a universally effective soil improver. In other words, a typical alkaline soil conditioner using sulfuric acid is one in which an excessive amount of sulfuric acid is mixed with gypsum, but in addition to being short-lasting, it is also difficult to make alkaline soil suitable for cultivation. However, even if some soil improvement has been achieved, the salt concentration in the soil will increase, which may actually hinder crop cultivation. Furthermore, since the product is sulfuric acid, there are handling problems. By the way, when soil is said to be acidic, it refers to a state in which there are many hydrogen ions and few hydroxide ions in the soil. On the other hand, when soil is said to be alkaline, it is the opposite of the former case, and refers to a state in which there are few hydrogen ions and many hydroxide ions in the soil. Acidic soil is divided into active acidity and latent acidity, and the former is indicated by the hydrogen ion concentration of the soil solution, while the latter is expressed by the hydrogen ions that bind to the negative charges of soil particles. It is indicated by concentration. Therefore, the essential degree of acidity of soil depends on the concentration of hydrogen ions bonded to soil particles, and the concentration of hydrogen ions in soil solution is influenced by the concentration of hydrogen ions in soil particles. When slaked lime is applied to acidic soil to improve its properties, the hydrogen ions bonded to clay particles in the soil replace the lime ions in the slaked lime, liberating hydrogen ions, and the hydrogen ions are released into the slaked lime water. It is neutralized with acid ions, thereby improving the soil. On the other hand, when trying to improve alkaline soil or high PH soil by applying an appropriate acid, it is possible to neutralize the hydroxide ions in the soil solution with the hydrogen ions of the acid. Of course,
It is difficult to replace various bases bound to soil particles with hydrogen ions of sulfuric acid. Therefore, simply applying an acid such as sulfuric acid to alkaline soil or high PH soil will not eliminate the problem of alkalinity. The reason is as follows. That is, soil contains neutral and poorly soluble salts such as carbonate lime and carbonate magnesium, and alkaline and high PH soils have a high content of these carbonates. When such soil is treated with sulfuric acid, for example, the chemical reaction shown by the following chemical formula occurs, and the effectiveness of sulfuric acid is limited. CaCO ₃ +H ₂ SO ₄ →CaSO ₄ +H ₂ O+CO ₂ ↑ [Object of the Invention] The main purpose of the present invention is to improve alkaline soil to soil suitable for plant cultivation. Another object of the present invention is to provide a soil improvement agent that provides unsaturated colloid and thereby improves alkaline soil into soil suitable for plant cultivation, and a method for producing the same. [Structure and effects of the invention] The alkaline soil improver provided by the present invention contains 60 to 90 parts by weight of montmorillonite clay mineral and 8 to 38 parts by weight of gypsum or a mixture of gypsum and magnesium sulfate.
It is characterized by containing 0.2 to 2.0 parts by weight of manganese oxide, more preferably 0.4 to 10.0 parts by weight of ferric oxide, based on Mn. The present invention has been completed as a result of extensive research by the present inventors, as described below. Soil particles in which the negatively charged particles are bonded to hydrogen ions are called unsaturated colloids, and those in which they are bonded to various bases are called saturated colloids. Acidic soil has a lot of unsaturated colloids. However, the present inventor focused on the fact that alkaline soil contains a lot of saturated colloid, and developed an alkaline soil, highly saturated colloid, which does not have the above-mentioned problems. Research has been carried out to provide a soil conditioner that can universally improve PH soil and make it reusable. The present inventor first identified alkaline soil or high PH soil.
Attempts were made to add unsaturated substances to the soil. By the way, the unsaturated colloid is generally represented by clay minerals, and the clay minerals include kaolinite,
There are halloysite and montmorillonite types. The present inventor first attempted to add these to alkaline soil or high PH soil. As a result, the following was found. In other words, although both kaolinite and halloysite compounds are acidic, they have a small amount of negative charge, so if they are to be used to improve soil, they must be applied in fairly large amounts. ,
In that case, even if the problem of alkalinity could be eliminated, the soil would be unsuitable for growing plants. On the other hand, regarding the montmorillonite type,
Although the amount of negative charges is large, its PH value is 7.2 to 7.2.
10.5 and is alkaline, it is completely unsuitable for improving alkaline soil or high PH soil as it is. The inventor of the present invention discovered that although montmorillonite clay minerals are not suitable as they are for improving alkaline soil as described above, clay minerals of this type are easily available, as represented by bentonite. Since it is easy to process and process, we explored the possibility of using it to improve alkaline soil or high PH soil. The present inventor first investigated bentonite from various angles, and as a result, the following points were found. -Contains a large amount of base, which provides alkalinity. - Depending on the type of substitutable base in bentonite,
There are sodium bentonite and calcium bentonite, the former having a pH in the range of 9.9 to 10.5, and the latter having a pH in the range of 7.2 to 8.7. - Sodium and potassium affect the pH of clay minerals, and these are strongly adsorbed with negative charges. Calcium and magnesium are either adsorbed in a state that is very weakly negatively charged or are mixed in the form of slaked lime or carbonate lime. - When acid treatment is applied, calcium and magnesium can be removed relatively easily, but sodium and potassium are difficult to remove. - Sodium and potassium remain even if washed with natural acidic water similar to acid clay. - Even in calcium bentonite, the content of sodium and potassium is not low. By the way, a method for removing sodium from this kind of clay ore is known, and this method is based on the following chemical reaction formula. Clay/2Na+CaSO ₄ (Gypsum) Clay/Ca+Na ₂ SO ₄ However, removing sodium from cultivated land using this method requires the application of several tons of gypsum per 10 are of cultivated land, and it takes several years to achieve the goal. It will take more than 10 years. The inventor of the present invention tried adding gypsum to sodium bentonite, adding water and leaving it to stand using this method, but found that unsaturated colloid could not be obtained in a short period of time. For these reasons, the inventor of the present invention conducted intensive research through various trial and errors, and as a result, the inventors added and mixed gypsum or a mixture of gypsum and magnesium sulfate, and manganese oxide to the montmorillonite clay mineral. It was found that the above formulation produces an unsaturated colloid when water is present. Further research based on this knowledge revealed that 8 to 38 parts of gypsum or a mixture of gypsum and magnesium sulfate was added to 60 to 90 parts by weight of montmorillonite clay mineral.
Parts by weight and manganese oxide based on Mn 0.2-2.0
Parts by weight are added and blended to provide the desired unsaturated colloid, and ferric oxide is added to said blend.
It has been found that the presence of 0.4 to 10.0 parts by weight provides a more favorable unsaturated colloid. When this mixture was applied to alkaline soil, the sodium in it became sodium sulfate, and if water was present, it would be washed away, and the alkalinity of the soil would change to neutrality in a short period of time, and the treated soil would When the crops were cultivated, they were found to grow in favorable conditions. Any montmorillonite clay mineral can be used, but specifically, what is commonly called bentonite is preferred, especially calcium-type bentonite. Moreover, even sodium type bentonite can be used. Such montmorillonite clay minerals are usually used in granular form, and the size may be about 0.5 cm in diameter, but it is more preferable if they are in fine granular form. Further, it is not necessarily necessary to take special consideration regarding the mineral when the soil conditioner of the present invention is used for soil with high moisture content, but when it is used for soil with low moisture content, consideration should be given to the water content. If so, typically 20%
It may be a certain amount, but preferably 20 to 30%. The reason for this is that, as mentioned above, unsaturated colloid is formed in the presence of water, and as a result, sodium, which is the substance that makes the soil alkaline, is converted to sodium sulfate, and the water present in the system is reduced by 10%.
If the amount exceeds 30%, the formation of unsaturated colloid is insufficient, and on the other hand, if the amount exceeds 30%, the distribution of other components becomes uneven and the effect of the soil conditioner becomes insufficient. It depends. Regarding the gypsum, any known gypsum such as natural gypsum, phosphogypsum, flue gas desulfurization gypsum, etc. can be used, and in addition to these, calcined gypsum, hemihydrate gypsum, dihydrate gypsum, or a mixture thereof. Good too. Regarding the sulfuric acid magnesium clay used with gypsum, there are sulfuric acid magnesium clay mixed with gypsum, hydroxide magnesium clay added to gypsum and neutralized with sulfuric acid, and slaked lime in the method of making flue gas desulfurization gypsum. Instead, those obtained by using magnesia lime or the like are preferably used. In that case, the ratio of gypsum to magnesium sulfate can be appropriately selected within the range of 10:1 to 1:1, but preferably 7:3. Manganese oxide commercially available for industrial use is usually used, but natural manganese ore may be crushed into coarse particles. Also,
It is also possible to use a material obtained by adding nitric acid to smelting slag, etc., which has a high manganese content and heat-treating it. Commercially available ferric oxide for industrial use is usually used. The alkaline soil conditioner of the present invention can be prepared by introducing a predetermined amount of each of the above-mentioned constituent substances, preferably in the form of fine particles, into a mixing device such as a mixer, fertilizer blender, compressed air mixer, etc., and thoroughly mixing the whole product. It is produced by homogenizing. Alternatively, a predetermined amount of granular montmorillonite clay mineral and a predetermined amount of granular or powdered gypsum may be mixed in advance and introduced into the above-mentioned apparatus, whereupon a predetermined amount of granular other constituent materials may be mixed. It can also be produced by adding and mixing to homogenize the whole. The composition obtained in this way can be used as the alkaline soil conditioner of the present invention as it is, but oils and fats, semi-synthetic or synthetic gelatinizing agents, and surfactants may be added in the mixing and homogenizing steps. , it can also be made into chunks. The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. Example 1 (1) Production of alkaline soil conditioner 90 parts by weight of finely divided calcium type bentonite, 9 parts by weight of finely divided phosphogypsum, 0.2 parts by weight of industrial granular manganese dioxide, and 0.8 parts by weight of industrial granular ferric oxide. were introduced into a fertilizer blender and mixed uniformly to prepare a soil conditioner composition. (2) 10 parts by weight of the alkaline soil conditioner of (1) above,
The mixture was added to 90 parts by weight of the characteristic alkaline soil shown in Table 2, packed into a No. 4.5 unglazed pot, and after adjusting the soil moisture to 60% of the field water capacity, the mixture was placed in a glass house. The soil was left to stand for 28 days while making up for the water shortage and irrigating with 100 ml of water, which corresponds to 10 mm of rainfall, every day. After that, the soil was collected, air-dried, crushed, and sieved with a 1-mm mesh sieve. After that, according to the standard method, PH, base displacement capacity (CEC), electrical conductivity (EC), displacement magnesium (MgO), lime (CaO), potash (K ₂ O), sodium (Na ₂ O)
was measured, and the degree of base saturation was determined by calculation. At the same time, the soil itself was treated as an untreated area, gypsum with 10% gypsum added, a sulfuric acid-impregnated gypsum area with 10% of a commercially available alkaline soil conditioner impregnated with excessive sulfuric acid, and montmorillonite clay. A plot containing only 10% minerals was set up, and after being managed in the same way as the test plot, it was analyzed and investigated in the same way.

【table】

【table】

[Table] From the above results, the effect of this alkaline improver is clearly recognized. It is considered that the difference in effectiveness between types of montmorillonite clay minerals is based on the difference in base substitution capacity. Example 2 The timing of addition of gypsum and other compounds to calcium-type bentonite used in Example 1 was
In line with the clay mineral manufacturing process, during mining and crushing of raw ore,
Three times, immediately before ore crushing, and immediately after crushing and manufacturing,
Table 4 shows the results of the additive treatment according to Example 1 and the effects investigated using the method of Example 1.

[Table] From the above results, the effect of adding and treating compounds such as gypsum during mining and crushing is somewhat high, but this is because the reaction time of clay minerals and compounds such as gypsum is long and they react well. judged to be the cause. However, in practical terms, it can be judged that it is effective to add and treat compounds such as gypsum from the time of mining and crushing the wind ore to the time of completing the clay mineral product. Example 3 A 0.1% solution of polyvinyl alcohol was added to the alkaline soil conditioner used in Example 1, which was prepared by adding and treating calcium-type bentonite with a compound such as gypsum, to prevent scattering during use.
Table 5 shows the results of experiments carried out in Example 1 using a mixture in which a considerable amount was sprayed and granulated with 5% waste molasses added thereto as an organic component.

[Table] Judging from the above results, there is no significant difference in effectiveness even if an anti-scattering agent is added to the powdered product or whether it is granulated. Example 4 The gypsum part of the gypsum mixture was made of 90 parts of gypsum and 10 parts of magnesium sulfate, and magnesium lime (CaO 40%,
(containing 10% MgO), equivalent to CaO, MgO,
Add sulfuric acid to create a mixture of gypsum and sulfuric acid magnesia, and use this in place of gypsum. This gypsum mixture was added to calcium-type montmorillonite clay minerals by the method of Example 1, and the effects were tested and investigated. The results are shown in Table 6.

[Table] From the above results, it is recognized that there is no difference in effectiveness even if part of the gypsum is replaced with sulfuric acid magnesium.

Claims (1)

[Claims] 1. 60 to 90 parts by weight of montmorillonite clay mineral, 8 to 38 parts by weight of gypsum, and manganese oxide.
1. A soil alkalinity improver characterized by containing 0.2 to 2.0 parts by weight based on Mn. 2. The soil alkalinity improver according to claim 1, further comprising 0.4 to 10.0 parts by weight of ferric oxide. 3. The soil alkalinity improver according to claim 1 or 2, characterized in that up to 30 parts by weight of gypsum is replaced with magnesium sulfate.