Soil crushing agent

Abstract

The present invention is a crushability enhancing agent comprising solid particles, and when the solid particles are made into pellets by pelletization at 20MPa, the pellets have a water contact angle of 55°-110° and a liquid paraffin (JIS K9003:2014 compliant product) contact angle of 10°-70°.

Description

[Technical Field]

[0001] The present invention relates to a soil-fracturing improver. [Background technology]

[0002] The condition of the soil is an important factor for good plant growth. The conditions for good soil for plant growth include sufficient root space, good breathability and drainage, excellent water and fertilizer retention, appropriate acidity, cleanliness, no foreign matter mixed in, and a high content of microorganisms. It is especially important that the soil allows roots to absorb water and air effectively. To allow water and air to be absorbed into the soil, cultivated land such as fields is tilled using a power tiller before growing crops. Various attempts have been made to improve the efficiency of tilling, such as increasing the mechanical power of power tillers.

[0003] In addition, when the soil is exposed to rainfall, the air between the soil particles is released, causing the soil to harden. Furthermore, soil with a high clay mineral content contains a lot of aluminosilicate, which acts as a binder that binds the soil together in the presence of water, and this bond makes the soil hard when it dries.

[0004] In recent years, rice consumption in Japan has declined, leading to the implementation of a rice production reduction policy. As a result, an increasing number of farmers are converting paddy fields into upland fields. Furthermore, the frequency of crop conversion is increasing in order to efficiently utilize cultivated land. When converting paddy fields to upland fields through crop conversion, the soil hardens as described above. This necessitates repeated tilling or the use of more powerful tillers to make the soil suitable for cultivation. Furthermore, natural disasters are on the rise due to the effects of climate change, and flooding of cultivated land caused by heavy rains such as typhoons and river flooding is on the rise. This, along with the problem of crop conversion, is causing the soil to harden, a condition known as a decrease in soil harrowing. For such hard soil, for example, Patent Document 1 (JP Patent Publication No. 2016-77282) discloses a W rotor (also known as a replacement rotor) that reduces the burden and damage on the tractor engine and the W rotor (also known as a replacement rotor) while increasing work efficiency and enabling cost reductions. Summary of the Invention

[0005] The present invention provides a soil crushing improver comprising solid particles, The solid particles are compressed at 20 MPa to form pellets, the pellets having a water contact angle of 55° to 110° and a liquid paraffin (JIS K9003:2014 compliant) contact angle of 10° to 70°.

[0006] In order to improve soil that has lost its harrowing ability and is unsuitable for plant growth, methods that use mechanical power, which consumes a great deal of energy, have been used to increase work efficiency. However, previous techniques have been insufficient to achieve high work efficiency with low energy consumption. This is particularly problematic for soil that has lost its harrowing ability after drying due to crop rotation, etc., and an effective method for improving soil harrowing has been sought. The present invention relates to providing a soil-crushing improver that exhibits excellent soil-crushing improving ability for soil with reduced soil-crushing ability.

[0007] The present inventors have found that a soil-crushing improver made of solid particles that meet certain requirements exhibits excellent soil-crushing improving ability for soil with poor soil-crushing ability. The present invention relates to the following [1] to [6]. [1] A soil crushing improver consisting of solid particles, The solid particles are compressed at 20 MPa to form pellets, the pellet surface of which has a water contact angle of 55° or more and 110° or less, and a liquid paraffin (JIS K9003:2014 compliant product) contact angle of 10° or more and 70° or less. [2] A soil-grinding property improver composition containing the soil-grinding property improver described in [1] above. [3] A method for improving soil harrowing properties in cultivated land, comprising a step of improving soil quality using the soil harrowing property improver described in [1] above or the soil harrowing property improver composition described in [2] above. [4] A method for producing the soil crushing improver described in [1] above, comprising the following steps 2A and 3A. Step 2A: A step of mixing the base material with a solution in which a hydrophobizing agent is dissolved in a solvent to obtain a mixture 2A. Step 3A: Removing the solvent from mixture 2A [5] A method for producing the soil crushing improver according to [1] above, comprising the following steps 1B to 3B: Step 1B: A step of mixing the base material with water to obtain mixture 1B Step 2B: A step of mixing the mixture 1B with a solution in which a hydrophobizing agent is dissolved in a solvent to obtain a mixture 2B. Step 3B: Removing the solvent from mixture 2B [6] A method for growing plants, comprising the step of cultivating plants in soil improved with the soil harrowing property improver described in [1] above or the soil harrowing property improver composition described in [2] above. The present invention provides a soil-crushing improver that exhibits excellent soil-crushing improving ability for soil with reduced soil-crushing ability.

[0008] [Soil pulverization improver] The soil crushability improver of the present invention is a soil crushability improver consisting of solid particles, and when the solid particles are compressed at 20 MPa, the water contact angle on the surface of the pellets is 55° or more and 110° or less, and the contact angle with liquid paraffin (JIS K9003:2014 compliant product) is 10° or more and 70° or less.

[0009] The soil-crushing property improver of the present invention can exhibit excellent soil-crushing property improving ability for soil with reduced soil-crushing property. It is expected that the plant growth ability will be improved in soil whose soil-crushing property has been improved by the soil-crushing property improver of the present invention. Although the details of the mechanism by which the effects of the present invention are obtained are not clear, it is thought to be as follows. In dry soil with reduced soil crushability, the bonds between soil particles become stronger and harder, requiring a great deal of energy to break down the bonds between soil particles. This tendency is more pronounced in soils with a high clay or silt content. It is believed that this is due to the fact that clay and silt contain a large amount of clay minerals such as aluminosilicates, which have small particle sizes and a large surface area per unit mass. This suggests that, with water as a binder, the aluminosilicates bond the soil particles more firmly, hardening the soil as a whole. By making it easier to break these strong bonds between soil particles, the soil crushability is improved, enabling cultivation with low energy and high work efficiency. The soil crushability improver of the present invention is a solid particle with at least a portion of its surface being hydrophobic. When mixed with soil, it is believed to inhibit or weaken the bonds between soil particles, reducing the soil hardness and the maximum load required during crushing. In addition, the soil-crushing improver of the present invention has a good balance of hydrophilicity and hydrophobicity on the surface, can be easily mixed with soil, and is presumed to facilitate the generation of voids throughout the soil by mixing with soil, thereby improving the soil's water permeability. Based on the above-mentioned presumed mechanism, it is presumed that the soil-crushing improver of the present invention can be used to obtain soil with improved soil-crushing properties.

[0010] (solid particles) The soil-grinding agent of the present invention is composed of solid particles. In this specification, "solid" means that the solid is solid at 25°C. The solid particles, which are the active ingredient of the soil crushing improver of the present invention, can be used as long as the water contact angle and liquid paraffin contact angle of the pellets obtained from the solid particles are within the specified numerical ranges, and preferably do not inhibit plant growth. The solid particles may be either solid particles composed only of a base material or solid particles composed of multiple components, such as a base material and other components. From the viewpoint of improving soil crushing properties, the other components are preferably compounds capable of imparting hydrophilicity, such as those used in hydrophilizing agents and anti-fogging agents, or compounds capable of imparting hydrophobicity, such as those used in hydrophobizing agents and water repellents, and more preferably hydrophobizing agents. Therefore, the solid particles preferably comprise a matrix and a hydrophobizing agent. When the solid particles contain a base material and a hydrophobizing agent, it is preferable that at least a portion of the surface of the base material is surface-treated with a hydrophobizing agent, from the viewpoint of controlling the balance between the hydrophilicity and hydrophobicity of the surface of the base material.

[0011] (base material) The base material may be a substance that is solid at 25° C. and insoluble in water and organic solvents. Specific examples of the base material include inorganic substances such as natural or artificial minerals, such as elemental minerals, sulfide minerals, oxide minerals, halide minerals, carbonate minerals, borate minerals, sulfate minerals, phosphate minerals, tungstate minerals, and silicate minerals, and organic substances such as lignocellulosic biomass, natural resins, and synthetic resins. From the viewpoint of improving soil crushing properties and promoting plant growth, the base material is preferably an inorganic substance, lignocellulosic biomass, or natural resin. Furthermore, from the viewpoint of improving soil crushing properties and availability, the base material is preferably an oxide mineral, silicate mineral, lignocellulosic biomass, or natural resin. The base material is more preferably lignocellulosic biomass. Specific examples of oxide minerals include silicon oxides such as silica gel, colloidal silica, fumed silica, quartz, silica sand, glass, etc. Specific examples of silicate minerals include mica, amphibole, talc, feldspar, kaolinite, montmorillonite, sericite, illite, zeolite, etc. Lignocellulosic biomass is biomass containing cellulose, hemicellulose, and lignin as its main components, and includes herbaceous biomass and woody biomass obtained from various parts of plants, such as leaves, branches, trunks, and seeds. Examples of herbaceous biomass include biomass obtained from plant materials of the Poaceae, Malvaceae, and Leguminosae families, and biomass obtained from non-woody materials of plants of the Palmaceae family. Examples of woody biomass include various types of wood, such as wood chips obtained from coniferous trees such as larch and bald cedar, and broad-leaved trees such as oil palm and cypress, and wood pulp produced from these woods. As lignocellulosic biomass, it is also possible to use seed shell components of the genus Elaeus of the Arecaceae family, seed shell components of the subfamily Fabaceae of the Leguminosae family, seed shell components of the Juglandaceae family, seed shell components of the genus Prunus of the Rosaceae family, seed shell components of the family Olea, etc., which have traditionally been discarded. For example, palm kernel shells (PKS), which are seed shell components of the genus Elaeus of the Arecaceae family, are generated in large quantities as a by-product in the process of producing palm oil and palm kernel oil. Lignocellulose biomass can also be used after treatment with alkali, acid, hot water, etc. Such treatment increases the surface area of the lignocellulose biomass and improves its affinity with soil, which is thought to contribute to improving soil crushability and plant growth ability. From the viewpoint of improving soil crushability, alkali treatment is preferred.

[0012] From the viewpoint of ease of particle size adjustment and surface treatment, the base material is preferably colloidal silica, glass, mica, talc, kaolinite, zeolite, sugarcane bagasse, wood pulp, or palm hard shell, more preferably colloidal silica, glass, kaolinite, or palm hard shell, and even more preferably kaolinite or palm hard shell. From the viewpoint of improving soil crushing properties, the proportion of the base material in 100 parts by mass of solid particles is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, even more preferably 50 parts by mass or more, and is preferably 100 parts by mass or less, more preferably 96 parts by mass or less, even more preferably 92 parts by mass or less. The base material may be any one of these materials alone or a combination of two or more materials.

[0013] (hydrophobizing agent) The soil crushing property improver of the present invention preferably further contains a hydrophobizing agent as a component other than the base material. The hydrophobizing agent is preferably at least one organic acid selected from fatty acids having from 12 to 25 carbon atoms, humic acids, and resin acids having from 12 to 25 carbon atoms. This is because the inclusion of the organic acid in the soil crushability improver imparts the desired hydrophobicity to the soil crushability improver, thereby achieving a high soil crushability improvement ability. From the viewpoint of improving soil crushability, the number of carbon atoms in the fatty acid and resin acid is more preferably 14 or more, even more preferably 16 or more, and more preferably 24 or less, even more preferably 22 or less. The fatty acid may be saturated or unsaturated, and from the viewpoint of improving soil crushability, it is preferably a saturated fatty acid. Specific examples of fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid. From the viewpoint of improving soil crushing properties, palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid are preferred, and from the viewpoint of availability, stearic acid is preferred. Humic acid, also known as humic acid, is an amorphous, acidic organic substance present in soil. Its composition varies depending on the source material, but its elemental composition is typically 50% to 60% carbon atoms, 4% to 6% hydrogen atoms, and the remainder is mostly oxygen atoms. It is a complex organic acid with aromatic rings and multiple functional groups, such as carboxyl and hydroxyl groups. Humic acid is also known to be produced, for example, during the oxidation process of carbon black. The humic acid used in the present invention can be obtained, for example, by extraction from soil or by subjecting carbon black to an oxidation treatment. Specific examples of resin acids include rosin acids such as abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, and dehydroabietic acid, with abietic acid being preferred from the viewpoint of availability. From the viewpoint of improving soil crushing properties, the proportion of the hydrophobizing agent in 100 parts by mass of solid particles is 0 parts by mass or more, preferably 4 parts by mass or more, more preferably 8 parts by mass or more, and preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. The hydrophobizing agent may be used alone or in combination of two or more kinds.

[0014] (solid particle morphology) The soil crushability improver is a solid particle from the viewpoint of improving soil crushability and ease of handling. The particle size of the solid particles is not limited as long as it does not impair the effects of the present invention. From the viewpoint of improving soil crushability and ease of handling, the average particle size of the solid particles is preferably 0.5 μm or more, more preferably 1.0 μm or more, and even more preferably 5.0 μm or more. From the same viewpoint, the average particle size of the solid particles is preferably 1000 μm or less, more preferably 800 μm or less, and even more preferably 600 μm or less. In other words, the soil crushability improver of the present invention is preferably a fine solid particle. The average particle size is determined by the median diameter (D 50 ) and is measured using a particle size distribution analyzer (laser diffraction / scattering particle size distribution analyzer LA-950, manufactured by Horiba, Ltd.). The shape of the particles of the soil crushing property improver is not particularly limited and may be spherical, polyhedral, ellipsoidal, irregular, etc. A combination of these shapes may also be used. The soil crushing property improver is preferably solid particles whose base material has been surface-treated, more preferably solid particles whose base material has been hydrophobized, and even more preferably solid particles whose base material has been surface-treated with the organic acid. The surface treatment may be performed on at least a portion of the base material surface, or may be performed on the entire surface of the base material. From the viewpoint of improving soil crushing property, the surface treatment is preferably performed on at least a portion of the base material surface. In other words, preferably, a portion of the base material surface is not surface-treated.

[0015] (contact angle) The soil crushability improver of the present invention has a water contact angle of 55° or more and 110° or less on the surface of pellets tableted at 20 MPa, and a contact angle with liquid paraffin (JIS K9003:2014 compliant product) of 10° or more and 70° or less. Liquid paraffin used is a reagent that complies with JIS K9003:2014.

[0016] In the soil-grinding property improver of the present invention, the water contact angle and liquid paraffin contact angle are measured on the surface of pellets obtained by compressing 0.3 g of the soil-grinding property improver into pellets with a diameter of 10 mm at a pressure of 20 MPa, as described in the Examples below. The contact angle is measured by the θ / 2 method, as described in the Examples below. From the viewpoint of improving soil crushing properties, the water contact angle is 55° or more, preferably 58° or more, more preferably 60° or more, and 110° or less, preferably 100° or less, more preferably 99° or less, even more preferably 95° or less, still more preferably 90° or less, and even more preferably 85° or less. More specifically, it is preferably 55° or more and 100° or less, more preferably 55° or more and 99° or less, even more preferably 55° or more and 95° or less, still more preferably 58° or more and 90° or less, and still more preferably 60° or more and 85° or less. From the viewpoint of improving soil crushing properties, the liquid paraffin contact angle is 10° or more, preferably 20° or more, more preferably 30° or more, even more preferably 40° or more, and 70° or less, preferably 65° or less, more preferably 60° or less, even more preferably 55° or less, and still more preferably 50° or less. More specifically, it is preferably 20° or more and 65° or less, more preferably 20° or more and 60° or less, even more preferably 30° or more and 55° or less, and still more preferably 40° or more and 50° or less.

[0017] The water contact angle is an index of the hydrophilicity of the soil-crushing improver, and the liquid paraffin contact angle is an index of the hydrophobicity (lipophilicity) of the soil-crushing improver. Since this is thought to contribute to further improving soil-crushing properties, it is preferable that the wettability be non-uniform on the surface of the solid particles that make up the soil-crushing improver. Non-uniform wettability means that one part of the surface of the solid particle is highly hydrophilic, and another part of the surface of the solid particle is highly lipophilic.

[0018] [Method of manufacturing soil-breaking agent] There are no particular restrictions on the method for manufacturing the soil crushing improver of the present invention, and any manufacturing method may be used as long as the solid particles are compressed at 20 MPa to produce pellets having a water contact angle of 55° or more and 110° or less on the surface and a liquid paraffin (JIS K9003:2014 compliant product) contact angle of 10° or more and 70° or less. From the viewpoint of improving soil crushability, it is preferable to surface-treat the base material. The surface treatment method is not particularly limited. From the viewpoint of producing solid particles having a water contact angle of 55° to 110° and a liquid paraffin (JIS K9003:2014-compliant) contact angle of 10° to 70° on the surface of pellets compressed at 20 MPa, the base material is preferably surface-treated with a compound capable of imparting hydrophilicity, such as used in hydrophilizing agents and antifogging agents, and / or a compound capable of imparting hydrophobicity, such as used in hydrophobizing agents and water repellents, to control the balance between hydrophilicity and hydrophobicity of the base material surface. From the viewpoint of workability, it is more preferable to surface-treat the base material with at least one organic acid selected from the group consisting of fatty acids having from 12 to 25 carbon atoms, humic acid, and resin acids having from 12 to 25 carbon atoms to impart hydrophobicity.

[0019] One embodiment of the method for producing a soil harrowing property improver of the present invention is preferably a method for producing a soil harrowing property improver including the following steps 2A and 3A. Step 2A: A step of mixing the base material with a solution in which a hydrophobizing agent is dissolved in a solvent to obtain a mixture 2A. Step 3A: Removing the solvent from mixture 2A

[0020] The base material in step 2A is preferably the base material of the soil crushing improver. The hydrophobizing agent used in step 2A is preferably a hydrophobizing agent for the soil crushing improver.

[0021] The solvent for dissolving the hydrophobizing agent may be any solvent that has good solubility for the hydrophobizing agent. From the viewpoint of ease of solvent removal, alcohol-based solvents, ether-based solvents, ketone-based solvents, ester-based solvents, hydrocarbon-based solvents, and halogen-based solvents are preferred. Among these, from the viewpoint of production efficiency and workability, solvents having a boiling point of less than 140°C are more preferred, even more preferred less than 130°C, and even more preferred less than 120°C, and solvents having a boiling point of 30°C or higher, even more preferred more preferred being solvents having a boiling point of 40°C or higher. More specifically, examples of alcohol-based solvents include methanol, ethanol, and isopropanol. Examples of ether-based solvents include tetrahydrofuran. Examples of ketone-based solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, and diethyl ketone. Examples of ester-based solvents include ethyl acetate. Examples of hydrocarbon-based solvents include n-hexane and toluene. Examples of halogen-based solvents include chloroform, trichloroethylene, and tetrachloroethylene. The amount of the solvent for dissolving the hydrophobizing agent is preferably small, but only enough to dissolve the hydrophobizing agent, from the viewpoint of ease of solvent removal.

[0022] In step 3A, the solvent is removed from mixture 2A. The means for removing the solvent is not particularly limited, and known means such as heating, introducing an air current, and reducing pressure can be used, and two or more of these may be used in combination. From the viewpoint of reducing the amount of residual solvent, it is preferable to remove the solvent by heating. The heating temperature may be any temperature that allows the solvent to be evaporated and removed. It may be a temperature equal to or higher than the boiling point of the solvent. From the viewpoint of production efficiency, the heating temperature is preferably 30°C or higher, more preferably 35°C or higher, even more preferably 40°C or higher, and even more preferably 45°C or higher. From the viewpoint of consideration of the working environment and safety, the heating temperature may be equal to or lower than the boiling point, and is preferably 100°C or lower, more preferably 90°C or lower, even more preferably 80°C or lower, even more preferably 70°C or lower, and even more preferably 60°C or lower. After step 3A, further processing can be carried out as necessary. The further processing preferably includes a process of crushing the solid particles. It is believed that the crushing process makes the wettability of the solid particle surface uneven, which contributes to improving the soil crushing ability. Thus, a soil-breaking improver is produced.

[0023] Another embodiment of the method for producing the soil harrowing property improver of the present invention is preferably a method for producing the soil harrowing property improver including the following steps 1B to 3B. Step 1B: A step of mixing the base material with water to obtain mixture 1B Step 2B: A step of mixing the mixture 1B with a solution in which a hydrophobizing agent is dissolved in a solvent to obtain a mixture 2B. Step 3B: Removing the solvent from mixture 2B

[0024] In step 1B, the base material and water are mixed to obtain mixture 1B. By performing step 1B, it is possible to form areas on the surface of the base material where no hydrophobizing agent film is formed, which is thought to make the wettability of the solid particle surfaces non-uniform and contribute to further improving the soil crushing properties. From the viewpoint of improving soil crushing properties, the amount of water mixed with the base material is preferably 15 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 35 parts by mass or more, per 100 parts by mass of the base material, and is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 45 parts by mass or less. Steps 2B and 3B are the same as steps 2A and 3A, except that mixture 1B is used instead of the base material in step 2A. As in step 3A, further processing can be carried out after step 3B, if necessary. Thus, a soil-breaking improver is produced.

[0025] [Soil-fracturing improver composition] The soil-grinding property improver of the present invention can be used alone or in combination with other components to form a soil-grinding property improver composition. Accordingly, the present invention also provides a soil-grinding property improver composition containing the soil-grinding property improver. Other components that can be used in combination include soil improving components, fertilizer components, microbial materials, etc. From the viewpoint of improving soil crushability, the soil crushability improver composition is preferably a mixture of solid particles. The content of the soil-grinding property improver in the soil-grinding property improver composition is preferably 10% by mass or more, more preferably 25% by mass or more, even more preferably 40% by mass or more, relative to the total mass of the soil-grinding property improver composition, in order not to impair the effects of both the soil-grinding property improver and the other components used in combination with it, and is preferably less than 100%, more preferably 90% by mass or less, even more preferably 75% by mass or less, and even more preferably 60% by mass or less. In addition, the soil-fracturing improver composition may be in the form of an aggregate, molded body, etc., which is disintegratable and easily returns to the soil-fracturing improver and any other components that may be included when used on the soil by mixing, spraying, etc., or by tilling, etc.

[0026] [Methods for improving soil pulverization in cultivated land] By improving soil with the soil harrowing property improver or soil harrowing property improver composition of the present invention, the soil harrowing property of cultivated land can be improved. The decrease in the soil harrowing ability of cultivated land soil is likely to occur when the soil repeatedly changes between wet and dry states. From the viewpoint of improving soil harrowing ability, the method for improving soil harrowing ability of the present invention is preferably carried out while the cultivated land is changing from a wet state to a dry state, or while the cultivated land is in a dry state before the next wet state. Examples of situations in which cultivated land changes from a wet state to a dry state include when converting cultivated land from a paddy field to a field, when cultivated land dries after heavy rain such as a typhoon, and when the water recedes after a river flood and the cultivated land dries. Furthermore, by carrying out the method for improving soil harrowing ability of the present invention on cultivated land in a dry state, the decrease in soil harrowing ability can be suppressed when the cultivated land next becomes wet and then dries again. From the viewpoint of energy and work efficiency, it is more preferable to carry out the method while the cultivated land is changing from a wet state to a dry state. In general, dry soil means that the water content in the soil is 5% by mass or less. The method for improving soil harrowing properties of cultivated land of the present invention includes a step of modifying the soil using the soil harrowing property improver or the soil harrowing property improver composition. Specifically, the soil can be modified by mixing the soil with the soil harrowing property improver or the soil harrowing property improver composition, spraying the soil with the soil harrowing property improver or the soil harrowing property improver composition, or a combination of these methods. From the viewpoint of improving soil harrowing properties, it preferably includes a step of mixing the soil with the soil harrowing property improver or the soil harrowing property improver composition. At the cultivated land site, for example, the soil harrowing property improver or the soil harrowing property improver composition can be sprayed on the cultivated land, and the soil harrowing property improver or the soil harrowing property improver composition can be used while being mixed into the soil using a tiller or the like.

[0027] From the viewpoint of improving soil crushability, the amount of the soil crushing improver of the present invention to be added to soil is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, even more preferably 0.05 parts by mass or more, and even more preferably 0.08 parts by mass or more per 100 parts by mass of soil, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less. When a soil-crushing property improver composition is used, the amount of the soil-crushing property improver composition added to the soil is preferably in the above-mentioned range. In addition, from the viewpoint of improving soil harrowing properties, the amount of the soil harrowing improver of the present invention used per unit area of cultivated land is preferably 10 kg or more, more preferably 30 kg or more, even more preferably 50 kg or more, and even more preferably 100 kg or more per 10 ares of cultivated land, and is preferably 6000 kg or less, more preferably 3000 kg or less, even more preferably 1500 kg or less, and even more preferably 1000 kg or less. When using a soil harrowing property improver composition, it is preferable to use an amount of the soil harrowing property improver composition such that the amount of the soil harrowing property improver used per unit area of cultivated land falls within the above range.

[0028] (soil) From the viewpoints of improving soil pulverization and plant growth ability, the soil targeted by the method for improving soil pulverization of the present invention preferably has a total clay and silt content of 3% to 100% by volume of the total volume of the dry components of the soil. "Dry components of soil" refers to all solid components (particles) that make up the soil other than water, i.e., sand, silt, and clay. Geologically, particles with a particle size of 1 / 256 mm or less are called clay, and particles with a particle size of 1 / 16 mm to 1 / 256 mm are called silt. In this invention, particles with a particle size of 20 μm or less that have a large surface area per unit mass and that deteriorate soil pulverization are defined as "clay and silt." The total clay and silt content in soil can be measured by the method shown in the Examples below. Although the type and content of sand is affected, a high total content of clay and silt relative to the total volume of dry components tends to cause soil particles to bond together and reduce soil crushability when the soil is dried from a wet state. Therefore, in the soil that is the target of the soil crushability improvement method of the present invention, the total content of clay and silt relative to the total volume of dry components is preferably 3% by volume or more, more preferably 15% by volume or more, and even more preferably 30% by volume or more, from the viewpoint of significantly reducing the soil crushability. On the other hand, the total content of clay and silt relative to the total volume of dry components is 100% by volume or less, and from the viewpoint of obtaining soil with appropriate voids between soil particles and permeability suitable for plant growth, the total content of clay and silt when dried is more preferably 85% by volume or less, and even more preferably 60% by volume or less.

[0029] (Soil hardness) The soil crushing property of the soil is improved by the soil crushing property improvement method using the soil crushing property improver or soil crushing property improver composition of the present invention. The soil crushing property can be evaluated, for example, by the hardness of pelletized soil. Specifically, as a simple and objective method for evaluating soil crushing property, a method shown in the examples below can be mentioned, in which 0.15 g of soil with a water content of 25% by mass is compressed into a pellet of 10 mm in diameter at 20 MPa, and the pellet is dried at 50 ° C for 2 hours to evaluate the hardness of the pellet. When soil dries in the presence of water, the bonds between soil particles become stronger, reducing its crushability, i.e., it becomes hard. To crush hardened soil, force, i.e., energy, must be applied, and as the soil hardness increases, the energy required for crushing synergistically increases. If soil hardness is defined as the hardness of a pellet obtained by compressing 0.15 g of soil with a moisture content of 25% by mass into a 10 mm diameter pellet at 20 MPa and drying it at 50°C for 2 hours, the hardness is preferably 0.12 kgf / mm from the viewpoint of good soil crushability. 2 Less than or equal to 0.11 kgf / mm 2 or less, more preferably 0.10 kgf / mm 2 On the other hand, from the viewpoint of reducing soil erosion, the hardness is preferably 0.050 kgf / mm 2 More preferably, it is 0.055 kgf / mm 2 More preferably, 0.060 kgf / mm 2 That's all. In the method for improving soil crushing properties of the present invention, the ratio of the hardness of the modified soil (treated) to the hardness of the soil before modification (untreated) [treated / untreated] is preferably 1.00 or less, more preferably 0.98 or less, and even more preferably 0.95 or less.

[0030] (water permeability) The hydraulic conductivity of soil measured in accordance with JIS A 1218:2009 can also be used to evaluate the soil's pulverization ability. A high hydraulic conductivity means that there are many paths through which water can pass through the soil, indicating that there are many areas where the soil particles are not bonded together when the soil is dry. This is an indicator of how easily the soil will pulverize when force and energy are applied, such as by tilling. The hydraulic conductivity can be measured using the variable head permeability test method in accordance with JIS A 1218:2009, as shown in the examples below. The soil hydraulic conductivity is preferably 1.6 x 10 at 20°C from the viewpoint of good soil pulverization. -5 cm / sec or more, more preferably 1.61 × 10 -5 cm / sec or more, more preferably 1.62 × 10 -5The upper limit is not particularly limited, but from the viewpoint of soil water retention, it is preferably 8.0 × 10 -2 cm / sec or less, more preferably 7.0 × 10 -2 cm / sec or less. In the method for improving soil pulverization of the present invention, the ratio of the hydraulic conductivity of the improved soil (treated) to the hydraulic conductivity of the soil before improvement (untreated) [treated / untreated] is preferably 1.80 or more, more preferably 1.90 or more.

[0031] [How to grow plants] The plant growing method of the present invention includes a step of cultivating plants in soil improved with the soil harrowing property improver or soil harrowing property improver composition. The plant growing method is preferably a method for growing agricultural crops or a method for cultivating agricultural crops. The method for growing plants preferably includes the steps of improving soil with the soil harrowing property improver or soil harrowing property improver composition of the present invention, and cultivating plants in the obtained soil. Soil improvement using the soil harrowing property improver or soil harrowing property improver composition is preferably carried out by the method described above in "Method for improving soil harrowing property of cultivated land." Fertilizer application to the soil, soil cultivation, etc. can be carried out before or simultaneously with soil improvement.

[0032] (Cultivation) Plants can be cultivated using the improved soil at any time from the start of cultivation (e.g., sowing, planting, etc.) to the end of cultivation (e.g., harvesting). Cultivation can be initiated by transplanting plants from cultivation in a different soil. Alternatively, plants can be transplanted into a different soil after cultivation has begun and before the end of cultivation (e.g., harvesting). (plant) The plants cultivated by the plant breeding method of the present invention are preferably plants used as agricultural crops. Examples of the plants include Cucurbitaceae, Solanaceae, Rosaceae, Malvaceae, Fabaceae, Poaceae, Brassicaceae, Liliaceae, Amaryllidaceae, Asteraceae, Amaranthaceae, Umbelliferae, Zingiberaceae, Lamiaceae, Araceae, Convolvulaceae, Dioscoreaceae, and Nelumbaceae. Specific examples of fruit vegetables include cucumber, pumpkin, watermelon, melon, tomato, eggplant, bell pepper, strawberry, okra, green beans, broad beans, peas, edamame, and corn. Examples of leafy vegetables include Chinese cabbage, lettuce, bok choy, cabbage, cauliflower, broccoli, Brussels sprouts, onion, leek, garlic, scallion, chive, asparagus, lettuce, lettuce, celery, spinach, garland chrysanthemum, parsley, mitsuba, Japanese parsley, udo, myoga, butterbur, and shiso. Examples of root vegetables include radish, turnip, burdock, carrot, potato, taro, sweet potato, mountain yam, ginger, and lotus root. Other examples include rice, wheat, and flowers, and more preferably grains such as soybeans, green soybeans, and other legumes that tend to be grown on a large scale.

[0033] The present invention further provides the following: <1> ~ <31> Disclose. <1> A soil crushability improver consisting of solid particles, wherein the water contact angle of the pellet surface when the solid particles are compressed at 20 MPa is 55° or more and 110° or less, and the contact angle with liquid paraffin (JIS K9003:2014 compliant product) is 10° or more and 70° or less.

[0034] <2> The solid particles are (i) solid particles composed only of a base material, or (ii) solid particles composed of a plurality of components, i.e., a base material and other components, and the other components preferably contain a compound capable of imparting hydrophilicity or a compound capable of imparting hydrophobicity, more preferably at least one compound capable of imparting hydrophilicity selected from a hydrophilizing agent and an anti-fogging agent, or at least one compound capable of imparting hydrophobicity selected from a hydrophobizing agent and a water-repellent agent, even more preferably a hydrophobizing agent. <1> The soil crushing improver described in .

[0035] <3> The solid particles include a base material and a hydrophobizing agent, and at least a portion of the surface of the base material is surface-treated with the hydrophobizing agent. <2> The soil crushing improver described in .

[0036] <4> The matrix is at least one selected from colloidal silica, glass, mica, talc, kaolinite, zeolite, sugarcane bagasse, wood pulp, and palm hard shell, preferably at least one selected from colloidal silica, glass, kaolinite, and palm hard shell, more preferably at least one selected from kaolinite and palm hard shell. <2> or <3> The soil crushing improver described in .

[0037] <5> The ratio of the base material to 100 parts by mass of the solid particles is 30 parts by mass or more and 100 parts by mass or less, preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and preferably 96 parts by mass or less, and even more preferably 92 parts by mass or less. <2> ~ <4> The soil crushing improver according to any one of the above.

[0038] <6> The hydrophobizing agent is at least one organic acid selected from fatty acids having 12 to 25 carbon atoms, humic acids, and resin acids having 12 to 25 carbon atoms. <2> ~ <5> The soil crushing improver according to any one of the above.

[0039] <7> The number of carbon atoms of the fatty acid and resin acid is 14 or more and 24 or less, preferably 16 or more and preferably 22 or less. <6> The soil crushing improver described in .

[0040] <8> The fatty acid is at least one selected from lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid, preferably at least one selected from palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid, more preferably stearic acid. <6> or <7> The soil crushing improver described in .

[0041] <9> The resin acid is at least one rosin acid selected from abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, and dehydroabietic acid, and is preferably abietic acid. <6> or <7> The soil crushing improver described in .

[0042] <10> the proportion of the hydrophobizing agent in 100 parts by mass of the solid particles is 0 parts by mass or more, preferably 4 parts by mass or more, more preferably 8 parts by mass or more, and preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 50 parts by mass or less. <2> ~ <9> The soil crushing improver according to any one of the above.

[0043] <11> The average particle size of the solid particles measured by laser diffraction / scattering particle size distribution measurement is 0.5 μm or more and 1000 μm or less, preferably 1.0 μm or more, more preferably 5.0 μm or more, and preferably 800 μm or less, more preferably 600 μm or less. <1> ~ <10> The soil crushing improver according to any one of the above.

[0044] <12> the water contact angle on the surface of pellets compressed at 20 MPa is from 55° to 110°, preferably from 58° to 60°, and preferably from 100° to 99°, and more preferably from 95° to 90°, and even more preferably from 90° to 85°; and the liquid paraffin contact angle is from 10° to 70°, and preferably from 20° to 70°, and more preferably from 20° to 30°, and even more preferably from 40° to 65°, and more preferably from 60° to 55°, and even more preferably from 50° to 50°. <1> ~ <11> The soil crushing improver according to any one of the above. <13> The water contact angle on the surface of the pellets compressed at 20 MPa is from 55° to 110°, preferably from 55° to 100°, more preferably from 55° to 99°, even more preferably from 55° to 95°, still more preferably from 58° to 90°, and even more preferably from 60° to 85°, and the liquid paraffin contact angle is from 10° to 70°, preferably from 20° to 65°, more preferably from 20° to 60°, even more preferably from 30° to 55°, and still more preferably from 40° to 50°. <1> ~ <12> The soil crushing improver according to any one of the above.

[0045] <14> The above, including the following steps 2A and 3A. <1> ~ <13> A method for producing the soil crushing improver described in any one of the above. Step 2A: A step of mixing the base material with a solution in which a hydrophobizing agent is dissolved in a solvent to obtain a mixture 2A. Step 3A: Removing the solvent from mixture 2A

[0046] <15> The above method, including the following steps 1B to 3B: <1> ~ <13> A method for producing the soil crushing improver described in any one of the above. Step 1B: A step of mixing the base material with water to obtain mixture 1B Step 2B: A step of mixing the mixture 1B with a solution in which a hydrophobizing agent is dissolved in a solvent to obtain a mixture 2B. Step 3B: Removing the solvent from mixture 2B

[0047] <16> The solvent for dissolving the hydrophobizing agent is an alcohol-based solvent, an ether-based solvent, a ketone-based solvent, an ester-based solvent, a hydrocarbon-based solvent, or a halogen-based solvent. <14> or <15> A method for producing the soil crushing improver described in claim 1.

[0048] <17> The above-mentioned step 3A or 3B is a step of removing the solvent by heating, and the heating temperature is preferably 30°C or higher, more preferably 35°C or higher, even more preferably 40°C or higher, still more preferably 45°C or higher, and is preferably 100°C or lower, more preferably 90°C or lower, even more preferably 80°C or lower, still more preferably 70°C or lower, and still more preferably 60°C or lower. <14> ~ <16> A method for producing the soil crushing improver described in any one of the above.

[0049] <18> The amount of water mixed with the base material is 15 parts by mass or more and 60 parts by mass or less, preferably 25 parts by mass or more, more preferably 35 parts by mass or more, and preferably 50 parts by mass or less, more preferably 45 parts by mass or less, per 100 parts by mass of the base material. <14> ~ <17> A method for producing the soil crushing improver described in any one of the above.

[0050] <19> the above <1> ~ <13> A soil crushability improver composition containing the soil crushability improver according to any one of the preceding claims.

[0051] <20> The content of the soil-fracturing improver is 10% by mass or more but less than 100%, preferably 25% by mass or more, more preferably 40% by mass or more, and preferably 90% by mass or less, more preferably 75% by mass or less, and even more preferably 60% by mass or less, based on the total mass of the soil-fracturing improver composition. <19> The soil crushing improver composition according to claim 1.

[0052] <21> the above <1> ~ <13> The soil crushing improver according to any one of the above, or <19> or <20> A method for improving soil harrowing properties in cultivated land, comprising a step of improving soil quality using the soil harrowing properties improver composition described in claim 1.

[0053] <22> The soil has a total clay and silt content of 3% by volume or more and 100% by volume or less, preferably 15% by volume or more, more preferably 30% by volume or more, and preferably 85% by volume or less, more preferably 60% by volume or less, based on the total volume of the dry components of the soil. <21> A method for improving soil crushing properties of cultivated land as described above.

[0054] <23> The above is carried out while the cultivated land is changing from a wet state to a dry state, or while the land is in a dry state before the next wet state. <21> or <22> A method for improving soil crushing properties of cultivated land as described above.

[0055] <24> The above steps are taken when converting rice paddies into fields. <21> ~ <23> A method for improving soil pulverization in cultivated land according to any one of the above.

[0056] <25> The amount of the soil-fracturing improver added is 0.01 to 10 parts by mass, preferably 0.03 to 10 parts by mass, more preferably 0.05 to 10 parts by mass, even more preferably 0.08 to 10 parts by mass, and preferably 5 to 10 parts by mass, more preferably 3 to 10 parts by mass, even more preferably 2 to 10 parts by mass, per 100 parts by mass of soil. <21> ~ <24> A method for improving soil pulverization in cultivated land according to any one of the above.

[0057] <26> The amount of soil harrowing improver used is 10 kg or more, preferably 30 kg or more, more preferably 50 kg or more, even more preferably 100 kg or more, and 6000 kg or less, preferably 3000 kg or less, more preferably 1500 kg or less, even more preferably 1000 kg or less per 10 ares of cultivated land. <21> ~ <24> A method for improving soil pulverization in cultivated land according to any one of the above.

[0058] <27> The hardness of the amended soil was 0.050 kgf / mm when 0.15 g of soil with a moisture content of 25% by mass was compressed into pellets with a diameter of 10 mm at 20 MPa and dried at 50°C for 2 hours. 2 More than 0.12kgf / mm 2 less than or equal to 0.11 kgf / mm 2 Less than or equal to 0.10 kgf / mm 2 or less, preferably 0.055 kgf / mm 2 More preferably, 0.060 kgf / mm 2 That's all, <21> ~ <26> A method for improving soil pulverization in cultivated land according to any one of the above.

[0059] <28> The ratio of the hardness of the improved soil (treated) to the hardness of the soil before improvement (untreated) [treated / untreated] is 1.00 or less, preferably 0.98 or less, more preferably 0.95 or less. <21> ~ <27> A method for improving soil pulverization in cultivated land according to any one of the above.

[0060] <29> The hydraulic conductivity of the improved soil is 1.6 x 10 at 20°C. -5 cm / sec or more, preferably 1.61 × 10 -5 cm / sec or more, more preferably 1.62 × 10 -5 cm / sec or more, preferably 8.0 × 10 -2 cm / sec or less, more preferably 7.0 × 10 -2 cm / sec or less, <21> ~ <28> A method for improving soil pulverization in cultivated land according to any one of the above.

[0061] <30> The ratio of the hydraulic conductivity of the improved soil (treated) to the hydraulic conductivity of the soil before improvement (untreated) [treated / untreated] is 1.80 or more, preferably 1.90 or more, and more preferably 0.95 or less. <21> ~ <29> A method for improving soil pulverization in cultivated land according to any one of the above.

[0062] <31> the above <1> ~ <13> The soil crushing improver according to any one of the above, or <19> or <20> A method for growing plants, comprising the step of cultivating plants in soil improved with the soil shredding property improving composition described in claim 1. [Example]

[0063] Examples and comparative examples will be described below, and the measurements and evaluations of the various physical properties were carried out by the following methods. Unless otherwise specified, "%" means "% by mass".

[0064] [Materials etc.] <Raw material for soil pulverization improver> The following materials were used as raw materials for the soil crushing improver. (Component A: Base material) *Palm kernel shell: "Palm kernel shell" (manufactured by Shodensha Corporation, moisture content 2.3%, lignin content 48.8% by mass) was crushed five times for 20 seconds using a mini speed mill (MS-05, manufactured by LabNect Co., Ltd.). The crushed material was sieved, passed through a 500 μm diameter metal sieve, and the material remaining on a 355 μm diameter metal sieve was used. *Alkali-treated palm kernel shells: "Palm kernel shells" (Japan Pulp and Paper Co., Ltd.) were coarsely crushed using a roll breaker (RBT-1716G, Mayekawa Industries Co., Ltd.) with a gap of 2 mm. 200 g of the resulting coarsely crushed material (dry mass) was placed in a 2 L glass beaker, and 0.1% sodium hydroxide solution was added to adjust the coarsely crushed material concentration to 20% by mass. The glass beaker was placed in an 80°C hot bath and heated for 2 hours while stirring with a stirring rod. The mixture was then suction filtered through a polyethylene filter cloth (Sankyo Wire Mesh Mfg. Co., Ltd., 40 mesh), and the resulting residue was vacuum dried at 80°C. The mixture was then crushed for 5 minutes using a batch-type vibration mill (MB-1, a small vibration mill for testing and research, Chuo Kakoki Co., Ltd., pot capacity 3.4 L) and a rod (φ30 mm, length 218 mm, circular cross-section, made of SUS304) at a rod filling rate of 57% by volume. The obtained pulverized product was sieved, passing through a metal sieve with a diameter of 500 μm, and the product remaining on a metal sieve with a diameter of 355 μm was used. *Kaolinite: "Kaolin (Hakutou soil)", manufactured by Kanto Chemical Co., Ltd., average particle size 8.4 μm

[0065] (Component B: Hydrophobizing agent) *Stearic acid: "Lunac S-98", manufactured by Kao Corporation *Rosin acid: "Abietic acid", manufactured by Tokyo Chemical Industry Co., Ltd. *Humic acid: Fujifilm Wako Pure Chemical Industries, Ltd. (Component B (comparative example)) *D(+)-galacturonic acid: "D(+)-galacturonic acid monohydrate", manufactured by Fujifilm Wako Chemical Co., Ltd. *p-Isopropylbenzoic acid: Fujifilm Wako Pure Chemical Industries, Ltd.

[0066] <Soil> The soils used were soils 1 to 6 shown in Table 1. Table 1 shows the results of measuring the water content, the total clay and silt content, and the water permeability of soils 1 to 6.

[0067] [Table 1]

[0068] [Measurement method etc.] <Method for measuring the moisture content in soil> The moisture content in the soil was measured using a halogen moisture meter (HG63, manufactured by METTLER TOLEDO).

[0069] <Method for measuring the total clay and silt content in soil> Ten grams of soil samples (10 g) were dried in a dryer at 100°C for 24 hours and placed in a 500-mL glass beaker. 50 mL of ion-exchanged water was added, followed by 10 mL of hydrogen peroxide (30–35.5%, Nacalai Tesque, Inc.). The mixture was stirred for 4 hours using a stainless steel anchor-type impeller. The mixture was then heated to 50°C and stirred for an additional 2 hours. The mixture was then heated at 80°C for 20 minutes to decompose the organic matter and remove volatile components. For soil 3, an allophanic andosol, 4 mL of 1 mol / L hydrochloric acid was added. For the other soils (soils 1, 2, 4, 5, and 6), 4 mL of 1 mol / L sodium hydroxide solution was added and stirred for an additional 2 hours at 80°C to obtain the test solution. The particle size distribution of the total particles in the soil samples was measured using a particle size analyzer (LA-950 laser diffraction / scattering particle size analyzer, Horiba, Ltd.) while diluting the test solution appropriately. Based on the measurement results, the total volume percentage of particles with a particle size of 20 μm or less relative to the total particles was taken as the total clay and silt content.

[0070] <Method for measuring water permeability> Measurements were performed using a soil permeability measuring device (DIK-4012, manufactured by Daiki Rika Kogyo Co., Ltd.) in accordance with the variable head permeability test method of JIS A 1218:2009, using the following procedure. First, soil was added to a 100 mL stainless steel sample cylinder without compacting it to the top of the cylinder. After attaching a lid to the cylinder, it was placed in an overflow tank filled with water, and the water was allowed to soak up to the top of the soil and left to stand. Next, a standpipe with the valve closed was attached to the lid, and water was added. The height h1 (cm) between the water surface and the water surface in the overflow tank was measured. The valve on the standpipe was opened, and the time (t2 - t1 (seconds)) required to reach an arbitrary height h2 (cm) was measured. The test was performed at room temperature of 20°C, and the hydraulic conductivity K t was calculated using the following formula. The measurement was performed three times and the average value was used.

[0071]

number

[0072] K t : Permeability coefficient (cm / sec) a: cross-sectional area of the standpipe (cm 2 ) L: Height of the stainless steel sample cylinder (cm) A: Cross-sectional area of the stainless steel sample cylinder (cm 2 ) t2-t1: Time taken to reach height h2 from height h1 (seconds) h1: Water surface height (cm) at the start of measurement (t1) h2: Water surface height at the end of measurement (t2) (cm)

[0073] <Observation of the condition of the soil-breaking agent> The appearance of the produced soil crushing improver was visually observed at 25°C.

[0074] <Contact angle measurement method> 0.3 g of dry soil-grinding agent was pressed to 20 MPa using a powder molding machine (Mini Labo Press MP-50, manufactured by LabNect Co., Ltd.) to form pellets (10 mm in diameter). 5 μL of ion-exchanged water or liquid paraffin (Fujifilm Wako Pure Chemical Industries, special grade reagent) was dropped onto the surface of the resulting pellets, and the pellets were photographed at 25x magnification using a digital microscope (VHX-1000, manufactured by Keyence Corporation). The contact angle was determined from the photographed images using the θ / 2 method. Measurements were performed at least three times, and the average value was calculated.

[0075] <Hardness measurement method> Ion-exchange water was added to the soil for evaluation so that the moisture content was 25% by mass, and the mixture was stirred using a medicine spoon to homogenize it, obtaining a measurement sample. 0.15 g of the measurement sample was pressed to 20 MPa using a powder molding machine (Mini Labo Press MP-50, manufactured by Labnect Co., Ltd.) to form pellets (10 mm in diameter). The obtained pellets were dried at 50°C for 2 hours, and then a rheometer (Sun Rheo Meter CR-3000EX-S, manufactured by Sun Scientific Co., Ltd.) was used to perform the No. 2 pressure test. A pressure-sensitive shaft with a spherical tip was applied to a depth of 1.0 mm, and the hardness (kgf / mm 2 The measurement was repeated three or more times and the average value was calculated.

[0076] <Method for evaluating improvement in soil crushing ability> The ratio of hardness and permeability of soil with and without the addition of the soil-fracturing improver was calculated to evaluate the improvement in soil-fracturing. (1)Hardness ratio The ratio of hardness (added / unadded) was calculated for soil with and without the addition of a soil-breaking agent. A ratio of less than 1 indicates that the addition of the soil-breaking agent improved soil-breaking properties, and the smaller the value, the greater the improvement in soil-breaking properties. This evaluation simulated a dry state after rainfall and the conversion of paddy fields to upland fields. Pellets were formed at a high moisture concentration of 25% by mass, and then dried to measure the soil hardness. (2) Water permeability ratio The permeability ratio (added / unadded) was calculated for soils with and without the addition of a soil-clearing agent. A ratio of over 1 indicates that the addition of a soil-clearing agent improved permeability, and the higher the value, the greater the improvement in permeability.

[0077] [Manufacturing method] <Production Method 1 (Production of Soil Crushing Agents S1 to S3 and S7 to S8)> To a 500 mL glass beaker, 67 g of Component A shown in Table 2 was added. To a separate glass beaker, 33 g of Component B shown in Table 2 was added, and chloroform (manufactured by Nacalai Tesque, Inc.) in an amount sufficient to dissolve Component B at 25°C was added to dissolve Component B. The chloroform solution was poured into the 500 mL glass beaker containing Component A, and stirred with a medicine spoon to uniformly mix with Component A. Nitrogen was blown into the resulting mixture to evaporate and remove the chloroform, followed by heat treatment at 50°C for 12 hours. The sample was then cooled and crushed for 10 seconds using a simple crusher (Miller IFM-170G, manufactured by Iwatani Corporation) to obtain a soil crushing improver with particle sizes of approximately 10 to 300 μm.

[0078] <Manufacturing Method 2 (Manufacturing of Soil Crushing Improver S4)> To a 500 mL glass beaker, 67 g of Component A (Table 2) was added. 26.8 g of ion-exchanged water (40 parts by mass relative to 100 parts by mass of Component A) was added and stirred with a spoon to prepare a mixture of Component A and water. To a separate glass beaker, 33 g of Component B (Table 2) was added, and an amount of chloroform (Nacalai Tesque, Inc.) sufficient to dissolve Component B at 25°C was added to dissolve Component B. The chloroform solution was poured into the 500 mL glass beaker containing the mixture, stirred with a spoon, and mixed with the mixture of Component A and water. Nitrogen was blown into the resulting mixture to evaporate and remove the chloroform, followed by heat treatment at 50°C for 12 hours. The sample was then cooled and crushed for 10 seconds using a simple crusher (Miller IFM-170G, Iwatani Corporation) to obtain a soil crushing improver with particle sizes of approximately 10 to 300 μm.

[0079] <Manufacturing Method 3 (Manufacturing of Soil Crushing Improver S5)> 10 g of Component B shown in Table 2 was added to a 100 mL glass beaker, and 10 g of toluene (Fujifilm Wako Pure Chemical Industries, Ltd.) was added and stirred with a medicine spoon to obtain a mixture. 3 g of Component A shown in Table 2 was added to a 50 mL vial (No. 7, Maruemu Co., Ltd.), and 0.6 g of the mixture was added. toluene was added and mixed until a paste was formed, obtaining a paste. Nitrogen was blown in to evaporate and remove the toluene, followed by heat treatment at 50°C for 12 hours. The sample was then cooled and crushed in a mortar to obtain a soil crushing improver with a particle size of approximately 10 to 300 μm.

[0080] <Production Method 4 (Production of Soil Crushing Agent S6)> A soil crushability improver was obtained in the same manner as in Production Method 3, except that the amount of the mixture of Component B and toluene added was changed to 6 g.

[0081] [Example] <Examples 1-1 to 1-3> Soil crushing improvers S1 to S3 were produced by Production Method 1. Table 2 shows the water contact angles and liquid paraffin contact angles of the produced soil crushing improvers S1 to S3. <Examples 1-4> Soil crushing improver S4 was produced by production method 2. The water contact angle and liquid paraffin contact angle of the produced soil crushing improver S4 are shown in Table 2. <Examples 1-5> Soil crushing property improver S5 was produced by production method 3. The water contact angle and liquid paraffin contact angle of the produced soil crushing property improver S5 are shown in Table 2. <Examples 1-6> Soil crushing property improver S6 was produced by production method 4. The water contact angle and liquid paraffin contact angle of the produced soil crushing property improver S6 are shown in Table 2. <Comparative Examples 1-1 to 1-2> Soil crushing improvers S7 and S8 were produced by Production Method 1. Table 2 shows the water contact angles and liquid paraffin contact angles of the produced soil crushing improvers S7 to S8.

[0082] <Examples 2-1 to 2-13, Comparative Examples 2-1 to 2-8> (Soil pretreatment method) The mixture was dried in a dryer at 100°C for 24 hours to reduce the moisture content to 5% by mass or less, then crushed in an Extreme Mill (MX-1200X™, manufactured by Waring) for 1 minute and passed through a sieve (mesh opening 2 mm) to remove coarse particles, stones, and gravel. (Method of producing the soil for evaluation) The soil shown in Table 3 was pretreated and placed in a 100 mL polyethylene cup. The amount of soil-breaking improver shown in Table 3 was added per 100 mass parts of soil, and the mixture was stirred using a spoon to make it uniform, producing the soil for evaluation. (Evaluation of soil crushing improvement) The hardness and permeability of each of the obtained evaluation soils were measured, and the improvement in soil pulverization was evaluated. The results are shown in Table 3.

[0083] [Table 2]

[0084] [Table 3]

[0085] The results of the examples show that the soil-grinding property improver of the present invention improves the soil-grinding property of various soils. On the other hand, when the soil crushing improvers S7 and S8, which had water contact angles below the specified value, were used, the hardness actually increased compared to when no soil crushing improver was used, and the soil crushing ability did not improve.

Claims

1. A method for improving soil harrowing properties of cultivated land when converting a paddy field to an upland field, comprising a step of improving soil quality using the following soil harrowing property improver (i) or the following soil harrowing property improver composition (ii), When the soil-fracturing improver (i) is added to the soil, the amount of the soil-fracturing improver (i) added to the soil is 0.01 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the soil; A method for improving soil harrowing properties in cultivated land, wherein, when the soil harrowing property improver composition (ii) is added to soil, the amount of the soil harrowing property improver (i) contained in the soil harrowing property improver composition (ii) added to the soil is 0.01 mass parts or more and 10 mass parts or less per 100 mass parts of soil. Soil crushing improver (i): consisting of solid particles, the solid particles include a matrix and a hydrophobizing agent; The base material is lignocellulosic biomass or silicate mineral, A soil crushing improver, wherein the solid particles are compressed at 20 MPa to form pellets having a water contact angle of 55° to 110° and a liquid paraffin (JIS K9003:2014 compliant) contact angle of 10° to 70°. Soil-crushing property improver composition (ii): A soil-crushing property improver composition containing the soil-crushing property improver (i).

2. A method for improving the soil crushing properties of cultivated land as described in claim 1, wherein the solid particles include a base material having at least a portion of its surface treated with a hydrophobic agent.

3. A method for improving the soil pulverization properties of cultivated land according to claim 1 or 2, wherein the hydrophobizing agent contains at least one organic acid selected from fatty acids having 12 to 25 carbon atoms, humic acids, and resin acids having 12 to 25 carbon atoms.

4. A method for improving soil harrowing properties of cultivated land according to any one of claims 1 to 3, wherein the average particle size of the solid particles measured by laser diffraction / scattering particle size distribution measurement is 0.5 micrometers or more and 1000 micrometers or less.

5. The method for improving the soil crushing properties of cultivated land according to any one of claims 1 to 4, wherein the soil has a total clay and silt content of 3% by volume or more and 100% by volume or less, based on the total volume of the dry components of the soil.

6. A method for improving the soil harrowing properties of cultivated land according to any one of claims 1 to 5, wherein the ratio of the hardness of the modified soil (treated) to the hardness of the soil (untreated) before modification [treated / untreated] is 1.00 or less, and the ratio of the hydraulic conductivity of the modified soil (treated) to the hydraulic conductivity of the soil (untreated) before modification [treated / untreated] is 1.80 or more.

7. The method for improving the soil crushing properties of cultivated land according to any one of claims 1 to 6, which is carried out while the cultivated land is changing from a wet state to a dry state, or while the cultivated land is in a dry state before changing to the next wet state.

8. A step of improving soil quality by the method for improving soil pulverization of cultivated land according to any one of claims 1 to 7; and A method for growing plants, comprising the step of cultivating plants in the soil improved in the above step.

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