soil conditioner

Abstract

A soil modifier containing (A) lignocellulose-based biomass having a lignin content of more than 60 mass% and no more than 80 mass%.

Description

[Technical Field]

[0001] The present invention relates to a soil modifier, a method for producing a soil modifier, and a method for modifying soil.

[0002] Background technology In fields where agricultural crops are grown, soil properties are important factors in terms of productivity, etc. For example, soil composed of aggregates has adequate voids, excellent drainage and water retention, and is also soft. Because aggregated soil has these properties, it is ideal for growing crops. Various techniques have been proposed to improve soil properties, including those that use plant-based materials. Japanese Patent Application Laid-Open No. 2012-17459 describes a method for producing a soil improvement material in which lignocellulosic biomass is saccharified through a predetermined process. JP 2006-213900 A describes a method for producing a sieve made of a plant-based material containing 50% or more by weight of bark, with a density of 0.8 to 3.0 g / cm 3 The document describes a pellet-shaped soil conditioner that absorbs water and expands in volume by 2 to 100 times. Japanese Patent Publication No. 45-3171 describes a method for producing a suspension soil conditioner, which is characterized by immersing low-humus coals such as grass peat, peat, and lignite in an approximately 5 to 10% alkaline solution, adding acid to the solution, and then neutralizing the solution. Japanese Patent Application Laid-Open Publication No. 2017-190448 describes a soil conditioner containing, as an active ingredient, a lignin decomposition product that has an aldehyde yield of 5% by mass or more by alkaline nitrobenzene oxidation, a weight-average molecular weight of 300 or more and 100,000 or less, and a contact angle with water of 15° or more. International Publication No. 2019 / 078208 describes a plant growth promoter containing lignocellulose biomass, the lignocellulose biomass having a lignin content of 40% by mass or more and 60% by mass or less and a contact angle with water of 50° or less, and also describes a soil agglomeration agent containing the specified lignocellulose biomass. Furthermore, various solutions have been developed to address the issue of reduced seed emergence due to soil crust formation. J. Jpn. Soc. Soil Phys., 2006, 103, 3-12, describes how soil crust formation can be prevented by adding sandy pyroclastic flow deposits to soil where it is observed.

[0003] Summary of the Invention In order to improve the drainage and breathability of soil in fields, it is thought that promoting soil aggregation and reducing the amount of fine soil particles is more effective. It is also desirable for soil aggregates (hereinafter referred to as aggregates) to have excellent stability, such as excellent water resistance. On the other hand, in farm fields, crops are usually cultivated after the soil is tilled using a tiller, etc. In normal work with a tiller, it is desirable for the tiller to have excellent soil-crushing properties, such as being able to easily break up hardened soil and preventing the broken up soil from re-aggregating, from the perspectives of work efficiency and plant seedling establishment and growth.

[0004] The present invention provides a soil modifier that can reduce fine soil particles by forming stable aggregates from soil and also has excellent soil crushing properties during cultivation. In the present invention, soil modification may mean, for example, changing the physical properties of the soil to contribute to the intended use of the soil. Specifically, for example, it may mean improving the soil crushing properties, forming aggregates with excellent stability such as water resistance, reducing fine soil particles, or performing a combination of these.

[0005] The present invention relates to a soil conditioner containing (A) lignocellulosic biomass having a lignin content of more than 60 mass % and not more than 80 mass %.

[0006] The present invention relates to a method for producing a soil conditioner containing (A) lignocellulosic biomass having a lignin content of more than 60% by mass and not more than 80% by mass, the method comprising a step of hydrophilizing the lignocellulosic biomass.

[0007] The present invention also relates to a method for improving soil, which comprises mixing (A) lignocellulosic biomass having a lignin content of more than 60 mass % and not more than 80 mass % (hereinafter referred to as component (A)) with soil.

[0008] According to the present invention, a soil modifier and a method for producing the same, which can reduce fine soil particles by forming stable aggregates from soil and also have excellent soil crushing properties during tillage, as well as a method for modifying soil using the soil modifier, are provided. The present invention also provides a soil modifier for modifying soil to make it suitable for the growth of plants such as agricultural crops, a method for producing the same, and a method for modifying soil using the soil modifier. Excellent soil crushing properties may mean, for example, that it provides advantages when crushing soil, such as easily crushing hardened soil and preventing crushed soil from re-aggregating.

[0009] MODE FOR CARRYING OUT THE INVENTION <Soil conditioner> The soil conditioner of the present invention is a soil conditioner containing lignocellulosic biomass (hereinafter sometimes referred to as the lignocellulosic biomass of the present invention) having a lignin content of more than 60% by mass and not more than 80% by mass as component (A). The soil conditioner of the present invention contains the lignocellulosic biomass of the present invention as an active ingredient for soil conditioner.

[0010] From the viewpoint of soil crushability and reduction of fine particles due to crumbing, the lignocellulosic biomass of the present invention has a lignin content of more than 60% by mass, preferably 63% by mass or more, and 80% by mass or less, preferably 77% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less. The lignin content of the lignocellulosic biomass of the present invention refers to the lignin content in the raw material of the biomass, such as plant biomass. For example, the lignocellulosic biomass of the present invention may be obtained by subjecting plant biomass to hydrophilization treatment. In this case, the lignin content of the raw plant biomass is used. The lignin content of lignocellulosic biomass in this invention is determined by the Klason lignin method, which is the sum of the acid-insoluble and acid-soluble lignin content calculated according to TAPPI official analytical method T222om-83.

[0011] Furthermore, from the viewpoint of soil crushing properties and reduction of fine particles due to granulation, the lignocellulose biomass of the present invention may have a contact angle with water (hereinafter sometimes referred to as water contact angle) of, for example, 110° or less, further 100° or less, further 95° or less, further less than 70°, further 60° or less, further 55° or less, further 50° or less, and 0° or more, further 5° or more, further 10° or more, or further 15° or more.

[0012] The water contact angle of the lignocellulosic biomass of the present invention was measured under the following conditions. [Method for measuring water contact angle of lignocellulosic biomass] The lignocellulosic biomass to be measured is usually obtained as a solid such as powder. 0.1 to 0.3 g of the biomass is collected and compressed to a pressure of 20 MPa using a powder molding machine (Mini Labo Press MP-50, manufactured by LabNect Co., Ltd.). If the particles of the lignocellulosic biomass to be measured are large or irregular in shape, the biomass can be pulverized to adjust the particle size and shape, and then compressed as described above to use as the sample. The lignocellulosic biomass powder can also be pulverized by compression. A sample, such as a compressed lignocellulosic biomass, is placed so that its surface is horizontal, and pure water at 20°C is dropped onto the surface in droplets of 5 μm diameter. The contact angle is measured immediately after the drop. The contact angle is calculated by determining the angle between the line connecting the left and right endpoints of the droplet and the vertex relative to the solid surface and doubling this value (θ / 2 method). Measurements are performed three times for each sample, and the average value obtained is used as the water contact angle.

[0013] The raw material for the lignocellulose biomass of the present invention is preferably selected from plant biomass. Examples of plant biomass include herbaceous biomass and woody biomass. Among these, herbaceous biomass is preferred.

[0014] Herbaceous biomass refers to plant materials other than trees that grow on grasslands, or non-woody plant parts. Specific examples include plant materials from the Poaceae, Malvaceae, and Leguminosae families, and non-woody materials from plants in the Palmaceae family. Examples of plant materials from the Gramineae family include bagasse such as sugarcane bagasse and sorghum bagasse, switchgrass, elephantgrass, corn stover, corn cob, rice straw, wheat straw, barley, Miscanthus, turf, Johnsongrass, Erianthus, and Napier grass. Examples of plant materials from the Malvaceae family include kenaf and cotton. Examples of plant materials from the Leguminosae family include alfalfa. Examples of non-woody materials from palm trees include palm hard shells and palm empty fruit bunches.

[0015] The raw material for the lignocellulose biomass of the present invention can also be selected from plant biomass such as peach seed shells, prune seed shells, plum seed shells, peanut seed shells, walnut seed shells, etc. The hard shells of palm trees are also plant seed shells.

[0016] Examples of woody biomass include various types of wood, such as wood chips obtained from conifers such as larch and Japanese cedar, and broad-leaved trees such as oil palm and Japanese cypress, and wood pulp produced from these types of wood. These plant biomasses may be used singly or in combination of two or more.

[0017] Among these plant biomasses, lignocellulosic biomass is preferably used as a raw material. Lignocellulosic biomass contains cellulose, hemicellulose, and lignin as its main components. Lignocellulosic biomass with a lignin content of more than 60% by mass and not more than 80% by mass can be used as is as the lignocellulosic biomass of the present invention.

[0018] The lignocellulosic biomass of the present invention is preferably biomass from a palm plant.Furthermore, the lignocellulosic biomass of the present invention is preferably lignocellulosic biomass selected from palm kernel shells and coconut coir dust.

[0019] The lignocellulose biomass of the present invention may be the plant biomass that has been subjected to a hydrophilization treatment such as hot water treatment, alkali treatment, or acid treatment. The lignocellulose biomass of the present invention is preferably hydrophilized lignocellulose biomass that has been subjected to such treatment. Such treatment increases the surface area of ​​the lignocellulose biomass and improves its affinity with soil, which is thought to result in an environment favorable for plant growth, such as improved soil aggregation and soil pulverization. Therefore, hydrophilized lignocellulose biomass is more preferable for achieving the effects of the present invention.

[0020] The lignocellulosic biomass of the present invention is preferably in a solid form, and the solid may be in any form that is easy to form from natural biomass, such as powder or pellets.

[0021] The lignocellulosic biomass of the present invention has an average particle size of preferably 1,000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less, still more preferably 150 μm or less, still more preferably 100 μm or less, and preferably 0.1 μm or more, more preferably 1.0 μm or more, and even more preferably 10 μm or more. The average particle size of the lignocellulosic biomass of the present invention is measured using a laser diffraction / scattering particle size distribution analyzer "LA-950" (manufactured by Horiba, Ltd.).

[0022] The soil conditioner of the present invention may have a water contact angle of, for example, 110° or less, further 100° or less, further 95° or less, further less than 70°, further 60° or less, further 55° or less, further 50° or less, and 0° or more, further 5° or more, further 10° or more, or further 15° or more. The water contact angle of the soil conditioner is measured in the same manner as the above-mentioned method for measuring the water contact angle of lignocellulosic biomass, except that the lignocellulosic biomass is replaced with the soil conditioner.

[0023] The soil conditioner of the present invention is preferably in a solid form. The soil conditioner may be in any form, such as a powder or pellet, as long as it is easily formed from components containing natural biomass. Furthermore, when the soil conditioner is applied to actual agricultural land, it can be applied as a powder or granules. In particular, when it is likely to be blown away by the wind, it is preferable to mold it into granules and apply it to the soil. The soil conditioner granules applied to the soil break down into particles, preferably with an average particle size of 1,000 μm or less, in the soil when tilled, thereby exhibiting the effects of granulation and soil pulverization.

[0024] The soil conditioner of the present invention has an average particle size of preferably 1,000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less, even more preferably 150 μm or less, even more preferably 100 μm or less, and preferably 0.1 μm or more, more preferably 1.0 μm or more, even more preferably 10 μm or more. The average particle size of the soil conditioner of the present invention is measured using a laser diffraction / scattering particle size distribution analyzer "LA-950" (manufactured by Horiba, Ltd.).

[0025] The soil conditioner of the present invention contains the lignocellulosic biomass of the present invention in an amount of preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 100% by mass or less. The soil conditioner of the present invention may consist of the lignocellulosic biomass of the present invention. Furthermore, the soil conditioner of the present invention may contain components other than the lignocellulosic biomass of the present invention.

[0026] The soil conditioner of the present invention may contain (B) a cellulose derivative (hereinafter referred to as component (B)). Component (B) is a preferred component from the viewpoint of improving the water resistance of aggregates. Examples of the component (B) include one or more selected from the following (B1) to (B6). (B1) Carboxyalkyl cellulose or its salt (B2) Carboxyalkyl alkyl cellulose or its salt (B3) Alkyl cellulose (B4) Hydroxyalkyl cellulose (B5) Alkyl hydroxyalkyl cellulose (B6) Cationized cellulose

[0027] (B1) is a carboxyalkyl cellulose or a salt thereof. Examples of (B1) include carboxyalkyl cellulose or a salt thereof having a group in which a carboxy group is bonded to an alkyl group having 1 to 4 carbon atoms. Specific examples of (B1) include carboxymethyl cellulose or a salt thereof, and carboxyethyl cellulose or a salt thereof. Here, the salt of (B1) is a sodium, potassium, calcium, ammonium salt, etc.

[0028] (B2) is a carboxyalkyl alkyl cellulose or a salt thereof. Examples of (B2) include carboxyalkyl alkyl cellulose or a salt thereof having an alkyl group having 1 to 4 carbon atoms and a group in which a carboxy group is bonded to the alkyl group having 1 to 4 carbon atoms. Specific examples of (B2) include carboxymethyl methyl cellulose or a salt thereof, and carboxymethyl ethyl cellulose or a salt thereof. Here, the salt of (B2) is a sodium, potassium, calcium, ammonium salt, etc.

[0029] (B3) is an alkyl cellulose. Examples of (B3) include alkyl celluloses in which the number of carbon atoms in the alkyl group is 1 or more and 4 or less. Specific examples of (B3) include methyl cellulose and ethyl cellulose.

[0030] (B4) is a hydroxyalkyl cellulose. Examples of (B4) include hydroxyalkyl celluloses in which the carbon number of the hydroxyalkyl group is 2 or more and 4 or less. Specific examples of (B4) include hydroxyethyl cellulose and hydroxypropyl cellulose.

[0031] (B5) is an alkylhydroxyalkyl cellulose. Examples of (B5) include alkylhydroxyalkyl celluloses in which the alkyl group has 1 to 4 carbon atoms and the hydroxyalkyl group has 2 to 4 carbon atoms. Specific examples of (B5) include hydroxyethyl methyl cellulose, hydroxyethyl ethyl cellulose, hydroxypropyl methyl cellulose, and hydroxypropyl ethyl cellulose.

[0032] (B6) is a cationized cellulose. Examples of (B6) include cationized hydroxyalkyl cellulose. Examples of cationized hydroxyalkyl cellulose include cationized hydroxyalkyl cellulose having a cationic group and an alkyleneoxy group having 1 to 4 carbon atoms, which may have a substituent such as a hydroxyl group. The cationic group is preferably a quaternary ammonium group. Specific examples of (B6) include cationized hydroxymethyl cellulose, cationized hydroxyethyl cellulose, cationized hydroxypropyl cellulose, and cationized hydroxybutyl cellulose. More specific examples of cationized hydroxyethyl cellulose include hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether.

[0033] The component (B) is preferably a cellulose ether. (B1) to (B6) are cellulose ethers. The cellulose ethers have one or more substituents selected from a carboxymethyl group, a carboxyethyl group, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 2 to 4 carbon atoms, and a cationized hydroxyalkyl group, and more preferably a carboxymethyl group. The carboxy group may be a salt.

[0034] Component (B) may be a water-soluble cellulose. Here, with respect to component (B), water-soluble means that 1.0 g or more dissolves in 100 g of water at 25°C.

[0035] The component (B) is preferably (B1) carboxyalkyl cellulose or a salt thereof, more preferably carboxymethyl cellulose or a salt thereof.

[0036] When component (B) is a cellulose ether such as carboxymethyl cellulose, the average degree of substitution is preferably 0.5 or more and 1.5 or less.

[0037] Furthermore, the viscosity of a 1% by mass aqueous solution of component (B) at 20°C is preferably 5 mPa·s or more and 20,000 mPa·s or less, and more preferably 15,000 mPa·s or less. This viscosity is measured using a Brookfield viscometer on a 1% by mass aqueous solution at 20°C.

[0038] When the soil conditioner of the present invention contains component (B), from the viewpoint of improving the water resistance of aggregates, it contains component (B) in an amount of preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, even more preferably 1 part by mass or more, and preferably 10,000 parts by mass or less, more preferably 1,000 parts by mass or less, even more preferably 100 parts by mass or less, per 100 parts by mass of component (A).

[0039] The soil conditioner of the present invention may contain (C) a hydroxy acid or a salt thereof (hereinafter referred to as component (C)). Component (C) is a preferred component from the viewpoint of improving soil aggregation and / or the water resistance of the aggregates. Examples of component (C) include malic acid, citric acid, isocitric acid, isopropyl citrate, hydroxymalonic acid, tartaric acid, 3-hydroxy-3-methylglutaric acid, mucic acid, gluconic acid, gallic acid, mevalonic acid, pantoic acid, orsellinic acid, gentisic acid, quinic acid, and salts thereof. Examples of salts include sodium salts, potassium salts, calcium salts, and ammonium salts. Component (C) is preferably a polycarboxylic acid having a hydroxy group or a salt thereof, more preferably citric acid, malic acid, or a salt thereof, and even more preferably citric acid or a salt thereof. The polycarboxylic acid having a hydroxy group may have 1 to 4 hydroxy groups. The carbon number of the polycarboxylic acid having a hydroxy group may be, for example, 3 to 10. Furthermore, component (C), such as a polycarboxylic acid having a hydroxy group or a salt thereof, may be a hydrate.

[0040] When the soil conditioner of the present invention contains component (C), from the viewpoint of improving soil aggregation and / or water resistance of the aggregates, the amount of component (C) per 100 parts by mass of component (A) is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 1 part by mass or more, even more preferably 5 parts by mass or more, and preferably 10,000 parts by mass or less, more preferably 1,000 parts by mass or less, even more preferably 100 parts by mass or less. When the soil conditioner of the present invention contains components (B) and (C), from the same viewpoint, it is preferable to contain component (C) in the above range per 100 parts by mass of component (A).

[0041] When component (C) is used, it is preferable to use component (B) and component (C) in combination with component (A) from the viewpoint of improving the water resistance of the aggregates.

[0042] The soil modifier of the present invention can be applied to various soils, but is suitable for agricultural soil, particularly for field soil. That is, the soil modifier of the present invention is preferably for agricultural use, more preferably for field use.

[0043] The soil conditioner of the present invention may contain, as other optional components, for example, (1) Fertilizer ingredients, (2) Mineral powders or clay components such as zeolite, vermiculite, bentonite, soft silica (silica clay), perlite, peat moss, bark compost, or other soil improvement components; (3) Polymeric substances such as polyethyleneimine, polyvinyl alcohol, and polyacrylic acid, (4) signal molecules such as chitooligosaccharides, chitinous compounds, flavonoids, e.g., isoflavones, and rutin; (5) Fungi such as arbuscular mycorrhizal fungus, (6) Bacteria such as Bacillus, Pseudomonas, Azospirillum, Paenibacillus, Burkholderia, Serratia, Enterobacter, Brevibacterium, Curtobacterium, and legume symbiotic rhizobia; (7) Soyasaponin It may contain the following:

[0044] Among the above components, examples of arbuscular mycorrhizal fungi (5) include fungi belonging to the genera Gigaspora and Glomus, and an example of a fungus belonging to the Glomus genus is Glomus intraradices.

[0045] Among the above components, examples of the Bacillus bacteria in (6) include Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus subtilis, and Bacillus thuringiensis. Examples of the Pseudomonas bacteria include Pseudomonas putida and Pseudomonas fluorescens. Examples of bacteria of the genus Azospirillum include Azospirillum brasilense, Azospirillum lipoferum, Azospirillum halopraeferans, and Azospirillum amazonense. Examples of bacteria of the genus Paenibacillus include Paenibacillus polymyxa and Paenibacillus macerans. Examples of bacteria of the genus Burkholderia include Burkholderia gladioli. Examples of bacteria of the genus Seratia include Serratia marcescens. Examples of bacteria of the genus Enterobacter include Enterobacter cloacae, and examples of bacteria of the genus Brevibacterium include Brevibacterium iodinum and Brevibacterium brevis.An example of a Curtobacterium bacterium is Curtobacterium flaccumfaciens. Examples of legume symbiotic root nodule bacteria include bacteria belonging to the Rhizobium, Bradyrhizobium, or Azorhizobium genera. Examples of Bradyrhizobium bacteria include Bradyrhizobium diazoefficiens, Bradyrhizobium japonicum, Bradyrhizobium elkanii, and Ensifer fredii.

[0046] Among the above components, examples of soyasaponin (7) include those described in

[0028] of WO 2018 / 159393.

[0047] The soil conditioner of the present invention can contain 1% by mass or more and 50% by mass or less of the fertilizer component (1). The soil conditioner of the present invention can contain 1% by mass or more and 50% by mass or less of (2) mineral powder, clay component, or other soil improving component, or (3) polymeric substance. The soil conditioner of the present invention can regulate the signal molecule (4) at 2.5 × 10 -13 Mass% or more 2.5×10 -11 It may contain up to % by mass. The soil conditioner of the present invention contains the fungus (5) and / or the bacterium (6) in an amount of 10 per 1 g of the lignocellulosic biomass of the present invention. 2 cfu (colony forming units) or more than 10 7 In the case of fungi, colony forming units refers to the number of spores. The soil conditioner of the present invention can contain soyasaponin (7), for example, in the amount described in

[0040] of WO 2018 / 159393.

[0048] By adding the soil conditioner of the present invention to soil, useful microorganisms present in the soil, such as arbuscular mycorrhizal fungus, Bacillus bacteria and Pseudomonas bacteria, Azospirillum bacteria, Paenibacillus bacteria, Burkholderia bacteria, Serratia bacteria, Enterobacter bacteria, Brevibacterium bacteria, Curtobacterium bacteria, etc. It is expected that the activity of plant growth-promoting bacteria, and legume symbiotic rhizobia and the amount of bacteria attached to plants can be improved. Similarly, the soil conditioner of the present invention contains arbuscular mycorrhizal fungi, Bacillus bacteria, Pseudomonas bacteria, Azospirillum bacteria, Paenibacillus bacteria, Burkholderia bacteria, Serratia bacteria, Enterobacter bacteria, Brevibacterium bacteria, Curtobacterium bacteria, and other plant growth-promoting bacteria, or legume symbiotic rhizobia. It is expected that the activity and amount of adhesion to plants can be improved.

[0049] The soil conditioner of the present invention may contain a surfactant from the viewpoint of increasing the adhesion and penetration amount of the lignocellulosic biomass of the present invention at the site of action. Examples of the surfactant include one or more surfactants selected from nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Nonionic surfactants are preferred as the surfactant. When the soil conditioner of the present invention contains a surfactant, it preferably contains at least 0.01 parts by mass of surfactant per 100 parts by mass of the lignocellulosic biomass of the present invention, more preferably at least 0.1 parts by mass, even more preferably at least 1 part by mass, and preferably at most 100 parts by mass, more preferably at most 80 parts by mass, even more preferably at most 50 parts by mass.

[0050] The soil conditioner of the present invention may contain a water-soluble polymer (excluding component (B)) from the viewpoint of soil aggregation. Here, "water-soluble" in relation to a water-soluble polymer means that 1 g or more of the polymer dissolves in 100 g of water at 20°C. Natural, semi-synthetic, and synthetic polymers can all be used as the water-soluble polymer, with polysaccharide-based water-soluble polymers being preferred. Specific examples of polysaccharide-based water-soluble polymers include guar gum, xanthan gum, starch, tara gum, roasted bean gum, carrageenan, and derivatives thereof. When the soil conditioner of the present invention contains a water-soluble polymer, the water-soluble polymer is preferably contained in an amount of 1 part by mass or more, more preferably 10 parts by mass or more, even more preferably 50 parts by mass or more, and preferably 1,900 parts by mass or less, more preferably 600 parts by mass or less, and even more preferably 300 parts by mass or less, per 100 parts by mass of the lignocellulosic biomass of the present invention.

[0051] In addition to these, for example, the soil conditioner of the present invention can contain fertilizer components, etc. Specifically, fertilizer components available under trade names such as Hyponica (Kyowa Co., Ltd.) and Hyponex can be contained in an amount of 1 part by mass to 1,900 parts by mass per 100 parts by mass of the lignocellulosic biomass of the present invention.

[0052] The soil conditioner of the present invention is usually in the form of particles containing the lignocellulosic biomass of the present invention, but it can also be in the form of a molded product of the lignocellulosic biomass of the present invention, a composite product of the lignocellulosic biomass of the present invention and another product, etc.

[0053] <Method for manufacturing soil conditioner> The present invention provides a method for producing the soil conditioner of the present invention, which includes a step of hydrophilizing lignocellulosic biomass. The preferred embodiment of the raw plant biomass used in the method for producing the soil conditioner of the present invention is the same as that of the soil conditioner of the present invention. Furthermore, the matters described regarding the soil conditioner of the present invention can be appropriately applied to the method for producing the soil conditioner of the present invention.

[0054] In the method for producing a soil conditioner of the present invention, the lignin content of the lignocellulosic biomass (hereinafter sometimes referred to as raw lignocellulosic biomass) before hydrophilization treatment is preferably more than 60 mass % and not more than 80 mass %. Furthermore, the water contact angle of the raw material lignocellulosic biomass may be 110° or less.

[0055] The hydrophilization treatment is preferably an alkali treatment, a hot water treatment, an acid treatment, or a combination thereof, more preferably an alkali treatment, a hot water treatment, or a combination thereof, and even more preferably a combination of an alkali treatment and a hot water treatment (hereinafter sometimes referred to as an alkaline hot water treatment). The hydrophilization treatment may include a neutralization treatment, a drying treatment, etc., as necessary.

[0056] The hydrophilization treatment is preferably carried out in a medium containing water.

[0057] The hydrophilization treatment step preferably provides the lignocellulosic biomass of the present invention having a contact angle with water of, for example, 95° or less, further less than 70°, further 60° or less, further 55° or less, and further 50° or less.

[0058] Furthermore, the lignocellulose-based biomass after the hydrophilization treatment preferably has a lignin content of more than 60 mass % and not more than 80 mass %.

[0059] The alkali treatment will now be described. The alkaline treatment is carried out by contacting the raw lignocellulosic biomass with an alkaline medium at a predetermined temperature for a certain period of time. The alkaline medium preferably contains water. Specific examples include aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, aqueous lithium hydroxide solution, aqueous calcium hydroxide solution, aqueous magnesium hydroxide solution, aqueous sodium carbonate solution, aqueous potassium carbonate solution, aqueous ammonia, and aqueous tetramethylammonium hydroxide solution. The pH of the alkaline medium is preferably 10 or more and 14 or less. The temperature of the alkaline medium is preferably 10°C or more and 50°C or less. The contact time with the alkaline medium is preferably 0.05 hours or more and 7 days or less. An example of the alkali treatment is as follows. 100 parts by mass of raw lignocellulosic biomass is mixed with 100 to 2,000 parts by mass of an alkaline medium of any concentration, preferably an alkaline medium selected from aqueous sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, potassium carbonate, ammonia water, and tetramethylammonium hydroxide, to prepare a slurry. The slurry is then left to stand or stirred at 10 to 50°C, for example, at room temperature, for 0.05 hours to 7 days, to perform an alkali treatment. After the alkali treatment, it is preferable to carry out neutralization. Neutralization is carried out by adding a neutralizing agent, for example, hydrochloric acid or sulfuric acid at an arbitrary concentration, so that the pH of the slurry containing lignocellulosic biomass after the treatment is near neutral, for example, pH 5.5 or higher, further 6.0 or higher, and 8.0 or lower, further 7.0 or lower. After the alkali treatment, preferably after neutralization, drying can also be carried out.

[0060] The hot water treatment will now be described. The hot water treatment is carried out by contacting the raw lignocellulosic biomass with hot water for a certain period of time. The temperature of the hot water is preferably 80° C. or higher and 200° C. or lower. The contact time with hot water is preferably 0.05 hours or higher and 36 hours or lower. An example of the hot water treatment is as follows. A slurry is prepared by mixing 100 parts by mass of raw lignocellulosic biomass with hot water, e.g., 200 to 2,000 parts by mass of heated ion-exchanged water. For example, the treatment temperature can be selected from 80°C to 200°C, and the treatment time can be selected from 0.05 to 36 hours. Under these conditions, the slurry is left to stand or stirred for hot water treatment. Drying can also be performed after the hot water treatment.

[0061] The acid treatment will now be described. The acidic medium is contacted with the raw lignocellulosic biomass at a predetermined temperature for a certain period of time. The acidic medium preferably contains water. Specific examples include aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, peracetic acid, sulfurous acid, nitrous acid, oxalic acid, carbonic acid, boric acid, and hypochlorous acid. The pH of the acidic medium is preferably 1 or more and 5 or less. The temperature of the acidic medium is preferably 25°C or more and 200°C or less. The contact time with the acidic medium is preferably 0.05 hours or more and 7 days or less. An example of the acid treatment is as follows. A slurry is prepared by mixing 100 parts by mass of raw lignocellulosic biomass with 200 to 2,000 parts by mass of an acidic medium of any desired concentration, preferably an acid selected from hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, peracetic acid, sulfurous acid, nitrous acid, oxalic acid, carbonic acid, boric acid, and hypochlorous acid, and water. For example, the treatment temperature can be selected from 80°C to 200°C, and the treatment time can be selected from 0.05 to 36 hours. Under these conditions, the slurry is left to stand or stirred for acid treatment. After the acid treatment, it is preferable to carry out neutralization. Neutralization is carried out by adding a neutralizing agent, for example, an aqueous solution of sodium hydroxide at an arbitrary concentration, so that the pH of the slurry containing lignocellulosic biomass after the treatment is near neutral, for example, pH 5.5 or higher, further 6.0 or higher, and 8.0 or lower, further 7.0 or lower. After the acid treatment, preferably after neutralization, drying can also be carried out.

[0062] The alkaline hot water treatment will now be described. In the alkaline hot water treatment, the alkaline treatment is carried out in a high-temperature alkaline medium containing water. Specific examples of the alkaline medium are the same as those in the alkaline treatment. The pH of the alkaline medium used in the alkaline hot water treatment is preferably 9.0 or higher, more preferably 10.0 or higher, and preferably 14.0 or lower, more preferably 13.5 or lower. The temperature of the alkaline medium used in the alkaline hot water treatment is preferably 10°C or higher, more preferably 50°C or higher, and preferably 180°C or lower, more preferably 150°C or lower. The contact time of the alkaline medium used in the alkaline hot water treatment is preferably 0.05 hours or higher, more preferably 0.5 hours or higher, and preferably 36 hours or lower, more preferably 24 hours or lower. An example of the alkaline hot water treatment is as follows. A slurry is prepared by mixing 100 parts by mass of raw lignocellulosic biomass with an alkaline medium of any desired concentration, preferably 100 to 2,000 parts by mass of an alkaline medium selected from aqueous sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, potassium carbonate, ammonia water, and tetramethylammonium hydroxide. For example, the treatment temperature can be selected from 10°C to 180°C, and the treatment time can be selected from 0.05 to 36 hours. Under these conditions, the slurry is left to stand or stirred while undergoing alkaline hot water treatment. After the alkaline hot water treatment, it is preferable to carry out neutralization in the same manner as the alkaline treatment. After the alkaline hot water treatment, preferably after neutralization, drying can also be carried out.

[0063] In the present invention, when the hydrophilization treatment is carried out in a medium containing water, it is preferable to dry the treated product after the hydrophilization treatment, preferably after neutralization. Drying can be carried out, for example, at 50°C or higher and 200°C or lower. Specifically, drying can be carried out in a reduced pressure dryer at a predetermined temperature, for example, 50°C, until the moisture content reaches 10 parts by mass or less.

[0064] The obtained lignocellulose biomass having a lignin content of more than 60% by mass and not more than 80% by mass can be used as the soil conditioner of the present invention either as is or after being processed into an appropriate shape and size.

[0065] The water contact angle of the hydrophilically treated lignocellulose biomass may be, for example, 95° or less, further less than 70°, further 60° or less, further 55° or less, further 50° or less, and 0° or more, further 5° or more, further 10° or more, or further 15° or more.

[0066] An example of the production method of the present invention will be given below. The raw lignocellulosic biomass and water are placed in a treatment vessel to a solids content of preferably 5% to 50% by mass. The raw lignocellulosic biomass may be crushed in advance to an average particle size of preferably 0.1 μm to 10 mm. An alkaline aqueous solution containing an alkaline agent such as sodium hydroxide is preferably used as the water. The pH of the mixture is preferably within the above range. The contents are treated preferably at 25°C to 150°C, preferably for 0.1 to 24 hours, to obtain a liquid mixture containing the lignocellulosic biomass of the present invention. An autoclave can be used for treatment. If necessary, the pH of the mixture is adjusted to near neutral, preferably 5.5 to 8.0, using an acidifying agent. The mixture is then dried, preferably at 40°C to 120°C, to obtain the solid lignocellulosic biomass of the present invention that serves as the soil conditioner of the present invention. The obtained lignocellulosic biomass can also be optionally mixed with component (B) and optionally component (C) to produce the soil conditioner of the present invention.

[0067] <Soil improvement method> The soil reforming method of the present invention is a method of reforming soil in which lignocellulosic biomass having a lignin content of more than 60 mass% and not more than 80 mass% in component (A) is mixed with soil. The matters described for the soil reforming agent of the present invention can be appropriately applied to the soil reforming method of the present invention. Specific examples and preferred embodiments of component (A) are also the same. The soil reforming method of the present invention can be carried out using the soil reforming agent of the present invention.

[0068] The soil targeted by the present invention is preferably soil in cultivated land for growing plants and crops. The soil targeted by the present invention is preferably field soil.

[0069] In the present invention, the addition of component (A) to the soil can be carried out by mixing component (A) or the soil conditioner of the present invention with the soil, spraying component (A) or the soil conditioner of the present invention on the soil, or a combination of these.

[0070] A specific method for adding component (A) or the soil modifier of the present invention to soil in a farm field includes using a sprayer in combination with a tiller or the like and tilling the soil while spraying component (A) or the soil modifier of the present invention.

[0071] In the present invention, the (A) component is added in an amount of preferably 0.0001 parts by weight or more, more preferably 0.005 parts by weight or more, even more preferably 0.01 parts by weight or more, and preferably 10 parts by weight or less, more preferably 5 parts by weight or less, even more preferably 2.5 parts by weight or less, even more preferably 2.0 parts by weight or less, even more preferably 1.0 parts by weight or less, and even more preferably 0.5 parts by weight or less per 100 parts by weight of the soil in which the plants are grown. That is, in the present invention, the (A) component is added in an amount of preferably 0.0001 parts by weight or more, more preferably 0.01 parts by weight or more, even more preferably 0.05 parts by weight or more, and preferably 10 parts by weight or less, more preferably 5 parts by weight or less, even more preferably 2.5 parts by weight or less, even more preferably 2.0 parts by weight or less, even more preferably 1.0 parts by weight or less, and even more preferably 0.5 parts by weight or less per 100 parts by weight of the soil in which the plants are grown. When using the soil modifier of the present invention, it is preferable to use the (A) component in an amount within this range.

[0072] When component (A) is added to soil by, for example, spraying in the soil according to the soil reforming method of the present invention, the amount of the component (A) is 1000 ml of soil. 2 ) Component (A) is preferably added in an amount of 0.2 kg or more, more preferably 10 kg or more, even more preferably 20 kg or more, and preferably 20,000 kg or less, more preferably 10,000 kg or less, even more preferably 5,000 kg or less, even more preferably 4,000 kg or less, even more preferably 2,000 kg or less, and even more preferably 1,000 kg or less. When using the soil conditioner of the present invention, it is preferable to use it so that the amount of component (A) is within this range.

[0073] The soil reforming method of the present invention can be applied to, for example, soil when converting paddy fields to upland fields, soil after being used as upland fields, or soil in non-cultivated land. The soil reforming method of the present invention can also be applied to, for example, crushed soil such as soil after cultivation, or to soil that was non-cultivated land when converting non-cultivated land into cultivated land.

[0074] In relation to the above-described embodiments, the present invention further discloses the following soil modifier, method for producing the soil modifier, and method for modifying soil. The matters described in the soil modifier, method for producing the soil modifier, and method for modifying soil of the present invention can be mutually applied as appropriate to these aspects.

[0075] <1> (A) A soil conditioner containing lignocellulosic biomass having a lignin content of more than 60% by mass and not more than 80% by mass (hereinafter referred to as component (A)).

[0076] <2> The component (A) has a lignin content of more than 60% by mass, preferably 63% by mass or more, and 80% by mass or less, preferably 77% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less. <1> The soil conditioner according to claim 1.

[0077] <3> The component (A) has a contact angle with water of 110° or less, further 100° or less, further 95° or less, further less than 70°, further 60° or less, further 55° or less, further 50° or less, and 0° or more, further 5° or more, further 10° or more, further 15° or more. <1> or <2> The soil conditioner according to claim 1.

[0078] <4> The component (A) is a plant biomass, preferably one or more selected from herbaceous biomass and woody biomass, more preferably herbaceous biomass. <1> ~ <3> The soil conditioner according to any one of the above.

[0079] <5> The herbaceous biomass is one or more species selected from the group consisting of plants of the Poaceae, Malvaceae and Leguminosae families, and non-woody parts of plants of the Palmaceae family. <4> The soil conditioner according to claim 1.

[0080] <6> The grass family plant is one or more species selected from sugarcane, sorghum, switchgrass, elephantgrass, corn stover, corn cob, rice straw, wheat straw, barley, Miscanthus, turf, Johnsongrass, Erianthus, and Napier grass; the mallow family plant is one or more species selected from kenaf and cotton; the legume family plant is alfalfa; and the non-woody part of the palm family plant is one or more species selected from palm oil shells and palm oil empty fruit bunches. <5> The soil conditioner according to claim 1.

[0081] <7> The component (A) is a seed shell of one or more plant seeds selected from peach seed shells, prune seed shells, plum seed shells, peanut seed shells, walnut seed shells, and hard shells of palm trees. <1> ~ <4> The soil conditioner according to any one of the above.

[0082] <8> The woody biomass is one or more types of woody biomass selected from coniferous trees and broad-leaved trees, and the woody biomass may be processed into wood chips or wood pulp before use. <4> The soil conditioner according to claim 1.

[0083] <9> The component (A) is biomass from a palm plant and is one or more biomass selected from palm oil shells and coconut coir dust. <1> ~ <4> The soil conditioner according to any one of the above.

[0084] <10> The component (A) is obtained by subjecting the plant biomass to one or more hydrophilization treatments selected from hot water treatment, alkali treatment, and acid treatment. <4> ~ <9> The soil conditioner according to any one of the above.

[0085] <11> The component (A) is solid. <1> ~ <10> The soil conditioner according to any one of the above.

[0086] <12> The component (A) has an average particle size of preferably 1,000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less, even more preferably 150 μm or less, even more preferably 100 μm or less, and preferably 0.1 μm or more, more preferably 1.0 μm or more, even more preferably 10 μm or more. <1> ~ <11> The soil conditioner according to any one of the above.

[0087] <13> The soil conditioner has a water contact angle of 110° or less, further 100° or less, further 95° or less, further less than 70°, further 60° or less, further 55° or less, further 50° or less, and 0° or more, further 5° or more, further 10° or more, further 15° or more. <1> ~ <12> The soil conditioner according to any one of the above.

[0088] <14> The soil conditioner is in a solid state. <1> ~ <13> The soil conditioner according to any one of the above.

[0089] <15> The soil conditioner has an average particle size of preferably 1,000 μm or less, more preferably 500 μm or less, even more preferably 300 μm or less, even more preferably 150 μm or less, even more preferably 100 μm or less, and preferably 0.1 μm or more, more preferably 1.0 μm or more, even more preferably 10 μm or more. <1> ~ <14> The soil conditioner according to any one of the above.

[0090] <16> The above-mentioned composition contains the component (A) in an amount of preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 100% by mass or less. <1> ~ <15> The soil conditioner according to any one of the above.

[0091] <17> (B) a cellulose derivative (hereinafter referred to as component (B)), <1> ~ <16> The soil conditioner according to any one of the above.

[0092] <18> The component (B) is water-soluble cellulose. <17> The soil conditioner according to claim 1.

[0093] <19> The component (B) is a cellulose ether. <17> or <18> The soil conditioner according to claim 1.

[0094] <20> The component (B) is at least one selected from (B1) carboxymethyl cellulose or a salt thereof. <17> ~ <19> The soil conditioner according to any one of the above.

[0095] <21> The average degree of substitution of component (B) is 0.5 or more and 1.5 or less. <19> or <20> The soil conditioner according to claim 1.

[0096] <22> The component (B) has a viscosity of a 1% by mass aqueous solution at 20°C of 5 mPa·s or more and 20,000 mPa·s or less, and further 15,000 mPa·s or less. <17> ~ <21> The soil conditioner according to any one of the above.

[0097] <23> The composition contains, per 100 parts by mass of the component (A), preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 1 part by mass or more of the component (B), and preferably 10,000 parts by mass or less, more preferably 1,000 parts by mass or less, even more preferably 100 parts by mass or less of the component (B). <17> ~ <22> The soil conditioner according to any one of the above.

[0098] <24> (C) a hydroxy acid or a salt thereof (hereinafter referred to as component (C)), <1> ~ <23> The soil conditioner according to any one of the above.

[0099] <25> The component (C) is a polycarboxylic acid having a hydroxy group or a salt thereof, preferably citric acid, malic acid or a salt thereof, more preferably citric acid or a salt thereof. <24> The soil conditioner according to claim 1.

[0100] <26> The number of carbon atoms of the polycarboxylic acid having a hydroxy group is 3 or more and 10 or less. <25> The soil conditioner according to claim 1.

[0101] <27> The composition contains, per 100 parts by mass of the component (A), preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 1 part by mass or more, even more preferably 5 parts by mass or more of the component (C), and preferably 10,000 parts by mass or less, more preferably 1,000 parts by mass or less, even more preferably 100 parts by mass or less. <24> ~ <26> The soil conditioner according to any one of the above.

[0102] <28> (A) A method for producing a soil conditioner containing lignocellulosic biomass having a lignin content of more than 60% by mass and not more than 80% by mass, the method comprising a step of hydrophilizing the lignocellulosic biomass.

[0103] <29> The hydrophilization treatment is an alkali treatment, a hot water treatment, an acid treatment, or a combination thereof. <28> A method for producing the soil conditioner described in claim 1.

[0104] <30> The pH of the alkaline medium used in the alkaline treatment is preferably 10 to 14, the temperature of the alkaline medium is preferably 10 to 50°C, and the contact time between the alkaline medium and the lignocellulosic biomass is preferably 0.05 hours to 7 days. <29> A method for producing the soil conditioner described in claim 1.

[0105] <31> The temperature of the hot water used in the hot water treatment is preferably 80°C or higher and 200°C or lower, and the contact time between the hot water and the lignocellulosic biomass is preferably 0.05 hours or higher and 36 hours or lower. <29> or <30> A method for producing the soil conditioner described in claim 1.

[0106] <32> The pH of the acidic medium used in the acid treatment is preferably 1 or more and 5 or less, the temperature of the acidic medium is preferably 25°C or more and 200°C or less, and the contact time between the acidic medium and the lignocellulosic biomass is preferably 0.05 hours or more and 7 days or less. <29> ~ <31> A method for producing the soil modifier according to any one of the above.

[0107] <33> The hydrophilization treatment is an alkaline hot water treatment, and the pH of the alkaline medium used in the alkaline hot water treatment is preferably 9.0 or more, more preferably 10.0 or more, and preferably 14.0 or less, more preferably 13.5 or less; the temperature of the alkaline medium is preferably 10°C or more, more preferably 50°C or more, and preferably 180°C or less, more preferably 150°C or less; and the contact time between the alkaline medium and the lignocellulosic biomass is preferably 0.05 hours or more, more preferably 0.5 hours or more, and preferably 36 hours or less, more preferably 24 hours or less. <29> ~ <32> A method for producing the soil modifier according to any one of the above.

[0108] <34> A method for improving soil, comprising mixing (A) lignocellulosic biomass having a lignin content of more than 60% by mass and not more than 80% by mass (hereinafter referred to as component (A)) with soil.

[0109] <35> The target soil is cultivated soil for growing plants and crops. <34> The method for improving soil according to claim 1.

[0110] <36> The target soil is field soil. <34> The method for improving soil according to claim 1.

[0111] <37> In the soil <1> ~ <27> and then mixing the soil with the soil modifier described in any one of the above, and then mixing the component (A) with the soil. <34> ~ <36> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve, a gel, a

[0112] <38> In the soil, component (A) or <1> ~ <27> spraying the soil conditioner according to any one of the above items, and then mixing the component (A) into the soil; <34> ~ <37> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve, a gel, a

[0113] <39> Component (A) or the above <1> ~ <27> 1. The soil is tilled while spraying the soil modifier according to any one of the above onto the soil. <34> ~ <38> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve, a gel, a

[0114] <40> The component (A) is added in an amount of preferably 0.0001 part by mass or more, more preferably 0.005 part by mass or more, even more preferably 0.01 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 2.5 parts by mass or less, still more preferably 2.0 parts by mass or less, still more preferably 1.0 part by mass or less, and still more preferably 0.5 parts by mass or less, per 100 parts by mass of soil for growing plants. <34> ~ <39> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve, a gel, a

[0115] <41> The component (A) is added in an amount of preferably 0.2 kg or more, more preferably 10 kg or more, even more preferably 20 kg or more, and preferably 20,000 kg or less, more preferably 10,000 kg or less, even more preferably 5,000 kg or less, still more preferably 4,000 kg or less, still more preferably 2,000 kg or less, and still more preferably 1,000 kg or less per 10 a of soil. <34> ~ <40> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve and a paste.

[0116] <42> The soil is the soil at the time of conversion from paddy field to field. <34> ~ <41> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve and a paste.

[0117] <43> The soil is soil after being used as a field. <34> ~ <41> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve and a paste.

[0118] <44> The soil is a non-cultivated soil. <34> ~ <41> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve and a paste.

[0119] <45> The soil is a crushed soil after tillage. <34> ~ <44> 2. The method for improving soil according to claim 1, wherein the soil is a mixture of a sieve and a paste.

[0120] Example <Production Example 1> The raw biomass, palm kernel shells (PKS) (Palm Kernel Shell, Japan Pulp and Paper Co., Ltd.), was pulverized for 5 minutes at a vibration frequency of 20 Hz and a total amplitude of 8 mm using a batch vibration mill "MB-1" (manufactured by Chuo Kakoki Co., Ltd., total container volume 3.5 L, medium: SUS304 rods with a diameter of 30 mm, a length of 218 mm, and a circular cross section, 13 rods) to obtain the soil conditioner, Product 1 of the present invention, in powder form. The average particle size of Product 1 of the present invention was 63.7 μm.

[0121] <Production Example 2> Palm kernel shells (PKS), the raw biomass (palm kernel shells, Japan Pulp and Paper Co., Ltd., the same as in Production Example 1), were coarsely pulverized using a roll breaker with a 2 mm milling roll gap. 200 g of the resulting coarsely pulverized PKS (dry mass) was placed in a glass beaker, and a 0.1% by mass aqueous sodium hydroxide solution was added to achieve a solids content of 20% by mass. The mixture was heated at 80°C for 2 hours in a water bath while stirring with a stirring rod to obtain a reaction product. The resulting slurry was vacuum filtered through a polyethylene filter cloth (Sankyo Wire Cloth Manufacturing Co., Ltd., 40 mesh), and the resulting solid was vacuum dried at 80°C. Then, 100 g of the dried product was ground for 5 minutes using a batch vibration mill "MB-1" (manufactured by Chuo Kakoki Co., Ltd., total container volume 3.5 L, medium: φ30 mm, length 218 mm, cross-sectional circular SUS304 rods, number of rods: 13) at a vibration frequency of 20 Hz and a total amplitude of 8 mm to obtain the soil conditioner Product 2 of the present invention in powder form. In this example, 400 parts by mass of 0.1% by mass sodium hydroxide aqueous solution and 0.4 parts by mass of NaOH were added to 100 parts by mass of the raw biomass PKS. The average particle size of Product 2 of the present invention was 65.05 μm. The treatment conditions shown in Table 1 indicate the amount added relative to 100 parts by mass of PKS.

[0122] <Contact angle measurement method> 0.2 g of dry soil conditioner 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 was dropped onto the resulting pellets, and the instantaneous contact angle was photographed at 25x magnification using a digital microscope (VHX-1000, manufactured by Keyence Corporation). The contact angle was calculated from the photographed image using the θ / 2 method. Measurements were performed three times, and the average value was calculated.

[0123] Table 1 shows the treatment conditions and lignin content of component (A) for the soil conditioner of the present invention and comparative examples used in the following examples and comparative examples. The lignin content of component (A) was determined by the Klason lignin method. That is, the total lignin content was calculated as the sum of the acid-insoluble lignin content and the acid-soluble lignin content according to TAPPI official analytical method T222om-83. Comparative product 1 was lignosulfonic acid calcium salt (Lignosuper D, manufactured by Kono New Materials Development Co., Ltd.) used as is.

[0124] [Table 1]

[0125] The ingredients in the table are as follows: CMC (1): Carboxymethylcellulose sodium, manufactured by Daicel Corporation, CMC2260 (degree of etherification: 0.8 to 1.0, viscosity of 1% by mass aqueous solution at 20°C: 4000 to 6000 mPa s) CMC (2): Carboxymethylcellulose sodium, manufactured by Daicel Corporation, CMC1390 (degree of etherification: 1.0 to 1.5, viscosity of 1% by mass aqueous solution at 20°C: 2500 to 4500 mPa s) HEC: Hydroxyethyl cellulose, manufactured by Daicel Miraize Co., Ltd., HEC Daicel SP900 (viscosity of 1% by weight aqueous solution at 25°C (catalog value): 4000 to 5500 mPa s) C-HEC: Hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether, manufactured by Kao Corporation, Poise C-150L (molecular weight: 1,500,000) HPMC: Hydroxypropyl methylcellulose, manufactured by Shin-Etsu Chemical Co., Ltd., Metrose 65SH-4000 (viscosity of a 2% by weight aqueous solution at 20°C (catalog value): 4000 mPa s) Sodium citrate: Trisodium citrate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Citric acid: Fujifilm Wako Pure Chemical Industries, Ltd. Sodium malate: DL-disodium malate n-hydrate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0126] <Example 1 and Comparative Example 1> 300 g of Arakida soil (particle size 2-8 mm) was placed in a Tupperware container, followed by 60 g of water. Then, 0.1 parts by weight of a soil conditioner selected from Table 1 per 100 parts by weight of soil was added. The mixture was stirred for 2 minutes and then dried at 80°C for 30 minutes. The contact angle on the aggregate surface was then measured. A single aggregate with a particle size of 5 mm was selected, and 5 μL of water was dropped onto the aggregate surface. The instantaneous contact angle was measured using a digital microscope (VHX-1000, Keyence Corporation) at 25x magnification. The contact angle was calculated from the image using the θ / 2 method. Five measurements were performed, and the average value was calculated. The results are shown in Table 2. This evaluation is an index of soil reaggregation prevention; a larger contact angle indicates a higher hydrophobicity. High soil hydrophobicity is considered desirable from the perspective of soil pulverization during tillage.

[0127] [Table 2]

[0128] <Example 2 and Comparative Example 2> A soil conditioner selected from Table 1 was uniformly spread over a 5m x 1.5m area of ​​soil at the dosage shown in Table 3 (kg per 10a of soil). The soil was then tilled using a large cultivator (Iseki & Co., Ltd., NTA-253, speed: 0.3 km / h, cultivator rotation speed: 250 rpm, number of tillage passes: 1). The soil was then collected from three random locations to a depth of 0-5cm, totaling 900cc. The collected soil was pooled and dried at 80°C for 24 hours. The soil was then measured using 2mm, 8mm, and 16mm metal sieves. The masses of particles with particle sizes of 2mm or less, 2mm to 8mm, 8mm to 16mm, and over 16mm were measured, and the respective proportions were calculated to obtain the particle size distribution. The results are shown in Table 3. This evaluation is an index of the soil's crushability (ease of crushing). The fewer soil clods with particle sizes greater than 16mm, the better the crushability.

[0129] [Table 3]

[0130] <Example 3 and Comparative Example 3> 50 g of soil was placed in a stainless steel pan (20 cm diameter, 7 cm height), 11.5 g of water was added, and the soil conditioner selected from Table 1 was added in the amount shown in Table 4 (parts by mass per 100 parts by mass of soil). The mixture was then mixed at 30 rpm for 5 minutes and 50 rpm for 2 minutes using a mixer (As One Corporation, PAN TYPE GRANULATOR PZ-01R). After mixing, images were taken and the particle size distribution was calculated using image analysis software ImageJ (developed by the National Institutes of Health, USA). This evaluation is an index of soil aggregation; the fewer particles below 2 mm in diameter and the more particles over 2 mm in diameter, the more appropriate the aggregates.

[0131] [Table 4]

[0132] <Example 4 and Comparative Example 4> 20 g of soil was placed in a 100 cc cup, and the soil conditioner listed in Table 1 was added in the amount listed in Table 5 (parts by weight per 100 parts by weight of soil). 2.5 g of water was then added and the mixture was stirred with a spatula to form aggregates. Aggregates approximately 3-5 mm in diameter were selected, and one of them was placed in a 35 mm diameter dish and shaken by hand 30 times to form spherical aggregates. The formed aggregates were gently placed in room temperature water and left to stand. The time until disintegration was measured and water resistance was evaluated. Measurements were repeated eight times, and the average value was calculated. The maximum measurement time was 600 seconds. If the aggregates did not disintegrate after 600 seconds, they were marked "over 600" in the table. This rating is an indicator of the water resistance of the aggregates; the longer the time, the better the water resistance.

[0133] [Table 5]

[0134] As with Inventive Product 2, when Inventive Products 1 to 11 were used, the aggregate surface contact angle (Example 1) was larger and the particle size distribution (Examples 2 and 3) was more favorable than when no soil modifier was used or when Comparative Product 1 was used. Therefore, Inventive Products 1 to 11 are soil modifiers that are advantageous for soil crushability and soil aggregation.

Claims

[Claim 1] A method for producing a soil conditioner containing (A) lignocellulosic biomass having a lignin content of more than 60% by mass and not more than 80% by mass and (B) a cellulose derivative (hereinafter referred to as component (B)), the method comprising the steps of: subjecting the lignocellulosic biomass to a hydrophilic treatment; and mixing the obtained lignocellulosic biomass with component (B), wherein the hydrophilic treatment is alkaline hot water treatment.

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