JP7238195B1 - soil conditioner - Google Patents

Abstract

An object of the present invention is to provide a soil improvement agent containing a lignin-based compound as an active ingredient and capable of efficiently improving the amount of microorganisms and the amount of inorganic components in soil. SOLUTION: The present invention has a phenolic hydroxyl group content of 0.1 to 5.0% by weight, a methoxyl group content of 1.0 to 15.0% by weight, and a sulfur atom content derived from a sulfone group of 2.0% or more. an improved soil composition comprising a soil conditioner and soil; a method of preparing improved soil comprising adding a soil conditioner to soil; using an improved soil composition To provide a plant production method for producing a plant. [Selection figure] None

Description

The present invention relates to soil conditioners.

Soil properties are important in industries that use soil, including agriculture. Among them, soil rich in microorganisms and inorganic components has merits in the cultivation of crops using it, such as suppression of crop diseases, suppression of continuous crop failure, realization of organic agriculture, and the like.

As a soil improver, for example, in Patent Document 1, an aldehyde yield by alkali nitrobenzene oxidation is 5% by mass or more, a weight average molecular weight is 300 or more and 100,000 or less, and a contact angle to water is 15° or more. It is described that a soil conditioner containing a lignin decomposition product such as soda lignin as an active ingredient reduces soil hardness. In addition, Patent Document 2 describes that a soil conditioner containing a lignin derivative extracted from a lignin-containing material with a solvent containing a predetermined organic solvent promotes aggregates while maintaining the soil microbial flora structure. ing.

JP 2017-190448 A JP 2021-80367 A

However, Patent Documents 1 and 2 do not describe anything about the effect of increasing the growth of microorganisms in the soil and the increase of inorganic components. An object of the present invention is to provide a soil improvement agent that contains a lignin-based compound as an active ingredient and is capable of efficiently improving the amount of microorganisms and the amount of inorganic components in soil.

The present invention provides the following [1] to [9].
[1] Lignin sulfonic acid having a phenolic hydroxyl group content of 0.1 to 5.0% by weight, a methoxyl group content of 1.0 to 15.0% by weight, and a sulfonic group-derived sulfur atom content of 2.0% or more A soil conditioner, comprising:
[2] of ligninsulfonic acid,
a sulfur atom content of 1.0% by weight or more;
sodium atom content is 0.3% by weight or more, and reducing sugar content is 0.1% by weight or more,
The agent according to [1], which satisfies at least one of the above.
[3] The agent according to [1] or [2], wherein the ligninsulfonic acid has a carboxyl group content of 0.1 to 4.5 mmol/g.
[4] The agent according to any one of [1] to [3], wherein the ligninsulfonic acid has a weight average molecular weight (RI) of 3,000 or more.
[5] The agent according to any one of [1] to [4], wherein the ligninsulfonic acid has a substituent derived from (poly)alkylene oxide.
[6] The agent according to any one of [1] to [5], wherein the soil is agricultural soil.
[7] An improved soil composition comprising the agent according to any one of [1] to [6] and soil.
[8] A method for preparing improved soil, comprising adding the agent according to any one of [1] to [6] to soil.
[9] A method for producing plants, comprising producing plants using the improved soil composition of [7].

According to the present invention, a soil improver applicable to various soils is provided. The soil improver of the present invention can proliferate microorganisms in soil and increase inorganic components. Therefore, by using it in the agricultural field, it is possible to lead to an increase in the yield of agricultural products, and to realize and popularize organic farming.

[1. Lignin sulfonic acid component]
The soil conditioner of the present invention contains a ligninsulfonic acid component.

[Lignin sulfonic acid]
The ligninsulfonic acid component is a component that mainly contains ligninsulfonic acid and is usually derived from sulfite digestion of pulp. Lignin sulfonic acid is a compound having a skeleton in which a sulfone group is introduced by cleavage of the side chain α-position carbon of the hydroxyphenylpropane structure of lignin.

Ligninsulfonic acid can take the form of salts. Salts include, for example, monovalent metal salts, divalent metal salts, ammonium salts and organic ammonium salts, among which calcium salts, magnesium salts, sodium salts and calcium/sodium mixed salts are preferred.

[Substituent]
Ligninsulfonic acids contain substituents other than sulfone groups. The substituent may be a lignin-derived substituent, or may be a substituent introduced by modification treatment and not possessed by the original lignin. Examples of substituents include hydroxyl groups (phenolic hydroxyl groups, alcoholic hydroxyl groups), methoxyl groups, carboxyl groups, sulfomethyl groups, aminomethyl groups, and (poly)alkylene oxide groups. Among these, it is more preferable to contain a phenolic hydroxyl group, a methoxyl group, a sulfone group and a (poly)alkylene oxide group within a predetermined range. This can promote plant growth.

-Phenolic hydroxyl group-
A phenolic hydroxyl group is generally a hydroxyl group directly attached to an aromatic ring such as benzene. The phenolic hydroxyl group content is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, still more preferably 1.0% by weight or more, and further preferably 1.1% by weight or more, based on the total amount of the ligninsulfonic acid component. more preferred. The upper limit is preferably 5.0% by weight or less, more preferably 4.0% by weight or less, even more preferably 3.0% by weight or less, and even more preferably 2.7% by weight or less. Therefore, the phenolic hydroxyl group content of ligninsulfonic acid is preferably 0.1 to 5.0% by weight, more preferably 0.5 to 4.0% by weight, further preferably 1.0 to 3.0% by weight, 1.1 to 2.7 wt% is even more preferred. The phenolic hydroxyl group content can be quantified from the absorbance measured by a spectrophotometer.

-Methoxyl group-
A methoxyl group is a group of the formula: —OCH ₃ . The methoxyl group content is preferably 1.0% by weight or more, more preferably 3.0% by weight or more, still more preferably 5.0% by weight or more, and even more preferably 6.0% by weight or more, based on the total amount of the ligninsulfonic acid component. preferable. The upper limit is preferably 15.0% by weight or less, more preferably 13.0% by weight or less, even more preferably 12.0% by weight or less, and even more preferably 11.5% by weight or less. Therefore, the methoxyl group content is preferably 1.0 to 15.0% by weight, more preferably 3.0 to 13.0% by weight, even more preferably 5.0 to 12.0% by weight, and 6.0 to 11.0% by weight. 0.5% by weight is even more preferred. The methoxyl group content of lignin can be measured by the Viebock and Schwappach method.

- Sulfone group -
A sulfone group (sulfonic acid group, sulfo group) is generally a group represented by the formula: —SO ₃ ⁻ M ⁺ (M is a counter cation (eg, H, Na, Ca, Mg, NH ₄ )). be. The sulfone group content can be indicated by the content of sulfur atoms derived from sulfone groups (sulfone group S content). The sulfone group S content is preferably 2.0% or more, more preferably 3.0% or more, still more preferably 4.0% or more, and even more preferably 4.5% or more, relative to the total amount of the ligninsulfonic acid component. Although the upper limit is not particularly limited, it is preferably 10.0% or less, more preferably 9.0% or less, even more preferably 8.0% or less, and even more preferably 7.0% or less. Therefore, the sulfone group S content is preferably 2.0 to 10.0%, more preferably 3.0 to 9.0%, even more preferably 4.0 to 8.0%, and 4.5 to 7.0%. % is even more preferred. The sulfone group S content can be determined by subtracting the inorganic sulfur atom content from the total sulfur atom content in the lignosulfonic acid.

-Carboxyl group-
A carboxyl group is generally a group of the formula -COOM ⁺ where M is a countercation (eg, H, Na, Ca, Mg, NH ₄ ). It is preferable that the carboxyl group content is within a predetermined range. That is, it is preferably 0.1 mmol/g or more, more preferably 0.3 mmol/g or more, and even more preferably 0.5 mmol/g or more per weight of the ligninsulfonic acid component. The upper limit is preferably 4.5 mmol/g or less, more preferably 4.0 mmol/g or less, even more preferably 3.0 mmol/g or less. Therefore, the carboxyl group content is preferably 0.1 to 4.5 mmol/g, more preferably 0.3 to 4.0 mmol/g, even more preferably 0.5 to 3.0 mmol/g. The carboxyl group content can be determined by neutralization titration.

- (poly) alkylene glycol group -
A (poly)alkylene glycol group is a substituent derived from a (poly)alkylene oxide. The average added mole number of alkylene oxide units constituting the polyalkylene glycol is usually 1 or more, 5 or more, or 10 or more, preferably 15 or more, more preferably 20 or more, still more preferably 25 or more, or 30 or more, and even more preferably is 35 or more. This can result in good dispersibility. Above all, it is preferable to have a water surface spreadability of 50 or more, 60 or more, 70 or more, 80 or more, or 90 or more. The upper limit is usually 300 or less or 200 or less, preferably 190 or less, more preferably 180 or less, and even more preferably 170 or less. As a result, deterioration of dispersion retention can be suppressed. Therefore, the average number of added moles is generally 10-200, preferably 15-190, more preferably 20-180, still more preferably 25-170. On the other hand, it is preferably 25-300, more preferably 30-200, even more preferably 35-150. The number of carbon atoms in the polyalkylene glycol is not particularly limited, and is usually 2-18, preferably 2-4, more preferably 2-3. Examples of alkylene oxide units include ethylene oxide units, propylene oxide units, and butylene oxide units, with ethylene oxide units or propylene oxide units being preferred. Lignin sulfonic acids containing (poly) alkylene oxide groups include, for example, lignin derivatives described in WO2021/066166.

[Inorganic component]
The ligninsulfonic acid component may further include inorganic components. Examples of inorganic components include inorganic salts such as sulfur, calcium, sodium, magnesium, nitrogen, phosphorus, potassium, and iron, ammonia, oxides of these inorganic salts (e.g., sulfur oxide, magnesium oxide, calcium oxide), and water. oxides (eg, magnesium hydroxide, calcium hydroxide, sodium hydroxide, ammonium hydroxide), carbonates (eg, calcium carbonate, sodium carbonate), nitric acid. The aspect of the inorganic component is not particularly limited, and may be a counter cation of ligninsulfonic acid or a free inorganic component (for example, an inorganic component added during the production of ligninsulfonic acid). Among these, it preferably contains at least one of sulfur, calcium, sodium, magnesium, nitrogen, phosphorus, and potassium.

-Sulfur ion-
The sulfur ion content can be expressed as the sulfur atom content (total S content) contained in lignosulfonic acid. The total S content is preferably 1.0% by weight or more, 2.0% by weight or more, or 3.0% by weight or more, more preferably 4.0% by weight or more, and even more preferably 5.0% by weight or more. The upper limit is not particularly limited, but is preferably 10.0% by weight or less, more preferably 9.0% by weight or less, and even more preferably 8.0% by weight or less. Therefore, the S content is preferably 1.0 to 10.0% by weight or more, 2.0 to 10.0% by weight or more, or 3.0 to 10.0% by weight, and 4.0 to 9.0% by weight. More preferably, 5.0 to 8.0% by weight is even more preferable. Total S content can be quantified by ICP emission spectroscopy.

-Sulfur Oxide-
The lignosulfonic acid may contain sulfur oxides. Examples of sulfur oxide include sulfur dioxide (SO ₂ ), sulfur trioxide (SO ₃ ) and sulfur tetroxide (SO ₄ ), with SO ₃ and SO ₄ being preferred. _{The SO3} content is usually 0% or more, preferably 0.001% by weight or more, more preferably 0.005% by _weight or more, more preferably 0.01 % by weight or more or 0.04% by weight or more is more preferable. The upper limit is preferably 3.0% by weight or less, more preferably 2.0% by weight or less, even more preferably 1.0% by weight or less, and even more preferably 0.5% by weight or less. Therefore, the SO ₃ content is usually 0 to 3.0% by weight, preferably 0.001 to 3.0% by weight, more preferably 0.005 to 2.0% by weight, and 0.01 to 1.0% by weight. 0% by weight is more preferred, and 0.04-0.5% by weight is even more preferred. The _SO4 content is preferably 0.2% by weight or more, more preferably 0.4% by weight or more, and even more preferably 0.5% by weight or more, 2.0% or more, or 3.0% or more. The upper limit is preferably 10% by weight or less, more preferably 9.5% by weight or less, and even more preferably 9.0% by weight or less. Therefore, the SO ₄ content is preferably 0.2-10% by weight, more preferably 0.4-9.5% by weight, still more preferably 0.5-9.0% by weight, and 2.0-9.0% by weight. % by weight or 3.0 to 9.0% by weight is even better. The sulfur oxide content can be quantified by ion chromatography.

-Proportion of sulfone group S to total S content-
The ratio of the sulfur atom content derived from the sulfone group to the sulfur atom content contained in the lignosulfonic acid is preferably 0.5 or more, more preferably 0.6 or more. The upper limit is generally 0.9 or less, preferably 0.8 or less, but is not particularly limited.

-Ratio of _SO3 to _SO4-
The ratio of SO ₃ content to SO ₄ content contained in lignosulfonic acid is usually 0 or more, preferably 0.01 or more, more preferably 0.02 or more. The upper limit is preferably 0.05 or less, more preferably less than 0.03.

－Sodium ions, Calcium ions, Magnesium ions－
Each ion content of Na ⁺ , Ca ²⁺ , Mg ²⁺ can be expressed as their atomic content. The sodium atom content (Na content) is preferably 0.3% by weight or more, more preferably 0.5% by weight or more, and even more preferably 1.0% by weight or more. The upper limit is not particularly limited, but is preferably 10.0% by weight or less, more preferably 9.0% by weight or less, and more preferably 8.0% by weight or less. Therefore, the Na content is preferably 0.3 to 10.0% by weight, more preferably 0.5 to 9.0% by weight, even more preferably 1.0 to 8.0% by weight. The calcium atom content (Ca content) is preferably 0.001% by weight or more, more preferably 0.01% by weight or more, and even more preferably 0.03% by weight or more. The upper limit is preferably 3.0% by weight or less, more preferably 1.0% by weight or less. Therefore, the Ca content is preferably 0.001 to 3.0 wt%, more preferably 0.01 to 1.0 wt%, even more preferably 0.03 to 1.0 wt%. Magnesium atom content (Mg content) is preferably 0.05% by weight or more, more preferably 0.07% by weight or more, 0.1% by weight or more, 0.5% by weight or more, 1.0% by weight or more, 2 0 wt% or more, 3.0 wt% or more, or 3.2 wt% or more is more preferable. The upper limit is preferably 10.0% by weight or less, more preferably 8.0% by weight or less, and even more preferably 5.0% by weight or less. Therefore, the Mg content is preferably 0.05 to 10.0 wt%, more preferably 0.07 to 8.0 wt%, 0.1 to 5.0 wt%, 0.5 to 5.0 wt% , 1.0 to 5.0% by weight, 2.0 to 5.0% by weight, 3.0 to 5.0% by weight or 3.2 to 5.0% by weight. Na content, Ca content and Mg content can be quantified by an inductively coupled plasma (ICP) method.

-Reducing sugars-
Preferably, the ligninsulfonic acid component further comprises reducing sugars. As used herein, a reducing saccharide refers to a saccharide having reducing properties, that is, having the property of generating an aldehyde group or a ketone group in a basic solution. Reducing sugars include, for example, all monosaccharides; disaccharides such as maltose, lactose, arabinose, invert sugar of sucrose; polysaccharides. Reducing sugars typically include cellulose, hemicellulose, and degradation products thereof. Decomposition products of cellulose and hemicellulose include, for example, monosaccharides such as rhamnose, galactose, arabinose, xylose, glucose, mannose and fructose; oligosaccharides such as xylo-oligosaccharides and cello-oligosaccharides; and modified products thereof. A modified substance is a chemically modified substance such as oxidation or sulfonation. Compounds in which two (two types) or more are bonded can be mentioned.

The reducing saccharide content is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and further preferably 0.5% by weight or more, or 2.0% by weight or more. The upper limit is preferably 35% by weight or less, more preferably 30% by weight or less, and even more preferably 25% by weight or less. Therefore, the reducing sugar content is preferably 0.1 to 35% by weight, more preferably 0.3 to 30% by weight, even more preferably 0.5 to 25% by weight, or even more preferably 2.0 to 25% by weight. The content of reducing sugars can be calculated as a glucose conversion value by the Somogyi-Schaffer method.

[Other ingredients]
The ligninsulfonic acid component may contain components other than the above. Examples include organic components and ash. Examples of organic components include low-molecular-weight organic substances (eg, organic acids having 5 or less carbon atoms) such as formic acid, acetic acid, propionic acid, valeric acid, pyruvic acid, succinic acid, and lactic acid. The low-molecular-weight organic substance may be contained singly or in combination.

The amount of low-molecular-weight organic substances is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and even more preferably 1% by weight or more. The upper limit is preferably 25% by weight or less, more preferably 20% by weight or less, and even more preferably 15% by weight or less. Therefore, the amount of low-molecular-weight organic substances is preferably 0.01 to 25% by weight, more preferably 0.1 to 20% by weight, and even more preferably 1 to 15% by weight. The amount of low-molecular-weight organic substances can be measured, for example, as the amount of acetic acid fraction in fractional determination of organic acids by silica gel column chromatography with ether extraction.

[Weight average molecular weight (RI)]
The weight average molecular weight (RI) of the ligninsulfonic acid component is preferably 3,000 or more, more preferably 3,500 or more, even more preferably 3,700 or more, and even more preferably 4,000 or more. Although the upper limit is not particularly limited, it is preferably 50,000 or less, more preferably 40,000 or less, and even more preferably 35,000 or less. Therefore, the weight average molecular weight (RI) is preferably 3,000 to 50,000, more preferably 3,500 to 50,000, even more preferably 3,700 to 40,000, and 4,000 to 35,000. Even more preferred. As used herein, the weight average molecular weight (RI) is the weight average molecular weight determined by GPC using a differential refractive index detector (RI).

[Weight average molecular weight (UV)]
The weight average molecular weight (UV) of the ligninsulfonic acid component is preferably 4,000 or more, more preferably 5,000 or more, and even more preferably 6,000 or more. Although the upper limit is not particularly limited, it is preferably 70,000 or less, even more preferably 60,000 or less, and even more preferably 50,000 or less. Therefore, the weight average molecular weight (UV) is preferably 4,000 to 70,000, more preferably 5,000 to 60,000, even more preferably 6,000 to 50,000. As used herein, weight average molecular weight (UV) is the weight average molecular weight determined by GPC using an ultraviolet-visible absorbance detector.

-Ratio of weight average molecular weight RI/UV-
The ratio of the weight average molecular weight (RI) to the weight average molecular weight (UV) is preferably 0.95 or less, more preferably 0.93 or less. The lower limit is usually 0.4 or more, preferably 0.5 or more, and is not particularly limited.

As the ligninsulfonic acid component, for example, from Sunligphon (scheduled to be sold by Nippon Paper Industries Co., Ltd. after July 2022), those having the above substituents and inorganic component amounts may be selected and used.

[1.2 Method for producing ligninsulfonic acid component]
The method for producing the ligninsulfonic acid component is not particularly limited, but it can be produced, for example, by a method of subjecting a lignocellulose raw material to a sulfurous acid treatment, or a method of decomposing and sulfonating lignin. By adjusting the production conditions, it is possible to adjust the type and content of the substituents that the ligninsulfonic acid component has, the type and content of each component such as inorganic components and reducing sugars.

-material-
The lignocellulose raw material as an example of the raw material is not particularly limited as long as it contains lignocellulose in the structure. Examples thereof include pulp materials such as wood and non-wood. Examples of wood include coniferous wood such as radiata pine, Ezo spruce, Japanese red pine, cedar and Japanese cypress, and broadleaf wood such as white birch and beech. The age of the wood and the part from which it is harvested do not matter. Therefore, lumber collected from trees of different ages or lumber collected from different parts of trees may be used in combination. Non-wood materials include, for example, bamboo, kenaf, reeds, and rice. The lignocellulose raw materials may be used singly or in combination of two or more.

Other examples of lignin as a raw material include naturally derived lignin and artificially produced lignin (eg, dehydrogenated polymer of hydroxycinnamic alcohol analog).

－Sulfite treatment－
The sulfite treatment can be carried out by bringing at least one of sulfite and sulfite into contact with the lignocellulose raw material. Conditions for the sulfite treatment are not particularly limited as long as the conditions are such that a sulfo group can be introduced into the α-carbon atom of the side chain of lignin contained in the lignocellulose raw material.

The sulfite treatment is preferably carried out by a sulfite digestion method. Thereby, lignin in the lignocellulose raw material can be sulfonated more quantitatively. The sulfite cooking method is a method of reacting a lignocellulose raw material at a high temperature in a solution of at least one of sulfite and sulfite (eg, aqueous solution: cooking liquor). This method is industrially established and practiced as a method for producing sulfite pulp, and is therefore advantageous in terms of economy and ease of implementation.

Examples of sulfite salts include magnesium salts, calcium salts, sodium salts, and ammonium salts when sulfite digestion is performed.

The sulfite (SO ₂ ) concentration in the solution of at least one of sulfite and sulfite is not particularly limited, but the ratio of the mass (g) of SO ₂ to 100 mL of the reaction chemical solution is preferably 1 g/100 mL or more, and sulfite digestion is performed. In some cases, 2 g/100 mL or more is more preferable. The upper limit is preferably 20 g/100 mL or less, and more preferably 15 g/100 mL or less when sulfite digestion is performed. The SO ₂ concentration is preferably 1 g/100 mL to 20 g/100 mL, and more preferably 2 g/100 mL to 15 g/100 mL when sulfite digestion is performed.

Although the pH value of the sulfite treatment is not particularly limited, it is usually 10 or less. When sulfite digestion is carried out, it is preferably carried out under an acidic condition, with a pH of 5 or less being more preferable, and a pH of 3 or less being even more preferable. Thereby, the lignin derivative (for example, lignin sulfonic acid) can be efficiently extracted, and higher quality pulp can be obtained. The lower limit of the pH value is preferably 0.1 or more, and more preferably 0.5 or more when sulfite digestion is performed. The pH value for the sulfite treatment is preferably 0.1 to 10, more preferably 0.5 to 5, and still more preferably 0.5 to 3 for sulfite digestion.

The temperature of the sulfite treatment is not particularly limited, but is preferably 170°C or less, and more preferably 150°C or less when sulfite digestion is performed. The lower limit is preferably 70°C or higher, and more preferably 100°C or higher when sulfite digestion is performed. The temperature condition for sulfite treatment is preferably 70 to 170°C, and more preferably 100 to 150°C when sulfite digestion is performed.
The treatment time of the sulfite treatment is not particularly limited, and is preferably 0.5 to 24 hours, more preferably 1.0 to 12 hours, depending on various conditions of the sulfite treatment.

In the sulfite treatment, it is preferable to add a compound that supplies counter cations to the lignosulfonic acid. The pH value in the sulfite treatment can be kept constant by adding compounds that supply countercations. Compounds that provide countercations include, for example, MgO, Mg(OH) ₂ , CaO, Ca(OH) ₂ , _CaCO3 , _NH3 , _NH4OH , NaOH, _{NaHCO3 , Na2CO3} . The counter cation is preferably magnesium ion or sodium ion.

In the sulfite treatment, when a solution of at least one of sulfite and sulfite is used, in addition to SO ₂ , the solution may optionally contain the above counter cations (salts), a digestion penetrant (e.g., anthraquinone sulfonate, Cyclic ketone compounds such as anthraquinone and tetrahydroanthraquinone) may be included.

The equipment used for the sulfite treatment is not limited, and for example, commonly known dissolving pulp manufacturing equipment can be used.

Separation of the intermediate product from the solution of at least one of sulfurous acid and sulfite may be carried out according to a conventional method. The separation method includes, for example, a separation method (for example, filtration) of sulfite digestion effluent after sulfite digestion.

Lignin sulfonic acid obtained by sulfite treatment (for example, obtained as a filtrate or a filtration residue after filtering the insoluble matter of the sulfite solution, preferably as a filtrate) can be used as it is or as an active ingredient after concentrating as necessary. It may also be used as a certain lignosulfonic acid component. On the other hand, other processing may be performed as necessary. This makes it possible to increase the purity or introduce other substituents that the raw material does not originally have. Other treatments include, for example, alkali treatments, oxidation treatments, dialysis treatments, ultrafiltration treatments, modification treatments, and combinations thereof.

(alkali treatment)
Alkaline treatment may be carried out by subjecting the target sample to alkaline conditions. Placing under alkaline conditions generally means placing under an aqueous solution having a pH value of 8 or higher, preferably 9 or higher. The upper limit of the pH value is usually 14.

In alkali treatment, an alkaline substance is usually brought into contact with the sulfite treated product. Examples of alkaline substances include, but are not limited to, calcium hydroxide, magnesium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonia. Among them, sodium hydroxide and calcium hydroxide are preferred. Alkaline substances may be used singly or in combination of two or more.

As a method of contacting an alkaline substance with a sulfite-treated product, a method of preparing a dispersion or solution (e.g., aqueous dispersion, aqueous solution) of a sulfite-treated product and adding an alkaline substance to the dispersion or solution; A method of adding a solution or dispersion (eg, water dispersion, aqueous solution) of an alkaline substance to the treated material is exemplified.

Although the temperature of the alkali treatment is not particularly limited, it is preferably 40° C. or higher, more preferably 60° C. or higher. The upper limit is preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 110°C or lower.

The amount of alkaline substance in alkali treatment is relative to the solid content of the sulfite-treated product, or when preparing an aqueous solution or dispersion in which the alkali-treated extract is dispersed in an aqueous solvent (e.g., water), the aqueous solution or dispersion is 0.5 to 40% by mass, more preferably 1.0 to 30% by mass, based on the mass of

The alkali treatment time is not particularly limited, but is preferably 0.1 hour or longer, more preferably 0.5 hour or longer. The upper limit is preferably 10 hours or less, more preferably 6 hours or less.

Prior to the alkali treatment, if necessary, the sulfite-treated product may be dissolved, dispersed, and adjusted for concentration (preparation of a solution or dispersion in an aqueous solvent such as water). Dispersion treatment can be carried out by passage through a disc refiner, addition to a mixer or disperser, kneader treatment, or the like. Adjustment of the concentration can be performed, for example, using an aqueous solvent such as water.

(Oxidation treatment)
Oxidation treatment can be performed on a treated product obtained after sulfite treatment (for example, filtrate after filtration) or on a treated product after alkali treatment. The oxidation treatment may be carried out using an appropriate oxidizing agent, and when the oxidizing agent is a gas, it can be carried out by passing the gas through the filtrate. When the oxidizing agent is a liquid, it can be carried out by adding the liquid to the filtration residue or filtrate. The oxidant is preferably air, oxygen, hydrogen peroxide, ozone, or combinations thereof. The oxidation treatment is preferably performed under alkaline conditions (alkali oxidation treatment). The treatment pH of the alkaline oxidation treatment is usually 8 or higher, preferably 10 or higher, more preferably 12 or higher. The temperature of the oxidation treatment is usually 20 to 200°C, preferably 50 to 180°C. The oxidation treatment time is generally preferably 0.1 hour or longer, more preferably 0.5 hour or longer. The upper limit is preferably 5 hours or less, more preferably 3 hours or less.

(Dialysis treatment or UF treatment)
A dialysis treatment can be performed on a treated material obtained after the sulfite treatment (for example, filtrate after filtration). Dialysis membranes include, for example, cellulose-based membranes such as cellulose acetate, synthetic polymer-based membranes such as ethylene vinyl alcohol, polyacrylonitrile, polymethyl methacrylate, polysulfone, and polyethersulfone, and the molecular weight fraction is usually 5,5. 000 to 100,000, preferably 7,000 to 80,000, more preferably 10,000 to 50,000.

An ultrafiltration process (UF process) can be used instead of the dialysis process. A known UF membrane can be used as the UF membrane. Examples include hollow fiber membranes, spiral membranes, tubular membranes, and flat membranes. A known material can be used for the UF membrane. Examples include cellulose acetate, aromatic polyamide, polyvinyl alcohol, polysulfone, polyvinylidene fluoride, polyethylene, polyacrylonitrile, and ceramics. Note that the UF membrane may be a commercially available product.

The cutoff molecular weight of the UF membrane is preferably from 5,000 to 30,000, more preferably from 10,000 to 25,000, even more preferably from 15,000 to 23,000. Using a UF membrane having a molecular weight cut off of 5,000 or more can prevent the separation speed of the treated liquid from becoming excessively slow. In addition, the use of a UF membrane having a molecular weight cutoff of 30,000 or less can prevent lignin from being separated from the treated liquid.

The concentration ratio by the UF treatment using the UF membrane can be arbitrarily set. That is, the UF process should be stopped when the outflow amount of the concentrated liquid reaches an arbitrary amount. Preferably, it is concentrated 2- to 6-fold. Concentrating 2 to 6 times means that the amount of stock solution (black liquor) becomes 1/2 to 1/6.

The temperature of the treatment liquid during UF treatment is not particularly limited. For example, the temperature is preferably 20 to 80°C, and more preferably 20 to 70°C considering the heat resistance of the UF membrane material. The pH value of the treatment solution during UF treatment is preferably 2-11. The solid content concentration (w/w) of black liquor during UF treatment is preferably 2 to 30%, more preferably 5 to 20%.

Modification treatments include, for example, hydrolysis, alkylation, alkoxylation, sulfonation, sulfonate esterification, sulfomethylation, aminomethylation, desulfonation, alkalinization, condensation reaction with (poly)alkylene oxide, and other chemical reactions. A method of denaturing and modifying ligninsulfonic acid by ultrafiltration to fractionate the molecular weight is exemplified. Among these, the chemical modification method is hydrolysis, alkoxylation, desulfonation and alkylation, condensation reaction with (poly)alkylene oxide (e.g., WO 2021/066166) 1 selected from Or two or more reactions are preferred.

[1.3 Soil improvement effect]
The lignosulfonic acid component has the effect of improving soil.

[soil]
The target soil may be natural soil, and may be sand, fine soil, or clay. Examples of sand include coarse sand, fine sand, and gravel. Examples of soil include black soil (e.g., volcanic ash soil), diluvial soil (e.g., red-yellow soil, brown forest soil, red forest soil, red soil, yellow soil, dark red soil, gray plateau soil, grai plateau soil), alluvial soils (eg, brown lowland soil, gray lowland soil, dune immature soil). The plasticity of the soil is not particularly limited, and examples thereof include heavy clay, clayey soil, clay loam, loam, sandy loam, sandy soil, gravel soil, and humus soil. Applications of soil include agriculture (e.g., paddy field soil, field soil, forest soil, grassland soil (e.g., grazing land, racetrack)), civil engineering, and green space (e.g., gardens, parks, schools, facilities, etc.). lawn grass and flower beds), and agricultural use is preferred, but not particularly limited.

Soil improvement includes, for example, increasing the amount of inorganic components (eg, phosphorus atoms, iron atoms, etc.) in the soil, microbial proliferation, dispersing agricultural chemicals, and promoting granulation.

[1.4 Optional Components]
A soil improvement agent may also contain components (optional components) other than a ligninsulfonic-acid component as needed. Optional components include, for example, soil improvement components other than ligninsulfonic acid components (e.g., sugars (e.g., glucose), inorganic components, polycarboxylic acids), excipients, coloring agents, preservatives, pH adjusters, stabilizers. , disintegrants, carriers, binders, pH adjusters, antifoaming agents, nonionic surfactants, cationic surfactants, amphoteric surfactants and other optional components (formulation aids).

Soil conditioners include, for example, inorganic components. Examples of inorganic components include inorganic salts such as essential elements nitrogen, phosphorus, and potassium, and trace elements sulfur, calcium, magnesium, iron, manganese, zinc, boron, molybdenum, chlorine, iodine, and cobalt, oxides thereof, Inorganic salts containing these are mentioned. Examples of inorganic salts include magnesium hydroxide, magnesium oxide, calcium carbonate (slaked lime), potassium nitrate, ammonium nitrate, ammonium chloride, sodium nitrate, potassium monohydrogen phosphate, sodium dihydrogen phosphate, potassium oxide, potassium chloride, potassium sulfate ( sulfur), ammonium sulfate (ammonium sulfate), magnesium sulfate, calcium sulfate, ferrous sulfate, ferric sulfate, manganese sulfate, zinc sulfate, copper sulfate, sodium sulfate, calcium chloride, magnesium chloride, boric acid, molybdenum trioxide, molybdenum sodium phosphate, potassium iodide, cobalt chloride, monobasic calcium phosphate, mixtures thereof (for example, perlite (a mixture of monocalcium phosphate and calcium sulfate)), and hydrates thereof.
As for the content of optional components, an appropriate amount may be selected for each optional component.

[1.5 dosage form, manufacturing method]
The dosage form of the soil improver includes, for example, powder, granules, granules, and liquid, and is not particularly limited. By being granular or granular, it can be easily spread. In addition, being liquid facilitates mixing with the functional component and stabilizes the slurry after mixing. The plant growth promoter may be formulated together with the functional ingredient, or may be formulated separately. A suitable method for producing the soil conditioner can be appropriately selected according to the dosage form.

[2. Improved soil composition]
The soil to which the above-described soil conditioner has been added can be used as an improved soil composition in various applications such as agriculture and civil engineering, and agriculture is preferred. This is expected to increase crop yields and realize and spread organic farming.

In the improved soil composition, the content of the soil conditioner of the present invention is usually 0.000001% by weight or more, preferably 0.00001% by weight or more, more preferably 0% by weight, based on the weight of the soil, as the amount of the ligninsulfonic acid component. .00005% by weight or more. Although the upper limit is not particularly limited, it is usually 10% by weight or less.

The improved soil composition may contain other components than the soil conditioner of the present invention and soil. Other components include soil conditioners other than the plant growth promoter of the present invention, artificial soil (for example, artificial soil such as rice husk charcoal, coconut fiber, vermiculite, perlite, peat moss, glass beads, rice husks; foamed phenolic resin, porous moldings such as rock wool; solidifying agents (eg, agar or gellan gum), combinations of two or more of these). Appropriate amounts may be selected for the contents of other components.

[3. Method for preparing improved soil composition]
The improved soil composition may be prepared by adding a soil conditioner to the soil. A stirring device may optionally be used during mixing. The soil conditioner and other components other than the soil may be added to the soil together with the soil conditioner, or may be added sequentially.

[4. Plant production method]
The improved soil composition can be used for plant production.

[plant]
Target plants include herbaceous plants and woody plants. Herbaceous plants include, for example, Brassicaceae, Leguminosae, Cucurbitaceae, Solanaceae, Capsicumaceae, Rosaceae, Malvaceae, Gramineae, Allium, Amaryllidaceae, Asteraceae, Amaranthaceae, Umbelliferae, Gingeraceae, Perilla plants of the family Araceae, Convolvulaceae, Dioscoreaceae, Lotus family, and the like. Specifically, for example, Japanese mustard spinach, Chinese cabbage, onion, green onion, garlic, scallion, chive, tsukena, bok choy, cabbage, cauliflower, broccoli, Brussels sprouts, asparagus, lettuce, salad greens, celery, spinach, chrysanthemum, parsley, mitsuba, Leaf vegetables such as parsley, udo, myoga, butterbur, perilla; fruit vegetables such as soybeans, edamame, broad beans, peas, cucumbers, eggplants, melons, corn, pumpkins, watermelons, tomatoes, green peppers, strawberries, okra, and green beans; carrots, turnips Root vegetables such as , Japanese radish, burdock, potato, taro, sweet potato, yam, ginger, and lotus root; rice (eg, paddy rice, upland rice), wheat (eg, wheat, barley); and flowers. Examples of woody plants include cedar (eg, cedar), cypress (eg, cypress), pinaceae (pine (eg, black pine), larch (eg, larch, pine), fir (eg, Todomatsu)), Eucalyptus (e.g., eucalyptus), Prunus (e.g., cherry, Japanese apricot, Prunus japonicum), Mango (e.g., mango), Acacia, Bayberry, Sawtooth (e.g., sawtooth oak), Grape, Apple Genus Rosa, Camellia (e.g. Tea), Jacaranda (e.g. Jacaranda), Alligator (e.g. Avocado), Pear (e.g. Pear), Sandalwood (e.g. Sandalwood) be done. Among these, herbaceous plants are preferred, and cruciferous and leguminous plants are more preferred.

The improved soil composition may be used during the entire growing period of the plant, or during a part thereof. Moreover, it may be used not only for breeding from seeds and seedlings, but also for tissue culture of cuttings, cuttings, and the like.

For plant production using the improved soil composition, plant cultivation conditions (e.g., temperature, light intensity, irrigation amount, humidity, carbon dioxide gas concentration, presence or absence of adjustment of these, seeding density, irrigation method, irrigation amount, cultivation facility / container (eg, presence or absence of planter, pot, vat, container, cell tray) is not particularly limited and can be selected as appropriate. Fertilizers may also be added to the improved soil composition. Fertilizers include, for example, inorganic components, silver ions, antioxidants, carbon sources, vitamins, amino acids, plant hormones, and other components that can serve as sources of nutrients for plants. The form of the additive is not particularly limited, and may be solid (eg, powder, granule) or liquid (eg, liquid fertilizer).

EXAMPLES The present invention will now be described with reference to examples. The following examples do not limit the invention.

Table 1 shows the compositions of the main samples used in the examples.

[Footnote to Table 1]
*1 “%” represents % by mass relative to the dry weight of the sample.

*2 Amount of phenolic hydroxyl groups By subtracting the absorption spectrum of a neutral solution containing the same concentration of lignin from the absorption spectrum of an alkaline solution containing a lignin sample, an ionization differential spectrum was obtained, and the phenolic hydroxyl groups (% ). In the formula, Δαmax [L / (g cm)] indicates the differential absorption coefficient (Junzo Nakano, “Chemistry of Lignin – Basics and Applications – Enlarged and Revised Edition”, Uni Publishing, May 25, 1990, page 541 ).
Phenolic hydroxyl group (%) = (17 × Δαmax) / 4100 × 100

*3 Carboxyl group content 60 ml of a 0.5% by mass aqueous dispersion of a sample was prepared, and 0.1 M hydrochloric acid aqueous solution was added to adjust the pH to 2.5. After that, a 0.05N sodium hydroxide aqueous solution was added dropwise, and the electrical conductivity was measured until the pH reached 11. Calculated from the amount of sodium hydroxide consumed (a) in the neutralization step of the weak acid, whose electrical conductivity changes slowly, using the following formula:
Carboxyl group amount [mmol/g sample] = a [ml] x 0.05/mass of sample

*4 Amount of reducing sugars The content of reducing sugars in the lignin fertilizer was calculated by converting the measured value measured by the Somogyi-Schaffer method into the amount of glucose.

* 5 Methoxyl (OCH ₃ ) group content The methoxyl group content of lignin is determined by the Viebock and Schwappach method for quantifying methoxyl groups (“Lignin Chemical Research Method”, pp. 336-340, 1994, published by Uni Publishing). It was measured.

*6 Total sulfur atom (S) content The S content was quantified by ICP emission spectrometry.

*7 Sulfur oxide (SO ₃ , SO ₄ ) content The SO ₃ content and SO ₄ content were each quantified by ion chromatography.

*8 Sulfur Atom (S) Content of Sulfone Group The S content of the sulfone group was determined by the following formula.
S content (% by mass) of sulfone group = S content (% by mass) - Inorganic S content (% by mass)
In the formula, % by mass is the ratio of the S content to the solid content of lignosulfonic acid.
The S content is a value measured by the method described above. The inorganic S content is the total amount of _SO3 content and _SO4 content obtained by the method described above.

*9 weight average molecular weight (RI)
It was measured by gel permeation chromatography (GPC) under the following conditions.
Measuring device; manufactured by Tosoh Column used; Shodex Column OH-pak SB-806HQ, SB-804HQ, SB-802.5HQ
Eluent; 0.05 mM sodium nitrate/acetonitrile 8/2 (v/v)
Reference material; Polyethylene glycol (manufactured by Tosoh Corporation or GL Science)
Detector: Differential refractometer (manufactured by Tosoh Corporation)
Calibration curve; polyethylene glycol standard

*10 weight average molecular weight (UV)
Except for using a UV detector (280 nm, manufactured by Tosoh Corporation) as a detector, the measurement was carried out under the same conditions as for the weight-average molecular weight by RI detection described above.

*11 Ca content, Na content, Mg content Each metal ion (Ca ²⁺ , Na ⁺ , Mg ²⁺ ) was quantified by an inductively coupled plasma (ICP) method, and the quantitative results were respectively Ca content, Na content and Mg content ( % by mass).

<Production Example 1: Production of Sample 1>
Wood (radiata pine) was treated with sulfite based on the sulfite cooking method to obtain an intermediate composition. In the sulfite treatment, a magnesium sulfite solution with an SO ₂ concentration of 4 g/100 mL was used at a temperature of 140° C., a pH of 2, and a treatment time of 3 hours. Next, the insoluble matter was filtered off, and the obtained filtrate was concentrated with a rotary evaporator until the solid content reached 50%, thereby obtaining an intermediate composition A. Sample 1, which is a solidified composition, was obtained by spray drying.

<Production Example 2: Production of Sample 2>
From the intermediate composition A obtained in Production Example 1, alkali reaction (addition rate of calcium hydroxide solution 9 wt.% (based on solid content), reaction temperature 90 ° C., reaction time 4 hours) and oxidation reaction (treatment with oxygen, oxygen pressure of 200 kPa, reaction time of 2 hours), and the pH was adjusted to 7.0. Sample 2, which is a solidified composition, was obtained by spray-drying this.

<Production Example 3: Production of Sample 3>
Wood (radiata pine) was treated with sulfite based on the sulfite cooking method to obtain an intermediate composition. In the sulfite treatment, a sodium sulfite solution with an SO ₂ concentration of 4 g/100 mL was used at a temperature of 140° C., a pH of 2, and a treatment time of 3 hours. Next, the insoluble matter was filtered off, and the resulting filtrate was adjusted to pH 5.0. This was subjected to ultrafiltration using a polysulfone-based ultrafiltration membrane with a molecular weight cut off of 20,000, and the concentrate was spray-dried to obtain Sample 3, which is a solidified composition.

<Test Example 1: Effect on microbial activity (Examples 1-3 and Comparative Examples 1-2)>
[Amount of carbon dioxide generated]
Volcanic ash soil (from Kitamoto, Saitama Prefecture) and red-yellow soil (from Takashigahara, Aichi Prefecture) were each mixed with each sample shown in Table 2 to prepare a soil sample. left undisturbed. After 30 days from preparation, the amount of carbon dioxide in the soil sample was measured using a carbon dioxide absorbent according to the following procedure. A soil sample and 8 mL of 0.1N NaOH were placed in a beaker and incubated for 24 hours, after which 1 mL of 50% barium chloride was added to precipitate carbon dioxide absorbed by NaOH in white. The remaining sodium hydroxide was titrated with 0.1N hydrochloric acid using phenolphthalein as an indicator.

In addition, 50 g of a soil sample of volcanic ash soil was filled in a reflux apparatus, and 0.3 L of culture solution (composition: 1.2% lignin solution) was refluxed for 7 days, and then the number of colonies in each of the reflux liquid and the refluxed soil was diluted. Plate method (medium: albumin agar medium (egg albumin 0.25 g/L, glucose 1.0 g/L, _{K2HPO4 0.5} g/L, _{MgSO4.7H2O 0.2} g/L, Fe( _SO4 ) ₃ 1% 1 mL, Agar 18.0 g/L, pH 6.8-7.0), culture period 26.5° C., 14 days) and measured by a conventional method (N=1: Table 3).

[Footnote to Table 2]
*1 Low-molecular-weight organic matter was measured using an anthrone coloring product aqueous solution (4 times the amount of dry soil).
Water soluble: leached with water four times the amount of dry soil. Acid soluble: leached with 0.5N-H ₂ SO ₄ water four times the amount of dry soil. 5 mL of sample (10 to 100 g as glucose) and 10 mL of anthrone reagent (0.2% anthrone 95% H ₂ SO ₄ solution) were added and allowed to cool. After cooling, colorimetric determination was performed with a standard (glucose) at 625 nm.
Organic acid: 40 mL of the aqueous solution was neutralized with 1N-NaOH and then concentrated to dryness under reduced pressure. 40 mL of the acid solution was continuously extracted with liquid ether for 48 hours. Fractional determination of organic acids was carried out by silica gel column chromatography. Fraction I indicates butyric acid, propionic acid, valeric acid, etc., II indicates acetic acid, III indicates formic acid, pyruvic acid, IV indicates lactic acid, succinic acid, etc. Table 2 shows the amount of fraction II as the amount of organic acid. It was shown to.
*2 The ash content was measured by incineration at 550°C in accordance with JIS P 8251:2003 "Paper, paperboard and pulp - Ash content test method -".
*3 Total CaO and MgO were measured by ICP and converted to oxides.
*4 SO ₂ was measured by ion chromatography.
*5 Carbon content C was diluted 6-fold with 1/10-1/15M monopotassium phosphate solution to make it weakly acidic, exposed to N2 gas to remove dissolved carbon dioxide, and measured by total organic carbon meter. It was measured.
*6 Dialyzed lignin is the dialyzed product of sample 2. Dialysis was performed using a dialysis membrane (BIOTECH CE TRIAL KIT, manufactured by Funakoshi Co., Ltd.) under the conditions for 3.5-5.0 kDa fractionation.
*7 Glucose used was D-(+)-Glucose manufactured by FUJIFILM Wako Pure Chemical Industries.
Reducing sugars and sulfur were quantified by the method shown in the footnote of Table 1.

The soil samples of Examples 1 to 3 (both volcanic ash soil and red-yellow soil) using samples containing ligninsulfonic acid generated more carbon dioxide than Comparative Examples 1 and 2 (Table 3), and lignin It was suggested that the addition of sulfonic acid improved the growth environment of microorganisms. In addition, in Example 1, the number of colonies in the refluxed liquid and the refluxed soil was increased compared to Comparative Example 1 in which no additives were added. was suggested (Table 3).

<Test Example 2: Effect on divalent iron content in paddy field soil (Examples 4 to 5 and Comparative Example 3)>
Add the sample shown in Table 4 to 7.2 g of air-dried fine soil of 2 mm or less (paddy field soil in Nagano Prefecture) in the amount shown in Table 4, collect 20 mL (± 5 g) into a syringe, collect 10 g of water and fill it. After watering (reproducing the state of the paddy field), incubation was continued for 35 days in a constant temperature room at 26.5°C. The ratio of air-dried fine soil and water was adjusted to (1:2). Samples on day 0, day 2, day 7, day 14, day 21, and day 35 from the start of incubation were extracted with 1M sodium acetate-hydrochloric acid buffer of pH 2.8, Colorimetric determination of ferric ions (FeII) by the orthophenanthroline method was performed. That is, the amount of bivalent iron ions was calculated using a calibration curve prepared by the following method (N=1: Table 5).
1. 0.0, 0.2, 0.4, 0.6, 0.8 mL of iron standard solution (50 μg/mL) was accurately pipetted into five 10 mL volumetric flasks, respectively.
2. After adding 0.4 mL of 6 mol/L hydrochloric acid, 0.25 mL of hydroxylammonium chloride solution (100 g/L) was added and shaken.
3. After adding 0.5 mL of phenanthroline solution (1 g/L) and 1 mL of ammonium acetate solution (500 g/L), deionized water was added to make exactly 10 mL.
4. The absorbance at 510 nm was measured using ion-exchanged water as a reference.

Examples 4 and 5 containing ligninsulfonic acid had a higher content of divalent iron ions than Comparative Example 3 containing no additive, and Example 5 exhibited a significantly higher value (Table 5).

<Test Example 3: Effect on phosphoric acid permeation amount (Examples 6 to 7 and Comparative Example 4)>
Air-dried soil (Pleistocene volcanic ash non-fertilizer soil, heavy clay soil, and Pleistocene red forest soil) was subjected to a 2 mm sieve, and the portion that passed through was used as sample soil (Table 6). 50 g of sample soil was weighed into a 500 mL beaker, 225 mL of the following P-containing aqueous solution was added, and after stirring well, the mixture was allowed to stand at room temperature for 24 hours. Water was added to this to obtain a paddy water sample of 500 mL in total while containing the soil. This was filtered through dry filter paper (Toyo Filter Paper No. 5A). A portion of the filtrate was transferred to an aluminum measuring dish and evaporated to dryness. The counts (CPM: Counter Per Minute) were measured with an M counter and compared with the standard P counts to calculate the total P value in the paddy water sample. Phosphate uptake was expressed as % of soil adsorbed ^P32 to total P added (N=1: Table 7). The ^P32 used is from The Radiochemical Centre, UK, orthophosphate solution (pH 2-3), radiochemically pure >99%.
[P-containing aqueous solution]
_{P2O5 550 mg} ( _NaH2PO4 )
50 mg N ( _NH4Cl )
K 50 mg (KCl)
0.0001% (=0.05 mg) and 0.001% (=0.5 mg) of the lignin sample were dissolved in the P-containing aqueous solution with respect to the soil.

In Examples 6 and 7 using ligninsulfonic acid, the amount of residual phosphoric acid in the paddy water was greater in each soil than in Comparative Example 4 (Table 7).

<Test Example 4: Calcium carbonate dispersion test (B type viscosity test) (Example 8, Comparative Examples 5 to 6)>
The effect of calcium carbonate, which is used as a bulking agent for pesticides, on dispersibility was evaluated.
37.56 g of water and each dispersant shown in Table 8 were added to 172.44 g of calcium carbonate (water content: 30%) and stirred to prepare a slurry. The slurry concentration of water and calcium carbonate was 57%, and the amount of dispersant added (solid content addition rate) was 0.05 or 0.1% based on the total amount of the slurry. Stirring was performed at 3000 rpm for 2 minutes with a homodisper. Using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.), the slurry after stirring was measured at 20° C., 60 rpm, No. 3 rotors or no. The B-type viscosity was measured after stirring under the conditions of 2 rotors and no guard (Table 8).

Example 8 using Sample 3 had a lower viscosity than Comparative Example 5 using only water. It has become clear that the dispersibility of the components of (1) can also be enhanced, and that the effect of forming aggregates and the like can be enhanced by improving familiarity with the soil.

<Test Example 5: Agglomeration action (Examples 9 to 13 and Comparative Examples 7 to 8)>
Take 50 to 100 g of each test soil (Table 9) in a petri dish (90 mm x 20 mm) or beaker (200 cc), apply the sample in the amount shown in Tables 9 and 10 (% by weight: relative to absolute dry soil), and stir well. 60% of the maximum amount of water was added and incubated at 30°C for 7 days. After incubation, air-dried for 5-7 days to obtain samples for aggregate analysis (N=3). Agglomerate analysis was performed by a conventional underwater sieving method. The analysis results were expressed by the degree of agglomeration of particles of 0.25 mm or less, and the agglomeration forming power was compared. The degree of agglomeration was calculated by the following formula.
Degree of aggregation (%) = {(secondary particles - primary particles) / absolute dry amount of test soil} x 100

The lignosulfonic acid component had a higher granule-aggregating effect than azmin, and tended to exhibit a high granule-aggregating effect depending on the amount added.

Claims (9)

ligninsulfonic acid having a phenolic hydroxyl group content of 0.1 to 5.0% by weight, a methoxyl group content of 1.0 to 15.0% by weight, and a sulfonic group-derived sulfur atom content of 2.0% or more, Soil conditioner. of lignosulfonic acid,
a sulfur atom content of 1.0% by weight or more;
sodium atom content is 0.3% by weight or more, and reducing sugar content is 0.1% by weight or more,
The agent according to claim 1, which satisfies at least one of The agent according to claim 1 or 2, wherein the lignosulfonic acid has a carboxyl group content of 0.1 to 4.5 mmol/g. The agent according to claim 1 or 2, wherein the weight average molecular weight (RI) of ligninsulfonic acid is 3,000 or more. The agent according to claim 1 or 2, wherein the ligninsulfonic acid has a substituent derived from (poly)alkylene oxide. The agent according to claim 1 or 2, wherein the soil is agricultural soil. An improved soil composition comprising the agent according to claim 1 or 2 and soil. A method for preparing improved soil, comprising adding the agent according to claim 1 or 2 to soil. A method for producing plants, comprising producing plants using the improved soil composition according to claim 7.