Soil conditioner

Abstract

The purpose of the present invention is to provide a soil-improving agent which contains a lignin-based compound as an active ingredient and which can effectively increase the amount of microorganisms or inorganic components in soil. The present invention provides: a soil conditioner comprising a lignosulfonic acid having a phenolic hydroxyl group content of 0.1-5.0 wt%, a methoxy group content of 1.0-15.0 wt%, and a sulfo group-derived sulfur atom content of 2.0% or more; a soil improvement composition comprising a soil conditioner and soil; the conditioning method for improving the soil comprises the step of adding a soil conditioner into the soil, and a method of producing a plant using the improved soil composition to produce a plant.

Description

Technical Field

[0001] The present invention relates to a soil conditioner. Background Art

[0002] The properties of soil are important in industries that use soil, such as agriculture. In particular, soil rich in microorganisms or inorganic components has advantages in suppressing crop diseases, preventing continuous cropping problems, and achieving organic agriculture in the cultivation of crops using the soil.

[0003] As a soil conditioner, for example, Patent Document 1 describes that a soil conditioner containing lignin decomposition products such as soda lignin as an effective ingredient reduces soil hardness, wherein the soda lignin has an aldehyde yield of 5% or more based on oxidation with alkaline nitrobenzene, a weight average molecular weight of 300 or more and 100,000 or less, and a contact angle with respect to water of 15° or more. In addition, Patent Document 2 describes that a soil conditioner containing a lignin derivative promotes aggregation while maintaining the bacterial community structure of the soil, wherein the lignin derivative is extracted from a lignin-containing material using a solvent containing a predetermined organic solvent.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-190448;

[0007] Patent document 2: Japanese Patent Application Publication No. 2021-80367. Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, there is no description of the effects on the proliferation of microorganisms and the increase of inorganic components in the soil in Patent Documents 1 and 2. The present invention aims to provide a soil improver that contains a lignin compound as an active ingredient and can effectively increase the amount of microorganisms or inorganic components in the soil.

[0010] Means for solving problems

[0011] The present invention provides the following [1] to [9].

[0012] [1] A soil conditioner comprising lignin sulfonic acid having a phenolic hydroxyl group content of 0.1 to 5.0% by weight, a methoxy group content of 1.0 to 15.0% by weight, and a sulfur atom content derived from a sulfonic group of 2.0% or more.

[0013] [2] The agent according to [1], which satisfies at least one of the following:

[0014] The sulfur atom content of the lignin sulfonic acid is 1.0 wt% or more;

[0015] The sodium atom content is 0.3% by weight or more; and

[0016] The reducing sugar content is 0.1% by weight or more.

[0017] [3] The agent according to [1] or [2], wherein the carboxyl group content of the lignin sulfonic acid is 0.1 to 4.5 mmol / g.

[0018] [4] The agent according to any one of [1] to [3], wherein the weight average molecular weight (RI) of the lignin sulfonic acid is 3,000 or more.

[0019] [5] The agent according to any one of [1] to [4], wherein the lignin sulfonic acid has a substituent derived from a (poly)alkylene oxide.

[0020] [6] The agent according to any one of [1] to [5], wherein the soil is agricultural soil.

[0021] [7] A soil biostimulant comprising lignin sulfonic acid having a phenolic hydroxyl group content of 0.1 to 5.0% by weight, a methoxy group content of 1.0 to 15.0% by weight, and a sulfur atom content derived from a sulfonic group of 2.0% or more.

[0022] [8] A soil improvement composition comprising the agent according to any one of [1] to [6] or the biostimulant according to [7] and soil.

[0023] [9] A method for improving soil, comprising adding the agent according to any one of [1] to [6] or the biostimulant according to [7] to the soil.

[0024]

[10] A method for producing plants, comprising producing plants using the soil improving composition according to [8].

[0025]

[11] Use of lignin sulfonic acid for producing a soil conditioner or a biostimulant, wherein the lignin sulfonic acid has a phenolic hydroxyl content of 0.1 to 5.0% by weight, a methoxy content of 1.0 to 15.0% by weight, and a sulfur atom content derived from a sulfonic group of 2.0% or more.

[0026] Effects of the Invention

[0027] According to the present invention, a soil conditioner applicable to various soils is provided. The soil conditioner of the present invention can proliferate microorganisms in the soil and increase inorganic components. Therefore, by using the soil conditioner in the agricultural field, it can promote the increase of crop yields and realize and popularize organic agriculture. DETAILED DESCRIPTION

[0028] [1. Lignin sulfonic acid component]

[0029] The soil conditioner of the present invention contains a lignin sulfonic acid component.

[0030] [Lignin sulfonic acid]

[0031] The lignin sulfonic acid component is a component mainly containing lignin sulfonic acid, and is generally derived from sulfite digestion of pulp. Lignin sulfonic acid is a compound having a skeleton in which a sulfonic group is introduced by cleavage of the carbon at the α position of the side chain of the hydroxyphenylpropane structure of lignin.

[0032] The lignin sulfonic acid may be in the form of a salt. Examples of the salt include monovalent metal salts, divalent metal salts, ammonium salts, and organic ammonium salts, and among these, calcium salts, magnesium salts, sodium salts, and calcium / sodium mixed salts are preferred.

[0033] [Substituent]

[0034] Lignin sulfonic acid contains substituents other than sulfo groups. The substituents may be substituents derived from lignin, or may be substituents introduced by modification treatment that are not originally present in lignin. Examples of substituents include hydroxyl groups (phenolic hydroxyl groups, alcoholic hydroxyl groups), methoxy groups, carboxyl groups, sulfomethyl groups, aminomethyl groups, and (poly)oxyalkylene groups. Among these, phenolic hydroxyl groups, methoxy groups, sulfo groups, and (poly)oxyalkylene groups are more preferably contained within a specified range. This can promote plant growth.

[0035] -phenolic hydroxyl group-

[0036] Phenolic hydroxyl groups are usually hydroxyl groups directly bonded to aromatic rings such as benzene. The phenolic hydroxyl content is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, further preferably 1.0% by weight or more, and further preferably 1.1% by weight or more relative to the total amount of lignin sulfonic acid components. The upper limit is preferably 5.0% by weight or less, more preferably 4.0% by weight or less, further preferably 3.0% by weight or less, and further preferably 2.7% by weight or less. Therefore, the phenolic hydroxyl content of lignin sulfonic 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, and further preferably 1.1 to 2.7% by weight. The phenolic hydroxyl content can be quantified by the absorbance measured using a spectrophotometer.

[0037] -Methoxy-

[0038] The methoxy group is represented by the formula -OCH 3The group represented by . The methoxy content is preferably 1.0 wt% or more, more preferably 3.0 wt% or more, further preferably 5.0 wt% or more, and further preferably 6.0 wt% or more relative to the total amount of lignin sulfonic acid components. The upper limit is preferably 15.0 wt% or less, more preferably 13.0 wt% or less, further preferably 12.0 wt% or less, and further preferably 11.5 wt% or less. Therefore, the methoxy content is preferably 1.0 to 15.0 wt%, more preferably 3.0 to 13.0 wt%, further preferably 5.0 to 12.0 wt%, and further preferably 6.0 to 11.5 wt%. The methoxy content of lignin can be measured by the Viebock and Schwappach method.

[0039] -sulfo-

[0040] Sulfonic acid group, sulfonic acid group is usually represented by the formula -SO 3 - M + (M is a counter cation (e.g. H, Na, Ca, Mg, NH 4 )) is a group represented by sulfonic group. The sulfonic group content can be represented by the sulfur atom content derived from the sulfonic group (sulfonic group S content). The sulfonic group S content is preferably 2.0% or more, more preferably 3.0% or more, further preferably 4.0% or more, and further preferably 4.5% or more relative to the total amount of lignin sulfonic acid components. There is no particular restriction on the upper limit, but it is preferably 10.0% or less, more preferably 9.0% or less, further preferably 8.0% or less, and further preferably 7.0% or less. Therefore, the sulfonic group S content is preferably 2.0-10.0%, more preferably 3.0-9.0%, further preferably 4.0-8.0%, and further preferably 4.5-7.0%. The sulfonic group S content can be obtained by deducting the inorganic sulfur atom content from the total sulfur atom content in the lignin sulfonic acid.

[0041] -carboxyl-

[0042] The carboxyl group is usually represented by the formula -COOM + (M is a counter cation (e.g. H, Na, Ca, Mg, NH 4 )) is a group represented by. The carboxyl content is preferably within a specified range. That is, per unit weight of lignin sulfonic acid component, it is preferably 0.1 mmol / g or more, more preferably 0.3 mmol / g or more, and further preferably 0.5 mmol / g or more. The upper limit is preferably 4.5 mmol / g or less, more preferably 4.0 mmol / g or less, and further preferably 3.0 mmol / g or less. Therefore, the carboxyl content is preferably 0.1 to 4.5 mmol / g, more preferably 0.3 to 4.0 mmol / g, and further preferably 0.5 to 3.0 mmol / g. The carboxyl content can be determined by neutralization titration.

[0043] -(Poly)alkylene glycol group-

[0044] The (poly)alkylene glycol group is a substituent derived from a (poly)alkylene oxide. The average addition mole number of the alkylene oxide unit 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, further preferably 25 or more, or 30 or more, and further preferably 35 or more. Thus, the dispersibility can be improved. Among them, by being 50 or more, 60 or more, 70 or more, 80 or more, or 90 or more, the water surface expansion is further improved, so it is preferred. The upper limit is usually 300 or less or 200 or less, preferably 190 or less, more preferably 180 or less, and further preferably 170 or less. Thus, the reduction in dispersion retention can be suppressed. Therefore, the average addition mole number is usually 10 to 200, preferably 15 to 190, more preferably 20 to 180, and further preferably 25 to 170. On the other hand, it can be preferably 25 to 300, more preferably 30 to 200, and further preferably 35 to 150. The number of carbon atoms of the polyalkylene glycol is not particularly limited, but is generally 2 to 18, preferably 2 to 4, and more preferably 2 to 3. Examples of the alkylene oxide unit include ethylene oxide units, propylene oxide units, and butylene oxide units, preferably ethylene oxide units or propylene oxide units. Examples of the lignin sulfonic acid containing a (poly)oxyalkylene group include lignin derivatives described in International Publication No. 2021 / 066166.

[0045] [Inorganic ingredients]

[0046] The lignin sulfonic acid component may further include an inorganic component. Examples of the inorganic component 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, and calcium oxide), hydroxides (e.g., magnesium hydroxide, calcium hydroxide, sodium hydroxide, and ammonium hydroxide), carbonates (e.g., calcium carbonate and sodium carbonate), and nitric acid. The form of the inorganic component is not particularly limited, and it may be a counter cation of lignin sulfonic acid or a free inorganic component (e.g., an inorganic component added when manufacturing lignin sulfonic acid). Among these, it is preferred to include at least one of sulfur, calcium, sodium, magnesium, nitrogen, phosphorus, and potassium.

[0047] -Sulfide ion-

[0048] The content of sulfide ions can be expressed as the content of sulfur atoms contained in lignin sulfonic acid (total S content). 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 further preferably 5.0% by weight or more. There is no particular restriction on the upper limit, but it is preferably 10.0% by weight or less, more preferably 9.0% by weight or less, and further preferably 8.0% by weight or less. Therefore, the S content is preferably 1.0 to 10.0% by weight, 2.0 to 10.0% by weight, or 3.0 to 10.0% by weight, more preferably 4.0 to 9.0% by weight, and further preferably 5.0 to 8.0% by weight. The total S content can be quantified by ICP emission spectrometry.

[0049] - Sulfur oxides -

[0050] Lignosulfonic acid may contain sulfur oxides. Examples of sulfur oxides include sulfur dioxide (SO 2 ), sulfur trioxide (SO 3 ), sulfur tetroxide (SO 4 ), preferably SO 3 、SO 4 . SO 3 Transformed into SO 4 The possibility of state, SO 3 The content is usually 0 wt% or more, preferably 0.001 wt% or more, more preferably 0.005 wt% or more, further preferably 0.01 wt% or more or 0.04 wt% or more. The upper limit is preferably 3.0 wt% or less, more preferably 2.0 wt% or less, further preferably 1.0 wt% or less, and further preferably 0.5 wt% or less. Therefore, SO 3 The content is usually 0 to 3.0 wt%, preferably 0.001 to 3.0 wt%, more preferably 0.005 to 2.0 wt%, further preferably 0.01 to 1.0 wt%, and further preferably 0.04 to 0.5 wt%. SO 4 The content is preferably 0.2 wt% or more, more preferably 0.4 wt% or more, further preferably 0.5 wt% or more, 2.0 wt% or more, or 3.0 wt% or more. The upper limit is preferably 10 wt% or less, more preferably 9.5 wt% or less, and further preferably 9.0 wt% or less. Therefore, SO 4 The content is preferably 0.2 to 10% by weight, more preferably 0.4 to 9.5% by weight, further preferably 0.5 to 9.0% by weight, further preferably 2.0 to 9.0% by weight or 3.0 to 9.0% by weight. The sulfur oxide content can be quantified by ion chromatography.

[0051] -The proportion of sulfonic S in the total S content-

[0052] The ratio of the sulfur atom content derived from the sulfonic group to the sulfur atom content contained in the lignin sulfonic acid is preferably 0.5 or more, more preferably 0.6 or more. The upper limit is not particularly limited, but is usually 0.9 or less, preferably 0.8 or less.

[0053] -SO 3 On SO 4 The proportion of

[0054] SO contained in lignin sulfonic acid 3 Content relative to SO 4 The content ratio 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.

[0055] -Sodium ions, calcium ions, magnesium ions-

[0056] Na + , Ca 2+ Mg 2+ The content of each ion can be expressed as the atomic content of each. The sodium atom content (Na content) is preferably 0.3% by weight or more, more preferably 0.5% by weight or more, and further preferably 1.0% by weight or more. There is no particular restriction on the upper limit, 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 0.3-10.0% by weight, more preferably 0.5-9.0% by weight, and further preferably 1.0-8.0% 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 further preferably 0.03% by weight or more. The upper limit is preferably 3.0% by weight or less, and more preferably 1.0% by weight or less. Therefore, the Ca content is preferably 0.001-3.0% by weight, more preferably 0.01-1.0% by weight, and further preferably 0.03-1.0% by weight. The magnesium atom content (Mg content) is preferably 0.05 wt% or more, more preferably 0.07 wt% or more, further preferably 0.1 wt% or more, 0.5 wt% or more, 1.0 wt% or more, 2.0 wt% or more, 3.0 wt% or more, or 3.2 wt% or more. The upper limit is preferably 10.0 wt% or less, more preferably 8.0 wt% or less, and further preferably 5.0 wt% or less. Therefore, the Mg content is preferably 0.05 to 10.0 wt%, more preferably 0.07 to 8.0 wt%, further preferably 0.1 to 5.0 wt%, 0.5 to 5.0 wt%, 1.0 to 5.0 wt%, 2.0 to 5.0 wt%, 3.0 to 5.0 wt%, or 3.2 to 5.0 wt%. The Na content, Ca content, and Mg content can be quantified by an inductively coupled plasma (ICP) method.

[0057] -Reducing sugars-

[0058] The lignin sulfonic acid component preferably further contains reducing sugars. In this specification, reducing sugars refer to sugars that have reducing properties, that is, sugars that have the property of generating aldehyde groups or ketone groups in alkaline solutions. Examples of reducing sugars include: all monosaccharides; disaccharides such as maltose, lactose, arabinose, and invert sugars of sucrose; and polysaccharides. Reducing sugars generally include cellulose, hemicellulose, and their degradation products. Examples of degradation products of cellulose and hemicellulose include: monosaccharides such as rhamnose, galactose, arabinose, xylose, glucose, mannose, and fructose; oligosaccharides such as xylooligosaccharides and cellooligosaccharides; and their modified products. Modified products refer to chemically modified products such as oxidation and sulfonation, and examples include: sugar derivatives in which functional groups such as hydroxyl groups, aldehyde groups, carbonyl groups, and sulfonic groups are introduced into the sugar skeleton, and compounds formed by combining two (two kinds) or more of the sugar derivatives.

[0059] The reducing sugar content is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, 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, further 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, further preferably 0.5 to 25% by weight or 2.0 to 25% by weight. The reducing sugar content can be calculated as a glucose amount conversion value by the Somogyi-Schaffer method.

[0060] [Other ingredients]

[0061] The lignin sulfonic acid component may contain components other than the above. For example, organic components and ash can be mentioned. As organic components, for example, small molecule organic substances (for example, organic acids with a carbon number of 5 or less) such as formic acid, acetic acid, propionic acid, valeric acid, pyruvic acid, succinic acid, and lactic acid can be mentioned. The small molecule organic substances may contain one kind alone or multiple kinds.

[0062] The amount of small molecule organic matter is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and further preferably 1% by weight or more. The upper limit is preferably 25% by weight or less, more preferably 20% by weight or less, and further preferably 15% by weight or less. Therefore, the amount of small molecule organic matter is preferably 0.01 to 25% by weight, more preferably 0.1 to 20% by weight, and further preferably 1 to 15% by weight. The amount of small molecule organic matter can be measured, for example, as the amount of acetic acid fraction when organic acids are separately quantified by silica gel column chromatography based on ether extraction.

[0063] [Weight average molecular weight (RI)]

[0064] The weight average molecular weight (RI) of the lignin sulfonic acid component is preferably 3,000 or more, more preferably 3,500 or more, further preferably 3,700 or more, and further preferably 4,000 or more. There is no particular restriction on the upper limit, but it is preferably 50,000 or less, more preferably 40,000 or less, and further 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, further preferably 3,700 to 40,000, and further preferably 4,000 to 35,000. The weight average molecular weight (RI) in this specification is a weight average molecular weight obtained by GPC using a differential refractive index detector (RI).

[0065] [Weight average molecular weight (UV)]

[0066] The weight average molecular weight (UV) of the lignin sulfonic acid component is preferably 4,000 or more, more preferably 5,000 or more, and further preferably 6,000 or more. The upper limit is not particularly limited, but is more preferably 70,000 or less, further preferably 60,000 or less, and further 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, and further preferably 6,000 to 50,000. In this specification, the weight average molecular weight (UV) is a weight average molecular weight obtained by GPC using an ultraviolet-visible absorbance detector.

[0067] -Weight average molecular weight ratio RI / UV-

[0068] 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.

[0069] As the lignin sulfonic acid component, for example, a product having the above-mentioned substituent and inorganic component amount in SANLIGHON (scheduled to be sold by Nippon Paper Industries, Ltd. after July 2022) can be selected and used.

[0070] [1.2 Method for producing lignin sulfonic acid component]

[0071] The method for producing the lignin sulfonic acid component is not particularly limited, and it can be produced, for example, by a method of treating a lignocellulose raw material with sulfurous acid or by a method of decomposing lignin and then sulfonating it. By adjusting the production conditions, the type and content of the substituents possessed by the lignin sulfonic acid component, as well as the type and content of each component such as an inorganic component and a reducing sugar can be adjusted.

[0072] -raw material-

[0073] As an example of a raw material, the lignocellulose raw material is not particularly limited as long as it is a raw material containing lignocellulose in the structure. For example, pulp raw materials such as wood and non-wood can be listed. As wood, for example, coniferous wood such as radiata pine, fish-scale spruce, red pine, fir, cypress, and broad-leaved wood such as birch and beech can be listed. The age and collection site of the wood are not limited. Therefore, wood collected from trees of different ages or wood collected from different parts of trees can be used in combination. As non-wood, for example, bamboo, kenaf, reed, rice can be listed. The lignocellulose raw material can be used alone or in combination of two or more.

[0074] As other examples of lignin as a raw material, there can be mentioned, for example, naturally derived lignin and artificially produced lignin (for example, a dehydrogenated polymer of a hydroxycinnamyl alcohol analogue).

[0075] - Sulfurous acid treatment -

[0076] The sulfite treatment can be performed by contacting at least one of sulfurous acid and sulfite with the lignocellulose raw material. The conditions for the sulfite treatment are not particularly limited as long as a sulfonic group can be introduced into the α carbon atom of the side chain of lignin contained in the lignocellulose raw material.

[0077] The sulfite treatment is preferably carried out by a sulfite digestion method. In this way, the lignin in the lignocellulose raw material can be sulfonated more quantitatively. The sulfite digestion method is a method of reacting the lignocellulose raw material at a high temperature in a solution (e.g., an aqueous solution, a digestion solution) of at least one of sulfurous acid and a sulfite. This method has been established and implemented industrially as a method for producing sulfite pulp, and is therefore advantageous in terms of economy and ease of implementation.

[0078] As a salt of sulfite, when performing sulfurous acid decomposition, a magnesium salt, a calcium salt, a sodium salt, and an ammonium salt are mentioned, for example.

[0079] The sulfurous acid (SO 2 ) concentration is not particularly limited, preferably SO 2 The mass (g) of SO is 1 g / 100 mL or more relative to 100 mL of the reaction solution, and more preferably 2 g / 100 mL or more in the case of sulfurous acid decomposition. The upper limit is preferably 20 g / 100 mL or less, and more preferably 15 g / 100 mL or less in the case of sulfurous acid decomposition. 2 The 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 distillation is performed.

[0080] The pH value of the sulfite treatment is not particularly limited, but is usually 10 or less. When sulfite digestion is performed, it is preferably performed under acidic conditions, more preferably at a pH of 5 or less, and further preferably at a pH of 3 or less. In this way, lignin derivatives (e.g., 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 when sulfite digestion is performed, it is more preferably 0.5 or more. The pH value during the sulfite treatment is preferably 0.1 to 10, and when sulfite digestion is performed, it is more preferably 0.5 to 5, and further preferably 0.5 to 3.

[0081] The temperature of the sulfite treatment is not particularly limited, but is preferably 170°C or lower, and more preferably 150°C or lower when sulfite distillation is performed. The lower limit is preferably 70°C or higher, and more preferably 100°C or higher when sulfite distillation is performed. The temperature conditions of the sulfite treatment are preferably 70 to 170°C, and more preferably 100 to 150°C when sulfite distillation is performed.

[0082] The treatment time of the sulfite treatment is not particularly limited and depends on various conditions of the sulfite treatment, but is preferably 0.5 to 24 hours, more preferably 1.0 to 12 hours.

[0083] In the sulfite treatment, it is preferred to add a compound that supplies counter cations to the lignin sulfonic acid. By adding a compound that supplies counter cations, the pH value during the sulfite treatment can be kept constant. Examples of the compound that supplies counter cations include MgO, Mg(OH) 2 , CaO, Ca(OH) 2 、CaCO 3 NH 3 NH 4 OH, NaOH, NaHCO 3 、Na 2 CO 3 The counter cation is preferably a magnesium ion or a sodium ion.

[0084] When a solution of at least one of sulfurous acid and sulfite is used in the sulfiting treatment, the solution may contain SO 2 In addition, the above-mentioned counter cation (salt) and a decomposition penetrant (for example, a cyclic ketone compound such as anthraquinone sulfonate, anthraquinone, and tetrahydroanthraquinone) may be contained.

[0085] The equipment used for the sulfite treatment is not limited, and for example, a generally known dissolving pulp production equipment can be used.

[0086] The 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. Examples of the separation method include a separation method (for example, filtration) of sulfurous acid decomposition waste liquid after sulfurous acid decomposition.

[0087] The lignin sulfonic acid obtained by the sulfurous acid treatment (for example, the filtrate or the residue obtained by filtering the insoluble matter of the sulfurous acid solution, preferably the filtrate) can be used directly or concentrated as needed as an effective component, i.e., a lignin sulfonic acid component. On the other hand, other treatments can be further performed as needed. Thus, the purity can be improved, or other substituents that the raw material does not originally have can be introduced. Examples of other treatments include: alkali treatment, oxidation treatment, dialysis treatment, ultrafiltration treatment, modification treatment, and combinations thereof.

[0088] (Alkali treatment)

[0089] The alkali treatment may be carried out by placing the sample under alkaline conditions. Placing under alkaline conditions generally means placing the sample in an aqueous solution having a pH value of 8 or higher, preferably a pH value of 9 or higher. The upper limit of the pH value is generally 14.

[0090] In the alkali treatment, an alkaline substance is usually brought into contact with the sulfite-treated product. The alkaline substance is not particularly limited, and examples thereof include calcium hydroxide, magnesium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonia. Among them, sodium hydroxide and calcium hydroxide are preferred. The alkaline substance may be used alone or in combination of two or more.

[0091] Examples of a method for bringing the alkaline substance into contact with the sulfite-treated product include a method of preparing a dispersion or solution (e.g., an aqueous dispersion or aqueous solution) of the sulfite-treated product and adding the alkaline substance to the dispersion or solution; or a method of adding a solution or dispersion (e.g., an aqueous dispersion or aqueous solution) of the alkaline substance to the sulfite-treated product.

[0092] The temperature of the alkali treatment is not particularly limited, but 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 further preferably 110° C. or lower.

[0093] The amount of the alkaline substance in the alkali treatment is preferably 0.5 to 40% by mass, more preferably 1.0 to 30% by mass, relative to the mass of the solid content of the sulfite-treated product, or in the case of preparing an aqueous solution or dispersion obtained by dispersing the alkali-treated extract in an aqueous solvent (e.g., water), relative to the mass of the aqueous solution or dispersion.

[0094] The time of the alkali treatment is not particularly limited, but is preferably 0.1 hour or longer, more preferably 0.5 hour or longer, and the upper limit is preferably 10 hours or shorter, more preferably 6 hours or shorter.

[0095] Before the alkali treatment, the sulfite treatment product may be dissolved, dispersed, or concentration adjusted (a solution or dispersion of an aqueous solvent such as water is prepared) as needed. The dispersion treatment may be carried out by using a disc refiner, adding to a mixer or disperser, kneading machine treatment, etc. The concentration adjustment may be carried out using an aqueous solvent such as water, for example.

[0096] (Oxidation treatment)

[0097] The oxidation treatment can be carried out on the treated material obtained after the sulfurous acid treatment (for example, the filtrate after filtration) or the treated material after the alkali treatment. The oxidation treatment can be carried out using an appropriate oxidant. When the oxidant is a gas, it can be carried out by passing the gas into the filtrate. When the oxidant is a liquid, it can be carried out by adding a liquid to the filter residue or the filtrate. The oxidant is preferably air, oxygen, hydrogen peroxide, ozone or a combination thereof. The oxidation treatment is preferably carried out under alkaline conditions (alkaline oxidation treatment). The treatment pH of the alkaline oxidation treatment is generally above 8, preferably above 10, and more preferably above 12. The temperature of the oxidation treatment is generally 20 to 200°C, preferably 50 to 180°C. The time of the oxidation treatment is generally preferably above 0.1 hours, and more preferably above 0.5 hours. The upper limit is preferably below 5 hours, and more preferably below 3 hours.

[0098] (dialysis treatment or UF treatment)

[0099] The dialysis treatment can be performed on the treated product obtained after the sulfite treatment (e.g., the filtrate after filtration). Examples of the dialysis membrane include cellulose membranes such as cellulose acetate, and synthetic polymer membranes such as ethylene vinyl alcohol, polyacrylonitrile, polymethyl methacrylate, polysulfone, and polyethersulfone, with a molecular weight fraction of usually 5,000 to 100,000, preferably 7,000 to 80,000, and more preferably 10,000 to 50,000.

[0100] Ultrafiltration treatment (UF treatment) can be used instead of dialysis treatment. As the UF membrane, a known UF membrane can be used. For example, hollow fiber membrane, spiral membrane, tubular membrane, flat membrane can be mentioned. The material of the UF membrane can use a known material. For example, cellulose acetate, aromatic polyamide, polyvinyl alcohol, polysulfone, polyvinylidene fluoride, polyethylene, polyacrylonitrile, ceramics can be mentioned. It should be noted that the UF membrane can be a commercially available product.

[0101] The molecular weight cutoff of the UF membrane is preferably 5,000 to 30,000, more preferably 10,000 to 25,000, and further preferably 15,000 to 23,000. If a UF membrane with a molecular weight cutoff of 5,000 or more is used, the separation rate of the treatment liquid can be prevented from being too slow. In addition, if a UF membrane with a molecular weight cutoff of 30,000 or less is used, lignin can be prevented from not being separated from the treatment liquid.

[0102] The concentration ratio of the UF treatment using the UF membrane can be set arbitrarily. That is, when the outflow of the concentrated liquid reaches an arbitrary amount, the UF treatment can be stopped. Preferably, the concentration is 2 to 6 times. Concentration 2 to 6 times means that the amount of the original liquid (black liquor) becomes 1 / 2 to 1 / 6.

[0103] The temperature of the treatment liquid during UF treatment is not particularly limited. For example, it is preferably 20 to 80°C, and more preferably 20 to 70°C in consideration of the heat resistance of the UF membrane material. The pH value of the treatment liquid during UF treatment is preferably 2 to 11. The solid content concentration (w / w) of the black liquor during UF treatment is preferably 2 to 30%, more preferably 5 to 20%.

[0104] As modification treatment, for example, chemical modification methods such as hydrolysis, alkylation, alkoxylation, sulfonation, sulfonate esterification, sulfomethylation, aminomethylation, desulfonation, alkalization, and condensation reaction with (poly)oxyalkylenes can be exemplified; and a method of molecular weight fractionation of lignin sulfonic acid by ultrafiltration. Among them, as a chemical modification method, it is preferred to select one or more reactions from hydrolysis, alkoxylation, desulfonation and alkylation, and condensation reaction with (poly)oxyalkylenes (for example, International Publication No. 2021 / 066166).

[0105] [1.3 Soil improvement effect]

[0106] The lignin sulfonic acid component has the effect of improving the soil.

[0107] [soil]

[0108] The target soil can be any natural soil, and can be any of sand, fine soil, and clay. Examples of sand include coarse sand, fine sand, and gravel. Examples of soil include dark soil (e.g., volcanic ash soil), alluvial soil (e.g., reddish yellow soil, brown forest soil, red forest soil, red soil, loess, dark red soil, gray highland soil, and eutrophic highland soil), and alluvial soil (e.g., brown lowland soil, gray lowland soil, and dune soil). The plasticity of the soil is not particularly limited, and can be any of heavy clay, clay, clay loam, loam, sandy loam, sand, gravel, and humus. The use of the soil is not particularly limited, and examples include: agricultural use (e.g., paddy field soil, dry field soil, forest soil, grassland soil (e.g., pasture, racecourse)), civil engineering use, and green space use (e.g., lawns and flower beds in gardens, parks, schools, facilities, etc.), preferably agricultural use.

[0109] Examples of soil improvement include an increase in the amount of inorganic components (for example, phosphorus atoms, iron atoms, etc.) in the soil, growth of microorganisms, dispersion of pesticides, and promotion of granulation.

[0110] [1.4 Biostimulants]

[0111] Lignin sulfonic acid components can improve the physiological state of plants or soil by effectively utilizing the natural forces inherent in plants or their surroundings, increase the number of microorganisms in the soil, or adjust inorganic components (phosphorus, nitrogen, iron, etc.) that cannot be absorbed as nutrients into an absorbable form, so they can also be used as a biostimulant for soil. The target soil when used as a biostimulant is the same as that described for soil conditioners.

[0112] [1.5 Optional ingredients]

[0113] Each of the above agents (soil conditioner, biostimulant) may contain components (optional components) other than the lignin sulfonic acid component as required. Examples of the optional components include soil conditioner components other than the lignin sulfonic acid component (e.g., sugars (e.g., glucose), inorganic components, polycarboxylic acids), biostimulants other than the lignin sulfonic acid component, excipients, colorants, preservatives, pH adjusters, stabilizers, disintegrants, carriers, binders, pH adjusters, defoamers, nonionic surfactants, cationic surfactants, amphoteric surfactants, and other optional components (formulation adjuvants).

[0114] As for the inorganic component as a soil improvement component, for example, there can be mentioned inorganic salts of essential elements such as nitrogen, phosphorus, and potassium, and trace elements such as sulfur, calcium, magnesium, iron, manganese, zinc, boron, molybdenum, chlorine, iodine, and cobalt, and their oxides, and inorganic salts thereof. As inorganic salts, for example, there can be mentioned magnesium hydroxide, magnesium oxide, calcium carbonate (slaked lime), potassium nitrate, ammonium nitrate, ammonium chloride, sodium nitrate, potassium hydrogen phosphate, sodium dihydrogen phosphate, potassium oxide, potassium chloride, potassium sulfate (potassium sulfate), 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, sodium molybdate, potassium iodide, cobalt chloride, calcium dihydrogen phosphate, mixtures thereof (for example, superphosphate (a mixture of calcium dihydrogen phosphate and calcium sulfate)), and hydrates thereof.

[0115] As other biostimulants, for example, there can be listed: materials derived from organisms (for example, organic acids such as humic acid and fulvic acid, humus; seaweed; microorganisms such as Trichoderma, mycorrhizal fungi, yeast, Bacillus subtilis, and rhizobia; animals and plants; and their metabolites), materials derived from seaweed extracts (seaweed and its extracts), sugars (for example, polysaccharides), peptides (including amino acids), minerals, vitamins, etc.

[0116] The content of the arbitrary component can be selected in an appropriate amount according to the type of the arbitrary component.

[0117] [1.6 Dosage form, manufacturing method]

[0118] As the dosage form of each of the above-mentioned agents (soil conditioner, biostimulant), for example, powder, granular, granular, liquid can be listed, without particular limitation. The granular or granular form can facilitate spreading. In addition, the liquid form makes it easy to mix with the functional components, and the slurry can be stabilized after mixing. Each agent can be prepared together with the functional components, or can be prepared separately. The method for preparing each agent can be appropriately selected according to the dosage form.

[0119] [2. Soil improvement composition]

[0120] The soil to which the soil conditioner or biostimulant is added can be used as a soil conditioner composition for various purposes such as agriculture and civil engineering, preferably agriculture. This can increase crop yields and realize and popularize organic agriculture.

[0121] In the soil improvement composition, the content of each agent is usually 0.000001% by weight or more, preferably 0.00001% by weight or more, and more preferably 0.00005% by weight or more per unit soil weight in terms of the amount of lignin sulfonic acid component. The upper limit is not particularly limited, but is usually 10% by weight or less.

[0122] The improved soil composition may contain the soil conditioner or biostimulant of the present invention and other components other than soil. Other components include: soil conditioners other than the soil conditioner of the present invention, artificial soils (e.g., artificial soils such as carbonized rice husks, coconut fiber, vermiculite, perlite, peat moss, glass beads, and rice husks; porous molded products such as foamed phenolic resins and rock wool; curing agents (e.g., agar or gellan gum), and combinations of two or more of these). The contents of other components may be selected in appropriate amounts.

[0123] [3. Method for preparing soil improvement composition]

[0124] The soil improvement composition can be adjusted by adding a soil improver or a biostimulant to the soil. During mixing, a stirring machine can be used as needed. Other components other than the soil improver and the soil can be added to the soil together with the soil improver or can be added sequentially.

[0125] [4. Plant production method]

[0126] The soil improving composition can be used in plant production.

[0127] [plant]

[0128] The target plants include herbaceous plants and woody plants. Examples of herbaceous plants include plants of the family Cruciferae, Leguminosae, Cucurbitaceae, Solanaceae, Capsicumaceae, Rosaceae, Malvaceae, Gramineae, Allium, Amaryllis, Asteraceae, Amaranthaceae, Apiaceae, Zingiberaceae, Lamiaceae, Araceae, Convolvulaceae, Dioscoreaceae, and Nelumbo. Specific examples include: leafy vegetables such as komatsuna, Chinese cabbage, onion, scallion, garlic, shallot, leek, pickled vegetables, green cabbage, cabbage, cauliflower, broccoli, Brussels sprouts, asparagus, lettuce, escarole, celery, spinach, chrysanthemum, parsley, duck celery, water celery, Chinese angelica, lotus root, butterbur, and perilla; fruit vegetables such as soybeans, edamame, broad beans, peas, cucumbers, eggplants, melons, corn, pumpkins, watermelons, tomatoes, bell peppers, strawberries, okra, and lentils; root vegetables such as carrots, turnips, radishes, burdocks, potatoes, taro, sweet potatoes, yams, ginger, and lotus roots; rice (e.g., paddy rice and upland rice), wheat (e.g., wheat and barley); and flowers. Examples of woody plants include: fir (e.g. fir), juniper (e.g. juniper), Pinaceae (pine (e.g. black pine), larch (e.g. larch, sakhalin larch), abies (e.g. abies sakhalin)), eucalyptus (e.g. eucalyptus), cherry (e.g. cherry, plum, cherry), mangifera (e.g. mango), acacia, myrica, oak (e.g. oak), grape, apple, rose, camellia (e.g. tea), jacaranda (e.g. jacaranda), persea (e.g. avocado), pear (e.g. pear), and white sandalwood (e.g. white sandalwood). Among these, herbaceous plants are preferred, and cruciferous plants and leguminous plants are more preferred.

[0129] The improved soil composition can be used during the entire period of the growth and development of the plant, or can be used during a portion of the period. In addition, it can be used not only for breeding from seeds and seedlings, but also for tissue culture such as cuttings and cuttings.

[0130] When using the improved soil composition for plant production, there is no particular limitation on the cultivation conditions of the plants (e.g., temperature, light intensity, watering amount, humidity, carbon dioxide concentration, whether these are adjusted, sowing density, watering method, watering amount, presence or absence of cultivation facilities / containers (e.g., seedling troughs, seedling pots, seedling boxes, seedling trays)), and they can be appropriately selected. In addition, fertilizers can be added to the improved soil composition. As fertilizers, for example, inorganic components, silver ions, antioxidants, carbon sources, vitamins, amino acids, plant hormones, and other components that can be a source of nutrients for plants can be listed. There is no particular limitation on the form of the additive, and it can be any of a solid (e.g., powder, granules) or a liquid (e.g., liquid fertilizer).

[0131] Example

[0132] The present invention will be described below by way of examples, but the following examples do not limit the present invention.

[0133] The compositions of the main samples used in the examples are shown in Table 1.

[0134] [Table 1]

[0135] Table 1. Main samples used in the examples

[0136]

[0137] [Footnote to Table 1]

[0138] *1 "%" indicates mass % relative to the dry weight of the sample.

[0139] *2 Phenolic hydroxyl content

[0140] The absorption spectrum of the neutral solution containing the same concentration of lignin was subtracted from the absorption spectrum of the alkaline solution containing the lignin sample to obtain the ionization differential spectrum, and the phenolic hydroxyl group (%) was calculated by the following formula. In the formula, Δαmax [L / (g·cm)] represents the differential absorption coefficient (Junzo Nakano, "Chemistry of Lignin - Fundamentals and Applications - Supplementary Revised Edition" UNI Publishing, May 25, 1990 (Heisei 2), 541 pages).

[0141] Phenolic hydroxyl group (%) = (17 × Δαmax) / 4100 × 100

[0142] *3 Carboxyl group amount

[0143] 60 ml of a 0.5 mass % aqueous dispersion of the sample was prepared, and a 0.1 M hydrochloric acid aqueous solution was added to adjust the pH to 2.5. Then, a 0.05 N sodium hydroxide aqueous solution was added dropwise, and the conductivity was measured until the pH reached 11. The amount of sodium hydroxide (a) consumed in the neutralization stage of the weak acid, whose conductivity changes slowly, was calculated using the following formula:

[0144] Carboxyl group amount [mmol / g sample] = a [ml] × 0.05 / sample mass

[0145] *4 Reducing sugar content

[0146] 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.

[0147] *5Methoxy (OCH 3 ) Base content

[0148] The methoxy group content of lignin is measured by a methoxy group quantitative method based on the method of Viebock and Schwappach ("Lignin Chemical Research Methods", pp. 336-340, 1994, published by UNI Publishing).

[0149] *6Total sulfur atom (S) content

[0150] The S content was quantified by ICP emission spectrometry.

[0151] *7 Sulfur oxide (SO 3 、SO 4 )content

[0152] SO 3 Content and SO 4 The contents were quantified by ion chromatography.

[0153] *8 Sulfur atom (S) content of sulfonic group

[0154] The S content of the sulfonic group can be calculated by the following formula.

[0155] Sulfonic acid S content (mass %) = S content (mass %) - inorganic S content (mass %)

[0156] In the formula, mass % is the ratio of the S content to the solid content of lignin sulfonic acid.

[0157] The S content is the measured value based on the above method. The inorganic S content is SO 3 Content and SO 4 The total amount of content.

[0158] *9Weight average molecular weight (RI)

[0159] The measurement was performed by gel permeation chromatography (GPC) under the following conditions.

[0160] Measuring device: manufactured by Tosoh.

[0161] Columns used: Shodex Column OH-pak SB-806HQ, SB-804HQ, SB-802.5HQ;

[0162] Eluent: 0.05 mM sodium nitrate / acetonitrile 8 / 2 (v / v);

[0163] Standard substance: polyethylene glycol (manufactured by Tosoh Corporation or GL Science Corporation);

[0164] Detector: Differential refractometer (manufactured by Tosoh Corporation);

[0165] Standard curve; polyethylene glycol reference.

[0166] *10Weight average molecular weight (UV)

[0167] The measurement was performed under the same conditions as the above-mentioned weight average molecular weight measurement by RI detection, except that a UV detector (280 nm, manufactured by Tosoh Corporation) was used as a detector.

[0168] *11Ca content, Na content, Mg content

[0169] The inductively coupled plasma (ICP) method was used to quantify the amount of metal ions (Ca 2+ 、Na + Mg 2+ ), and the quantitative results were converted into Ca content, Na content and Mg content (mass %) for calculation.

[0170] <Manufacturing Example 1: Manufacture of Sample 1>

[0171] The intermediate composition was obtained by sulfiting wood (radiata pine) based on the sulfite digestion method. In the sulfite treatment, SO 2 A magnesium sulfite solution with a concentration of 4 g / 100 mL was prepared at a temperature of 140° C., a pH of 2, and a treatment time of 3 hours. Next, the insoluble matter was separated by filtration, and the obtained filtrate was concentrated to a solid content of 50% by a rotary evaporator to obtain an intermediate composition A. By spray drying, a sample 1 as a solidified composition was obtained.

[0172] <Manufacturing Example 2: Manufacture of Sample 2>

[0173] The intermediate composition A obtained in Manufacturing Example 1 was subjected to an alkali reaction (addition rate of calcium hydroxide solution was 9wt.% (relative to solid content), reaction temperature was 90°C, and reaction time was 4 hours) and an oxidation reaction (treatment with oxygen, oxygen pressure was 200kPa, and reaction time was 2 hours), and adjusted to pH 7.0. It was spray dried, thereby obtaining a sample 2 as a solidified composition.

[0174] <Manufacturing Example 3: Manufacture of Sample 3>

[0175] The intermediate composition was obtained by sulfiting wood (radiata pine) based on the sulfite digestion method. In the sulfite treatment, SO 2 A sodium sulfite solution having a concentration of 4 g / 100 mL was added, and the temperature was set to 140° C., pH 2, and the treatment time was 3 hours. Next, the insoluble matter was separated by filtration, and the resulting filtrate was adjusted to pH 5.0. It was subjected to ultrafiltration treatment using a polysulfone ultrafiltration membrane with a fractional molecular weight of 20,000, and the concentrated solution was spray-dried to obtain Sample 3 as a solidified composition.

[0176] <Test Example 1: Effect on Microbial Activity (Examples 1 to 3 and Comparative Examples 1 to 2)>

[0177] [Carbon dioxide production]

[0178] The samples shown in Table 2 were mixed with volcanic ash soil (produced in Kitamoto, Saitama Prefecture, Japan) and red-yellow soil (produced in Koshigen, Aichi Prefecture, Japan) to prepare soil samples, and then left to stand at 26.5°C and 50% humidity. The amount of carbon dioxide in the soil sample after 30 days of preparation was measured using a carbon dioxide absorber in the following order. The soil sample and 8 mL of 0.1 N NaOH were placed in a beaker, and after 24 hours of incubation, 1 mL of 50% barium chloride was added to make the carbon dioxide absorbed by NaOH a white precipitate. Phenolphthalein was used as an indicator, and the remaining sodium hydroxide was titrated with 0.1 N hydrochloric acid.

[0179] In addition, 50 g of volcanic ash soil sample was placed in a reflux device, and 0.3 L of culture solution (composition: 1.2% lignin solution) was refluxed for 7 days. Then, the culture medium was diluted to 40 μg / L using the dilution plate method (culture medium: albumin agar medium (0.25 g / L egg albumin, 1.0 g / L glucose, 0.5 g / L K 2 HPO 4 , 0.2 g / L MgSO 4 7H 2 O, 1mL 1% Fe(SO 4 ) 3 , 18.0 g / L agar, pH 6.8-7.0), culture period 26.5°C, 14 days), and the colony counts of the reflux liquid and reflux soil were measured according to the conventional method (N=1: Table 3).

[0180] [Table 2]

[0181] Table 2. Samples used in microbial activity tests (unit: mg / 100 g soil)

[0182]

[0183] [Footnote to Table 2]

[0184] *1 Small molecular organic matter is determined by the water-soluble anthrone colorimetric substance (4 times the amount relative to dry soil).

[0185] Water-soluble matter: leached with 4 times the amount of water relative to dry soil;

[0186] Acid solubles: Use 4 times the amount of 0.5NH 2 SO 4 Water leaching.

[0187] For both substances, 5 mL of sample (10-100 g in terms of glucose) and 10 mL of anthrone reagent (0.2% anthrone in 95% H 2 SO 4 After cooling, the solution was subjected to colorimetric quantification at 625 nm with a standard substance (glucose).

[0188] Organic acid: 40mL of water-soluble matter is neutralized with 1N-NaOH, and then concentrated under reduced pressure and dried to solidify. 40mL of acid-soluble matter is directly subjected to liquid ether extraction for 48 hours continuously, and the extract is neutralized and concentrated under reduced pressure and dried to solidify. The graded quantification of organic acid is directly carried out by silica gel column chromatography. It should be noted that fraction I represents butyric acid, propionic acid, valeric acid, etc., II represents acetic acid, III represents formic acid, pyruvic acid, and IV represents lactic acid, succinic acid, etc., and the amount of fraction II is shown in Table 2 as the amount of organic acid.

[0189] *2 Ash content was measured by incineration at 550°C in accordance with JIS P 8251:2003 "Paper, board and pulp - Ash content test method -".

[0190] *3Total CaO and MgO are calculated by measuring Ca and Mg by ICP and converting them into oxides.

[0191] *4SO 2 Determined by ion chromatography.

[0192] *5 Carbon content C is obtained by diluting 1 / 10-1 / 15M potassium dihydrogen phosphate solution to 6 times to make it weakly acidic. 2 The organic carbon is measured by exposing the sample to air to remove dissolved carbon dioxide and then measuring it with a total organic carbon meter.

[0193] *6 Dialyzed lignin is the dialyzed product of Sample 2. The dialysis was performed using a dialysis membrane (BIOTECH CE TRIAL KIT, manufactured by Funakoshi Co., Ltd.) under conditions of 3.5-5.0 kDa fractionation.

[0194] *7 Glucose used was D-(+)-glucose manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

[0195] In addition, reducing sugars and sulfur were quantified by the method shown in the footnotes of Table 1.

[0196] [Table 3]

[0197] Table 3. Microbial activity test results

[0198]

[0199] Compared with Comparative Examples 1 and 2, the soil samples (volcanic ash soil and red-yellow soil) of Examples 1 to 3 using samples containing lignin sulfonic acid produced more carbon dioxide (Table 3), suggesting that the growth and development environment of microorganisms is improved by adding lignin sulfonic acid. In addition, compared with Comparative Example 1 without addition, the colony counts of the reflux liquid and reflux soil of Example 1 increased, suggesting that the growth and development environment of microorganisms such as bacteria is improved and the soil is activated (Table 3).

[0200] <Test Example 2: Effect on the Content of Divalent Iron Ions in Paddy Field Soil (Examples 4 to 5 and Comparative Example 3)>

[0201] The samples listed in Table 4 were added to 7.2 g of air-dried fine soil (paddy field soil in Nagano Prefecture, Japan) with the amount shown in Table 4, collected in a 20 mL (±5 g) syringe, and 10 g of water was collected for irrigation (reproducing the paddy field state), and cultured directly in a constant temperature chamber at 26.5°C for 35 days. The ratio of air-dried fine soil to water was adjusted to (1:2). After the start of culture, 1 M sodium acetate-hydrochloric acid buffer with a pH of 2.8 was used to extract from samples on the 0th, 2nd, 7th, 14th, 21st, and 35th days, and the colorimetric quantification of divalent iron ions (FeII) was performed using the o-phenanthroline method. That is, the amount of divalent iron ions was calculated using a standard curve prepared according to the following method (N=1: Table 5).

[0202] 1. Use a graduated pipette to accurately measure 0.0, 0.2, 0.4, 0.6, and 0.8 mL of iron standard solution (50 μg / mL) into five 10 mL volumetric flasks.

[0203] 2. After adding 0.4 mL of 6 mol / L hydrochloric acid, add 0.25 mL of hydroxylammonium chloride solution (100 g / L) and shake to mix.

[0204] 3. After adding 0.5 mL of phenanthroline solution (1 g / L) and 1 mL of ammonium acetate solution (500 g / L), add ion exchange water and accurately make up to 10 mL.

[0205] 4. Using ion exchange water as a reference (reference), measure the absorbance at 510 nm.

[0206] [Table 4]

[0207] Table 4. Addition amount and composition of reagents used

[0208]

[0209] [Table 5]

[0210] Table 5. Determination results of divalent iron ions

[0211]

[0212] Compared with Comparative Example 3 in which no lignin sulfonic acid was added, Examples 4 and 5 containing lignin sulfonic acid had high contents of divalent iron ions, and Example 5 showed a significantly high value (Table 5).

[0213] <Test Example 3: Effect on Phosphoric Acid Permeation (Examples 6 to 7 and Comparative Example 4)>

[0214] Air-dried soil (alluvial volcanic ash fertilizer-free soil, heavy clay soil, alluvial red forest soil) was fed to a 2 mm sieve, and the portion that passed through was used as the sample soil (Table 6). 50 g of sample soil was measured into a 500 mL beaker, and 225 mL of the following P-containing aqueous solution was added and stirred thoroughly, and then placed at room temperature for 24 hours. Water was added thereto, and a total of 500 mL of paddy field water sample was obtained in the state containing soil. It was filtered with dry filter paper (Toyo filter paper No. 5A). A portion of the filtrate was taken into an aluminum measuring dish, evaporated and dried to solidify, and the count value (CPM: counts per minute (Counter Per Minute)) was measured with a GM counter, and compared with the count value of the standard P, the total P value in the paddy field water sample was calculated. The phosphate absorption rate is expressed as the P adsorbed by the soil. 32 The percentage relative to the total P added is expressed (N=1: Table 7). 32 It is an orthophosphate solution (pH 2-3) manufactured by The Radiochemical Centre in the UK with a radiochemical purity of >99%.

[0215] [P-containing aqueous solution]

[0216] P 2 O 5 550mg(NaH 2 PO 4 );

[0217] N 50mg(NH 4 Cl);

[0218] K 50mg (KCl);

[0219] The lignin sample was dissolved in the P-containing aqueous solution so as to be 0.0001% (= 0.05 mg) or 0.001% (= 0.5 mg) relative to the soil.

[0220] [Table 6]

[0221] Table 6. Composition of sample soil

[0222]

[0223] [Table 7]

[0224] Table 7. Phosphoric acid penetration test results

[0225]

[0226]

[0227] The residual amount of phosphoric acid in paddy field water in each soil of Examples 6 and 7 using lignin sulfonic acid was larger than that in Comparative Example 4 where no lignin sulfonic acid was added (Table 7).

[0228] <Test Example 4: Calcium carbonate dispersion test (Type B viscosity test) (Example 8, Comparative Examples 5-6)>

[0229] To evaluate the effect on the dispersibility of calcium carbonate used as a bulking agent for pesticides.

[0230] 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% relative to the total amount of the slurry. The stirring was performed at 3000 rpm for 2 minutes using a homogenizer. The B-type viscosity of the stirred slurry was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.) at 20°C, 60 rpm, rotor No. 3 or rotor No. 2, and without protection (Table 8).

[0231] [Table 8]

[0232] Table 8. Test results

[0233]

[0234] Compared with Comparative Example 5 using only water, Example 8 using Sample 3 has a lower viscosity.

[0235] <Test Example 5: Agglomeration (Examples 9 to 13 and Comparative Examples 7 to 8)>

[0236] Collect 50-100g of each test soil (Table 9) into a culture dish (90mm×20mm) or a beaker (200cc), apply the sample in the amount shown in Tables 9 and 10 (weight %: relative to absolutely dry soil) and stir thoroughly, then add 60% of the maximum guest water and culture at 30°C for 7 days. After culturing, air-dry for 5-7 days to obtain samples for aggregate analysis (N=3). Aggregate analysis is performed using the water sieving method according to conventional methods. The analysis results are expressed as the degree of agglomeration of particles below 0.25mm, and the aggregate forming force is compared. The degree of agglomeration is calculated by the following formula.

[0237] Degree of agglomeration (%) = {(secondary particles - primary particles) / absolute dry weight of the test soil} × 100

[0238] [Table 9]

[0239] Table 9 Relationship between granulation and type of soil additive (Samples 2 and 6: 0.1 wt % added) (Unit: %)

[0240] Example 9 Comparative Example 7 Comparative Example 8 Test soil Sample 2 Sample 4AZUMIN blank Japanese Maoyue heavy clay dry field soil 19.4 18.5 17.2 Red lean soil volcanic ash dry field soil 41.6 34.0 40.8 Alluvial dry field soil in Saijo, Japan 16.2 15.8 12.4 Alluvial forest soil in Saijo, Japan 35.4 33.2 25.6

[0241] [Table 10]

[0242] Table 10 Relationship between the amount of lignin sulfonic acid component (sample 2) added and the degree of agglomeration (unit: %)

[0243]

[0244] The lignin sulfonic acid component has a higher agglomeration effect than AZUMIN, and there is a tendency that a higher agglomeration effect is observed in accordance with the amount added.

[0245] The results of the examples show that the lignin sulfonic acid component has good dispersibility in the soil and can also improve the dispersibility of other components added at the same time; and because the soil is well matured, the effects such as the formation of aggregates can be improved, so it is effective as a soil conditioner. In addition, these results show that lignin sulfonic acid is also effective as a biostimulant, which is presumably because it brings a better physiological state to the soil. By using the lignin sulfonic acid of the present invention as a biostimulant, not only can the quality of crops be improved (reducing the amount of crop decay, increasing yield, etc.), but also the yield can be improved by improving the fertilizer effect.

Claims

1. A soil conditioner comprising lignin sulfonic acid having a phenolic hydroxyl group content of 0.1 to 5.0% by weight, a methoxy group content of 1.0 to 15.0% by weight, and a sulfur atom content derived from a sulfonic group of 2.0% or more.

2. The agent according to claim 1, which satisfies at least any one of the following: Lignosulfonic acid The sulfur atom content is 1.0 wt% or more; The sodium atom content is 0.3% by weight or more; and The reducing sugar content is 0.1% by weight or more.

3. The agent according to claim 1 or 2, wherein the carboxyl content of the lignin sulfonic acid is 0.1 to 4.5 mmol / g. 4 . The agent according to claim 1 , wherein the weight average molecular weight (RI) of the lignin sulfonic acid is 3,000 or more. 5 . The agent according to claim 1 , wherein the lignin sulfonic acid has a substituent derived from a (poly)alkylene oxide.

6. The agent according to any one of claims 1 to 5, wherein the soil is agricultural soil.

7. A biostimulant for soil, comprising lignin sulfonic acid having a phenolic hydroxyl content of 0.1 to 5.0% by weight, a methoxyl content of 1.0 to 15.0% by weight, and a sulfur atom content derived from a sulfonic group of 2.0% or more.

8. A soil improvement composition comprising the agent according to any one of claims 1 to 6 or the biostimulant according to claim 7 and soil.

9. A method for improving soil, comprising adding the agent according to any one of claims 1 to 6 or the biostimulant according to claim 7 to the soil.

10. A method for producing plants, comprising using the soil improving composition according to claim 8 to produce plants.

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