Soil anti-caking agent

Abstract

The present invention is an anti-caking agent for soil and a method for improving a plant using the same, the anti-caking agent for soil comprising lignin and diatomaceous earth as active ingredients, the lignin having a molecular weight peak within the molecular weight range of 10,000-40,000 at a wavelength of 254 nm in a GPC molecular weight analysis using a UV detector, and a method for improving a plant using the anti-caking agent for soil. The anti-caking agent for the soil has the effects of improving caking of the soil and improving poor growth of plants.

Description

[0001] The invention of this application is a divisional application of the application with application number 201880060439.X, invention name “anti-caking agent for soil” and application date September 26, 2018. Technical Field

[0002] The invention relates to an anti-caking agent for soil with lignin as an effective component. Background Art

[0003] Lignin is a complex natural polymer with a three-dimensional network structure containing phenylpropane units. In addition, lignin is contained in plants at about 20 to 30%, so it is known as the most abundant natural aromatic polymer and has attracted attention as a renewable resource. It is known that in addition to naturally occurring lignin, lignin can also be prepared through the pulp manufacturing process, etc. Among them, lignin sulfonic acid can be obtained in large quantities from the pulp manufacturing waste liquid. The use of lignin sulfonic acid in various applications has been studied, and in Non-Patent Document 1, it is expected to be used as a soil conditioner.

[0004] Soil conditioners are materials that are applied to the soil to change the physical properties of the soil and are beneficial to agricultural production. They have the effects of softening the soil, improving water retention, improving fertilizer retention, improving water permeability, promoting the formation of aggregates, etc. In general, peat, bark compost, humic acid materials, charcoal, diatomaceous earth, zeolite, vermiculite, perlite, bentonite, VA mycorrhizal materials, polyethyleneimine-based materials, polyvinyl alcohol-based materials, etc. are used as soil conditioners.

[0005] Lignin sulfonic acid has a sulfonic group as a hydrophilic group, so when used as a soil conditioner, although it binds to the soil, it has a granulation effect due to its high molecular weight, and shows a soil improvement effect on soils with little organic content and low granulation performance (Non-Patent Document 1). On the other hand, there is no report that lignin sulfonic acid has an anti-caking effect on soils such as clay soils that clumpingly hinder the growth of plant roots.

[0006] Prior art literature

[0007] Non-patent literature

[0008] Non-patent literature 1: Lignocellulose Biorefinery Engineering: Principles and applications P.82 (Hongzhang Chen) Summary of the invention

[0009] Problems to be solved by the invention

[0010] Provided is an anti-caking agent for soil containing lignin as an effective ingredient.

[0011] Methods for solving problems

[0012] The present inventors have conducted intensive studies and have found that lignin and diatomaceous earth having a molecular weight peak in the range of 10,000 to 40,000 at a wavelength of 254 nm in GPC molecular weight analysis using a UV detector have a high effect as an anti-caking agent for soil, thereby completing the present invention.

[0013] That is, the present invention has the following structures (1) to (5).

[0014] (1) A soil anti-caking agent comprising lignin and diatomaceous earth as active ingredients, wherein the lignin has a molecular weight peak in the range of 10,000 to 40,000 at a wavelength of 254 nm in a GPC molecular weight analysis using a UV detector.

[0015] (2) The soil anti-caking agent according to (1), wherein the lignin is an alkali extract of bagasse.

[0016] (3) The soil anti-caking agent according to (1) or (2), wherein the ratio of the lignin to the diatomaceous earth is 1:1 to 3 on a dry weight basis.

[0017] (4) A method for preventing soil caking, comprising preventing soil caking using the soil anti-caking agent according to any one of (1) to (3).

[0018] (5) A method for improving plant growth, comprising using the soil anti-caking agent according to any one of (1) to (3).

[0019] Effects of the Invention

[0020] The anti-caking agent for soil of the present invention has the effects of improving soil caking and improving poor growth of plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A specific example of GPC molecular weight analysis using a UV detector when the lignin used in the present invention is included

[0022] Figure 2 Specific example of GPC molecular weight analysis using a UV detector when lignin sulfonic acid is contained

[0023] Figure 3 A specific example of GPC molecular weight analysis of a liquid containing a bagasse alkali hot water extract subjected to solid-liquid separation using a filter press DETAILED DESCRIPTION

[0024] The scheme for implementing the present invention is described in detail.

[0025] Lignin is a high molecular weight phenolic compound derived from plants. The detailed structure of lignin is unclear due to its complex and diverse structure. In addition, the molecular weight varies depending on the type of biomass, extraction method, and analysis method, but the general number average molecular weight reported is 2,400 to 9,700 (Biofuels Bioproducts & Biorefinering, Volume 8, Issue 6, 836-856 (2014)).

[0026] The soil anti-caking agent of the present invention contains, as an active ingredient, lignin having a molecular weight peak in the range of 10,000 to 40,000 in GPC molecular weight analysis at a wavelength of 254 nm.

[0027] The above-mentioned lignin may have multiple molecular weight peaks as long as it is within the above-mentioned molecular weight range. In addition, it may have a molecular weight peak outside the present molecular weight range. However, in this case, it is preferred that the peak with the maximum height among the molecular weight peaks is within the molecular weight range of 10,000 to 40,000. A specific example of GPC molecular weight analysis of the lignin used in the present invention using a UV detector is shown in Figure 1 In GPC analysis, lignin with a maximum molecular weight peak of less than 10,000 often exists as a liquid under the pH conditions of the soil in which plants grow (pH = 5 to 8). Liquid lignin is not preferred because it flows out of the soil before the soil anti-caking effect is fully obtained.

[0028] exist Figure 2 A specific example of GPC molecular weight analysis using a UV detector is shown in the figure when lignin sulfonic acid, which is a general industrial lignin, is included. Lignin sulfonic acid, which is a general industrial lignin, is a substance produced as a by-product from lignin in wood in the pulp manufacturing process using the sulfite method, and is contained in large quantities in black liquor, which is a waste liquid. Its CAS registration number is 8062-15-5. Lignin sulfonic acid is produced by introducing sulfonic groups into lignin through treatment with sulfurous acid. According to Figure 2 The peak of the molecular weight with the maximum height of lignin sulfonic acid at a wavelength of 254 nm is located at a value higher than 40,000. The lignin used in the present invention is characterized by having a smaller molecular weight than general lignin sulfonic acid.

[0029] Lignin has a tendency to have higher hydrophobicity as its molecular weight increases. Lignin with high hydrophobicity has a strong force for solidification between each other, so it has the effect of forming soil into granules, but does not have an effective improvement effect on soil that is easy to clump and has a high proportion of clay. The lignin used in the present invention has a molecular weight peak in the range of molecular weight 10,000 to 40,000, so it is speculated that it has the following effects: when mixed with soil, it is dispersed in the soil to prevent the close adhesion between soil particles when the soil is mixed. By preventing the close adhesion between soil particles, it has the following effects: preventing soil from caking, improving the air permeability and water permeability of plant roots, thereby restoring the elongation of the roots and improving the growth of plants.

[0030] The molecular weight peak of the lignin used in the present invention preferably has a molecular weight in the range of 10,200 to 37,000, and more preferably 11,000 to 35,000.

[0031] The molecular weight of lignin can also be determined by the number average molecular weight. The preferred average molecular weight of lignin used in the present invention is preferably 4,000 to 40,000, more preferably 8,000 to 20,000, as the number average molecular weight in GPC molecular weight analysis using a UV detector.

[0032] GPC molecular weight analysis is an abbreviation of Gel Permeation chromatography, which can separate the compounds in the test sample into each molecular size. In addition, the relative amount of the separated polymer is detected by a detector, and the molecular weight can also be calculated. For GPC molecular weight analysis, the relationship between the dissolution time and the molecular weight is calculated in advance using a standard polymer, and the molecular weight of the test sample is converted based on the relationship. The molecular weight of the lignin used in the present invention is a value measured using polyethylene glycol and polyethylene oxide as standard polymers. In addition, the number average molecular weight is calculated by the following formula (1) from the value of the measured molecular weight. Mn in formula (1) represents the number average molecular weight, M represents the molecular weight, N represents the number of polymers, and C represents the sample concentration.

[0033] Mn=Σ(Mi·Ni) / Σ(Ni)=ΣCi / Σ(Ci / Mi) Equation (1).

[0034] The detector for GPC analysis utilizes a detector that can detect 250 to 300 nm, which is the absorption wavelength region of lignin. As the wavelength used for GPC analysis, any wavelength that has the absorption range of aromatic compounds can be measured. As representative wavelengths, there are 254 nm, 280 nm, 300 nm, etc., but the value analyzed at 254 nm is used in the present invention. As a detector for GPC analysis, a value detected by a multi-wavelength ultraviolet-visible absorption detector (SPD-M20A) manufactured by Shimadzu Corporation is used.

[0035] There is no particular limitation on the column used for the GPC molecular weight analysis, but the molecular weights of the present invention are values ​​measured using TSKgel GMPWXL and G2500PWXL.

[0036] The lignin used in the present invention preferably does not contain a sulfonic group. If a sulfonic group is contained, sulfur molecules are excessively supplied to the soil, sometimes hindering the growth of plants. In addition, the sulfur molecules in the sulfonic group are also likely to cause bad odors.

[0037] Plants used as the raw material of lignin used in the present invention are preferably plants of the grass family, more preferably rice straw, wheat straw, bagasse which is the residue of sugarcane, sugarcane tips, and sugarcane leaves, and most preferably bagasse.

[0038] As a method for extracting lignin used in the present invention from the above-mentioned plants, there are extraction using an organic solvent (ethanol, ethyl acetate, etc.), acid extraction, alkali extraction, etc., and alkali extraction is preferred. Among alkali extractions, alkali hot water extraction is more preferred.

[0039] The alkaline compound used in the alkaline extraction method is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, ammonia, etc., preferably sodium hydroxide and potassium hydroxide, and more preferably sodium hydroxide.

[0040] The conditions of the alkali hot water extraction method are preferably pH 10 to 13.5, temperature 80°C to 120°C, and reaction time of 0.5 hours or more, and more preferably pH 10.5 to 13.0, temperature 90°C to 120°C, and reaction time of 1 hour or more. The upper limit of the alkali concentration is not particularly limited as long as the lignin used in the present invention is obtained. When the alkali concentration is too high relative to the biomass, the lignin is de-molecularized, so that the effective component as the anti-caking agent of the soil of the present invention cannot be obtained, and the residual salt becomes large in amount, and it takes time and effort to separate the salt from the lignin. Therefore, if it is sodium hydroxide, for example, it is preferably treated with 180 g or less for 1 kg of dry weight of bagasse.

[0041] As a specific example of the alkaline hot water extraction method, for example, a solution of 50 g / L (dry weight) concentration of bagasse is reacted with a 0.45 (wt / wt)% sodium hydroxide aqueous solution at 90°C for 2 hours, thereby extracting the lignin used in the present invention. The so-called dry weight in this specification refers to the weight after the biomass is dried at 105°C until the weight becomes constant.

[0042] The lignin used in the present invention can be recovered on the solid component side after being extracted from plants by an alkaline hot water extraction method or the like, neutralized to a pH of 5 or less, and solid-liquid separation is performed. The high molecular weight lignin that is insoluble under the condition of pH 5 can be redissolved in water by making the pH again more alkaline than pH 5, for example, pH 10 or more. In the anti-caking agent for soil of the present invention, the lignin used in the present invention is used in the state of a solid component.

[0043] The diatomaceous earth used in the present invention is a deposit formed by fossilized shells of diatoms, which are a type of algae. The shells of diatoms are composed of silicon dioxide, and diatomaceous earth also has silicon dioxide as a main component. As a type of diatomaceous earth, calcined diatomaceous earth is preferred.

[0044] In addition, as a soil conditioner containing silicon, there is silicate clay, which is also called soft silica. Montmorillonite (chemical formula (Na, Ca) 0.33 (Al, Mg)2Si4O 10 Silicate minerals such as (OH)2·nH2O) are used as main components and are substances different from diatomaceous earth used in the present invention.

[0045] The soil anti-caking agent of the present invention has a small soil anti-caking effect when the amount of the soil anti-caking agent mixed is small, and when the amount is too much, the overall environmental balance such as the soil's original fertility retention capacity and the effect on plants obtained by retaining microorganisms collapses, and the improvement in plant growth becomes relatively weak.

[0046] The mixing ratio of the lignin used in the present invention to the soil is not particularly limited as long as the anti-caking effect of the soil occurs. Relative to 100 parts by weight of the soil, 2 to 20 parts by weight of the dry weight of the lignin is preferably mixed, and 3 to 10 parts by weight is more preferably mixed. The lignin used in the present invention can be preferably used in a dried state or in a state containing water as long as it is a solid component. In addition, for the anti-caking of the soil of the cultivated land, it is preferred to mix 8 to 80 tons of lignin by dry weight per 10a of cultivated land.

[0047] The mixing ratio of diatomaceous earth to soil is not particularly limited as long as the anti-caking effect of the soil is achieved. It is preferred to mix 3 to 20 parts by weight of diatomaceous earth per 100 parts by weight of soil, and more preferably 5 to 20 parts by weight. In addition, for the anti-caking of cultivated soil, it is preferred to mix 12 to 80 tons of diatomaceous earth per 10a of cultivated land in terms of dry weight.

[0048] In the anti-caking agent used in the present invention, the preferred ratio of lignin and diatomaceous earth used in the present invention is not particularly limited as long as the anti-caking effect of soil is achieved. It is preferred that diatomaceous earth is mixed in a ratio of 1 to 3 by weight relative to 1 by weight of lignin as a dry weight.

[0049] The mixing ratio of the anti-caking agent of the present invention to the soil is not particularly limited as long as the anti-caking effect of the soil is present, and preferably 5 to 25 parts by weight are mixed relative to 100 parts by weight of the soil as the dry weight of the total amount of lignin and diatomaceous earth used in the present invention. In addition, for the anti-caking of the soil of cultivated land, it is preferred to spread 20 to 92 tons of the anti-caking agent of the present invention for mixing per 10a of cultivated land.

[0050] Here, the dry weight of lignin, diatomaceous earth, and soil used in the present invention is calculated as the weight after the object is dried at 105° C. until the weight becomes constant, in the same manner as the calculation method of the dry weight of the above-mentioned biomass. In addition, when calculating the dry weight ratio of soil, it is calculated as the weight of cultivated soil 30 cm from the ground surface. In addition, when cultivating plants using flower pots, etc., it is calculated as the weight of the soil in the flower pots.

[0051] The anti-caking agent for soil of the present invention may include other anti-caking agents for soil in addition to the lignin and diatomaceous earth used in the present invention, and the anti-caking effect of soil may be improved by using it in combination with other soil improvers. Other soil improvers include peat, bark compost, humic acid materials, charcoal, zeolite, vermiculite, perlite, bentonite, VA mycorrhizal fungi materials, polyethyleneimine materials, polyvinyl alcohol materials, etc.

[0052] There is no particular limitation on the mixing ratio of the soil anti-caking agent of the present invention and other soil improvers as long as the effect is achieved. It is preferred that the other soil improvers be mixed in a ratio of 1 to 3 by dry weight relative to 1 of the soil anti-caking agent of the present invention.

[0053] The method of mixing the soil anti-caking agent with the soil may be either mixing using an agricultural machine or manual mixing, and any degree of mixing may be used as long as the soil is mixed uniformly to an extent that soil caking is suppressed.

[0054] The lignin and diatomaceous earth used in the present invention may be mixed in advance and then mixed with the soil, or may be mixed separately. In addition, when using an anti-caking agent for another soil other than the lignin and diatomaceous earth used in the present invention, the anti-caking agent for each soil may be mixed with the soil separately, or the anti-caking agent may be mixed in advance and then mixed with the soil. In the case of mixing separately, the order of mixing is irrelevant.

[0055] As soil that exerts the anti-caking effect of soil, it is soil that is easy to solidify and clump, so that the roots cannot physically extend, or soil that is insufficient in oxygen because the air cannot deeply enter the soil due to caking. Specifically, soil in which clay is more than 20% by weight in the particle size composition of the soil can be cited. As soil that can be particularly expected to have the anti-caking effect of the soil of the present invention, soil with a viscosity of 20 to 40% by weight can be cited. In addition to viscosity, the soil also contains sand, silt, etc. The so-called clay in this specification is a general term for debris with a particle size of less than 2μm, the so-called sand is a debris with a particle size of 2 to 0.02mm, and the so-called silt is a general term for debris with a particle size of 0.02 to 0.002mm.

[0056] As the anti-caking effect of soil, for soil that hinders the elongation of roots due to soil caking, the tension of the roots of plants is improved by preventing caking. By improving the elongation of roots, more nutrients can be absorbed from the roots, improving the growth of the aboveground parts. Specifically, when the anti-caking agent for soil of the present invention is used, the growth improvement of the plant can be evaluated by the increase in the fresh weight of the aboveground parts of the plant or the dry weight of the underground parts compared to the case where it is not used. Preferably, both the fresh weight of the aboveground part and the dry weight of the underground part are increased. The so-called aboveground part in this specification refers to the part of the plant body that appears on the ground. The so-called underground part in this specification refers to the part of the plant body that exists underground, and the aboveground part and the underground part are distinguished by the ground surface. In addition, the so-called fresh weight is the weight of the plant body itself including the moisture in the plant body at the time of harvest.

[0057] Plants whose growth can be expected to be improved by using the anti-caking agent for soil of the present invention are not particularly limited, but preferably are plants of the Gramineae family, root vegetables, and plants of the Umbelliferae family. Plants of the Gramineae family are preferably rice, wheat, barley, corn, sugar cane, sorghum, and Erianthus, and more preferably sugar cane. Root vegetables are yams, radishes, burdocks, carrots, and turnips, and more preferably yams or radishes. Yams are preferably potatoes, sweet potatoes, and cassava, and more preferably cassava. Radishes are preferably rouge radish (Radish). Plants of the Umbelliferae family are preferably Angelica keiskei, celery, celery, carrots, coriander, water celery, and parsley, and more preferably coriander.

[0058] Example

[0059] The present invention will be described in detail below with reference to Examples. Comparative Examples 1 to 10 and Examples 1 to 5 were tested five times simultaneously under various conditions. Each value in Table 1, Table 2, and Table 3 is an average value of the five tests.

[0060] (Reference Example 1) GPC Molecular Weight Distribution Measurement

[0061] GPC molecular weight analysis was carried out under the following conditions.

[0062] Detector: Multi-wavelength UV-visible absorption detector UV (SPD-M20A manufactured by Shimadzu Corporation, wavelength 254nm)

[0063] Column: TSKgel GMPWXL, G2500PWXL, 1 each in series (φ7.8mm×30cm, Tosoh)

[0064] Solvent: Ammonia buffer (pH 11) / methanol (1 / 1 = v / v)

[0065] Flow rate: 0.7mL / min

[0066] Column temperature: 23°C

[0067] Injection volume: 0.2mL

[0068] Standard sample: Monodisperse polyethylene oxide, polyethylene glycol manufactured by Tosoh, Polymer Laboratories

[0069] The number average molecular weight was calculated by formula (1).

[0070] The relationship between the elution time and the logarithm of the molecular weight was obtained in advance using a standard sample, and converted to a weight fraction dW / dlogM (W is weight) relative to the unit LogM (M is molecular weight). The horizontal axis was plotted as the logarithm of the molecular weight, and the vertical axis was plotted so that the peak area became 1 for analysis.

[0071] (Reference Example 2) Method for measuring the fresh weight of above-ground parts

[0072] The plant body was cut close to the ground, and the aerial part was harvested and its weight was measured.

[0073] (Reference Example 3) Method for measuring dry weight of underground part

[0074] The plant body was cut close to the ground, and the soil was removed from the underground part and soil remaining in the pot under running water so as not to cut the roots as much as possible. The plant body was dried at 105°C and the dry weight was measured.

[0075] (Reference Example 4) Sulfur Analysis

[0076] In order to measure the sulfonic groups contained in lignin, sulfur analysis was performed by the following method: The sample was weighed and burned in a combustion tube of an analysis device under the following device and conditions, and the generated gas was absorbed by a solution, and a part of the absorption solution was analyzed by ion chromatography (repeated twice).

[0077] <Combustion and absorption conditions>

[0078] System: AQF-100, GA-100 (Mitsubishi Chemical)

[0079] Electric furnace temperature: inlet 1000℃ outlet 1100℃

[0080] Gas: Air / O2 200mL / min.

[0081] O2 400mL / min.

[0082] Absorption solution: H2O2 0.1%, internal standard Br 2μg / mL

[0083] Absorption liquid volume: 10mL

[0084] <Ion chromatography, anion analysis conditions>

[0085] System: ICS1500 (made by DIONEX)

[0086] Mobile phase: 2.7mmol / L Na2CO3 / 0.3mmol / L NaHCO3

[0087] Flow rate: 1.50mL / min.

[0088] Detector: Conductivity detector

[0089] Injection volume: 100 μL.

[0090] (Comparative Example 1) Sugarcane bowl test (no anti-caking agent added to soil)

[0091] 1 kg of red soil (derived from the Kanto loam layer, containing 25% clay by weight) and river sand in a weight ratio of 8:2 was added to a No. 6 pot, and sugarcane seedlings (Okinawa stem height 7-8 cm) were planted. As a base fertilizer, 5 kg / 10a of chemical fertilizer (nitrogen-phosphorus-potassium = 8-8-8) was applied in terms of nitrogen, and 2 kg / 10a was further applied as topdressing after 1 month. If the top soil is dry, water it appropriately until water flows out from the bottom of the pot. After 80 days, the fresh weight of the above-ground part and the dry weight of the underground part were measured, and the results are shown in Table 1.

[0092] (Comparative Example 2) Sugarcane bowl test (lignin sulfonic acid)

[0093] The same procedure as in Comparative Example 1 was performed except that 10 parts by weight of lignin sulfonic acid (Bannirex HW manufactured by Nippon Paper Chemical Co., Ltd. neutralized to pH 7 with 10N sodium hydroxide. The sulfur content analyzed in Reference Example 4 was 2.8%) was added as an anti-caking agent for soil to 100 parts by weight of red soil (derived from the Kanto loam layer, containing 25% clay) and river sand mixed at a weight ratio of 8:2 in Comparative Example 1. After 80 days, the fresh weight of the above-ground part and the dry weight of the underground part were measured, and the results are shown in Table 1.

[0094] (Comparative Example 3) Sugarcane bowl test (burned diatomaceous earth)

[0095] The same procedure as in Comparative Example 1 was carried out except that 10 parts by weight of calcined diatomaceous earth was added to 100 parts by weight of soil in which red soil (derived from the Kanto loam layer and containing 25% clay) and river sand were mixed at a weight ratio of 8:2 as an anti-caking agent for soil. After 80 days, the fresh weight of the above-ground part and the dry weight of the underground part were measured, and the results are shown in Table 1.

[0096] (Comparative Example 4) Sugarcane bowl test (lignin used in the present invention)

[0097] 1 kg of bagasse (purchased from Taiwan Sugar Agricultural Products Co., Ltd., made in Vietnam) was added and mixed at 5% by weight in a 0.45% by weight sodium hydroxide aqueous solution, and the mixture was reacted at 90°C for 2 hours to extract lignin into an alkaline hot water solution. The alkaline hot water solution was adjusted to pH 5 using 6N hydrochloric acid to produce the lignin used in the present invention as a precipitate. The liquid containing the lignin used in the present invention was subjected to solid-liquid separation using a filter press (YTO type manufactured by Yabuta Machinery Co., Ltd.) to recover the solid content of the lignin used in the present invention. The recovered lignin was dried at 40°C to a moisture content of 20% by weight. The lignin used in the present invention was used as an anti-caking agent for soil, and 10 parts by weight (8 parts by weight as dry weight) was mixed with 100 parts by weight of soil in which red soil and river sand were mixed in a ratio of 8:2 in Comparative Example 1. The same operation as Comparative Example 1 was performed except that the fresh weight of the above-ground part and the dry weight of the underground part were measured after 80 days, and the results are shown in Table 1.

[0098] In addition, the lignin solid content used in the present invention was dissolved in a solution with a pH of 12 or higher prepared with NaOH, and the molecular weight distribution was measured under the conditions of Reference Example 1. The results were as follows: Figure 1 As shown, there was a molecular weight peak at a molecular weight of 21,000, and the number average molecular weight was 13,800. In addition, analysis was performed under the conditions of Reference Example 4, and as a result, no sulfur content was detected.

[0099] (Comparative Example 5) In the GPC molecular weight analysis, the molecular weight peak at a wavelength of 254 nm is less than the molecular weight of lignin of 10,000

[0100] The liquid fraction obtained by solid-liquid separation of the bagasse alkali hot water extract prepared in Comparative Example 4 was subjected to GPC molecular weight analysis under the conditions of Reference Example 1. The results are as follows: Figure 3 As shown, there is a peak at a molecular weight of 7,000, and the number average molecular weight is 4,000. Lignin having a peak at a molecular weight less than 10,000 becomes liquid at the pH of the region where plants grow, and it is judged that it cannot be used as an anti-caking agent for soil.

[0101] (Example 1) Sugarcane bowl test (combination use of lignin and calcined diatomaceous earth used in the present invention)

[0102] The anti-caking agent for soil (water content 10%) in which lignin used in the present invention and calcined diatomaceous earth were mixed was prepared by mixing 1 part by weight of lignin used in the present invention prepared in Comparative Example 4 with calcined diatomaceous earth at a dry weight ratio of 2. The anti-caking agent for soil mixed with lignin used in the present invention and calcined diatomaceous earth was prepared. The same operation as in Comparative Example 1 was performed except that 10 parts by weight of the anti-caking agent for the mixed soil was mixed with 100 parts by weight of soil in which red clay and river sand were mixed at a weight ratio of 8:2 in Comparative Example 1 (if the weight ratio is converted to dry weight, the lignin used in the present invention is 3 parts by weight and the diatomaceous earth is 6 parts by weight per 100 parts by weight of soil). After 80 days, the fresh weight of the above-ground part and the dry weight of the underground part were measured, and the results are shown in Table 1.

[0103] According to the results in Table 1, for sugarcane, Example 1, which used the lignin and diatomaceous earth used in the present invention as anti-caking agents for soil, increased both the fresh weight of the aboveground part and the dry weight of the underground part compared to Comparative Examples 1 to 4. It is believed that because the dry weight of the underground part increased in particular, the growth of the aboveground part was also improved by improving the elongation of the root. That is, it is believed that the lignin used in the present invention has a molecular weight peak at a wavelength of 254nm in the range of molecular weights of 10,000 to 40,000 in the GPC molecular weight analysis using a UV detector, and the lignin and diatomaceous earth are mixed with the soil as anti-caking agents for soil, thereby preventing soil caking, improving root growth, and improving the growth of the aboveground part of sugarcane. On the other hand, in Comparative Examples 2 and 3, compared with Comparative Example 1, the fresh weight of the aboveground part and the dry weight of the underground part were hardly confirmed to increase. Therefore, lignin sulfonic acid having a molecular weight peak value higher than 40,000 can hardly confirm the anti-caking effect of the soil. In addition, as an anti-caking agent for soil, Comparative Example 3 using diatomaceous earth and Comparative Example 4 using lignin used in the present invention showed an increase in both the fresh weight of the above-ground part and the dry weight of the underground part compared with Comparative Example 1, but the effect was lower than that of Example 1. From these results, it can be seen that when lignin and diatomaceous earth used in the present invention are used as anti-caking agents for soil, there is an effect that the increase in the fresh weight of the above-ground part and the dry weight of the underground part becomes higher than when each is used alone.

[0104] [Table 1] Sugarcane bowl test results (n=5)

[0105]

[0106]

[0107] (Comparative Example 6) Coriander bowl test (no anti-caking agent added to soil)

[0108] The same operation as in Comparative Example 1 was carried out except that coriander seedlings were used instead of sugarcane seedlings. The fresh weight of the above-ground part was measured after 80 days. Table 2 shows the obtained results.

[0109] (Comparative Example 7) Coriander bowl test (lignin sulfonic acid)

[0110] The same operation as in Comparative Example 2 was carried out except that coriander seedlings were used instead of sugarcane seedlings. The fresh weight of the above-ground part after 80 days was measured, and the obtained results are shown in Table 2.

[0111] (Comparative Example 8) Coriander bowl test (burned diatomaceous earth)

[0112] The same operation as in Comparative Example 3 was carried out except that coriander seedlings were used instead of sugarcane seedlings. The fresh weight of the above-ground part after 80 days was measured, and the obtained results are shown in Table 2.

[0113] (Comparative Example 9) Coriander bowl test (lignin used in the present invention)

[0114] In Comparative Example 4, the same operation as in Example 1 was carried out except that coriander seedlings were used instead of sugarcane seedlings. The fresh weight of the above-ground part after 80 days was measured, and the obtained results are shown in Table 2.

[0115] (Example 2) Coriander bowl test (combination use of lignin and calcined diatomaceous earth used in the present invention)

[0116] The same operation as in Example 1 was carried out except that coriander seedlings were used instead of sugarcane seedlings. The fresh weight of the above-ground part after 80 days was measured, and the obtained results are shown in Table 2.

[0117] According to the results in Table 2, for coriander, Example 2, which used lignin and diatomaceous earth used in the present invention as soil anti-caking agents, increased the fresh weight of the above-ground part compared with Comparative Examples 6 to 9. On the other hand, in Comparative Examples 7 and 8, the increase in the fresh weight of the above-ground part was hardly observed compared with Comparative Example 5.

[0118] [Table 2] Coriander bowl test results (n=5)

[0119]

[0120] (Comparative Example 10) Carrot pot test (no anti-caking agent added to soil)

[0121] 1 kg of red soil (derived from the Kanto loam layer, containing 25% clay by weight) and river sand was added to a No. 6 pot, and seeds of red radish (サカタのタネスピーディーベジタブル) were sown. After germination, the seedlings were thinned to 3 plants per pot. As a base fertilizer, chemical fertilizer (nitrogen-phosphorus-potassium = 8-8-8) was applied in terms of nitrogen at 5 kg / 10a. If the topsoil is dry, water it appropriately until the water flows out from the bottom of the pot. The fresh weight of the aboveground part 16 days after sowing was measured, and the results are shown in Table 3.

[0122] (Example 3) Carrot bowl test (combination of lignin and calcined diatomaceous earth used in the present invention)

[0123] The lignin used in the present invention prepared in Comparative Example 4 was mixed with calcined diatomaceous earth at a dry weight ratio of 1, and an anti-caking agent for soil (water content 10%) in which lignin used in the present invention and calcined diatomaceous earth were mixed was prepared. The anti-caking agent for the mixed soil was mixed with 10 parts by weight of soil in which red soil and river sand were mixed at a weight ratio of 8:2 in Comparative Example 1 (if the weight ratio is converted to dry weight, the lignin used in the present invention is 4.5 parts by weight and the diatomaceous earth is 4.5 parts by weight per 100 parts by weight of soil), except that the operation was carried out in the same manner as in Comparative Example 10. The fresh weight of the above-ground part 16 days after sowing was measured, and the results obtained are shown in Table 3.

[0124] (Example 4) Carrot bowl test (combination of lignin and calcined diatomaceous earth used in the present invention)

[0125] The lignin used in the present invention prepared in Comparative Example 4 was mixed with calcined diatomaceous earth at a dry weight ratio of 2 to prepare an anti-caking agent for soil (water content 10%) in which lignin used in the present invention and calcined diatomaceous earth were mixed. The same operation as in Comparative Example 10 was performed except that 10 parts by weight of the anti-caking agent for the mixed soil were mixed with 100 parts by weight of soil in which red soil and river sand were mixed at a weight ratio of 8:2 in Comparative Example 1 (if the weight ratio is converted on a dry weight basis, the lignin used in the present invention is 3 parts by weight and the diatomaceous earth is 6 parts by weight per 100 parts by weight of soil). The fresh weight of the above-ground part 16 days after sowing was measured, and the results are shown in Table 3.

[0126] (Example 5) Carrot bowl test (combination of lignin and calcined diatomaceous earth used in the present invention)

[0127] The lignin used in the present invention prepared in Comparative Example 4 was mixed with calcined diatomaceous earth at a dry weight ratio of 2 to prepare an anti-caking agent for soil (water content 10%) in which lignin used in the present invention and calcined diatomaceous earth were mixed. The anti-caking agent for the mixed soil was mixed with 10 parts by weight of soil in which red soil and river sand were mixed at a weight ratio of 8:2 in Comparative Example 1 (if the weight ratio is converted on a dry weight basis, the lignin used in the present invention is 2.25 parts by weight and the diatomaceous earth is 6.75 parts by weight per 100 parts by weight of soil). The fresh weight of the above-ground part 16 days after sowing was measured, and the results are shown in Table 3.

[0128] According to the results of Comparative Example 10 and Examples 3 to 5, when the lignin used in the present invention is mixed with diatomaceous earth in a dry weight ratio of 1:1 to 1:3 and used as an anti-caking agent for soil, the effect of increasing the fresh weight of the above-ground part of radish can be confirmed compared to the case where no anti-caking agent is added to the soil.

[0129] [Table 3] Test results of rouge radish pot test (n=5)

[0130] Comparative Example 10 Example 3 Example 4 Example 5 Lignin used in the present invention: diatomaceous earth (dry weight ratio) none 1:1 1:2 1:3 Average fresh weight of above-ground part (g) 2.5 3.2 3.5 3.1

Claims

1. A soil anti-caking agent, which contains lignin and diatomaceous earth as active ingredients, The lignin has a molecular weight peak in the range of 11,000 to 35,000 at a wavelength of 254 nm in a GPC molecular weight analysis using a UV detector, and a number average molecular weight in the GPC molecular weight analysis using a UV detector is 8,000 to 20,000, and the lignin is lignin that is insoluble under pH 5 and is contained in an alkali extract of bagasse.

2. The anti-caking agent for soil according to claim 1, wherein the ratio of the lignin to the diatomaceous earth is 1:1 to 3 based on dry weight ratio.

3. A method for preventing soil from caking, which uses the anti-caking agent for soil according to claim 1 or 2 to prevent soil from caking.

4. A method for improving plant growth, using the anti-caking agent for soil according to claim 1 or 2.

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