Particle-containing material for seedling-raising soil

Abstract

To provide a particle-containing material for seedling-raising soil that exhibits good transplantability, and also to provide a seedling-raising soil, a transplantability improving agent, and a transplantability improving method, using the particle-containing material for seedling-raising soil.SOLUTION: The particle-containing material for seedling-raising soil of the present invention contains resin-impregnated porous particles.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a material used in seedling raising soil, particularly to a material for improving transplantability. [Background technology]

[0002] In the agricultural sector, the aging and declining workforce are driving demands for greater agricultural efficiency. To address this issue, the use of mechanical transplanting of seedlings has become increasingly common in recent years. However, mechanical transplanting poses problems, such as the seedlings being damaged by the mechanical claws when being removed from the cell trays, making it difficult to transplant neatly.

[0003] Therefore, the culture medium used for mechanical transplanting must not collapse during the transplanting process, and methods of solidifying the culture medium using natural polymers or synthetic polymers derived from petroleum have been proposed. However, there are technical issues with uniform dispersion in the culture medium, long-term solidification performance, and growth disorders. Furthermore, some types of culture medium cannot fully solidify. For example, mechanical transplanting of outdoor vegetables is required to save labor, but since vegetable culture medium is composed of a large amount of highly water-repellent culture medium components such as peat moss, a consolidating agent that can fully solidify the culture medium regardless of the type of culture medium component is required.

[0004] Furthermore, against the backdrop of growing environmental awareness and the problem of marine plastic waste, non-biodegradable plastics are being replaced with biodegradable plastics, and biodegradable resins are beginning to be used in the agricultural field as well. Known technologies for using biodegradable resins in the agricultural field include molded processed products such as agricultural films (Patent Document 1) and spray-on shading agents for agricultural films (Patent Document 2), but there has been little research into their use as consolidating agents in seedling soil. Patent Document 3 proposes a technology for using biodegradable resins as consolidating agents in seedling soil. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-116798 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-147523 [Patent Document 3] Japanese Patent Application Publication No. 2017-176027 Summary of the Invention [Problem to be solved by the invention]

[0006] However, further technical improvements are desired in terms of the transplantability of seedlings, particularly in terms of maintaining compaction performance even after repeated irrigation over a long period of time and providing mechanical resistance during transplantation.

[0007] The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a particle-containing material for seedling cultivation soil that provides good seedling transplantability, seedling cultivation soil using the same, a transplantability improver, and a method for improving transplantability. [Means for solving the problem]

[0008] In order to solve the above problems, the inventors conducted extensive research and found that the use of resin-impregnated porous particles provides excellent transplantability for seedlings, and in particular, the amount of elution in the culture soil can be controlled, and the resin, which is the solidifying component, is gradually eluted, thereby demonstrating excellent solidification performance over a long period of time.Furthermore, since it is not affected by the type of culture soil constituent material, it can be used in a wide range of applications, and it is less likely to have a negative impact on plant growth, so it can be used even for plants that are prone to growth disorders, and this has led to the completion of the present invention. That is, the particle-containing composition for seedling culture soil of the present invention is characterized by containing resin-impregnated porous particles. The seedling raising soil of the present invention contains the particle-containing material for seedling raising soil. The transplantability improving agent of the present invention contains the above-mentioned seedling culture medium containing particles as an active ingredient. The method for improving transplantability of the present invention is characterized by using the particle-containing seedling culture medium. [Effects of the Invention]

[0009] According to the present invention, the transplantability of seedlings can be improved, and this effect is significant and exceeds the range of effects that a person skilled in the art could have predicted from the configuration of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail. <Particle-containing materials for seedling cultivation soil> The particle-containing material for seedling culture medium of the present invention contains resin-impregnated porous particles. The particle-containing material has a bulk and uniform shape, particularly a powder or granular shape. The particle-containing material may be dry or wet to the touch.

[0011] The method for impregnating the porous particles with the resin is not particularly limited, but examples thereof include a method of impregnating the porous particles with a resin dispersion, a method of dissolving the resin in a solvent and impregnating the porous particles with the resin, and a method of applying heat to a resin in a molten state and impregnating the porous particles with the molten resin.

[0012] (resin) In the present invention, the resin is impregnated into the porous particles and gradually elutes as a solidifying component in the culture soil, thereby imparting solidifying properties. The resin is not particularly limited, but examples thereof include biodegradable resins, synthetic resins, etc. Among these, biodegradable resins are preferred.

[0013] The biodegradable resin is not particularly limited, but examples thereof include polylactic acid, copolymers of lactic acid and other hydroxycarboxylic acids, dibasic acid polyesters such as polybutylene succinate, polybutylene succinate adipate, polyethylene succinate, and polybutylene adipate, polycaprolactone, copolymers of caprolactone and other hydroxycarboxylic acids, polyhydroxybutyrate, copolymers of hydroxybutyrate and other hydroxycarboxylic acids, etc. These may be used alone or in combination of two or more.

[0014] Among the above biodegradable resins, the other hydroxycarboxylic acids in the copolymer are not particularly limited, but examples thereof include glycolic acid, 2-hydroxybutyric acid, 2-hydroxyvaleric acid, 2-hydroxycaproic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctanoic acid, 2-hydroxy-2-methylpropionic acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxy-2-ethylbutyric acid, 2-hydroxy-2-methylvaleric acid, 2-hydroxy-2-ethylvaleric acid, 2-hydroxy-2-propylvaleric acid, 2-hydroxy-2-butylvaleric acid, 2-hydroxy Examples include 2-hydroxy-2-methylcaproic acid, 2-hydroxy-2-ethylcaproic acid, 2-hydroxy-2-propylcaproic acid, 2-hydroxy-2-butylcaproic acid, 2-hydroxy-2-pentylcaproic acid, 2-hydroxy-2-methylheptanoic acid, 2-hydroxy-2-ethylheptanoic acid, 2-hydroxy-2-propylheptanoic acid, 2-hydroxy-2-butylheptanoic acid, 2-hydroxy-2-methyloctanoic acid, 3-hydroxypropionic acid, 4-hydroxybutyric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 7-hydroxyheptanoic acid, etc. These may be used alone or in combination of two or more.

[0015] Lactic acid and hydroxycarboxylic acid may take the form of D-form, L-form, D / L-form, etc., but any form may be used without any limitation. When polylactic acid is used, the D-lactic acid content is preferably 1 to 30 mol%, more preferably 5 to 20 mol%.

[0016] Among these, polylactic acid and polycaprolactone are preferred because they are suitable for fully achieving the effects of the present invention, and polycaprolactone is more preferred because it provides better implantability even without a plasticizer.

[0017] The molecular weight of the biodegradable resin is not particularly limited, but for example, the weight-average molecular weight of polylactic acid is preferably 50,000 to 1,000,000, more preferably 100,000 to 800,000, and even more preferably 200,000 to 600,000, from the viewpoint of being suitable for fully achieving the effects of the present invention. The weight-average molecular weight of polycaprolactone is preferably 1,000 to 200,000, more preferably 10,000 to 150,000, and even more preferably 50,000 to 100,000, from the viewpoint of being suitable for fully achieving the effects of the present invention.

[0018] The weight average molecular weight (Mw) of polylactic acid and polycaprolactone can be determined, for example, by gel permeation chromatography (GPC) in comparison with standard substances of known molecular weight, according to the method described in the Examples section below.

[0019] The synthetic resin is not particularly limited, but examples thereof include polyolefin, polyester, polyether, polythioether, polysulfone, polycarbonate, polyurea, polyurethane, polyurethane polyurea, polyurea, polyamide, phenol resin, urea resin, melamine resin, guanamine resin, epoxy resin, acrylic resin, fluororesin, and silicone resin.

[0020] In the seedling culture medium containing particles of the present invention, the resin preferably has a low minimum film formation temperature (MFT) in order to form a film on the culture medium surface and exhibit high transplanting performance. Considering that a film is easily formed at atmospheric temperatures, the minimum film formation temperature of the resin is preferably 100°C or lower, more preferably 60°C or lower.

[0021] The particle-containing seedling soil of the present invention may contain a plasticizer together with the resin, which improves the film-forming properties of the resin.

[0022] A plasticizer is preferably blended when the biodegradable resin contains polylactic acid or the like, which has a high minimum film-forming temperature. When a plasticizer is blended, the amount is preferably such that the minimum film-forming temperature of the biodegradable resin is 100°C or less, more preferably 60°C or less. Depending on the type of biodegradable resin, the amount of plasticizer blended, including when polylactic acid is blended, is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 100 parts by mass or more, per 100 parts by mass of the biodegradable resin, from the viewpoint of improving film properties through plasticization. Furthermore, from the viewpoint of suppressing bleed-out of the plasticizer, the amount is preferably 400 parts by mass or less, more preferably 300 parts by mass or less, per 100 parts by mass of the biodegradable resin.

[0023] The plasticizer is not particularly limited, but examples thereof include adipic acid derivatives such as diisopropyl adipate, diisobutyl adipate, dioctyl adipate, diethylhexyl adipate, diisononyl adipate, diisodecyl adipate, dibutoxyethoxyethyl adipate, esters of adipic acid with 2-(2-methoxyethoxy)ethanol and benzyl alcohol, phthalic acid derivatives such as ethyl phthalyl ethyl glycolate, ethyl phthalyl butyl glycolate, and butyl phthalyl butyl glycolate, citric acid derivatives such as triethyl citrate, tributyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate, ether ester derivatives such as diethylene glycol diacetate, triethylene glycol diacetate, and triethylene glycol dipropionate, and glycerin derivatives such as glycerin triacetate, glycerin tripropionate, and glycerin tributyrate. Among these, those using adipic acid derivatives and citric acid derivatives are preferred because they have a high effect of improving film-forming properties.

[0024] (resin dispersion) The term "resin dispersion" refers to a finely dispersed resin and includes the state after the resin has been impregnated into porous particles. In this specification, however, the term "resin dispersion" also includes the resin dispersion before impregnation. From the viewpoint of dispersibility, the resin dispersion is preferably an aqueous dispersion of resin. Therefore, from the viewpoint of improving the dispersibility of the resin in an aqueous medium and stably dispersing the resin particles, it is preferable to add a dispersant.

[0025] The dispersant is not particularly limited, but examples thereof include polymer surfactants, ionic surfactants such as anionic surfactants and cationic surfactants, nonionic surfactants, etc. These may be used alone or in combination of two or more.

[0026] Examples of polymer surfactants include anionic polymers, cationic polymers, nonionic polymers, and amphoteric polymers. These polymer surfactants may be water-soluble, and examples thereof include polyacrylates, polymethacrylates, polyacrylamides, acrylic acid-alkyl methacrylate copolymers, acrylate-acrylamide copolymers, maleated polybutene, maleated polybutadiene, polymethyl vinyl ether, polyvinylpyrrolidone, polystyrene sulfonates, cationized cellulose, carboxymethyl cellulose, and cationized cellulose.

[0027] Examples of anionic surfactants include fatty acid salts, higher alcohol sulfate salts, liquid fatty acid oil sulfate salts, sulfate salts of fatty amines and fatty amides, fatty alcohol phosphate salts, alkylbenzene sulfonates, fatty amide sulfonates, and sulfonates of dibasic fatty acid esters.

[0028] Examples of cationic surfactants include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, fatty acid triethanolamine monoester salts, and alkylpolyoxyethyleneamines.

[0029] The nonionic surfactant is not particularly limited, and examples thereof include water-soluble polymers such as polyvinyl alcohol and polyvinylpyrrolidone, cellulose compounds such as carboxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose, polyoxyalkylene condensates such as ethylene oxide-propylene oxide copolymers, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene alkylphenol ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters, glycerin alkyl esters, polyoxyalkylene glycerin alkyl esters, polyglycerin fatty acid esters, and polyoxyalkylene polyglycerin esters. Among these, polyvinyl alcohol is preferred because it is itself biodegradable and is suitable for fully achieving the effects of the present invention.

[0030] The polyvinyl alcohol is not particularly limited, but examples thereof include unmodified polyvinyl alcohol, special polyvinyl alcohol having a branched structure, and modified polyvinyl alcohol. Among these, the special polyvinyl alcohol having a branched structure is preferred from the viewpoint of improving releasability from the cell tray during transplantation.

[0031] The modified polyvinyl alcohol is not particularly limited, but examples thereof include ethylene-modified polyvinyl alcohol, carbonyl-modified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, alkyl ether-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, acetamide-modified polyvinyl alcohol, diacetone group-modified polyvinyl alcohol, acrylonitrile-modified polyvinyl alcohol, silicone-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, etc. These may be used alone or in combination of two or more.

[0032] The saponification degree of polyvinyl alcohol is not particularly limited, but from the viewpoint of being suitable for fully obtaining the effects of the present invention, it is preferably 98% or less, more preferably 96% or less, even more preferably 94% or less, and particularly preferably 90% or less. Moreover, the saponification degree of polyvinyl alcohol is preferably 70% or more, more preferably 72% or more, even more preferably 75% or more, and particularly preferably 78% or more.

[0033] The molecular weight of polyvinyl alcohol is not particularly limited, but from the viewpoint of improving transplantability, releasability from the cell tray during transplantation, and solidification, the average molecular weight based on the viscosity-average degree of polymerization is preferably 10,000 or more, more preferably 30,000 or more, even more preferably 50,000 or more, particularly preferably 70,000 or more, and especially preferably 90,000 or more. From the viewpoint of the handleability of the biodegradable resin aqueous dispersion, the average molecular weight based on the viscosity-average degree of polymerization is preferably 200,000 or less, more preferably 180,000 or less, even more preferably 160,000 or less, particularly preferably 140,000 or less, and especially preferably 120,000 or less.

[0034] The average molecular weight of polyvinyl alcohol can be calculated from the viscosity average degree of polymerization, the degree of saponification, and the molecular weights of vinyl acetate units and vinyl alcohol units.

[0035] As described in JIS K 6726, the degree of polymerization of polyvinyl alcohol can be calculated based on the following formula from the intrinsic viscosity [η] (unit: liter / g) measured in water at 30°C after resaponifying polyvinyl alcohol with sodium hydroxide. Viscosity average degree of polymerization=([η]×10000 / 8.29) (1 / 0.62) This viscosity-average degree of polymerization is converted into the molecular weight of vinyl acetate units and vinyl alcohol units according to the ratio of the saponification degree to obtain the average molecular weight. In the case of modified polyvinyl alcohol, the viscosity average degree of polymerization is calculated in the same manner as above.

[0036] The mass ratio of dispersant to resin (dispersant / resin) is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, it is more preferably 0.05 or more, 0.1 or more, and 0.5 or more. The upper limit of the mass ratio of dispersant to resin (dispersant / resin) is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, it is more preferably 20 or less, 10 or less, 5 or less, and 2 or less.

[0037] The average particle size of the resin particles in the resin dispersion before impregnation is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, it is more preferably 0.010 μm or more, 0.050 μm or more, 0.10 μm or more, and 0.30 μm or more. The upper limit of the average particle size of the resin particles in the resin dispersion before impregnation is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, it is more preferably 100 μm or less, 50 μm or less, 10 μm or less, 5.0 μm or less, 3.0 μm or less, and 1.0 μm or less.

[0038] The standard deviation of the resin particles in the resin dispersion before impregnation is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, it is more preferably 0.0010 or more, 0.0050 or more, 0.010 or more, and 0.050 or more. The upper limit of the standard deviation of the resin particles in the resin dispersion before impregnation is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, it is more preferably 0.90 or less, 0.70 or less, 0.50 or less, and 0.30 or less.

[0039] In the resin dispersion, the aqueous solvent is not particularly limited, but examples thereof include a mixed solvent of water and an organic solvent compatible with water, etc. The proportion of water in the mixed solvent is not particularly limited, but is preferably 90 mass % or more, and more preferably 95 mass % or more, based on the total amount of the mixed solvent.

[0040] In the mixed solvent, the organic solvent is not particularly limited, but examples thereof include monohydric alcohols, polyhydric alcohols, etc. Examples of monohydric alcohols include methanol, ethanol, butanol, isopropyl alcohol (IPA), normal propyl alcohol, butanol, etc. Examples of polyhydric alcohols include glycerin, butylene glycol, etc. These may be used alone or in combination of two or more.

[0041] The resin dispersion may contain other components in addition to those listed above, provided that the effects of the present invention are not impaired. Examples of other components include, but are not limited to, polymer compounds, organic solvents, and viscosity modifiers. These may be used alone or in combination of two or more.

[0042] Examples of polymer compounds include polyacrylic acid, cellulose, starch, chitin, natural rubber, polysaccharides (xanthan gum, guar gum, etc.), lignin, etc. These may be used alone or in combination of two or more. The use of polymer compounds improves caking performance.

[0043] The solid content of the resin dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and particularly preferably 20% by mass or more, based on the total amount of the resin dispersion. When the solid content is within this range, the proportion of resin particles in the dispersion is high, thereby improving drying efficiency. Furthermore, when the viscosity of the dispersion is within an appropriate range, the resin particles are stably dispersed. Furthermore, the solid content is preferably 50% by mass or less, more preferably 40% by mass or less. When the solid content is within this range, the viscosity of the dispersion does not become too high, resulting in good handleability. Here, the solid content refers to the mass percentage obtained by subtracting the amount of aqueous solvent such as water from the total amount of the resin dispersion.

[0044] (porous particles) The porous particles are not particularly limited, but examples thereof include plant fibrous materials such as bark compost, peat moss, coco peat, coconut shells, rice husks, sawdust, bamboo powder, bagasse, peat, and grass peat, and inorganic materials such as vermiculite, diatomaceous earth, attapulgite, sepiolite, zeolite, perlite, montmorillonite, talc, and silica. These may be used alone or in combination of two or more. Among these, inorganic materials are more preferred because they are more suited to fully achieving the effects of the present invention, and silica is particularly preferred.

[0045] The mass ratio of the total amount of resin and dispersant to the porous particles ((resin + dispersant) / porous particles) is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, the preferred ranges are 0.00010 or more, 0.00050 or more, 0.0010 or more, 0.0050 or more, 0.010 or more, 0.050 or more, 0.080 or more, and 0.15 or more. The upper limit of the mass ratio of the total amount of resin and dispersant to the porous particles ((resin + dispersant) / porous particles) from the viewpoint of being suitable for fully achieving the effects of the present invention is 40 or less, 20 or less, 10 or less, 5.0 or less, 3.0 or less, 1.0 or less, and 0.50 or less.

[0046] The average particle size of the porous particles is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, the more preferred sizes are 0.1 μm or more, 0.5 μm or more, 1 μm or more, and 3 μm or more. The upper limit of the average particle size of the porous particles is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, the more preferred sizes are 100,000 μm or less, 10,000 μm or less, 5,000 μm or less, 2,000 μm or less, 500 μm or less, 100 μm or less, 50 μm or less, 20 μm or less, and 8 μm or less.

[0047] The average particle size of the porous particles refers to a value measured using a scanning electron microscope, for example, the average value of the longest diameter of 50 randomly selected particles.

[0048] The BET specific surface area of ​​the porous particles is not particularly limited, but in order of preference, from the viewpoint of being suitable for fully obtaining the effects of the present invention, it is preferably 1 m 2 / g or more, 10m 2 / g or more, m 2 / g or more, 50m 2 / g or more, 100m 2 The upper limit of the BET specific surface area of ​​the porous particles is not particularly limited, but in order of preference, it is 1,000 m / g or more, from the viewpoint of being suitable for fully achieving the effects of the present invention. 2 / g or less, 800m 2 / g or less, 300m 2 / g or less, 200m 2 / g or less.

[0049] In the present invention, the BET specific surface area refers to the surface area of ​​a particle in a dry state measured by nitrogen gas adsorption and analyzed by the BET method. The BET specific surface area can be measured using a commercially available measuring device (e.g., Microtrac-Bel's high-precision gas / vapor adsorption measuring device "BELSORP® MAX").

[0050] The bulk density of the porous particles is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, the preferred values ​​are 0.1 g / L or more, 1 g / L or more, 10 g / L or more, 30 g / L or more, and 50 g / L or more. The upper limit of the bulk density of the porous particles is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, the preferred values ​​are 1,000 g / L or less, 500 g / L or less, 300 g / L or less, and 150 g / L or less.

[0051] The bulk density of porous particles is measured by the following method. Porous particles are added in several batches to a tared glass measuring cylinder, and after each addition, the measuring cylinder containing the porous particles is tapped until the measuring volume of the measuring cylinder is reached. The weight of the measuring cylinder containing the porous particles is then measured, and the bulk density of the porous particles is determined from the tared weight and volume of the measuring cylinder.

[0052] (Resin-impregnated porous particles) The average particle size of the resin-impregnated porous particles is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, the more preferred sizes are 1 μm or more, 7 μm or more, 12 μm or more, 17 μm or more, and 25 μm or more. The upper limit of the average particle size of the resin-impregnated porous particles is not particularly limited, but from the viewpoint of being suitable for fully achieving the effects of the present invention, the more preferred sizes are 3,000 μm or less, 800 μm or less, 300 μm or less, 100 μm or less, and 50 μm or less.

[0053] The average particle size of the resin-impregnated porous particles refers to a value measured with a scanning electron microscope, for example, the average value of the longest diameter of 50 randomly selected particles.

[0054] (Method of manufacturing a particle-containing material for seedling raising soil) The method for producing the particle-containing seedling soil of the present invention is not particularly limited, but for example, it can be produced by mixing and stirring a resin, a dispersant, and, if added, other components such as a plasticizer, together with an aqueous solvent to produce an aqueous dispersion of the resin, which can then be mixed with a porous body and impregnated.

[0055] Specifically, examples of such methods include a pressurized dispersion method in which a resin, dispersant, plasticizer, and water are simultaneously charged into a sealed tank equipped with a stirrer and pressurized while being heated and stirred to disperse the resin; a direct dispersion method in which a melt containing a resin, dispersant, and plasticizer is added to hot water held under pressure and stirred to disperse the resin; a phase inversion method in which a resin and plasticizer are heated and melted, and an aqueous solution containing a dispersant is added to the melt and stirred to disperse the resin in water; a method in which an organic solvent, water, resin, dispersant, and plasticizer are added and stirred to disperse the resin, and then the organic solvent is removed; and a method in which an aqueous solution containing a dispersant is added to an organic solvent solution of a resin and plasticizer and stirred to disperse the resin, and then the organic solvent is removed.

[0056] Considering that this method is applicable to a wide variety of resins and that the hydrolysis proceeds smoothly, a preferred method involves charging an organic solvent, water, a resin, a dispersant, and a plasticizer into a sealed tank equipped with a stirrer, raising the temperature while stirring, dissolving and dispersing the solid raw materials, cooling the mixture, and then removing the organic solvent under reduced pressure.

[0057] Alternatively, a preferred method involves charging an organic solvent, resin, and plasticizer into a sealed tank equipped with a stirrer, stirring and heating the mixture to dissolve the resin, preparing a biodegradable resin solution, charging water and a dispersant into another stirring tank, adding the resulting aqueous solution to the sealed tank, dispersing the resin while stirring and heating it to a temperature equal to or higher than the resin dissolution temperature, cooling the mixture, and then removing the organic solvent under reduced pressure.

[0058] The organic solvent is not particularly limited, but examples thereof include ester-based organic solvents such as formic acid esters (e.g., methyl formate, ethyl formate, propyl formate, butyl formate), acetate esters (e.g., methyl acetate, ethyl acetate, propyl acetate, butyl acetate), chlorine-based organic solvents (e.g., chloroform, carbon tetrachloride), and aromatic hydrocarbons (e.g., benzene, toluene, xylene). Among these, ester-based organic solvents, particularly formic acid esters and acetate esters, which have good resin solubility, are preferred. Considering sufficient dissolution of the resin, dispersant, etc., the ratio of organic solvent to water is preferably 1:9 to 9:1 by mass, and more preferably 7:3 to 3:7.

[0059] As a dispersing and stirring device for producing a particle-containing composition for seedling culture soil, a homomixer or high-pressure emulsifier may be used. However, instead of using these specialized devices, a rotary stirrer equipped with stirring blades such as propeller blades, paddle blades, turbine blades, anchor blades, or ribbon blades, which are commonly used for dispersing and mixing, can also be used. The stirring speed and rotation speed may also be the same as those used for normal dispersing and mixing. For example, a stirring blade having a ratio of the blade diameter (d1) of the stirring blade during dispersion to the inner diameter (d2) of the stirring tank (blade ratio: d1 / d2) of 0.5 to 0.85 can be used. The peripheral speed of the stirring blade can be 1 to 8 m / s.

[0060] <Soil for raising seedlings> The seedling raising soil of the present invention contains the seedling raising soil particle-containing material of the present invention. The seedling raising soil of the present invention uses a soil constituent material as a base material, and for example, the seedling raising soil particle-containing material of the present invention is mixed with the soil constituent material.

[0061] The materials constituting the soil for raising seedlings in the present invention are not particularly limited, but include those typically used as soil for agriculture or horticulture, such as plant fibrous materials, inorganic materials, fertilizers, soil, etc. These soil-constituting materials may be used alone or in combination of two or more.

[0062] The soil constituent materials that form the base material of the seedling raising soil can be appropriately combined with the materials that can be used as soil, as described above, depending on the plant species to be raised. By using such seedling raising soil, it is possible to accommodate seedlings with a small root area, and to form a root ball that is easy to plant and does not easily collapse.

[0063] When the seedling raising soil of the present invention uses the particle-containing composition for seedling raising soil of the present invention, it can exhibit high consolidation performance without being affected by the type of soil constituent material or the water temperature during irrigation, etc. Because it is not affected by the type of soil constituent material, it can be used in a wide range of applications, such as seedling raising soil containing soil constituent materials that are difficult to consolidate with conventional consolidating agents, such as plant fibrous materials.

[0064] The seedling raising soil of the present invention may contain other components depending on the plant species to be raised, as long as the effects of the present invention are not impaired. Examples of other components include, but are not limited to, agricultural chemicals. Examples of agricultural chemicals include herbicides, animal repellents, growth regulators, soil conditioners, useful microorganisms, useful bacteria, and permeable agents. These may be used alone or in combination of two or more.

[0065] In the seedling raising soil of the present invention, the content of the seedling raising soil particle-containing material of the present invention is not particularly limited, but from the viewpoint of good consolidation performance and suppressing the decrease in root ball strength, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, based on the total amount of the soil constituent materials. Also, from the viewpoint of growth, it is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5.0% by mass or less.

[0066] By adding and mixing the particle-containing composition for seedling raising soil of the present invention with the soil constituent material that serves as the base material for the seedling raising soil, unconsolidated seedling raising soil can be obtained, which can be used as is or packed and stored in bags. Unconsolidated seedling raising soil is typically in a granular state and has a moisture content of less than 60%.

[0067] As described above, the unconsolidated seedling raising soil can be distributed in a bagged granular state, making it easy to handle and allowing it to be filled into seedling containers of various shapes and cell counts. This allows farmers to use seedling containers they already own, reducing the cost of agricultural production.

[0068] The seedling raising soil before compaction is filled into a seedling raising container, for example, and after spreading and pressing, is air-dried at room temperature and then compacted to become a culture soil for raising plants.

[0069] As the seedling containers to be filled with the seedling raising soil before compaction, cells, pots, trays, seedling boxes, etc., similar to those conventionally used can be used, and the type, shape, structure, size, etc. of the seedling raising containers can be selected appropriately according to each situation. However, the seedling raising soil before compaction should be filled with a volume of 10 cm per cell. 3 It exerts a particularly remarkable effect when filled into the following small containers.

[0070] The seedling raising soil before compaction is filled into a seedling raising container and then compressed, i.e., pressed from above, to obtain a seedling raising soil with the desired root ball strength after compaction. The pressure during compression is not particularly limited, but is, for example, in the range of 0.1 to 10.0 MPa. If the pressure during compression is within the above range, the root ball strength is increased, and cracking or crumbling of the root ball can be suppressed during transportation from the seedling raising facility, removal with a transplanter, and planting in the field.

[0071] The optimum pressure for such spreading varies depending on the agricultural product being raised. For example, it is about 0.98 MPa for common vegetables, and about 4.9 MPa for onions. A commercially available seed drill or the like can be used to spread the seedling soil before compaction.

[0072] The seedling raising soil before compaction can be solidified by air-drying at room temperature. The time required for air-drying is not particularly limited, but is, for example, in the range of 1 to 15 days at room temperature. Specifically, air-drying is preferably performed for about 3 days when air-drying in a vinyl greenhouse, about 1 day in a germination room controlled at a temperature of 25 to 28°C and humidity of approximately 0%, or about 1 week indoors in an environment similar to that of an agricultural worker, such as a house or barn. The moisture content of the seedling raising soil after air-drying can be adjusted appropriately depending on the type of plant, such as an agricultural product, being raised.

[0073] The seedling raising soil of the present invention can be easily produced by simply filling the seedling raising soil into a seedling raising container without heating the unconsolidated seedling raising soil, spreading it, and air-drying it at room temperature. Therefore, no special equipment for heat consolidation is required, and the seedling raising container is less likely to deform or break, making it possible to reduce the cost of agricultural production.

[0074] When raising plants using the seedling raising soil of the present invention, for example, as described above, a commercially available cell tray is filled with pre-compacted seedling raising soil using a seeding machine, spread and compacted, and then air-dried to compact. Vegetable or other plant seeds are sown one seed per cell using a seeding machine, covered with pre-compacted seedling raising soil, and then germinate and raise seedlings using standard procedures such as irrigation. Alternatively, pre-compacted seedling raising soil can be mixed with vegetable or other plant seeds, filled into a commercially available cell tray using a seeding machine, spread and compacted, then air-dried to compact, and then germinate and raise seedlings using standard procedures such as irrigation. In addition to seeds, cuttings can also be taken and rooted for raising seedlings.

[0075] The seedling raising soil of the present invention can be used for agricultural purposes such as for vegetables and rice, and for horticultural purposes. Examples of plants suitable for raising seedlings using the seedling raising soil of the present invention include vegetable cell seedlings, fruit and vegetable cell seedlings, cut flowers, potted plants, seedlings, flower beds, and cut flowers.

[0076] Examples of uses for vegetable cell seedlings include Liliaceae (e.g., leeks, onions, chives, garlic, asparagus, etc.); Umbelliferae (e.g., celery, mitsuba, parsley, carrots, angelica tree, etc.); Chenopodiaceae (e.g., spinach, Swiss chard, and okahijiki, etc.); Brassicaceae (e.g., Chinese cabbage, cabbage, mizuna, komatsuna, Brussels sprouts, cauliflower, broccoli, bok choy, kohlrabi, tatsoi, takuna, takana, watercress, radish, and rape blossoms, etc.); Asteraceae (e.g., lettuce, shunjiu, burdock, butterbur, and yacon, and Lamiaceae (e.g., perilla); Amaranthaceae (e.g., beet, etc.) and Pedaliaceae (e.g., sesame, etc.); Asteraceae (e.g., endive, etc.); and Amaryllidaceae (e.g., leek, etc.). Among these, because of the high ratio of soil used in the culture medium and because the roots are thin and prone to collapse of the root ball, this method is suitable for raising Liliaceae seedlings.

[0077] Examples of uses for fruit and vegetable cell seedlings include Gramineae such as wheat, barley, and rice; Cucurbitaceae such as melon, cucumber, watermelon, pumpkin, wax gourd, golden melon, bitter melon, and zucchini; Solanaceae such as tomato, eggplant, bell pepper, paprika, chili pepper, and potato; Malvaceae such as okra and molukhiyah; Leguminosae such as sweet corn (maize) and kidney beans; and Leguminosae such as peas, edamame, and fava beans.

[0078] Plants suitable for taking cuttings in the nursery soil before or after compaction include plants that can be propagated by cuttings, such as chrysanthemums, carnations, and perennial baby's breath.

[0079] Examples of cut flowers include lisianthus, snapdragon, bupleurum, eustoma, stock, anemone, campanula, dahlia, scapiosa, delphinium, larkspur, nigella, polensis, blue lace flower, matricaria, lily of the valley, limonium sinuata, oxypetalum, craspedia, and vermilion.

[0080] Examples of plants for use in pots, seedlings, and flower beds include ageratum, isotoma, impatiens, exacum, gerbera, gazania, calceolaria, chrysanthemum, coleus, salvia, schizanthus, cineraria, geranium, torenia, pansy, vinca, primula, petunia, begonia, marigold, ranunculus, and carnation.

[0081] After raising plants using the seedling raising soil of the present invention, the cell seedlings or potted seedlings are separated using a transplanter, and the root ball is transplanted into a groundbed. The particle-containing seedling raising soil and seedling raising soil of the present invention have good consolidation performance and can suppress a decrease in root ball strength when hydrated, thereby suppressing the collapse of the root ball and separation of the roots from the soil during mechanical transplantation. Furthermore, if the resin dispersion contained as a consolidating agent in the seedling raising soil is a biodegradable resin dispersion, it has good biodegradability and there is no concern about environmental pollution.

[0082] <Portability improving agent, portability improving method> The seedling culture medium containing particles of the present invention is effective in improving the transplantability of seedlings, particularly in terms of its long-term solidification performance, its resistance to the effects of the type of culture medium constituent material, allowing it to be used in a wide range of applications, and its resistance to adverse effects on plant growth, making it usable for plants that are prone to growth disorders.Therefore, it can be suitably used in transplantability improvers that contain the seedling culture medium containing particles of the present invention as an active ingredient, and in methods for improving transplantability using the seedling culture medium containing particles of the present invention. [Example]

[0083] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. 1. Preparation of granular seedling soil In the examples and comparative examples, the following ingredients were used as the particle-containing seedling soil. (porous particles) Peat moss, average fiber length 1,000 μm, BET specific surface area 500 m 2 / g, bulk density 200g / l Vermiculite average particle size 1,000 μm, BET specific surface area 4 m 2 / g, bulk density 100g / l Zeolite average particle size 10 μm, BET specific surface area 700 m 2 / g, bulk density 650g / l Sepiolite, average particle size 200 μm, BET specific surface area 500 m 2 / g, bulk density 500g / l Silica-1 Average particle size 5 μm, BET specific surface area 180 m 2 / g, bulk density 70g / l Silica-2 Average particle size 10 μm, BET specific surface area 240 m 2 / g, bulk density 200g / l The average particle size of the porous particles was measured using a scanning electron microscope. The BET specific surface area and bulk density of the porous particles were measured by the methods described above.

[0084] (Non-porous particles) Silica sand average particle size 100μm

[0085] (biodegradable resin) Polylactic acid-1 Weight average molecular weight: approx. 400,000 Polylactic acid-2 Weight average molecular weight: approx. 120,000 Polycaprolactone-1 Weight average molecular weight 64,000 Polycaprolactone-2 Weight average molecular weight 2,000 The average molecular weight of a biodegradable resin, that is, the weight average molecular weight (Mw), refers to the average molecular weight in terms of polystyrene measured by gel permeation chromatography using the following apparatus and conditions. [GPC measurement device] Column: JASCO Corporation Detector: RI detector for liquid chromatography, JASCO Corporation RI-1530 [Measurement conditions] Solvent: Chloroform (special grade) Measurement temperature: 50℃ Flow rate: 1.0ml / min Sample concentration: 15mg / ml Injection volume: 2μl Calibration curve: Universal Calibration Analysis program: ChromNAV (Ver.1.19.02)

[0086] (dispersant) PVA-1 Polyvinyl alcohol Molecular weight: 100,000 Saponification degree: 80% PVA-2 Polyvinyl alcohol Molecular weight: 16,000 Saponification degree: 80% PVA-3 Polyvinyl alcohol Molecular weight: 16,000 Saponification degree: 88% Polyoxyethylene (5 moles) nonylphenyl ether Copolymer of ethylene oxide (EO) and propylene oxide (PO). Number average molecular weight: 3300. EO:PO ratio (EO:PO) = 46:54. The average molecular weight of polyvinyl alcohol is a value calculated from the viscosity average degree of polymerization, the degree of saponification, and the molecular weights of vinyl acetate units and vinyl alcohol units as described in JIS K 6726, as described above.

[0087] (plasticizer) Diisobutyl adipate

[0088] The raw materials other than the porous particles were charged into a sealed dispersion tank in the component ratios shown in Tables 1A to 1D. Ethyl acetate was then added in an amount 1.5 times the amount of ion-exchanged water charged, heated to 65°C, dispersed using a predetermined stirring and dispersion device, and then rapidly cooled to 40°C. The ethyl acetate was then removed under reduced pressure to obtain a biodegradable resin aqueous dispersion, which was then mixed with porous particles and impregnated to obtain a particle-containing composition for seedling culture soil. In Comparative Example 1, the biodegradable resin aqueous dispersion obtained above was not mixed with porous particles. In Comparative Example 3, the biodegradable resin aqueous dispersion obtained above was mixed with non-porous particles.

[0089] The average particle size and standard deviation of the particle size distribution of the biodegradable resin particles in the biodegradable resin aqueous dispersion were measured using a Shimadzu laser diffraction particle size distribution analyzer (Shimadzu Corporation, SALD-2300 model, refractive index 1.45-0.00i).

[0090] The average particle size of the resin-impregnated porous particles in the seedling culture medium was measured using a scanning electron microscope.

[0091] 2. Preparation of Seedling Growing Soil <Preparation of seedling soil> Various culture soil constituent materials were charged into a mixer (manufactured by Koyo Machinery Industry Co., Ltd.) in the following ratios (volume ratio: mountain soil 60%, leaf mold 10%, Akadama soil 30%) and mixed by stirring. Next, 1 part by mass of the seedling culture soil particle-containing material was added to 100 parts by mass of the culture soil base material, and the mixture was stirred and mixed for 10 minutes to obtain pre-consolidated seedling culture soil. This pre-consolidated seedling culture soil was packed in bags. In Comparative Example 1, when adding to the culture soil base material, the biodegradable resin aqueous dispersion was first added and mixed to the culture soil base material, and then the porous particles were added and mixed.

[0092] <Seeding work> Using a seeder (OSE-110, manufactured by Minoru Sangyo Co., Ltd.), a certain amount of the bagged unconsolidated seedling raising soil was filled into a 448-hole cell tray (448 pot seedling raising box, manufactured by Minoru Sangyo Co., Ltd.), and after spreading and compressing, onion seeds were sown again using the seeder, one seed per hole, and then covered with a certain amount of unconsolidated seedling raising soil. After that, a certain amount of watering was carried out to complete the sowing work. The following tests were carried out at a temperature of 20°C during watering and storage.

[0093] 3. Evaluation The seedling culture medium containing particles of the Examples and Comparative Examples were evaluated as follows. [Portability] Thirty or sixty days after the seedlings were raised, the transplantability of the onions from the cell trays using a transplanter (onion transplanter with four walking rows, manufactured by Minoru Sangyo Co., Ltd.) was evaluated according to the following criteria. A rating of ○ or better was considered to have resolved the problem. ◎+: The seedlings are sufficiently elastic that they do not crumble at all when removed from the cell tray by the claws of the transplanter. ◎: The seedlings are resilient and do not crumble when removed from the cell tray by the claws of the transplanter. ○: The seedlings are slightly fragile and crumble slightly when removed from the cell tray by the claws of the transplanter, but this does not affect the product. △: The seedlings are fragile and are significantly crumbled by the claws of the transplanter when removed from the cell tray. ×: The seedlings were very fragile and almost crumbled when removed from the cell tray by the claws of the transplanter.

[0094] [Growth: Growth status after germination] The seedling raising soil obtained in the above examples and comparative examples was watered once a day after sowing with a fixed amount of water, and the seedlings were raised. The rooting status after 30 to 60 days was evaluated according to the following criteria. ⊚+: The rooting condition is extremely good, and the main root of the onion can be visually confirmed on the outer surface of the seedling raising soil removed from the cell tray. ⊚: The rooting condition is good, and the main root of the onion can be visually confirmed on the outer surface of the seedling raising soil removed from the cell tray. ○: There is no problem with rooting. △: The rooting condition was rather poor, and the main root of the onion could not be visually confirmed on the outer surface of the seedling raising soil removed from the cell tray. ×: The rooting state is poor, and the main root of the onion cannot be visually confirmed on the outer surface of the seedling raising soil removed from the cell tray.

[0095] [Caking property] Sixty days after the seedlings were raised, the onion seedlings were removed from the cell tray and dropped from a height of 50 cm. The survival rate was calculated from the mass before and after the drop, and the root ball strength of the onion was evaluated according to the following criteria. ◎+: Residual rate is 95% or more ◎: Residual rate is 90% or more but less than 95% ○: Residual rate is 80% or more but less than 90% △: Residual rate is 70% or more but less than 80% ×: Residual rate is less than 70%

[0096] [Lack of clumping] The biodegradable resin aqueous dispersion was mixed with porous particles or non-porous particles and evaluated for its resistance to clumping according to the following criteria. ◎+: No lumps at all ◎: The rate of clumping is over 0% and less than 5% by weight of the mixture. ○: The rate of clumping is 5% or more but less than 10% by weight of the mixture. ×: The rate of clumping is 10% or more by weight of the mixture.

[0097] The results of the above evaluations are shown in Tables 1A to 1D.

[0098] [Table 1A]

[0099] [Table 1B]

[0100] [Table 1C]

[0101]

Table 1D

Claims

1. A particle-containing composition for seedling growing medium, comprising resin-impregnated porous particles.

2. The seedling soil containing particles according to claim 1, wherein the resin is a biodegradable resin.

3. 2. The seedling soil particle-containing composition according to claim 1, further comprising a dispersant, wherein the mass ratio of the total amount of the resin and dispersant to the porous particles is 40 or less.

4. 2. The seedling culture medium according to claim 1, wherein the resin-impregnated porous particles have an average particle size of 1 μm or more and 3,000 μm or less.

5. A seedling raising soil containing the particle-containing material for seedling raising soil according to any one of claims 1 to 4.

6. A transplantability improving agent containing the seedling raising soil particle-containing material according to any one of claims 1 to 4 as an active ingredient.

7. A method for improving transplantability using the seedling raising soil particle-containing material according to any one of claims 1 to 4.

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