JP7288801B2 - Seedling culture medium production method, seedling culture medium, plant cultivation method, and plant growth adjustment method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a seedling culture medium, a seedling culture medium, a plant cultivation method, and a plant growth regulation method.

2. Description of the Related Art In recent years, in the field of agriculture and gardening, mechanization and automation of various works are progressing for the purpose of improving work efficiency. As one of them, there is mechanical transplantation in which seeding, planting of seedlings, etc. are automatically performed. Mechanical transplanting is carried out by a procedure in which seedlings with soil obtained by sowing and raising seedlings in a nursery pot filled with culture soil are taken out by a transplanter and then planted.

When performing mechanical transplantation, as described above, the seedlings with soil are taken out from the seedling pot during the transplanting work, and at that time, it is desirable that the seedlings with soil are kept in a good solidified state without collapsing. Therefore, various methods have been investigated for solidifying the culture soil. When solidifying the culture soil, in addition to good solidification properties, it is biodegradable so that the material does not remain in the farmland, has the strength to prevent the seedlings from collapsing even in dry or water-retained conditions, is releasable from the seedling pot, and is water resistant. Performance such as permeability, air permeability, and good workability is required.

In Patent Document 1, the culture soil for raising seedlings, which is characterized in that specific heat-fusible fibers are blended in the culture soil base material, is heat-treated to melt and bond the heat-fusible fibers in the culture soil. A seedbed consolidation method is disclosed.
Patent Document 2 discloses a method for producing a seedling culture soil containing a seedling culture soil base material and an alginate, wherein the polyvalent cation equivalent (me) in the seedling culture soil is 160 of the anion equivalent (me) of the alginate. A method for producing a seedling culture medium is disclosed, which is characterized by mixing the above-mentioned seedling culture medium and alginate so that the content is 1% or more.

Japanese Patent Application Laid-Open No. 2003-339226 JP-A-2001-333635

However, in the method disclosed in Patent Document 1, it is necessary to heat the heat-fusible fibers when the culture soil is solidified, so heating equipment is required, and the material of the seedling pot that can be used is also limited. occurs. In addition, if enough fiber is added to the potting soil to allow fusion and solidification, workability may be deteriorated, for example, fiber clumps may be generated during the work of filling seedling pots. In addition, due to these problems, it becomes more necessary for buyers of potting soil to purchase potting soil that has been solidified in advance in seedling pots. there is a problem Furthermore, these materials have low biodegradability, and thus have a problem of poor environmental compatibility.

The method disclosed in Patent Document 2 uses polyvalent cations derived from inorganic compounds contained in slaked lime or soil as a supply source of polyvalent cations, and solidifies them by reacting them with alginate. However, slaked lime has a high concentration of polyvalent cations. For example, if the seedling culture soil containing slaked lime is mixed with alginate in a growing pot, the gelation on the surface of the culture soil proceeds too quickly, and the inside of the seedling pot There is a problem that alginate cannot permeate. In addition, polyvalent cations derived from inorganic compounds contained in slaked lime and soil are dissolved in water or exist in an ionic state, so it is difficult to control the concentration and dispersibility in the soil. Therefore, it was not possible to easily obtain a good solidified state.

Furthermore, according to the studies of the present inventors, it has been found that the addition of a biodegradable component to the seedling culture medium as in the method described in Patent Document 2 increases the number of bacteria in the seedling culture medium. An increase in the number of bacteria can unintentionally accelerate the germination period of plants, and can cause growth inhibition of plants after germination due to excessive nitric acid respiration (denitrification). It is desirable to adjust it within an appropriate range.

The present invention has been made to solve such problems, is made of a material with excellent biodegradability, achieves both excellent workability and excellent solidification, and increases the number of bacteria in the culture soil. An object of the present invention is to provide a method for producing a controlled seedling culture medium, a seedling culture medium obtained by the production method, a plant cultivation method using the seedling culture medium, and a plant growth regulation method.

As a result of intensive studies on the above-mentioned problems, the present inventors produced a seedling culture soil containing a culture soil base material, a polyvalent cation salt of alginic acid, a monovalent cation salt of alginic acid, and a bacteriostatic agent. The inventors have found that the above problems can be solved by a method, and have completed the present invention.
The present invention relates to the following [1] to [14].
[1] A method for producing seedling culture soil by blending a culture soil base material (A), a polyvalent cation salt of alginic acid (B), a monovalent cation salt of alginic acid (C), and a bacteriostatic agent (D).
[2] The method for producing seedling culture soil according to [1] above, wherein the polyvalent cation salt of alginic acid (B) is blended in the form of fibers.
[3] The method for producing seedling culture soil according to [2] above, wherein the fibers have an average fiber length of 1 to 50 mm and an average fiber diameter of 0.01 to 3 mm.
[4] A method for producing a seedling culture medium according to any one of [1] to [3] above, including the following steps A1 and A2.
Step A1: A step of mixing a culture soil base material (A) and a polyvalent cation salt of alginic acid (B) to obtain a culture soil mixture. Step A2: A monovalent cation salt of alginic acid (C) aqueous solution is added to the culture soil mixture. forming a solidifying agent by ion-exchanging at least a portion of the polyvalent cations of the polyvalent cation salt of alginic acid (B) with the monovalent cations of the monovalent cation salt of alginic acid (C); Step [5] A step of obtaining a seedling culture soil in which the culture soil base material (A) is solidified with an agent [5] The concentration of the monovalent cation salt of alginic acid (C) in the aqueous solution of the monovalent cation salt of alginic acid (C) is 0.01 to 0.01. The method for producing a seedling culture medium according to the above [4], wherein the content is 10% by mass.
[6] The method for producing seedling culture medium according to any one of [1] to [5] above, wherein the polyvalent cation salt of alginic acid (B) is calcium alginate.
[7] The method for producing seedling culture medium according to any one of [1] to [6] above, wherein the monovalent cation salt of alginic acid (C) is sodium alginate.
[8] Any of the above [1] to [7], wherein the amount of the polyvalent cation salt of alginic acid (B) is 0.1 to 50 parts by mass with respect to 100 parts by mass of the culture soil base material (A) The method for producing the nursery soil for raising seedlings according to (1).
[9] Any of the above [1] to [8], wherein the amount of the monovalent cation salt of alginic acid (C) is 0.05 to 20 parts by mass with respect to 100 parts by mass of the culture soil base material (A) The method for producing the nursery soil for raising seedlings according to (1).
[10] Any of the above [1] to [9], wherein the bacteriostatic agent (D) is one or more selected from the group consisting of ethanol, potassium sorbate, sodium benzoate, sodium citrate and sodium acetate. The method for producing the nursery soil for raising seedlings according to (1).
[11] Any one of the above [1] to [10], wherein the amount of the bacteriostatic agent (D) is 0.1 to 10 parts by mass with respect to 100 parts by mass of the culture soil base material (A). Method for producing seedling culture soil.
[12] A nursery medium for raising seedlings produced by the method for producing a nursery medium for raising seedlings according to any one of [1] to [11] above.
[13] A method for cultivating a plant, using the seedling culture medium described in [12] above.
[14] A method for regulating plant growth, using the seedling culture medium described in [12] above.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a method for producing nursery soil that is made of a material with excellent biodegradability, achieves both excellent workability and excellent solidification property, and suppresses an increase in the number of bacteria in the soil, and obtained by the production method. It is possible to provide a seedling culture medium, a plant cultivation method and a plant growth regulation method using the seedling culture medium.

1 is an appearance photograph of the culture soil (dry state) obtained in Example 1. FIG. 4 is an appearance photograph of the culture soil (dry state) obtained in Comparative Example 2. FIG.

An embodiment of the present invention will be described in detail below, but the present invention is not limited to the following embodiment.

[Method for producing nursery soil]
The method for producing a seedling culture medium of the present embodiment includes a culture soil base material (A), a polyvalent cation salt of alginic acid (B) (hereinafter also referred to as "polyvalent alginic acid salt (B)"), and a monovalent cation of alginic acid. A method for producing a seedling culture medium in which a salt (C) (hereinafter also referred to as "alginic acid monovalent salt (C)") and a bacteriostatic agent (D) are blended.

Although the mechanism by which the method for producing seedling culture soil of the present embodiment achieves both excellent workability and excellent solidification property is not clear, it is speculated as follows.
The production method of the present embodiment uses both the polyvalent alginic acid salt (B) and the monovalent alginic acid salt (C). Since the alginic acid polyvalent salt (B) is low in water solubility and excellent in dispersibility, it can be present in the soil while maintaining appropriate dispersibility. On the other hand, since the alginic acid monovalent salt (C) is excellent in water solubility, it can be uniformly distributed throughout the potting soil as an aqueous solution. Then, when the component (B) and the component (C) come into contact with each other in the potting soil, some of the polyvalent cations present near the surface of the polyvalent alginic acid salt (B) become monovalent cations of the monovalent alginic acid salt (C). The alginic acid monovalent salt (C), which is ion-exchanged with and spreads over the soil, is gently gelled. In this way, according to the production method of the present embodiment, a network structure formed by gelling the monovalent alginic acid salt (C) starting from the uniformly dispersed polyvalent alginic acid salt (B) spreads in the soil. It is considered that a good solidification state is maintained by
In addition, according to the production method of the present embodiment, the purchaser of the seedling culture soil can determine the timing of contacting the monovalent alginic acid salt (C) and the polyvalent alginic acid salt (B). Flexible usage is possible.
In addition, since both the polyvalent alginic acid salt (B) and the monovalent alginic acid salt (C) used in the production method of the present embodiment are excellent in biodegradability, they are also excellent in environmental compatibility. .
By adding the bacteriostatic agent (D) to the seedling culture medium obtained by the production method of the present embodiment, it is possible to suppress an increase in the number of bacteria caused by the addition of alginate. As a result, it is possible to suppress the unintended early germination of plants and the inhibition of post-germination plant growth due to excessive nitric acid respiration (denitrification).

<Culture base material (A)>
As the culture soil substrate (A), a known culture soil for raising seedlings can be used depending on the type of plant to be grown. Specifically, various horticultural soils such as Akadama soil, Kanuma soil, Arakida soil, humus soil, and Kiryu sand; Sands such as river sand, sea sand, beach sand, and mountain sand; Minerals; organic materials such as peat moss, coco peat, water moss, mulch, park compost, rice husks, lignite, charcoal, bran, and charcoal powder.
The culture soil substrate (A) may be used alone or in combination of two or more. In addition, if necessary, it may contain fertilizers such as inorganic fertilizers, organic fertilizers and chemical compost.

<Polyvalent cation salt of alginic acid (B)>
Alginic acid polyvalent salt (B) is not particularly limited as long as it is a polyvalent cation salt of alginic acid, alkaline earth metal alginate such as magnesium alginate, calcium alginate, strontium alginate, barium alginate; iron alginate; alginic acid transition metal salts such as alginate, zinc alginate, and alginate copper; trivalent or higher cation salts such as alginate aluminum; Among these, divalent cation salts of alginic acid are preferred, alkaline earth metal alginates are more preferred, and calcium alginate is even more preferred, from the viewpoint of versatility and soil solidification.
Alginic acid polyvalent salt (B) may be used alone or in combination of two or more.

The M/G ratio, which is the ratio of mannuronic acid (M) and guluronic acid (G) in the polyvalent alginic acid (B), is preferably 0.1 to 5 from the viewpoint of obtaining a solidified state with good hardness. 0.4 to 3 is more preferred, and 0.5 to 1.5 is even more preferred.

From the viewpoint of obtaining a solidified state with good hardness, the content of polyvalent cations in the polyvalent alginic acid salt (B) is 0.00 per 1 mol of alginate monomer units (C ₆ H ₈ O ₆ ). 01 to 3 mol is preferred, 0.05 to 2 mol is more preferred, and 0.1 to 1.5 mol is even more preferred.

The form in which the polyvalent alginic acid salt (B) is blended is not particularly limited, and for example, it is preferably blended in the form of fibers, powder, pellets, granules, flakes, etc., and is preferably blended in the form of fibers. more preferred.

When the alginic acid polyvalent salt (B) is blended in the form of powder, the average particle size of the powder may be appropriately determined according to the soil substrate (A) to be applied and the type of plant. 0.01 to 5 mm, preferably 0.1 to 4 mm, more preferably 0.5 to 2 mm. In addition, the average particle size of the powder is the average value of the maximum length that can be taken in the projected image of the powder and the maximum length in the direction orthogonal to the maximum length. It can be determined for the powder and averaged.

When the polyvalent alginic acid salt (B) is blended in the form of fibers, the average fiber length of the fibers is preferably 1 to 50 mm, more preferably 2 to 40 mm, even more preferably 3 to 30 mm. The average fiber diameter is preferably 0.01 to 3 mm, more preferably 0.05 to 2.5 mm, even more preferably 0.1 to 2 mm. The average fiber diameter and average fiber length of a fiber can be obtained by averaging the fiber diameter and fiber length in the projected image of the fiber for 10 arbitrarily selected fibers. In the present embodiment, the term "fiber" means a fiber having a ratio of the average fiber length to the average fiber diameter [average fiber length/average fiber diameter] of 2 or more. From the viewpoint of obtaining a good solidified state, the ratio of the average fiber length to the average fiber diameter [average fiber length/average fiber diameter] is preferably 3 or more, more preferably 5 or more, and even more preferably 7 or more. The ratio [average fiber length/average fiber diameter] may be 20 or less or 15 or less from the viewpoint of fiber dispersibility.
The cross-sectional shape of the fiber may be round, triangular, T-shaped, flat, multilobed, V-shaped, or hollow.

As a method for forming the polyvalent alginic acid salt (B) into fibers, for example, an aqueous monovalent cation salt solution of alginic acid such as sodium alginic acid is treated with a spinning nozzle or the like having a desired nozzle diameter. After extrusion-spinning in an aqueous solution of a polyvalent cation chloride such as an aqueous calcium solution, the formed fibrous polyvalent salt of alginic acid can be obtained by collecting and drying. The concentration of the monovalent cation salt aqueous solution of alginic acid is, for example, 0.5 to 10% by mass, and the concentration of the polyvalent cation chloride aqueous solution is, for example, 1 to 30% by mass.

From the viewpoint of versatility and solubility in water, the viscosity of a 1% by mass aqueous solution of alginic acid monovalent cation salt used in the production of alginic acid polyvalent salt (B) is preferably 10 to 1,000 mPa s, and 20 to 600 mPa s. s is more preferred, and 30 to 400 mPa·s is even more preferred.

In addition, when the polyvalent alginic acid salt (B) is blended in the form of fibers, powders, pellets, granules, flakes, etc., these are components other than the polyvalent alginic acid salt (B) within a range that does not impair the effects of the present invention. may contain

From the viewpoint of obtaining a good solidification state, the amount of the alginic acid polyvalent salt (B) is preferably 0.1 to 50 parts by mass, and 0.5 to 30 parts by mass with respect to 100 parts by mass of the culture soil base material (A). parts is more preferred, and 1 to 10 parts by mass is even more preferred.

<Monovalent cation salt of alginic acid (C)>
Alginic acid monovalent salt (C) is not particularly limited as long as it is a monovalent cation salt of alginic acid, and examples thereof include alginate alkali metal salts such as lithium alginate, sodium alginate and potassium alginate; and ammonium alginate. . Among these, from the viewpoint of versatility and soil solidification properties, alginate alkali metal salts are preferred, and alginate sodium salts are more preferred.
Alginic acid monovalent salt (C) may be used alone or in combination of two or more.

The 1% by mass aqueous solution viscosity of alginic acid monovalent salt (C) is preferably 10 to 1,000 mPa s, more preferably 20 to 600 mPa s, more preferably 30 to 400 mPa s, from the viewpoint of versatility and solubility in water. s is more preferred.

The M/G ratio, which is the ratio of mannuronic acid (M) and guluronic acid (G) in the alginic acid monovalent salt (C), is preferably 0.1 to 10 from the viewpoint of obtaining a solidified state having good hardness. 0.4 to 5 are more preferred, and 0.5 to 3 are even more preferred.

From the viewpoint of obtaining a solidified state having good hardness, the content of monovalent cation in alginic acid monovalent salt (C) is 0.00 per 1 mol of alginate monomer unit (C ₆ H ₈ O ₆ ). 5 to 3 mol is preferred, 0.6 to 2 mol is more preferred, and 0.8 to 1.5 mol is even more preferred.

The form in which the alginic acid monovalent salt (C) is blended is not particularly limited, and for example, it is preferably blended in the form of fibers, powder, pellets, granules, flakes, an aqueous solution, etc., and is blended in the form of an aqueous solution. is more preferable.
When the alginic acid monovalent salt (C) is blended in the form of a powder, the average particle size of the powder may be appropriately determined according to the soil substrate (A) to be applied and the type of plant. 0.01 to 3 mm, preferably 0.05 to 2.5 mm, more preferably 0.1 to 2 mm. The method for calculating the average particle size is the same as the method for calculating the average particle size of polyvalent alginic acid (B).

When the alginic acid monovalent salt (C) is blended in the form of an aqueous solution, the concentration in the aqueous solution is appropriately determined according to the alginic acid monovalent salt (C), the culture soil substrate (A) to be applied, the type of plant, etc. For example, it is 0.01 to 10% by mass, preferably 0.05 to 5% by mass, and more preferably 0.1 to 4% by mass.
The aqueous solution of alginic acid monovalent salt (C) can be prepared, for example, by adding a predetermined amount of alginic acid monovalent salt (C) to ion-exchanged water and, if necessary, heating and stirring.

In addition, when the alginic acid monovalent salt (C) is blended in the form of fibers, powders, pellets, granules, flakes, aqueous solutions, etc., these are other than the alginic acid monovalent salt (C) to the extent that they do not impair the effects of the present invention. may contain components of

The amount of alginic acid monovalent salt (C) is preferably 0.05 to 20 parts by mass with respect to 100 parts by mass of the culture soil base material (A) from the viewpoint of obtaining a good solidified state, and 0.1 to 10 parts by mass. parts is more preferred, and 0.12 to 5 parts by mass is even more preferred.
The compounding ratio ((B)/(C)) of the polyvalent cation derived from the polyvalent alginic acid salt (B) and the monovalent cation derived from the monovalent alginic acid salt (C) is, from the viewpoint of obtaining a good solidification state, 0.01 to 200 are preferred, 0.05 to 20 are more preferred, and 0.1 to 10 are even more preferred.

<Bacteriostatic agent (D)>
The bacteriostatic agent (D) may be any agent as long as it has bacteriostatic action, bactericidal action, etc. Examples include alcohols such as ethanol, phenethyl alcohol, benzyl alcohol, and chlorobutanol; citrates such as sodium citrate; , sodium dehydroacetate, acetates such as ammonium acetate; sorbates such as sodium sorbate, potassium sorbate; benzoates such as sodium benzoate; methyl parahydroxybenzoate, ethyl parahydroxybenzoate, propyl parahydroxybenzoate, paraoxy Paraoxybenzoic acid esters such as butyl benzoate; hypochlorous acid; hypochlorites such as sodium hypochlorite, potassium hypochlorite, calcium hypochlorite; acetic acid, citric acid, fumaric acid, succinic acid and organic acids such as malic acid.
Among these, one or more selected from the group consisting of ethanol, potassium sorbate, sodium benzoate, sodium citrate and sodium acetate is preferred.
The bacteriostatic agent (D) may be used alone or in combination of two or more.

The form in which the bacteriostatic agent (D) is added is not particularly limited. For example, when the bacteriostatic agent (D) is solid, it may be added as it is. It may be in the form of a solution dissolved in a solvent or the like. In addition, when the bacteriostatic agent (D) is liquid, it may be added as it is or may be diluted with a solvent to form a diluted solution.

When the bacteriostatic agent (D) is added in the form of a solution or diluent, the concentration of the bacteriostatic agent (D) in the solution or diluent is, for example, 0.1 to 10% by mass, and 2 to 8% by mass. % is preferable, and 4 to 6% by mass is more preferable.

Further, when the antibacterial agent (D) is added in the form of a solution or a diluent, the antibacterial agent (D) may be added in a state contained in the aqueous solution of the monovalent alginic acid (C). That is, an aqueous solution of alginic acid monovalent salt (C) is prepared as an aqueous solution containing alginic acid monovalent salt (C) and a bacteriostatic agent (D), and the aqueous solution is blended with soil or the like to obtain alginic acid monovalent salt ( C) and bacteriostatic agent (D) can be formulated at the same time. A suitable concentration of alginic acid monovalent salt (C) and a suitable concentration of bacteriostatic agent (D) in the aqueous solution containing alginic acid monovalent salt (C) and bacteriostatic agent (D) are Same as the preferred concentration.

The amount of the bacteriostatic agent (D) may be appropriately adjusted according to the purpose of adjusting the number of bacteria in the seedling culture medium to an appropriate range. It is 0.1 to 10 parts by mass, preferably 2 to 8 parts by mass, more preferably 4 to 6 parts by mass.

<Formulation method>
The method of blending each component is not particularly limited, but blending method A including the following steps A1 and A2 is preferred from the viewpoint of achieving both excellent workability and excellent solidification properties.
Step A1: A step of mixing a culture soil base material (A) and a polyvalent cation salt of alginic acid (B) to obtain a culture soil mixture. Step A2: A monovalent cation salt of alginic acid (C) aqueous solution is added to the culture soil mixture. forming a solidifying agent by ion-exchanging at least a portion of the polyvalent cations of the polyvalent cation salt of alginic acid (B) with the monovalent cations of the monovalent cation salt of alginic acid (C); Step of obtaining seedling culture soil in which the culture soil base material (A) is solidified with an agent

(Step A1)
Step A1 is a step of mixing the soil base material (A) and the polyvalent alginic acid (B) to obtain a soil mixture.
The method of mixing the culture soil base material (A) and the alginic acid polyvalent salt (B) is not particularly limited, and examples thereof include mechanical stirring such as known mixers and kneading machines; and manual stirring. .
Through step A1, a culture soil mixture obtained by mixing the culture soil substrate (A) and the polyvalent alginic acid (B) is obtained.

(Step A2)
In step A2, an aqueous monovalent cation salt of alginic acid (C) is added to the soil mixture obtained in step A1, and at least a portion of the polyvalent cation salt of alginic acid (B) is added to the alginic acid. forming a solidifying agent by ion exchange with the monovalent cation of the monovalent cation salt (C), and obtaining a seedling culture soil in which the culture soil base material (A) is solidified with the solidifying agent.

The method of adding the monovalent alginic acid salt (C) aqueous solution to the soil mixture is not particularly limited. and a method of immersing the culture soil mixture in an aqueous monovalent alginic acid (C) solution.
By adding the monovalent alginic acid salt (C) aqueous solution to the potting soil mixture, the polyvalent alginic acid salt (B) in the potting soil mixture and the monovalent alginic acid salt (C) in the aqueous solution react to obtain solidified potting soil. be done.

In the case of blending method A, the culture soil mixture obtained in step A1 is maintained in a non-solidified state until step A2 is carried out. Therefore, the user of the seedling culture medium can solidify the seedling culture medium by performing step A2 at a desired time.
In the case of blending method A, step A1 is preferably performed before filling the plant growing container with the culture soil base material (A), and step A2 is performed after filling the plant growing container with the culture soil mixture. is preferred.

In the blending method A, the timing of blending the bacteriostatic agent (D) is not particularly limited. between, at the same time as step A2, or after step A2. Among these, simultaneous with step A1 or simultaneous with step A2 is preferable.
That is, step A1 is preferably a step of mixing the culture soil base material (A), the polyvalent alginic acid (B) and the bacteriostatic agent (D) to obtain a culture soil mixture.
Further, step A2 is preferably a step of adding an aqueous solution containing the monovalent cation salt of alginic acid (C) and the bacteriostatic agent (D) to the culture soil mixture obtained in step A1.

When sowing the seedling culture soil obtained by the production method of the present embodiment, the time of sowing is not particularly limited, and before step A1, at the same time as step A1, between steps A1 and A2, at the same time as step A2, or at the same time as step A2. Any time after A2 is acceptable, but preferably after step A2.

The method for blending the culture soil substrate (A), the polyvalent alginic acid (B) and the monovalent alginic acid (C) may be a blending method B having the following step B1.
Step B1: A step of mixing a culture soil base material (A), a polyvalent alginic acid salt (B) and a solid monovalent alginic acid salt (C) to obtain a seedling culture soil.

The mixing method in step B1 may be the same method as in step A1 above. As described above, the solid monovalent alginic acid salt (C) may be in the form of fibers, powders, pellets, granules, flakes, etc. Preferred embodiments are also the same.

In the case of blending method B, the seedling culture medium obtained in step B1 is maintained in a non-solidified state until water is added. Therefore, the user of the seedling medium can solidify the seedling medium by adding water to the seedling medium at a desired time. The step of adding water to the seedling culture soil obtained in step B1 to solidify the culture soil is referred to as "step B2".
In the case of blending method B, step B1 is preferably performed before filling the plant growing container with the culture soil base material (A), and step B2 is performed after filling the plant growing container with the culture soil mixture. is preferred.

In the case of blending method B, the timing of adding the bacteriostatic agent (D) is before step B1, at the same time as step B1, between steps B1 and B2, at the same time as step B2, or after step B2. There may be.

When sowing the seedling culture soil obtained by the production method of the present embodiment, the time of sowing is not particularly limited, and before step B1, at the same time as step B1, between steps B1 and B2, at the same time as step B2, or at the same time as step B2. Any time after B2, but preferably after step B2.

<Usage of nursery soil>
The shape of the plant-growing container filled with the seedling culture soil obtained by the method for producing the seedling culture soil of the present embodiment is not particularly limited, and various shapes can be applied.
Examples of the plant-growing container include those having a bottom wall and a side wall and having a bottom wall shape such as a substantially circular shape, a substantially rectangular shape, and a substantially hexagonal shape. can be used. The seedling-raising cells may have the form of a seedling-raising tray in which a plurality of cells are arranged in a row.
The size of the seedling pot or seedling cell is, for example, an opening hole diameter of 20 to 60 mm, a depth of 40 to 65 mm, and a volume of 9 to 165 cm ³ .
The seedling culture soil produced by the method for producing the seedling culture soil of the present embodiment is suitable for agricultural and horticultural crops such as vegetables, flowers, seedlings and rice.

[Raising seedling soil]
The seedling culture soil of the present embodiment is a seedling culture soil produced by the method for producing a seedling culture soil of the present embodiment. Therefore, the seedling culture soil of the present embodiment is a culture soil substrate (A), a polyvalent cation salt of alginic acid (B), and one or more selected from the group consisting of components derived from the polyvalent cation salt of alginic acid (B). , one or more selected from the group consisting of the monovalent cation salt of alginic acid (C) and components derived from the monovalent cation salt of alginic acid (C), and the bacteriostatic agent (D).
The type, compounding amount, compounding method, etc. of each component are all as described above.

[Plant cultivation method and plant growth regulation method]
The plant cultivation method of the present embodiment is a plant cultivation method using the seedling culture medium of the present embodiment. Further, the plant growth regulation method of the present embodiment is a plant growth regulation method using the seedling culture medium of the present embodiment.
The plants cultivated by the plant cultivation method of the present embodiment and the plants whose growth is adjusted by the plant growth adjustment method of the present embodiment are not particularly limited, and include agricultural and horticultural crops such as vegetables, flowers, seedlings, and rice. be done.

By adding the bacteriostatic agent (D) to the seedling culture medium obtained by the production method of the present embodiment, an increase in the number of bacteria due to the addition of alginate is suppressed. As a result, it is possible to prevent the germination time of the plant from unintentionally advancing and inhibit the growth of the post-germination plant due to excessive nitric acid respiration (denitrification).
In addition, since some fungi contribute to the germination of plants, the germination of plants can be suppressed while the number of fungi in the seedling culture medium is adjusted to be small. Since the content of the bacteriostatic agent (D) in the seedling culture medium can be naturally or intentionally reduced by watering, volatilization, etc., the number of bacteria increases as the content of the bacteriostatic agent (D) decreases. increases, the germination inhibitory effect of the fungicide (D) is lost, and the plant germinates. In this way, according to the plant cultivation method and the growth regulation method of the present embodiment, the germination time of the plant can be adjusted, and it is possible to prevent the germination time from being unintentionally advanced by other factors, and to It is possible to adjust the shipping time by delaying the germination time.

EXAMPLES The present invention will be specifically described below by showing examples, but the present invention is not limited to these.

[Preparation of calcium alginate fiber]
Production example 1
20 g of alginate sodium salt (manufactured by Kimika Co., Ltd., trade name: Algitex LL) was added to 1,000 g of ion-exchanged water and then dissolved by stirring to obtain an aqueous alginate sodium salt solution (concentration: 2% by mass). Using a syringe (discharge diameter: 18 gauge (1.04 mm)), the sodium alginate aqueous solution is continuously discharged into a 5% by mass calcium chloride aqueous solution, and fibrous calcium alginate is discharged into the calcium chloride aqueous solution. was precipitated. The resulting fibrous calcium alginate was recovered from an aqueous calcium chloride solution, dried at 20°C for 60 minutes, and then cut into desired lengths to obtain calcium alginate fibers having the following physical properties. . The methods for measuring the average fiber length and the average fiber diameter are as described above.
Average fiber length: 5 mm
Average fiber diameter: 0.5mm
M/G ratio: 1.3
Polyvalent cation content: 0.5 mol/monomer unit 1 mol

[Production of sodium alginate aqueous solution]
Production example 2
(Preparation of alginate sodium salt and ethanol aqueous solution)
After adding 10 g of sodium alginate (manufactured by Kimika Co., Ltd., product name: Algitex LL) and a predetermined amount of ethanol as a bacteriostatic agent (D) into 5,000 g of ion-exchanged water, the sodium alginate was dissolved by stirring. and an ethanol aqueous solution were obtained.
The sodium alginate and ethanol aqueous solution have a sodium alginate concentration of 0.2% by mass and an ethanol concentration of 0.5% by mass, 1% by mass, 3% by mass, 5% by mass or 10% by mass. 5 types were prepared.

Production example 3
(Preparation of alginic acid sodium salt and citric acid aqueous solution)
In Production Example 2, sodium alginate and aqueous citric acid solution (sodium alginate concentration: 0.2% by mass, citric acid concentration: 1 mass%) were prepared in the same manner as in Production Example 2, except that ethanol was changed to citric acid. %) was obtained.

Production example 4
(Preparation of sodium alginate aqueous solution)
An alginate sodium salt aqueous solution (alginate sodium salt concentration: 0.2% by mass) was obtained in the same manner as in Production Example 2, except that ethanol was not blended in Production Example 2.

[Manufacturing of nursery soil]
Example 1
After 100 parts by mass of the soil base material and 3 parts by mass of the calcium alginate fiber prepared in Production Example 1 were put into a mixer container, they were stirred and mixed to obtain a soil mixture.
20 g of the culture soil mixture obtained above is put into a seedling pot (bottom diameter 18 mm, upper (opening) diameter 30 mm, height 45 mm), and after removing the excess culture soil mixture while vibrating, pressing is performed to raise the seedling. The compost mixture was filled into the pot. Next, 15 g of the sodium alginate and ethanol aqueous solution (ethanol concentration: 5% by mass) prepared in Production Example 2 are watered from the opening of the seedling pot filled with the culture soil mixture, and the culture soil base material is solidified with alginate. A solidified soil was obtained. The molar ratio (Ca/Na) between calcium ions derived from calcium alginate and sodium ions derived from sodium alginate is 5.5. A photograph of the appearance (dry state) of the solidified soil obtained is shown in FIG. As can be seen from FIG. 1, the solidified culture soil obtained in Example 1 has good solidification properties.

Example 2
A seedling culture was obtained in the same manner as in Example 1, except that the sodium alginate and aqueous ethanol solution were changed to the sodium alginate and aqueous citric acid solution prepared in Production Example 3.

Comparative example 1
In Example 1, instead of 3 parts by mass of calcium alginate fiber, 3 parts by mass of slaked lime was used, and 15 g of sodium alginate and ethanol aqueous solution were changed to 15 g of sodium alginate aqueous solution obtained in Production Example 4. A seedling culture medium was obtained in the same manner as in Example 1 except for the above.

Comparative example 2
Example 1 except that 3 parts by mass of calcium alginate fiber was not blended in Example 1, and 15 g of sodium alginate and ethanol aqueous solution were changed to 15 g of sodium alginate aqueous solution obtained in Production Example 4. Seedling culture soil was obtained in the same manner as above. A photograph of the external appearance (dry state) of the seedling culture soil obtained in Comparative Example 2 is shown in FIG. As can be seen from FIG. 2, the solidified culture soil of Comparative Example 2 had a weak solidification strength, and collapsed when the culture soil was removed from the seedling pot.

Comparative example 3
A seedling culture was obtained in the same manner as in Example 1, except that 15 g of water was sprayed instead of 15 g of sodium alginate and aqueous ethanol solution.

Reference example 1
A seedling culture was obtained in the same manner as in Example 1, except that 15 g of the sodium alginate and aqueous ethanol solution in Example 1 were changed to 15 g of the sodium alginate aqueous solution obtained in Production Example 4.

The hardening property of the seedling culture medium obtained in each example was evaluated by the method described below. Table 1 shows the evaluation results.

[Solidity of raising seedling soil]
The culture soil in the seedling-raising pot obtained in each example was removed by inverting the pot and applying vibration, and it was visually confirmed whether or not the culture soil collapsed at that time. Furthermore, the soil that did not collapse was subjected to a free drop test from a height of 30 cm, and the presence or absence of collapse was visually confirmed and evaluated based on the following criteria. Table 1 shows the results.
In addition, the culture soil was placed in an environment with a humidity of 50% and a temperature of 20 ° C. without adding water from 72 hours before extraction (dry state), and water was added 24 hours before extraction, humidity The test was performed in both a wet state placed in an environment of 50% and a temperature of 20°C.
A: Did not disintegrate when subjected to drop test C: Did not disintegrate when taken out, but disintegrated in drop test.
E: Disintegration occurred when taken out.

表中「－」は当該成分を使用しなかったことを意味する。

"-" in the table means that the component was not used.

From Table 1, it can be seen that the seedling culture soils of Examples 1 and 2 according to the present embodiment have excellent solidification properties in both dry and wet conditions. The seedling culture soil of Example 1 is excellent in workability because it can be solidified without heating after being filled in a seedling pot, and the ingredients used are excellent in biodegradability, so it is environmentally compatible. is also excellent.
On the other hand, in the seedling culture soil of Comparative Example 1, only the culture soil in the vicinity of the opening of the seedling pot was solidified, and the internal culture soil collapsed when the pot was taken out or in the drop test. The seedling culture soil of Comparative Examples 2 and 3 had weak solidification strength, and collapsed when the culture soil was removed from the seedling pot.

Next, the seedling culture medium obtained in each example was evaluated for bacterial count by the method shown below. Table 2 shows the evaluation results. In Reference Example 2 in Table 2, the culture soil base material used in Example 1 (that is, the culture soil base material to which the components (A) to (D) were not added) was used as it was.

[Method for measuring the number of bacteria]
A dry weight of 1 g of the seedling culture medium obtained in each example was sampled, 90 ml of distilled water was added, shaken for 30 minutes, and filtered to obtain an extract of each level. Using the extract, filamentous fungi and pigment-resistant fungi were counted on rose bengal agar medium, actinomycetes and bacteria were counted on egg albumin agar medium, and the number of fungi was counted by the dilution plate method. Fusarium fungi were plated on FOG1 agar medium. Counting was performed by the droplet plate method.

表中「－」は当該成分を使用しなかったことを意味する。

"-" in the table means that the component was not used.

From Table 2, the seedling culture soils of Examples 1 and 2 according to the present embodiment are compared to the seedling culture soil (D) in which no bacteriostatic agent was added, shown as Reference Example 1. The number of pigment-resistant bacteria is significantly reduced. I know you are.

Next, plants were cultivated using the seedling culture medium of the present embodiment, and the growth of the plants was confirmed.

Examples 3-7, Reference Examples 3 and 4
A culture soil mixture obtained in the same manner as in Example 1 was put into a cell tray (size of one cell: length 24 mm x width 24 mm x height 45 mm, total 200 cells), and the excess soil mixture was removed while vibrating. After that, pressing was performed to fill the culture soil mixture in the cell tray. Next, sodium alginate and ethanol aqueous solution (ethanol concentration: 0.5% by mass, 1% by mass, 3% by mass, 5% by mass or 10% by mass) are added to the cell tray filled with the culture soil mixture, derived from calcium alginate. was watered so that the molar ratio (Ca/Na) of calcium ions derived from sodium alginate and sodium ions derived from sodium alginate was 5.5 to obtain a solidified culture soil solidified with alginate.
On the other hand, in Reference Example 3, the solidified culture soil of Reference Example 1 was used as seedling culture soil.
In Reference Example 4, the culture soil substrate used in Example 1 (that is, the culture soil substrate to which the components (A) to (D) were not added) was used as it was as seedling culture soil.

[Measurement of germination rate]
One bok choy was sown per cell, and 500 ml of water was given by spraying water once a day in an environment exposed to sunlight, and the number of all germinated cells was measured every day. A germination rate (total number of germinated cells×100/200 cells) was calculated. Table 3 shows the results.

表中の値は発芽率（％）を意味する。

Values in the table mean germination rate (%).

From Table 3, it can be seen that Reference Example 3 with the addition of alginate has an earlier germination time than Reference Example 4 with no addition of alginate. On the other hand, in the seedling culture soils of Examples 3 to 7 of the present embodiment, in which ethanol was added as the bacteriostatic agent (D), the germination period that had been accelerated by the addition of alginate was reduced to can be delayed accordingly.

As described above, the method for producing the seedling culture soil of the present embodiment is made of a material with excellent biodegradability, achieves both excellent workability and excellent solidification properties, and suppresses the increase in the number of bacteria in the culture soil. It turns out that it is possible to manufacture

Claims (12)

A culture soil base material (A), a polyvalent cation salt of alginic acid (B), a monovalent cation salt of alginic acid (C), and a bacteriostatic agent (D) are blended, and the culture soil base material (A) is mixed. A method for producing a solidified seedling culture medium, comprising the following steps A1 and A2.
Step A1: A step of mixing a culture soil base material (A) and a polyvalent cation salt of alginic acid (B) to obtain a culture soil mixture.
Step A2: A monovalent cation salt of alginic acid (C) aqueous solution is added to the soil mixture, and at least a part of the polyvalent cations of the alginic acid polycation salt (B) is converted into the monovalent cation salt of alginic acid (C A step of forming a solidifying agent by ion exchange with the monovalent cation possessed by ), and obtaining a seedling culture soil in which the culture soil base material (A) is solidified with the solidifying agent 2. The method for producing a seedling culture medium according to claim 1, wherein the polyvalent cation salt of alginic acid (B) is blended in the form of fibers. The method for producing seedling culture soil according to claim 2, wherein the fibers have an average fiber length of 1 to 50 mm and an average fiber diameter of 0.01 to 3 mm. The raising seedling according to any one of claims 1 to 3 , wherein the concentration of the monovalent cation salt of alginic acid (C) in the aqueous solution of the monovalent cation salt of alginic acid (C) is 0.01 to 10% by mass. How to make potting soil. The method for producing a seedling culture medium according to any one of claims 1 to 4 , wherein the polyvalent cation salt of alginic acid (B) is calcium alginate. The method for producing a seedling culture medium according to any one of claims 1 to 5 , wherein the monovalent cation salt of alginic acid (C) is sodium alginate. The amount of the polyvalent cation salt of alginic acid (B) is 0.1 to 50 parts by mass with respect to 100 parts by mass of the culture soil base material (A), according to any one of claims 1 to 6 . A method for producing a seedling culture medium. The content of the monovalent cation salt of alginic acid (C) is 0.05 to 20 parts by mass with respect to 100 parts by mass of the culture soil base material (A), according to any one of claims 1 to 7 . A method for producing a seedling culture medium. The bacteriostatic agent (D) is one or more selected from the group consisting of ethanol, potassium sorbate, sodium benzoate, sodium citrate and sodium acetate, according to any one of claims 1 to 8 . A method for producing a seedling culture medium. The seedling culture soil according to any one of claims 1 to 9 , wherein the amount of the bacteriostatic agent (D) is 0.1 to 10 parts by mass with respect to 100 parts by mass of the culture soil base material (A). Production method. A method for cultivating a plant using a seedling culture medium produced by the method for producing a seedling culture medium according to any one of claims 1 to 10 . A method for regulating the growth of a plant, using a seedling culture medium produced by the method for producing a seedling culture medium according to any one of claims 1 to 10 .

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