JP2021168624A - Seedling raising mat producing method, seedling raising mat, and plant cultivation method - Google Patents

Abstract

To provide a method for producing a seedling raising mat made of an excellent biodegradability material and having excellent workability and solidification property, a seedling raising mat obtained by the method, and a plant cultivating method using the seedling raising mat.SOLUTION: A method for producing a seedling raising mat comprises the following steps 1 to 4. Step 1 is a step of mixing a soil base material A and an aqueous solution of an alginic acid monovalent cation salt B to obtain a soil base material mixture. Step 2 is a step of forming the soil base material mixture into a mat format having slits 2 to obtain a soil base material mixture. Step 3 is a step of drying the soil base material mixture to obtain a seedling raising soil intermediate in which the soil base material A is solidified by the alginic acid monovalent cation salt B. Step 4 is a step of impregnating the seedling growing soil intermediate with an aqueous solution of a polyvalent cation salt C to form a solidifying agent obtained by ion-exchanges at least a part of the monovalent cation of the alginic acid monovalent cation salt B with the polyvalent cation, thereby obtaining a seedling raising mat 1 having a slit 2 in which the soil base material A is solidified by the solidifying agent.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a seedling raising mat, a seedling raising mat, and a method for cultivating a plant.

In recent years, in the fields of agriculture and horticulture, mechanization and automation of various operations have been progressing for the purpose of improving work efficiency. One of them is mechanical transplantation that automatically sows, plants seedlings, and so on. Mechanical transplantation is carried out by a procedure in which seedlings with soil obtained by raising seedlings are taken out by a transplanting machine and then planted.

When performing mechanical transplantation, it is desirable that the soiled seedlings are maintained in a good solidified state without collapsing. Therefore, various methods for solidifying the hilling are being studied. When solidifying the hilling, in addition to good solidification, the material is biodegradable so that it does not remain on the agricultural land, strength that the soiled seedlings do not collapse even in a dry or water-retaining state, releasability from the seedling raising container, water Performance such as permeability, breathability, and good workability is required.

Patent Document 1 is characterized in that the soil for raising seedlings, which is characterized by blending a specific heat-sealing fiber with the soil base material, is heat-treated to melt-bond the heat-sealing fibers in the soil. The method of solidifying the nursery is disclosed.
Patent Document 2 describes a method for producing a seedling raising soil containing a seedling raising soil base material and alginate so that the polyvalent cation equivalent in the seedling raising soil is 160% or more of the anion equivalent of the alginate. , A method for producing a seedling raising soil, which comprises mixing the above-mentioned seedling raising soil base material and alginate, is disclosed.

Japanese Unexamined Patent Publication No. 2003-339226 Japanese Unexamined Patent Publication No. 2001-333635

However, the method disclosed in Patent Document 1 requires heating equipment because it is necessary to heat the heat-sealing fibers when the soil is solidified, and the material of the seedling raising container that can be used is also limited. Occurs. Further, if fibers are added to the soil so as to enable fusion and solidification, workability may be deteriorated such as fiber lumps being generated during the filling operation into the seedling raising container. In addition, due to these problems, it becomes more necessary for the purchaser of the hilling to purchase the solidified soil in the nursery container in advance, and the purchaser cannot adjust the solidification time, etc., and the usage is restricted. There is a problem to be done. Further, since these materials have low biodegradability, there is a problem that they are inferior in environmental compatibility.

The method disclosed in Patent Document 2 uses a polyvalent cation derived from an inorganic compound contained in slaked lime or soil as a source of the polyvalent cation, and reacts the polyvalent cation with alginate to solidify it. However, slaked lime has a high concentration of polyvalent cations. For example, when seedling cultivated soil containing slaked lime and alginate are mixed in a seedling raising pot, gelation on the surface of the cultivated soil progresses too quickly, and inside the seedling raising container. There is a problem that alginate cannot penetrate until. Further, since the polyvalent cation derived from the inorganic compound contained in slaked lime or soil is soluble in water or exists in an ionic state, it is difficult to control the concentration and dispersibility in the soil. Therefore, a good solidified state could not be easily obtained.

The present invention has been made to solve such a problem, and is a method for producing a seedling raising mat, which is made of a material having excellent biodegradability and has excellent workability and solidification property, and a seedling raising method obtained by the manufacturing method. The present invention provides a mat and a method for cultivating a plant using the seedling raising mat.

As a result of diligent studies on the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a method for producing a seedling raising mat including a specific step, and have completed the present invention.
The present invention relates to the following [1] to [12].
[1] A method for producing a seedling raising mat in which the soil base material (A) is solidified by a solidifying agent, which comprises the following steps 1 to 4.
Step 1: The soil base material (A) and an aqueous solution of the monovalent cation salt of alginate (B) are mixed to obtain a soil base material mixture (1). Step 2: The soil base material mixture (1) Step 3: Dry the soil base material mixture (2) so that the soil base material (A) has the monovalent alginic acid. Step 4: Immerse the seedling growing soil intermediate with an aqueous solution of the polyvalent cation salt (C) to obtain at least the alginic acid monovalent cation salt (B). A slit in which a solidifying agent formed by ion-exchange of a part of monovalent cations with the polyvalent cation of the polyvalent cation salt (C) is formed, and the soil base material (A) is solidified by the solidifying agent. [2] The seedling raising mat according to the above [1], wherein the step 3 is a step of drying the soil base material mixture (2) until the water content becomes 40% by mass or less. How to make a mat.
[3] The seedling raising mat according to the above [1] or [2], wherein the step 4 is a step of impregnating the seedling raising soil intermediate by immersing the seedling raising soil intermediate in an aqueous solution of the polyvalent cation salt (C). Production method.
[4] The above-mentioned [1] to [3], wherein the concentration of the alginic acid monovalent cation salt (B) in the aqueous solution of the alginic acid monovalent cation salt (B) is 0.5 to 10% by mass. How to make a seedling mat.
[5] The above-mentioned [1] to [4], wherein the blending amount of the alginic acid monovalent cation salt (B) is 0.5 to 10 parts by mass with respect to 100 parts by mass of the soil base material (A). The method for manufacturing a seedling raising mat according to any one.
[6] The method for producing a seedling raising mat according to any one of [1] to [5] above, wherein the polyvalent cation salt (C) is a calcium salt.
[7] The method for producing a seedling raising mat according to any one of [1] to [6] above, wherein the polyvalent cation salt (C) is calcium chloride.
[8] The seedling raising mat according to any one of [1] to [7] above, wherein the concentration of the polyvalent cation salt (C) in the aqueous solution of the polyvalent cation salt (C) is 1 to 20% by mass. Production method.
[9] The step 2 is a step of obtaining the soil base material mixture (2) formed by forming the soil base material mixture (1) into a mat shape having a plurality of linear slits parallel to each other. The method for producing a seedling raising mat according to any one of [1] to [8].
[10] The soil base material mixture (2) in which the step 2 forms the soil base material mixture (1) in a mat shape having slits, and further forms seeding holes in a portion where the slits are not formed. The method for producing a seedling raising mat according to any one of the above [1] to [9], which is a step of obtaining).
[11] A seedling raising mat produced by the method for producing a seedling raising mat according to any one of the above [1] to [10].
[12] A method for cultivating a plant using the seedling raising mat according to the above [11].

According to the present invention, there is provided a method for producing a seedling raising mat, which is made of a material having excellent biodegradability and has excellent workability and solidification, a seedling raising mat obtained by the manufacturing method, and a method for cultivating a plant using the seedling raising mat. can do.

It is a schematic diagram which shows one aspect of the nursery mat of this embodiment. It is an appearance photograph of the nursery mat obtained in Example 1. It is an appearance photograph of the nursery mat obtained in Example 2. It is an external photograph of the seedling raising mat obtained in Reference Example 1.

Hereinafter, one embodiment of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[Manufacturing method of nursery mat]
The method for producing a seedling raising mat of the present embodiment is a method for producing a seedling raising mat in which the soil base material (A) is solidified by a solidifying agent, and is a production method including the following steps 1 to 4.
Step 1: The soil base material (A) and an aqueous solution of the monovalent cation salt of alginate (B) are mixed to obtain a soil base material mixture (1). Step 2: The soil base material mixture (1) Step 3: Dry the soil base material mixture (2) so that the soil base material (A) has the monovalent alginic acid. Step 4: Immerse the seedling growing soil intermediate with an aqueous solution of the polyvalent cation salt (C) to obtain at least the alginic acid monovalent cation salt (B). A slit in which a solidifying agent formed by ion-exchange of a part of the monovalent cation with the polyvalent cation of the polyvalent cation salt (C) is formed, and the soil base material (A) is solidified by the solidifying agent. Steps for obtaining a seedling raising mat having the above. Hereinafter, each step included in the production method of the present embodiment will be described in order.

<Step 1>
Step 1 is a step of mixing the soil base material (A) and the aqueous solution of the alginic acid monovalent cation salt (B) to obtain the soil base material mixture (1).
That is, the soil base material mixture (1) obtained in this step contains the soil base material (A), alginic acid monovalent cation salt (B), and water.

The production method of the present embodiment uses an alginic acid monovalent cation salt (B) as a precursor of a solidifying agent that solidifies the soil base material (A).
Since the alginic acid monovalent cation salt (B) and the solidifying agent obtained from the alginic acid monovalent cation salt (B) are excellent in biodegradability, the seedling raising mat obtained by the production method of the present embodiment is excellent in environmental compatibility.
Further, the alginic acid monovalent cation salt (B) has high solubility in water, and a uniform solution can be obtained. Therefore, in this step, by mixing the soil base material (A) and the aqueous solution of the alginic acid monovalent cation salt (B), the alginic acid monovalent cation salt (B) is uneven on the entire soil base material (A). It spreads without. As a result, the solidifying agent derived from the alginic acid monovalent cation salt (B) formed in the step 4 also solidifies the soil base material (A) uniformly and uniformly, and the seedling raising obtained by the production method of the present embodiment. The mat will have excellent solidification strength.

(Cultivated soil base material (A))
As the hilling base material (A) used in step 1, a known hilling 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, rotten leaf soil, Kiryu sand; sands such as river sand, sea sand, beach sand, mountain sand; perlite, vermiculite, rock wool, zeolite, mineral slag, etc. Minerals: Organic materials such as peat moss, coco peat, water moss, leaf mold, perlite, fir, sub-charcoal, scented charcoal, fusuma, and charcoal powder.
As the hilling base material (A), one type may be used alone, or two or more types may be used in combination.
When two or more kinds of soil base material (A) are used, a seedling raising mat containing different types of soil base material (A) as different layers may be used.
Further, if necessary, fertilizers such as inorganic fertilizers, organic fertilizers, and chemical composts may be blended.

(Alginic acid monovalent cation salt (B))
The monovalent cation salt of alginic acid (B) is not particularly limited, and examples thereof include alkali metal alginate salts such as lithium alginate salt, sodium alginate salt, and potassium alginate salt; ammonium alginate salt and the like. Among these, an alkali metal alginate salt is preferable, and a sodium alginate salt is more preferable, from the viewpoint of versatility and solidification of the soil.
One type of alginic acid monovalent cation salt (B) may be used alone, or two or more types may be used in combination.

The aqueous viscosity of the alginic acid monovalent cation salt (B) is preferably 0.1 to 200 Pa · s, more preferably 0.5 to 150 Pa · s, from the viewpoint of solidification, versatility, and solubility in water. ~ 100 Pa · s is more preferable, and 10 to 50 Pa · s is particularly preferable.

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

The content of the monovalent cation in the alginic acid monovalent cation salt (B) is 0 with respect to 1 mol _{of the monomer unit (C 6} H ₈ O _{6) of alginate from the viewpoint of obtaining a solidified state having good hardness.} .5 to 3 mol is preferable, 0.6 to 2 mol is more preferable, and 0.8 to 1.5 mol is further preferable.

The blending amount of the alginic acid monovalent cation salt (B) is preferably 0.5 to 10 parts by mass, preferably 1 to 8 parts by mass, based on 100 parts by mass of the soil base material (A) from the viewpoint of obtaining a good solidified state. Is more preferable, and 3 to 7 parts by mass is further preferable.

The alginic acid monovalent cation salt (B) is mixed with the soil base material (A) in the state of an aqueous solution. The concentration of the alginic acid monovalent cation salt (B) in the aqueous solution of the alginic acid monovalent cation salt (B) may be appropriately determined according to the soil base material (A) to be applied, the type of plant, and the like. It is 5 to 10% by mass, preferably 1 to 8% by mass, and more preferably 2 to 5% by mass. Further, the aqueous solution of the alginic acid monovalent cation salt (B) having the above concentration is mixed so that the blending amount of the alginic acid monovalent cation salt (B) with respect to the soil base material (A) is within the above-mentioned suitable range. Is preferable.

An aqueous solution of the alginic acid monovalent cation salt (B) can be prepared, for example, by adding a predetermined amount of the alginic acid monovalent cation salt (B) to ion-exchanged water or the like, and heating and stirring as necessary.
The aqueous solution of the alginic acid monovalent cation salt (B) may contain components other than the alginic acid monovalent cation salt (B) and water as long as the effects of the present invention are not impaired.

The aqueous solution of the alginic acid monovalent cation salt (B) does not necessarily have to be prepared before being mixed with the soil base material (A), and the soil base material (A) and the aqueous solution of the alginic acid monovalent cation salt (B) are mixed. The mixing order of each component is not limited as long as it is a method for obtaining the soil-based mixture (1). For example, the soil base material (A) and the powdered alginic acid monovalent cation salt (B) are mixed, water is added to the mixture, and then the mixture is further mixed. A soil-based material mixture (1) formed by mixing an aqueous solution of a monovalent cation salt (B) may be obtained.

The method of mixing the soil base material (A) and the aqueous solution of the alginic acid monovalent cation salt (B) is not particularly limited, and for example, stirring by a machine such as a known mixer or kneader; a method such as manual stirring. Can be mentioned.

<Process 2>
Step 2 is a step of obtaining the soil base material mixture (2) formed by forming the soil base material mixture (1) into a mat shape having slits.
According to the production method of the present embodiment, after the step 1, the soil base material mixture (1) is formed into a mat having slits before the drying in the step 3, so that the seedling raising mat finally obtained can be obtained. It is possible to suppress the occurrence of warpage that occurs. Further, this slit can also play a role of facilitating alignment and division when a plurality of seedlings raised on a seedling raising mat are separated into individual pieces.

The soil-based material mixture (2) obtained in this step is then dried and solidified while maintaining its basic shape to become the seedling raising mat of the present embodiment. That is, the suitable shape of the soil base material mixture (2) produced in this step is the same as the suitable shape of the seedling raising mat of the present embodiment described later.
As a method of forming the soil base material mixture (1) in a mat shape, there is a method of spreading the soil base material mixture (1) in a seedling raising container having a mat shape.

The step 2 is carried out before the drying of the step 3 from the viewpoint of facilitating the formation of the slit and from the viewpoint of suppressing the occurrence of the warp that occurs before the slit is formed.
From the same viewpoint, in step 2, the water content in the soil base material mixture (1) is preferably 75 to 98% by mass, more preferably 80 to 95% by mass, and further preferably 85 to 90% by mass. It is preferable to carry out. The water content in the hilling base material mixture (1) was obtained by heat-treating the untreated hilling base material mixture (1) and the hilling base material mixture (1) at 100 ° C. for 8 hours. It can be calculated by the following formula from the mass of the hilling substrate mixture (1) after the heat treatment.
Moisture content (%) of the hilling substrate mixture (1) = [(mass of untreated hilling substrate mixture (1))-(mass of hilling substrate mixture (1) after heat treatment)] × 100 / Mass of untreated soil base material mixture (1)

The soil base material mixture (2) produced in this step has slits.
The slit in the present embodiment means a non-penetrating notch in the thickness direction of the mat-shaped soil base material mixture (2).
According to the study by the present inventors, when the mat-shaped hilling is solidified using alginate, a solidified hilling having a desired shape can be obtained, such as warpage due to shrinkage of the entire hilling, especially in a dried state. However, according to the manufacturing method of the present embodiment, a seedling raising mat having excellent shape retention can be obtained by providing the slit.
The slit may be linear or curved in a plan view of the mat-shaped hilling substrate mixture (2), but is preferably linear.
The number of the slits is not particularly limited and may be 2 or more, 5 or more, 10 or more or 15 or more, and may be 100 or less, 60 or less, 40 or less, 30 or less or 20 or less.
The length of the slit is not particularly limited, but is usually formed up to both ends of the soil base material mixture (2).
When a plurality of linear slits are provided as the slits, it is preferable that the plurality of linear slits are provided in a direction parallel to each other in a plan view of the mat-shaped soil substrate mixture (2). Further, a plurality of linear slits provided in a direction parallel to each other and a plurality of other linear slits provided in a direction parallel to each other may intersect at an arbitrary angle. It may be orthogonal.
When the slits have a plurality of linear slits parallel to each other, the distance between adjacent slits (the distance between the center lines of the slits) is not particularly limited, but is preferably equal.

The width of the slit is not particularly limited, but is preferably 0.5 to 5 mm, more preferably 1 to 4 mm, and even more preferably 1.5 to 3 mm from the viewpoint of shape retention and strength of the seedling raising mat.
The depth of the slit is not particularly limited, but from the viewpoint of shape retention, the depth is preferably 20 to 80%, preferably 30 to 70%, based on the thickness of the mat-like hilling substrate mixture (2). Depth is more preferred, and a depth of 40-60% is even more preferred.
When the slits are arranged at equal intervals, the distance between the slits (the distance between the center lines of the slits) is not particularly limited, but is preferably 5 to 60 mm, more preferably 15 to 45 mm, and 25 to 35 mm. More preferred.

The method for forming the slit is not particularly limited, and examples thereof include a method of embossing a jig having the same shape as the desired slit on the soil base material mixture formed in a mat shape. The slits may be formed one by one, or a plurality or all of them may be formed collectively.
In the above description, the mode in which the slits are provided only in a certain direction has been described, but the method for producing the seedling raising mat of the present embodiment is not limited to the above mode, and is a mode in which the slits are provided in a plurality of directions. You may. For example, a plurality of horizontal slits and a plurality of vertical slits may be interlaced to form a grid pattern.

In step 2, a seeding hole may be further provided in the soil base material mixture (2). The seeding hole is usually provided in a portion where a slit is not formed (hereinafter, this portion is also referred to as a “non-slit forming portion”). When the linear slits are formed at equal intervals, the non-slit forming portions are also formed linearly at equal intervals.
When the soil base material mixture (2) has a linear non-slit forming portion, the seeding holes are preferably formed at equal intervals along the center line in the width direction of the non-slit forming portion. In that case, the distance between the adjacent seeding holes (distance between the centers of the seeding holes) is not particularly limited and may be appropriately set according to the type of plant, but is preferably 5 to 60 mm, more preferably 15 to 45 mm. 25 to 35 mm is more preferable.
The size of the sowing hole is not particularly limited and may be appropriately set according to the type of plant, but may be, for example, 1 to 10 mm or 2 to 7 mm.

<Step 3>
Step 3 is a step of drying the soil base material mixture (2) to obtain a seedling raising soil intermediate in which the soil base material (A) is solidified with an alginic acid monovalent cation salt (B).

The soil base material mixture (2) obtained in step 2 mainly contains an aqueous solution of the soil base material (A) and the alginic acid monovalent cation salt (B). By drying the soil base material mixture (2) in this step, water is removed, and a seedling raising soil intermediate in which the soil base material (A) is solidified by the alginic acid monovalent cation salt (B) is obtained. Therefore, the seedling raising soil intermediate obtained in this step has a mat shape having slits, similarly to the soil base material mixture (2).
By drying the soil base material mixture (2) in this step, the water existing in the gaps between the soil base materials is removed, and the aqueous solution of the polyvalent cation salt (C) described later becomes the soil base material mixture ( A structure having a gap sufficient to penetrate into the inside of 2) is formed. As a result, the seedling raising mat obtained by the production method of the present embodiment is sufficiently solidified to the inside.

The drying conditions in the step 3 may be appropriately determined according to the amount of water contained in the soil base material mixture (2) and the like, and may be naturally dried or heat-dried.
The drying temperature in the case of heat-drying is, for example, 30 to 150 ° C., preferably 40 to 120 ° C., and even more preferably 45 to 80 ° C. The drying time for heat-drying is, for example, 3 to 24 hours, preferably 5 to 12 hours.
The drying device for heating and drying is not particularly limited, and a known drying device such as a hot air dryer, a vacuum drying device, or an infrared heating device may be used. These dryers may be batch type or continuous type.

Step 3 is preferably a step of drying the soil base material mixture (2) until the water content is 40% by mass or less, and more preferably 30% by mass or less. It is more preferable that the step is to dry until it becomes 20% by mass or less.
The water content of the seedling raising soil intermediate obtained by drying is the heat-treated seedling raising soil intermediate obtained by heat-treating the untreated seedling raising soil intermediate and the seedling raising soil intermediate at 100 ° C. for 8 hours. It can be calculated from the mass of the body by the following formula.
Moisture content of seedling raising soil intermediate (%) = [(mass of untreated seedling raising soil intermediate)-(mass of seedling raising soil intermediate after heat treatment)] × 100 / mass of untreated seedling raising soil intermediate

<Step 4>
In step 4, the seedling growing soil intermediate is impregnated with an aqueous solution of the polyvalent cation salt (C), and at least a part of the monovalent cations of the alginic acid monovalent cation salt (B) is added to the polyvalent cation salt (C). This is a step of forming the solidifying agent formed by ion exchange with the polyvalent cation possessed by), and obtaining a seedling raising mat having a slit in which the soil base material (A) is solidified by the solidifying agent.

The seedling raising soil intermediate obtained in step 3 is obtained by solidifying the soil base material (A) with an alginic acid monovalent cation salt (B).
In this step, the monovalent cation of the alginic acid monovalent cation salt (B) that binds the soil base material (A) is obtained by impregnating the seedling raising soil intermediate with an aqueous solution of the polyvalent cation salt (C). , Ion exchange with the polyvalent cation of the polyvalent cation salt (C) to form a solidifying agent. Since the solidifying agent is derived from alginic acid, it has excellent biodegradability, but since it has a crosslinked structure starting from a polyvalent cation, it has excellent solidifying properties in both a dry state and a wet state. Become.
Further, according to the production method of the present embodiment, the timing of impregnating the seedling raising soil intermediate with the aqueous solution of the polyvalent cation salt (C) can be determined by the purchaser of the seedling raising mat, so that the purchaser of the seedling raising soil is flexible according to the application. Can be used in various ways.

(Multivalent cation salt (C))
Examples of the polyvalent cation constituting the polyvalent cation salt (C) include ^{alkaline earth metal ions such as calcium ion (Ca 2+} ), barium ion (Ba ²⁺ ), and strontium ion (Sr ²⁺ ); copper ion (Cu). ²⁺ ), zinc ion (Zn ²⁺ ), iron ion (Fe ²⁺ ), cobalt ion (Co ²⁺ ), nickel ion (Ni ²⁺ ) and other divalent metal ions; iron ion (Fe ³⁺ ), aluminum ion (Al ³⁺⁾ ), Trivalent metal ions such as cesium ion (Ce ^{3+) and the like.}
Examples of the polyvalent cation salt (C) include chlorides, bromides, carbonates, sulfates, acetates, phosphates, nitrates, hydroxides and other inorganic salts of these polyvalent cations; and alginates and the like. Organic salts and the like can be mentioned, but inorganic salts are preferable from the viewpoint of handleability and economic efficiency.
Among these polyvalent cation salts (C), calcium salts are preferable, and calcium chloride is more preferable, from the viewpoint of handleability and economy.
As the polyvalent cation salt (C), one type may be used alone, or two or more types may be used in combination.

The method of impregnating the seedling growing soil intermediate with the aqueous solution of the polyvalent cation salt (C) is not particularly limited. For example, a method of irrigating the seedling growing soil intermediate with the aqueous solution of the polyvalent cation salt (C), the polyvalent cation salt. Examples thereof include a method of immersing the seedling raising soil intermediate in the aqueous solution of (C) (hereinafter, also referred to as “immersion method”). Among these, from the viewpoint of obtaining good solidification property, a method of immersing the seedling raising soil intermediate in an aqueous solution of the polyvalent cation salt (C) is preferable.

When the impregnation in step 4 is carried out by the dipping method, the time for immersing the seedling raising soil intermediate in the aqueous solution of the polyvalent cation salt (C) is not particularly limited, but is, for example, 3 to 120 minutes, preferably 20 to 100 minutes. , 40-80 minutes is more preferred.
The temperature of the aqueous solution of the polyvalent cation salt (C) in which the seedling raising soil intermediate is immersed is not particularly limited, but is, for example, 0 to 50 ° C, preferably 5 to 40 ° C, and more preferably 10 to 30 ° C.

The concentration of the polyvalent cation salt (C) in the aqueous solution of the polyvalent cation salt (C) is preferably 1 to 20% by mass, more preferably 3 to 10% by mass, still more preferably 4 to 7% by mass. When the concentration of the polyvalent cation salt (C) is at least the above lower limit value, the ion exchange rate with the alginic acid monovalent cation salt (B) becomes sufficient, and workability and solidification are excellent. Further, when the concentration of the polyvalent cation salt (C) is not more than the above upper limit value, the progress of ion exchange is suppressed locally, and the homogeneity of the obtained solidifying agent becomes good.

<Shape of nursery mat>
The shape of the seedling raising mat according to the manufacturing method of the present embodiment in a plan view is not particularly limited and may be any shape. Examples include combined shapes. Of these, it is usually a quadrangle, preferably a rectangle.

The thickness of the seedling raising mat is not particularly limited and may be appropriately determined according to the type of plant to be raised, but for example, it is 0.5 to 6 cm, preferably 1 to 5 cm, and more preferably 2 to 4 cm.

The size of the seedling mat is not particularly limited and may be appropriately determined depending on the type of plant or the like for raising seedling, for example, an area, a 300～5,000Cm ^2, preferably 500～4,000Cm ^2, More preferably 1,000 to 2,000 cm ^2.

When the seedling raising mat according to the production method of the present embodiment is rectangular, its vertical size is preferably 300 to 900 mm, more preferably 500 to 700 mm, and even more preferably 550 to 650 mm. The lateral size is preferably 100 to 600 mm, more preferably 200 to 400 mm, and even more preferably 250 to 350 mm.

The seedling raising mat obtained as described above can be used for raising seedlings of plants after being subjected to arbitrary processing as needed.
The seedling raising mat produced by the method for producing a seedling raising mat of the present embodiment is suitable for agricultural and horticultural crops such as vegetables, flowers, seedlings, and rice.

[Plant cultivation method]
The plant cultivation method of the present embodiment is a plant cultivation method using the seedling raising mat of the present embodiment.
The seedling raising mat obtained by the production method of the present embodiment is excellent in solidification strength and biodegradability of the solidifying agent. Therefore, the plant cultivation method of the present embodiment is excellent in workability of mechanical transplantation and also excellent in environmental compatibility.
The plant cultivated by the method for cultivating the plant of the present embodiment is not particularly limited, and examples thereof include agricultural and horticultural crops such as vegetables, flowers, seedlings, and rice.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

[Solidity of nursery mat]
The seedling raising mat in the seedling raising container obtained in each example was taken out by inverting the seedling raising container and applying vibration, and it was visually confirmed whether or not the soil was collapsed at that time. Further, a drop test was conducted in which those that did not collapse were naturally dropped from a height of 30 cm, and the presence or absence of collapse was visually confirmed and evaluated based on the following criteria.
The seedling raising mat was not added with water 72 hours before it was taken out, but was dried in an environment with a humidity of 50% and a temperature of 20 ° C. (dry state), and water was added 24 hours before it was taken out. The test was conducted in both a wet state and an environment in which the humidity was 50% and the temperature was 20 ° C.
A: It did not collapse during the drop test.
C: It did not collapse when taken out, but it collapsed in the drop test.
E: Collapse occurred when taken out.

[Measurement of warpage (evaluation of shape retention of nursery mat)]
For the shape retention of the seedling raising mat, a dry seedling raising mat was prepared in the above description of [solidification property of the seedling raising mat], and this was taken out from the seedling raising container and used for evaluation.
The seedling raising mat taken out is placed on a flat surface with the side that was in contact with the bottom of the seedling raising container facing up and the side that was the opening side of the seedling raising container facing down, and the maximum height from the flat surface. Was measured as the amount of warpage.

[Manufacturing of aqueous solution of sodium alginate]
Manufacturing example 1
30 g of sodium alginate salt (manufactured by Kimika Co., Ltd., trade name: Argitex H) was added to 970 g of ion-exchanged water and then stirred and dissolved to obtain an aqueous solution of sodium alginate salt (concentration: 3% by mass).

[Manufacturing of nursery mats]
Example 1
The nursery mat 1 represented by the schematic diagram of FIG. 1 was produced according to the following procedure.
The seedling raising mat 1 in FIG. 1 is a seedling raising mat having a plurality of linear slits 2 parallel to each other at equal intervals c, and the slits 2 have a width a and a depth b. Further, a non-slit forming portion 4 is provided between the adjacent slits 2, and a plurality of seeding holes 3 are provided at equal intervals d on the center line of the non-slit forming portion 4.
(1) Step 1
100 parts by mass of the soil base material (coco peat) and 200 parts by mass of the sodium alginate salt aqueous solution prepared in Production Example 1 were put into a mixer container and then stirred and mixed to obtain a soil base material mixture (1).
(2) Step 2
3,000 g of the soil base material mixture (1) obtained above was filled in a seedling raising container (length 580 mm, width 280 mm, depth 30 mm).
Next, the side surface of the plate-shaped jig having a thickness of 2 mm is pressed against the upper surface of the soil base material mixture (1) so as to be parallel to the short side of the seedling raising container, and the width (a in FIG. 1) is 2 mm. A mat-like soil base material mixture (2) having a plurality of slits was obtained. The depth of the slits (b in FIG. 1) is 15 mm, and a total of 19 slits at equal intervals so that the distance between adjacent slits (distance between center lines) (c in FIG. 1) is 29 mm. Was formed.
Further, along the center line of the non-slit forming portion (4 in FIG. 1), 10 seeding holes were formed at equal intervals per one non-slit forming portion. The diameter of the seeding holes was 4 mm, and the distance between the seeding holes (distance between centers) (d in FIG. 1) was 28 mm.
(3) Step 3
Next, the soil-growing base mixture (2) was dried at 50 ° C. for 8 hours while being filled in the seedling raising container to obtain a seedling-growing soil intermediate in which the soil base material was solidified with sodium alginate salt.
The water content of the obtained seedling raising soil intermediate was 20% by mass.
(4) Step 4
Subsequently, the seedling growing soil intermediate was immersed in a calcium chloride aqueous solution having a concentration of 5% by mass at 25 ° C. for 1 hour to form a solidifying agent formed by ion-exchange of sodium alginate salt with calcium chloride. A seedling raising mat having a slit in one direction was obtained in which the soil base material was solidified.
A photograph of the appearance of the seedling raising mat obtained in Example 1 is shown in FIG.

Example 2
In Example 1, in addition to forming slits and sowing holes under the same conditions, a plurality of slits having a width of 2 mm and a depth of 15 mm are formed parallel to the long side of the seedling raising container, and the distance between adjacent slits is 28 mm. A seedling raising mat having slits in two directions was obtained in the same manner as in Example 1 except that a mat-shaped soil base material mixture (2) having slits in a grid pattern was obtained. A photograph of the appearance of the seedling raising mat obtained in Example 2 is shown in FIG.

Comparative Example 1
The seedling raising container (length 580 mm, width 280 mm, depth 30 mm) was filled with 3,000 g of the soil base material mixture (1) obtained in step 1 of Example 1 without performing slit formation in step 2. A seedling raising mat was obtained by drying at 50 ° C. for 8 hours.

Comparative Example 2
100 parts by mass of the culture base material and 10 parts by mass of calcium chloride were put into a mixer container, and then stirred and mixed, and put into a seedling raising container of the same size as in Example 1 to prepare sodium alginate in Production Example 1. A seedling raising mat was obtained by irrigating with a salt aqueous solution.

Comparative Example 3
3,000 g of the soil base material mixture (1) obtained in step 1 of Example 1 was filled in a seedling raising container (length 580 mm, width 280 mm, depth 30 mm), and slit formation in step 2 and drying in step 3 were performed. A seedling raising mat was obtained by immersing the seedlings in a calcium chloride aqueous solution having a concentration of 5% by mass at 25 ° C. for 1 hour without carrying out the process.

Reference example 1
A seedling raising mat was obtained in the same manner as in Example 1 except that step 2 was not performed in Example 1. FIG. 4 shows an external photograph of the seedling raising mat obtained in Reference Example 1.

Table 1 shows the evaluation results of solidification and shape retention performed on the seedling raising mats obtained in each example.

From Table 1, it can be seen that the seedling raising mat of Example 1 obtained by the production method of the present embodiment has excellent solidification properties in a dry state and a wet state, and is also excellent in shape retention.
On the other hand, the seedling raising mat of Comparative Example 1 in which the polyvalent cation salt (C) was not used had good solidification property in a dry state, but easily disintegrated in a wet state.
In addition, the seedling raising mat of Comparative Example 2 in which calcium chloride was mixed with the soil base material in advance and the seedling raising mat of Comparative Example 3 in which the sodium alginate salt aqueous solution was irrigated without drying the soil base material mixture were both in a dry state. And did not have sufficient solidification properties in the wet state.
The reason why the seedling raising mat of Comparative Example 2 did not have sufficient solidification strength was that the seedling raising mat of Comparative Example 2 was irrigated with an aqueous solution of sodium alginate because calcium chloride was directly mixed with the soil base material. It is presumed that this is because the surface was rapidly solidified and the calcium chloride aqueous solution did not penetrate into the inside due to the solidified film on the surface.
The reason why the seedling raising mat of Comparative Example 3 did not have sufficient solidification strength was that the seedling raising mat of Comparative Example 3 was irrigated with an aqueous solution of sodium alginate without drying the soil base material mixture, so that the soil base material was used. It is presumed that this is because the water remaining on the surface of the mixture closes the gaps between the hilling substrates, the calcium chloride aqueous solution does not penetrate to the inside, and solidification occurs only on the surface.
The seedling raising mat of Reference Example 1 had sufficient solidification strength, but the amount of warpage after drying was large, and the shape retention was inferior.

1 Seedling mat 2 Slit 3 Sowing hole 4 Non-slit forming part a Slit width b Slit depth c Slit spacing d Sowing hole spacing

Claims (12)

A method for producing a seedling raising mat in which the soil base material (A) is solidified by a solidifying agent, which comprises the following steps 1 to 4.
Step 1: The soil base material (A) and an aqueous solution of the monovalent cation salt of alginate (B) are mixed to obtain a soil base material mixture (1). Step 2: The soil base material mixture (1) Step 3: Dry the soil base material mixture (2) so that the soil base material (A) has the monovalent alginic acid. Step 4: Immerse the seedling growing soil intermediate with an aqueous solution of the polyvalent cation salt (C) to obtain at least the alginic acid monovalent cation salt (B). A slit in which a solidifying agent formed by ion-exchange of a part of monovalent cations with the polyvalent cation of the polyvalent cation salt (C) is formed, and the soil base material (A) is solidified by the solidifying agent. The process of obtaining a seedling raising mat with The method for producing a seedling raising mat according to claim 1, wherein the step 3 is a step of drying the soil base material mixture (2) until the water content becomes 40% by mass or less. The method for producing a seedling raising mat according to claim 1 or 2, wherein the step 4 is a step of impregnating the seedling raising soil intermediate by immersing the seedling raising soil intermediate in an aqueous solution of the polyvalent cation salt (C). The seedling raising mat according to any one of claims 1 to 3, wherein the concentration of the alginic acid monovalent cation salt (B) in the aqueous solution of the alginic acid monovalent cation salt (B) is 0.5 to 10% by mass. Production method. The method according to any one of claims 1 to 4, wherein the blending amount of the alginic acid monovalent cation salt (B) is 0.5 to 10 parts by mass with respect to 100 parts by mass of the soil base material (A). How to make a seedling mat. The method for producing a seedling raising mat according to any one of claims 1 to 5, wherein the polyvalent cation salt (C) is a calcium salt. The method for producing a seedling raising mat according to any one of claims 1 to 6, wherein the polyvalent cation salt (C) is calcium chloride. The method for producing a seedling raising mat according to any one of claims 1 to 7, wherein the concentration of the polyvalent cation salt (C) in the aqueous solution of the polyvalent cation salt (C) is 1 to 20% by mass. The first step is a step of obtaining the soil base material mixture (2) formed by forming the soil base material mixture (1) into a mat shape having a plurality of linear slits parallel to each other. The method for producing a seedling raising mat according to any one of 8. In the step 2, the soil base material mixture (1) is formed in a mat shape having slits, and a seeding hole is formed in a portion where the slits are not formed to obtain a soil base material mixture (2). The method for producing a seedling raising mat according to any one of claims 1 to 9, which is a step. A seedling raising mat produced by the method for producing a seedling raising mat according to any one of claims 1 to 10. A method for cultivating a plant using the seedling raising mat according to claim 11.

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