JP2023075987A - Consolidation agent for nursery culture soil and nursery culture soil including the same - Google Patents

Abstract

To provide a consolidation agent for nursery culture soil that has excellent biodegradability with no risk of environmental pollution, also has an excellent consolidation performance, and can suppress decrease in root ball strength when the soil contains water, and nursery culture soil including the same.SOLUTION: A consolidation agent for nursery culture soil includes native gellan gum. Nursery culture soil includes native gellan gum and a culture soil constituting material.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a solidifying agent for raising seedling culture soil and a raising seedling culture soil using the same.

BACKGROUND ART In recent years, for the purpose of streamlining agricultural and horticultural work and increasing yields of agricultural products, the intensive cultivation of seedlings and the mechanical transplantation of grown seedlings have been actively carried out. Specifically, a transplanter is used to separate cell seedlings and pot seedlings grown in seedling soil and plant them in a field. According to this mechanical transplantation, comparatively uniform and strong seedlings can be obtained. Although it has the advantage that it is easy to transplant, it has the disadvantage that the culture soil (root bowl) of the roots of the seedlings collapses or the roots and the culture soil separate during mechanical transplantation.

In order to prevent such disintegration during mechanical transplantation, a technique has been proposed in which a polymer resin such as an acrylamide copolymer is added as a binder to the seedling culture medium (Patent Document 1). A technique of adding polyvinyl alcohol resin as a binder to charcoal powder in hydroponic solid medium cultivation has also been proposed (Patent Document 2). When used as a nursery soil for raising seedlings, if the soil after consolidation contains water, the strength of the root ball is remarkably reduced, and there is also the problem that the petroleum-derived synthetic polymer does not biodegrade and remains in the soil for a long time.

Techniques using polysaccharides have been proposed in order to impart caking properties and water retention to substrates such as culture media in plant cultivation. For example, iota-type carrageenan (Patent Document 3) as a gel medium for plant cultivation, agar or gellan gum (Patent Document 4) as a gelling agent for a solid medium for indoor ornamental plants added with powdered activated carbon, and water-retentive granular culture Carboxymethyl cellulose (Patent Document 5) as soil, carrageenan, locust bean gum, and xanthan gum (Patent Document 6) as superabsorbent polymer compositions, and alginic acid as a solidifying agent for the cover layer in the soil having a cover layer on top of the bed soil layer Sodium and chitosan (Patent Document 7) have been proposed. However, polysaccharides such as these often do not have sufficient solidification performance, which is required as a solidifying agent for seedling culture soil. Furthermore, when the seedling culture soil after solidification contains water, the strength of the root ball is significantly reduced, and it collapses at the time of transplanting. There were also problems.

Technology that uses tamarind-derived water-soluble polymer (Patent Document 8) or deacylated gellan gum (Patent Document 9), which is generally called gellan gum, as a solidifying agent in seedling culture soil to prevent collapse during mechanical transplantation. is also proposed.

JP 2016-154449 A JP-A-8-280281 JP 2013-111024 A JP-A-4-370046 JP 2017-55663 A JP-A-60-58443 JP 2005-229857 A JP-A-2016-15903 JP 2010-142176 A

However, even with the solidifying agents of Patent Documents 8 and 9, root ball strength is remarkably reduced when the seedling culture soil after solidifying contains water. When transplanting seedling culture soil using a transplanter, the moisture content of the seedling culture soil may be high due to weather such as rain, addition of water for raising seedlings, and especially when soil is included as a culture soil constituent material. In such a case, there is a problem that the strength of the root ball is remarkably lowered and the root ball collapses at the time of transplantation.

The present invention has been made in view of the above circumstances, and provides a plant that has good biodegradability, has no concern about environmental pollution, has good solidification performance, and suppresses a decrease in root ball strength when it contains water. It is an object of the present invention to provide a solidifying agent for raising seedling culture soil and a raising seedling culture soil using the same.

In order to solve the above problems, the solidifying agent for raising seedling culture soil of the present invention is characterized by containing native gellan gum.
The seedling culture medium of the present invention is characterized by containing native-type gellan gum and a culture-soil constituent material.

The solidifying agent for raising seedling culture soil and the raising seedling culture soil of the present invention have good biodegradability, have no concern about environmental pollution, have good solidifying performance, and can suppress a decrease in root ball strength when wet.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated concretely.
(Consolidating agent for raising seedling culture soil)
The solidifying agent for raising seedling culture soil of the present invention contains native gellan gum.
Native gellan gum in the present invention is a fermented polysaccharide produced by Sphingomonas elodea, which is an inoculum isolated from aquatic plants of the genus Elodea, and contains 1-3-linked glucose and 1-4-linked glucuronic acid. , 1 glyceryl group residue and acetyl The groups are on average 1/2 residues attached. Native gellan gum has one carboxyl group residue per structural unit. Since native gellan gum is of natural origin, its structure may vary slightly depending on the producing microorganism used and purification conditions. Therefore, the native gellan gum used in the present invention is not univocally limited based on a specific structural formula, as long as it has the properties of native gellan gum produced by microorganisms.

Native gellan gum is produced by recovering sugars after Sphingomonas elodea has fermented them and, for example, through the processes of separation, purification, drying and pulverization. Deacylated gellan gum is produced through deacylation, separation, purification, and other steps after fermentation, and this type is generally called gellan gum. Gellan gum is classified into native gellan gum and deacylated gellan gum depending on the presence or absence of acetyl groups and glyceryl groups present in 1-3-linked glucose, and the properties of the two are largely different. Native gellan gum has a strong gelling ability and dissolves in a small amount of water to form an elastic gel with little syneresis, whereas deacylated gellan gum does not form a gel even when dissolved in water. Gelation occurs only when a divalent cation is added to the gel, and the gel exhibits hard and brittle properties. The present invention is characterized by the use of native gellan gum.

Since native gellan gum is a natural polysaccharide, it has good biodegradability and does not remain in the soil for a long time after being decomposed by the action of microorganisms, and is suitable from the viewpoint of preventing environmental pollution.

The form of the seedling culture soil solidifying agent of the present invention is not particularly limited, and examples thereof include a solution form, a solid form, and a gel form. Among them, a solution in which native gellan gum is dissolved or dispersed in a solvent is preferable. The solvent is not particularly limited as long as it can dissolve or disperse native gellan gum, and examples thereof include water, organic solvents, and mixtures thereof. Among these, water is preferred. The concentration of the native gellan gum in the solution is preferably 0.01 to 10.0% by mass from the viewpoint of solidification performance, and 0.01 to 1.0% by mass from the viewpoint of viscosity and permeability to the soil substrate. is more preferred.

(Raising seedling soil)
The seedling culture medium of the present invention contains native gellan gum and culture soil constituent materials.
The native gellan gum in the seedling culture soil of the present invention is obtained, for example, by mixing the seedling culture soil solidifying agent of the present invention with a culture soil base material.

The material constituting the culture soil in the seedling culture soil of the present invention is not particularly limited, but includes those commonly used as culture soil for agriculture and horticulture. Inorganic substances with porous structures, fertilizers, soil, and the like can be mentioned. These culture soil constituent materials may be used singly or in combination of two or more.

Vegetable fibrous substances include, for example, peat moss, coconut husks, rice husks, sawdust, bamboo powder, bagasse, peat, and grass charcoal. These may be used individually by 1 type, and may use 2 or more types together.

Inorganic substances having a porous structure include, for example, vermiculite, attapulgite, diatomaceous earth, sepiolite, zeolite, and perlite. These may be used individually by 1 type, and may use 2 or more types together.

Examples of non-porous inorganic materials include silica sand, sea sand, alumina sand, talc, bentonite, and calcium carbonate. These may be used individually by 1 type, and may use 2 or more types together.

Fertilizers include, for example, nitrogen fertilizers, phosphate fertilizers, potash fertilizers, calcium compounds such as calcium hydroxide, magnesium compounds such as magnesium hydroxide, and zinc compounds such as zinc oxide. These may be used individually by 1 type, and may use 2 or more types together.

Examples of the soil include natural soils such as Kuroboku soil, Akadama soil, Kanuma soil, Hinata soil, Tada soil, Black soil, Masa soil, Keto soil, mountain soil, mountain sand, river sand, volcanic ash soil, mullet soil, and red soil. be done. These may be used individually by 1 type, and may use 2 or more types together.

As the culture soil constituent material, which is the base material of the seedling culture soil, it is possible to use an appropriate combination of materials that can be used as the culture soil as described above, depending on the plant species to be raised. By using such a seedling culture medium, it is possible to cope with seedlings with a small root circumference, and to form a root ball with good fixed planting properties and a less likely collapse of the root ball portion.

The seedling culture medium of the present invention preferably contains soil as a constituent material of the culture medium. When soil is included as a constituent material of the culture soil, the native gellan gum can particularly exhibit the effect of suppressing a decrease in root ball strength when water is present. From this point, when soil is included, the content thereof is preferably 1 to 100% by mass, more preferably 10 to 90% by mass, and even more preferably 30 to 80% by mass, relative to the total amount of the soil constituent material.

Other ingredients may be added to the seedling culture medium of the present invention, depending on the plant species to be raised and the like, within the range that does not impair the effects of the present invention. Examples of other components include, but are not limited to, agricultural chemicals. Agrochemicals include, for example, herbicides, animal repellents, growth regulators, soil conditioners, useful microorganisms, useful bacteria, and water permeable agents. These may be used individually by 1 type, and may use 2 or more types together.

In the seedling culture medium of the present invention, the content of the native gellan gum is preferably 0.01 to 10.0% by mass relative to the total amount of the constituent materials of the culture medium. The content of native gellan gum is in terms of solid content. When the content is in such a range, the solidification performance is good, it is possible to suppress the decrease in the strength of the root ball when it contains water, and the growth such as germination and rooting is good, and it is possible to use a transplanter. When the seedlings such as cell seedlings and potted seedlings using seedling culture soil are separated and planted in the field, they are easy to remove and can suppress root damage, so they are good for fixed planting. The content of the native gellan gum is more preferably 0.05% by mass or more relative to the total amount of the soil constituent materials, since it has good caking performance and can suppress the decrease in the strength of the root ball when it contains water. 0.1% by mass or more is more preferable. From the viewpoint of growth and plantability, it is more preferably 5.0% by mass or less, and even more preferably 3.0% by mass or less.

The seedling culture soil before solidification using the seedling culture soil solidifying agent of the present invention can produce a high degree of solidification even if the amount of the seedling culture soil solidifying agent added is small. Compared to a solidifying agent, the absolute amount of the seedling-growing soil solidifying agent added to the seedling-growing soil before solidification can be reduced, and the burden on the environment is very small.

When producing the seedling culture soil before solidification, the seedling culture soil solidifying agent may be used as it is or further diluted with water as appropriate, and this is added to and mixed with the culture soil constituent material that is the base material of the seedling culture soil. By doing so, a seedling culture medium before solidification can be obtained, which can be used as it is or stored in a bag. The seedling medium prior to consolidation is typically in a granular state and has a moisture content of less than 60%.

Since the seedling culture medium before consolidation can be distributed in the bagged granular state as described above, it is easy to handle and can be filled into containers for raising seedlings of various shapes and numbers of cells. For this reason, it is possible to use seedling-raising containers that farmers already have, and it is possible to reduce the cost of producing agricultural products.

The raising seedling culture soil before solidification is, for example, filled in a container for raising seedlings, expanded, air-dried at normal temperature, and solidified to become a culture soil for raising plants.

As the seedling-raising container for filling the seedling-raising culture soil before solidification, the same cells, pots, trays, seedling boxes, etc. as those conventionally used can be used. The size and the like can be appropriately selected according to each situation, but the seedling culture soil before solidification is particularly noticeable when used in a small container with a volume of 10 cm ³ or less per cell. Effective.

The seedling culture soil before consolidation is filled into a container for raising seedlings and then expanded, that is, pressed from above to provide a seedling culture soil having a desired root ball strength after consolidation. The pressure during expansion is not particularly limited, but is, for example, in the range of 0.1 to 10.0 MPa. If the pressure during spreading is within the above range, the strength of the root ball will be high, and the root ball will not crack or collapse during transportation from the seedling-raising facility, extraction with a transplanter, or planting in the field. can be suppressed.
A suitable value of the pressure during such spreading differs depending on the agricultural product to be raised. For general vegetables, it is, for example, about 0.98 MPa, and for onions, it is, for example, about 4.9 MPa.
For example, a commercially available seeding machine can be used to spread the seedling culture medium before consolidation.

The seedling culture medium before solidification can be solidified by air-drying at room temperature. The time required for air-drying is not particularly limited, but is, for example, in the range of 1 to 15 days at room temperature. Specifically, it is about 3 days when naturally dried in a vinyl house, about 1 day in a germination room controlled to a temperature of 25 to 28 ° C and a humidity of around 0%, and a farmer's residence such as a house or barn. It is preferable to air-dry for about one week indoors close to the environment. The moisture content of the air-dried seedling culture medium can be appropriately adjusted according to the type of plant such as agricultural products to be raised.

The seedling culture soil of the present invention can be simply filled in a seedling-raising container without heating the seedling culture soil before solidification in this way, and can be simply expanded and air-dried at room temperature. can be done. Therefore, special equipment for heat consolidation is not required, deformation and breakage of the seedling-raising container are less likely to occur, and the cost of agricultural product production can be reduced.

In addition, in conventional molded culture soil for sowing, water permeability may be lost when the water content is less than 50% by mass, but in the nursery culture soil of the present invention, air drying is performed until the moisture content is about 30% by mass. However, the water permeability is not impaired. Furthermore, it has a good solidification performance, and can suppress a decrease in root ball strength even when the water content increases. The moisture content of the seedling culture medium of the present invention is not particularly limited, but is preferably 10 to 50% by mass, more preferably 20 to 40% by mass. In such a range, growth such as germination and rooting is good, the possibility of causing root rot can be reduced, the solidification performance is good, and the decrease in root ball strength when water is contained can be suppressed. can.

When raising a plant using the seedling culture medium of the present invention, for example, as described above, a commercially available cell tray is filled with the seedling culture medium before solidification using a seeding machine and expanded, and then solidified by air drying. Then, seeds of plants such as vegetables are sown one by one per cell using a sowing machine, and after covering with seedling culture soil before solidification, normal work such as watering is performed to germinate and raise seedlings. be able to. In addition, the seeds of plants such as vegetables are mixed in advance with the seedling culture soil before solidification, and then filled in a commercially available cell tray using a seeding machine, expanded, solidified by air drying, and watered. You can also germinate and raise seedlings by performing normal work such as. In addition to seeds, cuttings can also be used for rooting and raising seedlings.

The seedling culture medium of the present invention can be used for agriculture such as vegetables and paddy rice, and for gardening. Examples of plants suitable for raising seedlings in the seedling culture soil of the present invention include vegetable cell seedlings, fruit vegetable cell seedlings, cut flowers, potted plants, seedlings, and cut flowers for flower beds.

For vegetable cell seedling applications, for example, Liliaceae such as green onions, onions, chives, garlic, and asparagus; Apiaceae, such as celery, Japanese honeywort, parsley, carrots, and Angelica keiskei; , cabbage, mizuna, komatsuna, Brussels sprouts, cauliflower, broccoli, bok choy, call rape, tasai, tsukena, mustard greens, watercress, radish, rape blossoms; Labiatae; Amaranthaceae, such as beets; Sesamaceae, such as sesame; Asteraceae, such as endive; Amaryllidaceae, such as leek.
Among these, it is suitable for raising seedlings of the family Liliaceae, which have thin roots and tend to collapse at the root ball part, because of the high proportion of soil used in the composting material.

Fruit vegetable cell seedling applications include, for example, grasses such as wheat, barley, and rice; Cucurbitaceae, such as melons, cucumbers, watermelons, pumpkins, cucumbers, melons, bitter gourds, and zucchini; tomatoes, eggplants, green peppers, paprika, red peppers, and potatoes. mallow family such as okra and molokheiya; legume subfamily such as sweet corn (maize) and kidney bean;
Plants suitable for cuttings in the pre-consolidation nursery medium or post-consolidation nursery medium include plants that can be propagated by cuttings, such as chrysanthemum, carnation, and perennial gypsophila.

For cut flowers, for example, snapdragon, bupleurum, eustoma, stock, anemone, campanula, dahlia, scapiosa, delphinium, larkspur, nigella, hanashinob, blue lace flower, matricaria, shinteppo lily, limonium sinuata, oxypetalum, craspedia , and the like.

Potted plants, seedlings, and flowerbeds include ageratum, isotoma, impatiens, exacum, gerbera, gazania, calceolaria, chrysanthemum, coleus, salvia, schizanthus, cineraria, geranium, torenia, pansy, vinca, primula, petunia, begonia, Examples include marigolds, ranunculus, and carnations.

After growing plants using the seedling culture medium of the present invention, cell seedlings or potted seedlings are separated using a transplanter, and the rootballs are transplanted into the ground. The solidifying agent for raising seedling culture soil and the raising seedling culture soil of the present invention have good solidifying performance and can suppress a decrease in root ball strength when it contains water. It is possible to suppress the collapse of the root ball and the separation of the root and the culture soil. In addition, native gellan gum contained as a solidifying agent in seedling culture soil has good biodegradability and is free from concerns about environmental pollution.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples.
The solidifying agent for raising seedling culture soil used is as follows.
<Bounding agent for seedling culture soil>
Solidifying agent A: native gellan gum solidifying agent B: sodium alginate solidifying agent C: kappa carrageenan solidifying agent D: iota carrageenan solidifying agent E: xanthan gum solidifying agent F: deacylated gellan gum solidifying agent G: agar Binder H: Guar Gum Binder I: Locust Bean Gum Binder J: Tamarind Seed Gum Binder K: Glucomannan Binder L: Gum Arabic Binder M: Gum Karaya Binder N: Gum Tragacanth Binder Agent O: LM pectin binder P: HM pectin binder Q: Cyrout seed gum binder R: CMC (carboxymethylcellulose)

(Examples 1 to 10, Comparative Examples 1 to 18)
<Production of nursery soil>
Various culture soil constituent materials shown in Table 1 were put into a mixer (manufactured by Koyo Machine Industry Co., Ltd.) and mixed by stirring to obtain culture soil base materials 1 to 4. Next, to 100 parts by mass of the culture soil base material, the solidifying agent for raising seedling culture soil shown in Tables 2A, 2B, and 2C is added so that the content (parts by mass) shown in the same table is obtained, and stirred and mixed for 10 minutes. Then, a seedling culture medium before consolidation was obtained. The seedling culture medium before consolidation was packed in a bag.
<Sowing work>
Using a sowing machine (OSE-110: manufactured by Minoru Sangyo Co., Ltd.), a certain amount of bagged seedling culture soil before solidification is filled into a 448-hole cell tray (pot 448 seedling box: manufactured by Minoru Sangyo Co., Ltd.), After rolling out, it was air-dried at room temperature for 1 week to solidify the seedling culture medium.
One onion seed per hole was again sown in the solidified seedling culture soil using a sowing machine, covered with a certain amount of seedling culture soil before solidification, and then a certain amount of water was applied. , completed the sowing work.

The seedling culture medium obtained in Examples and Comparative Examples was evaluated for onion growth using the rooting state and germination rate as indicators. In addition, plantability and root ball strength of onions were evaluated.

<Rooting status of onions>
Regarding the seedling-raising culture soil after seeding obtained in the above Examples and Comparative Examples, seedlings were raised by watering once a day at a constant amount after seeding, and the rooting state after 7 days was evaluated according to the following criteria.
Evaluation Criteria for Rooting Situation A: Rooting is extremely good, and taproots of onions can be visually observed on the outer peripheral surface of the seedling culture soil removed from the cell tray.
◯: Rooting is good, and the taproot of the onion can be visually confirmed on the outer peripheral surface of the seedling culture soil removed from the cell tray.
Δ: The rooting state is somewhat poor, and the taproot of the onion cannot be visually confirmed on the outer peripheral surface of the seedling culture medium removed from the cell tray.
x: The state of rooting is poor, and the taproot of the onion cannot be visually confirmed on the outer peripheral surface of the seedling culture medium removed from the cell tray.

The above evaluation results are shown in Tables 2A, 2B, and 2C.

<Germination rate of onion>
Of the above Examples and Comparative Examples, the Examples were further evaluated as follows. The seedling-raising culture soil after seeding obtained in Examples 1 to 9 was watered once a day after seeding to raise seedlings, and the germination rate after 7 days was evaluated according to the following criteria.
Evaluation criteria for germination rate 5: The germination rate is 90% or more.
4: The germination rate is 70% or more and less than 90%.
3: The germination rate is 50% or more and less than 70%.
2: The germination rate is 30% or more and less than 50%.
1: The germination rate is less than 30%.

Table 3 shows the above evaluation results.

<Firmness of onion>
60 days after raising the seedlings, the planting ability of the onions using a transplanter from the cell tray (onion transplanter walking 4-row planting: manufactured by Minoru Sangyo Co., Ltd.) was evaluated according to the following criteria for comprehensive evaluation such as removal from the cell tray and root pain. evaluated with
Criteria for evaluation of onion planting ability ⊚: Excellent planting ability with good extractability from the cell tray, no root damage at all.
◯: Easy to extract from the cell tray, almost no root damage, and good planting property.
Δ: Slightly poor extractability from the cell tray, slight root damage, and slightly poor planting ability.
x: Poor extractability from the cell tray, root damage, and poor planting ability.

The above evaluation results are shown in Tables 2A, 2B, and 2C.

<Strength of root ball of onion>
Sixty days after raising the seedlings, the onion seedlings were pulled out from the cell tray, dropped from a height of 50 cm, and the root ball strength of the onion was evaluated from the survival rate calculated from the mass before and after dropping. The moisture content of the seedling culture soil used in the drop test was adjusted to 10% by mass, 30% by mass, and 50% by mass, and the drop test was carried out under three conditions.

Drop test (1) (Moisture content of seedling soil 10% by mass)
Criteria for evaluation of onion root ball strength (survival rate calculated from mass before and after dropping)
5: Residual rate is 90% or more.
4: The residual rate is 70% or more and less than 90%.
3: The residual rate is 50% or more and less than 70%.
2: The residual rate is 30% or more and less than 50%.
1: The residual rate is less than 30%.

Drop test (2) (Moisture content of seedling soil 30% by mass)
Criteria for evaluation of onion root ball strength (survival rate calculated from mass before and after dropping)
5: Residual rate is 90% or more.
4: The residual rate is 70% or more and less than 90%.
3: The residual rate is 50% or more and less than 70%.
2: The residual rate is 30% or more and less than 50%.
1: The residual rate is less than 30%.

Drop test (3) (Moisture content of seedling culture soil: 50% by mass)
Criteria for evaluation of onion root ball strength (survival rate calculated from mass before and after dropping)
5: Residual rate is 90% or more.
4: The residual rate is 70% or more and less than 90%.
3: The residual rate is 50% or more and less than 70%.
2: The residual rate is 30% or more and less than 50%.
1: The residual rate is less than 30%.

The above evaluation results are shown in Tables 2A, 2B, and 2C.
In Tables 2A to 2C and Table 3, it was determined that the problem of the invention would not be solved if the score of 2 or less in the drop test in the evaluation of root ball strength was not achieved. In terms of the evaluation of the rooting state and plantability, it was determined that x does not solve the problem of the invention. A germination rate of 2 or less was judged not to solve the problem of the invention.

From Tables 2A to C and Table 3, the seedling culture soil of Examples to which native-type gellan gum was added had good caking performance, and even compared to various polysaccharides in Comparative Examples, the root ball strength when moistened did not decrease. could be suppressed. Plantability was not impaired, and growth was confirmed from the rooting state and germination rate. When soil was included as a constituent material of the culture soil, the effect of native gellan gum in suppressing the decrease in root ball strength when water was present was more pronounced.

Claims (4)

A solidifying agent for nursery soil containing native gellan gum. A nursery medium containing native gellan gum and a medium-forming material. The nursery soil for raising seedlings according to claim 2, wherein the content of the native gellan gum is 0.01 to 10.0% by mass with respect to the total amount of the constituent materials of the soil. 4. The seedling culture soil according to claim 2 or 3, wherein the soil is included as the culture soil constituent material.