Seedling-raising culture soil and seedling-raising method

Abstract

To provide seedling-raising culture soil that can be stably supplied, and can promote growth of seedlings or seedling trees, and a seedling-raising method the soil.SOLUTION: Provided is seedling-raising culture soil containing calcium type bentonite and grain husk.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a seedling raising soil and a seedling raising method. [Background technology]

[0002] The cyclical use of forest resources is being promoted, and the basis of forestry is to allow trees to regenerate after being cut down. When regeneration is carried out through afforestation rather than natural regeneration, cuttings or seedlings are planted. The most common regeneration method, especially in areas other than Kyushu (where cuttings are the norm), is to plant bare-rooted seedlings grown to a certain size in nurseries. Until recently, this method was used to plant seedlings of trees such as cypress, cedar, and larch. Because bare-rooted seedling planting is only possible for a limited period of time, in recent years, there has been an increase in the planting of seedlings (container seedlings) grown in greenhouses using multi-cavity containers filled with culture medium (growing soil). Furthermore, low-pollen or no-pollen cedar and cypress seedlings, which produce significantly fewer male flowers than traditional varieties (elite trees), are increasingly being planted. Cocopeat, an organic medium (coconut shell medium) made by fermenting coconut husk (mesocarp) crushed to about 0.1 to 10 mm, has traditionally been widely used as a nursery medium for growing container seedlings. (For example, Cocopeat (registered trademark), Cocoyuki (registered trademark), Top Cocopeat Old (registered trademark), and other coconut shell mediums are collectively referred to as "cocopeat (coconut shell medium)" below.) However, the main countries of origin for cocopeat (coconut shell medium) are India and Sri Lanka, and it is difficult to obtain due to political instability and other factors.

[0003] In addition to coco peat (coconut shell substrate), other types of compost made from grain husks are also known as seedling growing media, but their use is not widespread. For example, rice husks account for approximately 20% of Japan's rice harvest (for seed production) in 2021, with rice husks accounting for approximately 7.5 million tons, much of which is discarded. This is not limited to rice; wheat and buckwheat husks (wheat husks and buckwheat husks) are also discarded in large quantities worldwide. Therefore, there is a need for more effective utilization of composted grain husks. Because composted grain husks are composed of persistent components and are difficult for soil microorganisms to decompose, they have been composted or carbonized for use as growing media. However, the cost and effort required for this process are thought to be a hindrance to promoting the use of composted grain husks. Therefore, there is a need for a more convenient method for using composted grain husks as growing media. For example, Patent Document 1 discloses an invention for a plant growth medium containing rice husks or buckwheat husks as a base material that is not composted or carbonized, and organic and / or inorganic materials, characterized in that the organic and / or inorganic materials are attached to and filled into the depressions in the rice husks or buckwheat husks with a binder. The examples in this document describe a plant growth medium containing a blend of rice husks, peat moss or crushed coconut shells, powdered zeolite, and polyvinyl alcohol. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5825909 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a seedling raising soil that can be supplied stably and that can promote the growth of seedlings or saplings, and a seedling raising method using the same. [Means for solving the problem]

[0006] The present inventors have conducted extensive research in light of the above-mentioned problems and have found that seedling culture medium made by mixing calcium bentonite with cereal husks can promote plant growth. The present invention has been completed based on these findings.

[0007] The above-mentioned problems of the present invention have been solved by the following means. [1] Seedling growing soil containing calcium bentonite and grain husks. [2] The seedling raising soil according to [1] above, wherein the content ratio of the calcium bentonite to the cereal husks is, on a mass basis, calcium bentonite:cereal husks=0.5:1 to 3:1. [3] The seedling raising soil according to [1] or [2] above, containing a pH adjuster. [4] Cryptomeria genus ( Cryptomeria ), a tree belonging to the genus Chamaecyparis ( Chamaecyparis ), and trees belonging to the genus Larix ( Larix The seedling raising soil according to any one of [1] to [3] above, for growing seedlings of trees selected from trees belonging to the [5] The seedling soil according to any one of [1] to [4], wherein the grain husk is rice husk. [6] A seedling raising method for raising seedlings or saplings using the seedling raising soil according to any one of [1] to [5] above. [Effects of the Invention]

[0008] According to the seedling raising soil and seedling raising method of the present invention, it is possible to stably supply seedling raising soil and promote the growth of seedlings or saplings. [Brief explanation of the drawings]

[0009]

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[0010] In the present invention and this specification, "raising seedlings" means growing "seedlings" of herbaceous plants or "seedlings" of woody plants (sometimes simply referred to as "seedlings") until they reach a size suitable for planting. Herbaceous plants and woody plants are also collectively referred to simply as "plants."

[0011] [Soil for raising seedlings] A first aspect of the present invention is a seedling raising soil containing calcium-type bentonite and cereal husks (hereinafter also referred to as "seedling raising soil of the present invention"). In the seedling raising soil, the calcium-type bentonite and cereal husks exist in a mixed state. In other words, the seedling raising soil is a mixture of granular (powdered) calcium-type bentonite and cereal husks. The seedling culture medium of the present invention is a culture medium that can utilize grain husks, which have traditionally been discarded as industrial waste, and contributes to the effective use of resources. The seedling culture medium of the present invention is also suitable for growing seedlings, promoting their growth and allowing them to be planted earlier. Therefore, the present invention can contribute to the promotion of carbon neutral efforts to achieve virtually zero carbon dioxide emissions. Furthermore, by using abundant calcium bentonite and grain husks as raw materials, the seedling culture medium of the present invention can be supplied stably.

[0012] Clay soils generally have excellent water and fertilizer retention properties, but poor drainage and breathability. Grain husks, on the other hand, have high water repellency and poor water retention, so they are usually processed (composted, carbonized, etc.) before use. Neither is suitable for seedling cultivation when used alone. In contrast, the seedling cultivation soil of the present invention focuses on calcium-type bentonite, a type of bentonite, and by blending this with grain husks, it is possible to achieve both the water retention and fertilizer retention properties of calcium-type bentonite and the water repellency and breathability of grain husks within a range suitable for seedling cultivation. The ability to achieve these contradictory properties is thought to be due in part to the fact that calcium-type bentonite fills the depressions in the grain husks, maintaining appropriate water and fertilizer retention while allowing excess water to drain smoothly. Furthermore, air spaces are formed between the grain husks, ensuring breathability.

[0013] (Calcium bentonite) The seedling soil of the present invention contains calcium bentonite. Bentonite is a clay whose main component is montmorillonite, a type of layered silicate mineral whose main components are silica and alumina. That is, the calcium bentonite is bentonite in which the main interlayer cation of the main component, montmorillonite, is calcium ion. In the present invention, the term "bentonite" is used in a broader sense than usual. That is, it may be naturally occurring bentonite, purified bentonite (preferably purified montmorillonite) obtained by purifying naturally occurring bentonite, or synthetic montmorillonite. From the viewpoint of production cost, the bentonite is preferably naturally occurring bentonite, and is preferably an unpurified product. Furthermore, it may be ion-exchanged bentonite, for example, in which sodium-type bentonite is used and the sodium ions, which are the main interlayer cations of montmorillonite, are replaced with calcium ions by ion exchange. An example of a commercially available product is Kunibond (manufactured by Kunimine Industries Co., Ltd.), which is calcium bentonite.

[0014] The seedling culture medium of the present invention contains calcium-type bentonite, which allows seedlings or saplings to grow better than in a seedling culture medium containing sodium-type bentonite. Calcium-type bentonite has a lower pH than sodium-type bentonite. Therefore, by mixing it with grain husks, the pH of the water passing through the water can be appropriately lowered, and it is presumed that the seedling culture medium of the present invention containing calcium-type bentonite will allow seedlings or saplings to grow better.

[0015] In the present invention, the term "calcium-type bentonite" refers to bentonite in which the amount of calcium ions (unit: meq / 100 g) in the amount of leached cations (i.e., the total amount of leached cations, unit: meq / 100 g) is 50% or more (preferably 60% or more, more preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more). The amount of leached cations in bentonite can be calculated by leaching interlayer cations of bentonite (montmorillonite) for 4 hours or more using, for example, 100 mL of 1 M ammonium acetate aqueous solution per 0.5 g of bentonite, and measuring the concentrations of various cations in the resulting solution using ICP emission spectrometry, atomic absorption spectrometry, or the like. The content of montmorillonite in the bentonite is preferably 50% by mass or more, or may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. The remainder of the bentonite components, excluding montmorillonite as the main component, may include associated minerals (impurity minerals) such as cristobalite, quartz, feldspar, zeolite, calcite, and mica.

[0016] The cation exchange capacity (CEC) of the calcium bentonite is preferably 15 meq (milliequivalent) / 100 g or more, more preferably 20 meq / 100 g or more, and even more preferably 25 meq / 100 g or more, from the viewpoint of improving water retention. The cation exchange capacity of the calcium bentonite is usually 250 meq / 100 g or less. The cation exchange capacity of bentonite can be measured by a method based on the Schollenberger method (Clay Handbook, Third Edition, edited by the Clay Science Society of Japan, May 2009, pp. 453-454). More specifically, it can be measured by the method described in JBAS-106-77, Standard Test Method of the Japan Bentonite Industry Association.

[0017] In the seedling soil of the present invention, the calcium bentonite content in the remainder after excluding water is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.

[0018] The particle size of the calcium-type bentonite is not particularly limited and can be set appropriately depending on the purpose as long as the calcium-type bentonite can fill the depressions in the grain husks. For example, the particle size of the calcium-type bentonite may be 0.1 μm or more, 1 μm or more, or 10 μm or more. The upper limit of the particle size may be 5 mm or less, 1 mm or less, 500 μm or less, or 100 μm or less. This particle size can be determined by a sieving test using a method in accordance with JIS Z8815:1994.

[0019] (grain husks) The seedling raising soil of the present invention contains cereal husks. In the present invention and this specification, "cereal husks" refers to the outer skin of cereal or pseudocereal seeds. Examples of the cereals include rice, wheat (wheat, barley, rye), foxtail millet, barnyard millet, millet, and corn, with rice and wheat being preferred, and rice being more preferred. Examples of the pseudocereals include buckwheat and quinoa.

[0020] The husks, which encase the seeds, have a concave (bay- or boat-shaped) shape in their unprocessed state. By mixing calcium-type bentonite with husks, the calcium-type bentonite fills the husks' concave shapes, and the water-repellent and breathable properties of the husks work in unison with the water-retaining and fertilizer-retaining properties of the calcium-type bentonite, maintaining an appropriate pH level in the water passing through the husks and promoting seedling growth. The cereal husk is preferably cereal husk itself (untreated cereal husk) obtained by threshing, hulling, etc. Although cereal husk that has been crushed to some extent may be used, it is preferable that the cereal husk retains some of the recessed structure into which calcium bentonite is filled. Also, from the viewpoint of water repellency, the cereal husk is preferably untreated cereal husk that has not been subjected to treatment such as composting or carbonization.

[0021] In the seedling soil of the present invention, the content of the grain husk in the remainder after excluding water is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

[0022] The content ratio of the calcium bentonite to the grain husks (calcium bentonite:grain husks) is preferably 0.2:1 to 5:1 by mass, more preferably 0.3:1 to 4:1, even more preferably 0.5:1 to 3:1, and even more preferably 1:1 to 3:1. By setting the content ratio of calcium bentonite to grain husks within the above range, the resulting seedling raising soil can be made more suitable for raising seedlings.

[0023] (pH adjuster) The pH of the seedling raising soil of the present invention is preferably adjusted to a range of 4.5 to 7. Generally, calcium bentonite is weakly alkaline, so it is preferable to incorporate a pH adjuster to adjust the pH of the seedling raising soil of the present invention to within the above-mentioned preferred range. Examples of pH adjusters that can be incorporated into the seedling raising soil of the present invention include purified water cake (dehydrated cake), peat moss, sulfur, ammonium sulfate, sulfur dioxide, etc., with purified water cake being preferred from the viewpoint of reducing production costs. Because purified water cake, like grain husks, is conventionally discarded as industrial waste, using the purified water cake as a pH adjuster can further contribute to the effective utilization of resources.

[0024] When a pH adjuster is contained in the seedling raising soil of the present invention, the content of the pH adjuster is appropriately blended so that the pH of the seedling raising soil is 4.5 to 7. For example, when the pH adjuster is purified water cake, the content ratio of the pH adjuster to the grain husk (purified water cake:grain husk) is preferably 0.25:1 to 1:1 by mass.

[0025] (Other ingredients) The total content of the calcium bentonite and cereal husks in the seedling culture medium of the present invention, excluding water, is preferably 60 to 100% by mass, more preferably 65 to 100% by mass, and even more preferably 69 to 90% by mass. In addition to the calcium bentonite and cereal husks, the seedling culture medium of the present invention can contain any component within a range that does not impair the effects of the present invention. Examples of such components include seaweed powder, rice bran, soybean pulp, various fertilizers including slow-release fertilizers, yeast extract, and plant residues such as straw. In particular, rice bran, unless composted through fermentation, is known to adversely affect seedling growth when incorporated into seedling culture medium. On the other hand, even when non-composted rice bran is incorporated into the seedling culture medium of the present invention, the above-mentioned adverse effects are not observed, and a good seedling culture medium containing the nutrient source from rice bran can be obtained. These components may be incorporated alone or in combination of two or more. The seedling raising soil of the present invention is preferably in a form that does not contain a binder as described in Patent Document 1. Because bentonite becomes viscous when it contains water, it is thought that once bentonite adheres to grain husks, it is not easily peeled off even by irrigation or the like, and can maintain its integral form while remaining packed into the grain husks. The seedling raising soil of the present invention exhibits a sufficiently high seedling raising promotion effect without using artificial materials that are not essentially necessary for seedling raising, such as organic binders. The seedling raising soil of the present invention may be used in combination with other seedling raising soils, such as Coco Peat (registered trademark) and Top Coco Peat Old (registered trademark) manufactured by Top Co., Ltd.

[0026] Furthermore, by using the seedling raising soil of the present invention, it is possible to reduce the amount of applied chemical fertilizers (fertilizer reduction). Because the seedling raising soil of the present invention has excellent fertilizer retention properties, the fertilizer components in the applied fertilizer (e.g., liquid fertilizer) can be retained in the soil for a long time. Therefore, for example, by applying oxidized glutathione (GSSG) in combination to promote the absorption of fertilizer components by seedlings, it is possible to sufficiently promote the growth of seedlings even if the application amount of fertilizer such as slow-release fertilizer or liquid fertilizer is reduced.

[0027] (Applicable plants) The types of plants to which the seedling raising soil of the present invention is applied (herbaceous plants and woody plants to be grown using the seedling raising soil of the present invention) are not particularly limited. Examples include grains; vegetables such as potatoes, root vegetables, bulbs, beans, cucurbit vegetables, solanaceous fruit vegetables, cruciferous vegetables, leafy vegetables, stem vegetables, and edible flowers; fruit trees such as small fruits such as citrus fruits, pome fruits, stone fruits, and berries; pasture grasses; turfgrass; special-purpose crops such as spice crops; flowering plants and ornamental plants; trees such as woody plants; and tea. Examples of the vegetables include komatsuna ( Brassica rapa var. perviridis ) etc.

[0028] (woody plants) The type of woody plant is not particularly limited, and may be, for example, an evergreen tree, a deciduous tree, a coniferous tree, or a broad-leaved tree. Examples of the above trees include Malvaceae ( Malvaceae ), Sterculiaceae ( Sterculiaceae ), Rubiaceae ( Rubiaceae ), Akebia family ( Lardizabalaceae ), Aquifoliaceae ( Sabiaceae ), Celastraceae ( Flacourtiaceae ), Taxaceae ( Taxaceae ), Ginkgoaceae ( Ginkgoaceae ), Celastraceae ( Cephalotaxaceae ), Urticaceae ( Urticaceae ), Araliaceae ( Araliaceae ), Cucurbitaceae ( Alangiaceae ), Anacardiaceae ( Anacardiaceae ), Styraxaceae ( Styracaceae ), Hypericaceae ( Hypericaceae ), Maple family ( Aceraceae ), Ebenaceae ( Ebenaceae ), Cercidiphyllum ( Cercidiphyllaceae ), Betulaceae ( Betulaceae ), Asteraceae ( Asteraceae ), Asparagaceae ( Asparagaceae ), Stachyuraceae ( Stachyuraceae ), Apocynaceae ( Apocynaceae ), Lauraceae ( Lauraceae ), Verbenaceae ( Verbenaceae ), Elaeaceae ( Elaeagnaceae ), Juglandaceae (Juglandaceae ), Rhamnaceae ( Rhamnaceae ), Moraceae ( Moraceae ), Scutellaria family ( Sciadopityaceae ), Piperaceae ( Piperaceae ), Scrophulariaceae ( Scrophulariaceae ), Pomegranate family ( Punicaceae ), Illicaceae ( Illiciaceae ), Tilia family ( Tiliaceae ), Thymelaeaceae ( Thymelaeaceae ), Caprifoliaceae ( Caprifoliaceae ), Cypress family ( Taxodiaceae ), Platanaceae ( Platanaceae ), Meliaceae ( Meliaceae ), Buxaceae ( Buxaceae ), Ericaceae ( Ericaceae ), Theaceae ( Theaceae ), Euphorbiaceae ( Euphorbiaceae ), Coriaceae ( Coriariaceae ), Aesculaceae ( Hippocastanaceae ), Eucommia ( Eucommiaceae ), Pittosporaceae ( Pittosporaceae ), Solanaceae ( Solanaceae ), Sciadopitys sieboldii ( Simaroubaceae ), Celastraceae ( Celastraceae ), Ulmaceae ( Ulmaceae ), Botryllaceae ( Nyssaceae ), Bignoniaceae ( Bignoniaceae ), Cypress family ( Symplocaceae ), Rosaceae ( Rosaceae ), Cupressaceae ( Cupressaceae ), Prunellaceae ( Euptelea ), Dipterocarpaceae ( Dipterocarpaceae ), Vitaceae ( Vitaceae ), Myrtaceae ( Myrtaceae ), Fagaceae ( Fagaceae ), Scleractinia ( Elaeocarpaceae ), Podocarpus family ( Podocarpaceae ), Actinidiaceae ( Actinidiaceae ), Pinaceae ( Pinaceae ), Bacillus family ( Schisandraceae ), Fabaceae ( Fabaceae ), Hamamelidaceae ( Hamamelidaceae ), Rutaceae ( Rutaceae ), Cornaceae ( Cornaceae ), Lythraceae ( Lythraceae ), Tricholomataceae ( Staphyleaceae ), Sapindaceae ( Sapindaceae ), Berberidaceae (Berberidaceae ), Oleaceae ( Oleaceae ), Magnoliaceae ( Magnoliaceae ), Ilex family ( Aquifoliaceae ), Palm family ( Palm family ), Mistletoe (Santalaceae) Mistletoe , Santalaceae ), Salicaceae ( Willows ), Ardisiaceae ( Primroses ), Araceae ( Trochodendraceae ), Myricaceae ( Myrtle family ), Saxifragaceae ( Saxifrageaceae ), Cerataceae ( Daphniphyllae ), Liliaceae ( Liliaceae ), Choleraceae ( Clethraceae ), Ceramiaceae ( Calycanthaceae Among them, trees belonging to the families Cupressaceae, Cupressaceae, Fagaceae and Pinaceae are preferred, and trees belonging to the families Cupressaceae, Cupressaceae and Pinaceae are more preferred. Trees that belong to the Cupressaceae family include the genus Cryptomeria ( Cryptomeria ), Metasequoia genus ( Metasequoia ), Bald Cypress ( Taxodium ), and Chinese fir ( Cunninghamia ) trees that belong to the Cupressaceae family include the genus Chamaecyparis ( Chamaecyparis ), Arborvitae ( Thuja ), and Juniperus spp. ( Juniper ) trees that belong to the Fagaceae family include the genus Fagus ( Beech ), Quercus spp. ( Oak ), Castanea ( Chestnut ), Castanopsis genus ( Chestnut tree ), and Lithocarpus genus ( Lithocarpus ) trees belonging to the Pinaceae family include the genus Larix ( Larch ), Pinus spp. ( Pine ), Abies genus ( Fir tree ), Picea genus ( Spruce ), and Cedrus spp. ( Cedar Among them, trees selected from the group consisting of trees belonging to the genus Cedar, trees belonging to the genus Chamaecyparis, and trees belonging to the genus Larix are preferred.

[0029] [Manufacturing method of seedling raising soil] The seedling culture medium of the present invention can be produced by mixing calcium-type bentonite and cereal husks, preferably in the ratio described above. Furthermore, the method for mixing the calcium-type bentonite and cereal husks is not particularly limited. However, it is preferable to thoroughly mix the cereal husks with water (the minimum amount of water normally used in seedling culture medium; for example, if the cereal husks are rice husks, the amount of water should be about three times the weight of the husks) so that the calcium-type bentonite can adhere to the cereal husks, and then gradually add the calcium-type bentonite (e.g., by sieving). If the seedling culture medium of the present invention contains purified water cake, etc., it is preferable to mix the purified water cake, etc., with the culture medium mixed as described above, with as little force as possible. By using the minimum amount of water, even when an enhanced release fertilizer, etc. is added, the combined calcium-type bentonite and rice husks will not disintegrate, resulting in a seedling culture medium with good fertilizer retention.

[0030] [Seedling raising method] According to a second aspect of the present invention, there is provided a seedling raising method (hereinafter also referred to as "the seedling raising method of the present invention") which comprises growing seedlings or seedlings in the seedling raising soil of the present invention.

[0031] In the seedling raising method of the present invention, seedlings or seedlings can be raised in the same manner as in conventional seedling raising methods, except that the seedling raising soil of the present invention is used as the seedling raising soil. The seedlings or seedlings to be raised may be potted seedlings or containerized seedlings. That is, the seedling raising soil of the present invention can be filled into pots, containers, or beds. Furthermore, the seedlings or seedlings to be raised in the seedling raising method of the present invention can be seedlings or seedlings of the plants described above in the seedling raising soil of the present invention. Furthermore, compared to conventional seedling raising soils (e.g., coco peat (coconut shell medium)), the seedling raising soil of the present invention has excellent moldability, so the soil at the roots is less likely to crumble, and is easier to handle when transplanting (e.g., planting).

[0032] The seedlings or saplings grown by the seedling raising method of the present invention have accelerated growth compared to seedlings or saplings grown in ordinary seedling raising soil. Therefore, for example, when growing seedlings by the seedling raising method of the present invention, the root system and aboveground parts can be increased at an early stage, and the time until they are ready to be planted can be shortened. [Example]

[0033] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0034] In this example, the details of the materials used for the seedling raising soil were as follows: In this example, Coco Peat (registered trademark) and Top Coco Peat Old (registered trademark), which are representative examples of coco peat (coconut shell medium), were used as reference examples of the seedling raising soil. (bentonite) Kunibond (calcium bentonite, manufactured by Kunimine Industries Co., Ltd.) Neokunibond (activated (Na (sodium) type) bentonite, manufactured by Kunimine Industries Co., Ltd.) (rice husks) ·JA Sunny Country Okayama (pH adjuster) Purified water cake (from Mizushima Water Purification Plant, Okayama Prefecture) (Cocopeat (coconut shell medium)) Cocopeat (registered trademark, fermented for 3-5 years, Top Co.) Top Coco Peat Old (registered trademark, manufactured by Top Co., Ltd., a medium fermented for 40 to 70 years) (Other materials) Rice bran

[0035] In this example, the small plug seedlings (seedlings for transplanting into containers) used in each seedling raising test were raised by the following method. Hinoki seeds were sown individually in 200 holes of Excelsoil (Minoru Sangyo Co., Ltd.), germination was accelerated, and the seeds were grown in a cultivation room until they were 9 weeks old. The growth conditions for the small plug seedlings were 28°C (15 hours light) / 18°C ​​(9 hours dark), with an illumination intensity of 150 μmoles photon density m -2 ·s -1 The temperature was set at 100°C, and humidity was left constant. The first liquid fertilizer application was performed 1.5 months after sowing, followed by second and third applications 1 and 2 weeks later. The liquid fertilizers used were a 1000-fold diluted solution of Hyponex (Professional Hyponex 20-20-20, manufactured by Hyponex Japan Co., Ltd.) (Liquid Fertilizer A), a 5000-fold diluted solution of Hyponex, and a 625-fold diluted solution of Kaneka Peptide W2 Wettable Powder (manufactured by Kaneka Corporation) (Liquid Fertilizer B). In this example, the seedlings to which Liquid Fertilizer A was applied are referred to as "control seedlings," and the seedlings to which Liquid Fertilizer B was applied are referred to as "GSSG seedlings." The 9-week-old small plug seedlings used for transplanting were all within the range of 4.5 to 7 cm in length and in good growth.

[0036] [Experimental Example 1] <Preparation of seedling soil> The above materials were mixed according to the mixing ratios shown in Table 1 below to prepare seedling culture media. The cocopeat (coconut shell medium) used in Experimental Example 1 was Cocopeat (registered trademark). An inner pot (65 mm diameter, 40 mm bottom diameter, 145 mm height, model number: 300R, manufactured by Yoshida Sangyo Co., Ltd.) was placed in each cavity (growth hole) of a 24-hole multi-cavity container (300 cc cavity capacity, manufactured by Tohoku Tachibana Co., Ltd.) and filled with the seedling culture media prepared above. When filling each seedling culture media into the inner pot, 4.5 g of a compound fertilizer (High Control 650 700-day type, manufactured by J-Cam Agri Co., Ltd.) was added per 300 cc cavity capacity.

[0037] [Table 1]

[0038] In this example, unless otherwise specified, the "Ca type" or "Na type" of each seedling culture medium indicates the type of bentonite used, and "X:Y" indicates the ratio (by mass) of bentonite to rice husks. For example, "Ca type (1:1)" seedling culture medium refers to a seedling culture medium containing Ca type bentonite, with a mass ratio of Ca type bentonite to rice husks of 1:1. Furthermore, "Ca type (1:1), C" seedling culture medium refers to a seedling culture medium containing Ca type (1:1) and purified water cake (C), with a mass ratio of rice husks to purified water cake of 1:0.5. Furthermore, the seedling soil of "Ca type (1:1), C, RB" means a seedling soil in which "rice bran (RB) is blended with Ca type (1:1), C, and the blending ratio of rice husk to rice bran is rice husk:rice bran = 3:1 by mass." This also applies to the following experimental examples.

[0039] <Seedling raising test> Holes (planting holes) of an appropriate size for the size of the small plug seedlings were drilled on the surface of the containers filled with each seedling raising soil, and the 9-week-old small plug seedlings (control seedlings, GSSG seedlings) were transplanted. The growth conditions were 28°C (15 hours light) / 18°C (9 hours dark), illuminance 150 μmoles photon density m -2 ·s -1 The plants were watered appropriately based on the weight of the entire container for the first month after repotting, and after one month had passed, water was given three times a week until the seedling soil was sufficiently moist. Figures 1 and 2 show photographs of Japanese cypress seedlings one month after transplanting small plug seedlings. As can be seen from Figure 2, seedling growth was significantly poorer in the nursery media using sodium bentonite (sodium type (1:1), sodium type (1.5:1), sodium type (2:1)) than in the media using coco peat. In contrast, as can be seen from Figure 1, seedling growth was favorable in the media using calcium bentonite (calcium type (1:1), calcium type (2:1), calcium type (3:1)), similar to that in the media using coco peat. Seedling growth was particularly favorable in the media containing purified water cake (calcium type (1:1), calcium type (C)). Furthermore, GSSG seedlings showed better growth than the control seedlings.

[0040] [Experimental Example 2] <Preparation of seedling soil> Seedling culture media were prepared in the same manner as in Experimental Example 1 above. The cocopeat (coconut shell medium) used in Experimental Example 2 was Cocopeat (registered trademark). When filling each seedling culture media into the inner pot, a chemical fertilizer (High Control 650 700-day type, manufactured by JCAM Agri) was added at 4.5 g per 300 cc cavity volume. This container was designated "with chemical fertilizer." A container without chemical fertilizer added when filling the seedling culture media was designated "without chemical fertilizer." Because the seedling culture media of the present invention are not composted, the fertilizer retention of the seedling culture media of the present invention can be determined by comparing the results of tests with and without chemical fertilizer.

[0041] <Seedling raising test> Holes (planting holes) of an appropriate size for the size of the small plug seedlings were drilled on the surface of the containers filled with each seedling raising soil, and the 9-week-old small plug seedlings (control seedlings, GSSG seedlings) were transplanted. The growth conditions were 28°C (15 hours light) / 18°C (9 hours dark), illuminance 150 μmoles photon density m -2 ·s -1 The plants were watered appropriately based on the weight of the entire container for the first month after repotting, and after one month had passed, water was given three times a week until the seedling soil was sufficiently moist. For each seedling one month, five months, and six months after transplanting, the seedling length, branch width (branch spread width), base diameter, above-ground weight (fresh weight), and root system development were measured and evaluated (all values ​​are the average of four plants).

[0042] Photographs of each seedling one month and five months after transplanting are shown in Figures 3 and 4. As can be seen from Figure 3, seedlings grew well in all of the seedling raising soils. Furthermore, seedlings grown in the seedling raising soil containing purified water cake grew better than seedlings grown in the seedling raising soil without purified water cake. Furthermore, as can be seen from Figure 4, seedlings grown in the seedling raising soil of the present invention (Ca type (1:1), Ca type (1:1), C) grew better than seedlings grown in coco peat.

[0043] The seedling length of each seedling after transplanting is shown in Figure 5. The application of chemical fertilizer tended to increase seedling length for seedlings at all stages. In particular, for seedlings grown in the seedling raising soil of the present invention (Ca type (1:1), Ca type (2:1), Ca type (3:1), Ca type (1:1), C), the application of chemical fertilizer significantly increased seedling length compared to seedlings grown without chemical fertilizer. This suggests that the seedling raising soil of the present invention has excellent fertilizer retention properties. Furthermore, in containers to which chemical fertilizers had been applied, seedlings grown in nursery soil containing sodium-type bentonite (sodium-type (1:1)) were shorter in length than seedlings grown in the coco peat of the reference example, whereas seedlings grown in the nursery soil of the present invention containing calcium-type bentonite were significantly taller than seedlings grown in coco peat, especially in the fifth and sixth months after transplanting.

[0044] The "seedling length x branch width" values ​​for each seedling five months after transplanting are shown in Figure 6. A larger "seedling length x branch width" value indicates a higher amount of photosynthesis, indicating that the seedlings will continue to grow well after planting. FIG. 6 shows that the seedlings grown in the seedling raising soil of the present invention containing Ca-type bentonite had a larger value for "seedling length x branch width" than the seedlings grown in coco peat.

[0045] The base diameter of each seedling 5 months after transplanting is shown in Figure 7. Figure 7 shows that the seedlings grown in the seedling raising soil of the present invention containing Ca-type bentonite had a larger base diameter than the seedlings grown in coco peat.

[0046] The weight of the above-ground parts of each seedling six months after transplanting is shown in Figure 8. For each seedling grown under the same conditions, seedlings grown in coco peat and seedlings grown in Na-type (1:1) nursery soil began to wither six months after transplanting, resulting in low above-ground weights. In contrast, when using the nursery soil of the present invention, the transplanted seedlings showed good growth even six months after transplanting, demonstrating that the nursery soil of the present invention also has excellent water retention properties.

[0047] Figure 9 shows photographs of GSSG seedlings six months after transplantation into the Ca type (1:1) and Ca type (1:1) C nursery soil. As shown in Figure 9, all seedlings grew well. In particular, the seedlings grown in the Ca type (1:1) C nursery soil containing purified water cake showed significant growth of the above-ground parts.

[0048] Six months after transplanting the GSSG seedlings, the root development of the seedlings was evaluated using the following evaluation method. <Root system development evaluation> As shown in Figure 10, the root conditions were classified into five levels, from 1 to 5, and the root condition of each seedling was visually judged to determine whether it was closest to a rating of 1 to 5 or an intermediate rating. For example, a rating of "3.5" means that the root condition of the seedling was closest to an intermediate rating of 3 and 4. Figure 11 shows the root development evaluation scores for GSSG seedlings six months after transplantation. Compared to seedlings grown in coco peat, all seedlings grown in the seedling soil of the present invention showed well-developed root systems.

[0049] Figure 12 shows the condition of the roots of GSSG seedlings six months after transplanting. All seedlings had grown sufficiently to be planted, and the nursery soil remained solid enough to be planted together with the nursery soil (the nursery soil was fixed to a state where it would not collapse). In particular, the seedlings grown in the Ca (1:1), C, and Ca (2:1) nursery soils showed more accelerated root development. Furthermore, while the root system development level considered suitable for planting is usually "3" or higher, the seedlings grown in the Ca (3:1) nursery soil showed root system development levels below "3," yet the nursery soil remained firmly solid. It has been reported that if the root development level is "2" or higher, subsequent growth will be good as long as the seedlings are planted (Kenichi Ogawa, "Selecting and Growing Good Mother Trees, Good Seeds, and Good Seedlings - Aiming to Reduce the Number of Weedings by Applying Glutathione," Journal of the Japan Forestry Association, No. 1680, published in 2024, pp. 36-44). Therefore, by using the seedling raising soil of the present invention, the range (stage) of seedlings that can be planted can be expanded, and the yield of seedlings grown in the mountains can be improved.

[0050] [Experimental Example 3] <Preparation of seedling soil> Seedling culture medium was prepared in the same manner as in Experimental Example 1. The coco peat (coconut shell medium) used in Experimental Example 3 was Top Coco Peat Old (registered trademark). When filling each seedling culture medium into the inner pot, 4.5 g of chemical fertilizer (High Control 650 700-day type, manufactured by JCAM Agri Co., Ltd.) was added per 300 cc of cavity volume, which was designated as a container with chemical fertilizer, and 4.5 g of chemical fertilizer ... no chemical fertilizer added.

[0051] <Seedling raising test> Holes (planting holes) of an appropriate size for the size of the small plug seedlings were drilled on the surface of the containers filled with each seedling raising soil, and the 9-week-old small plug seedlings (GSSG seedlings) were transplanted. The growth conditions were 28°C (15 hours light) / 18°C (9 hours dark), 150 μmoles photon density m -2 ·s -1The plants were watered appropriately based on the weight of the entire container for the first month after repotting, and after one month had passed, water was given three times a week until the seedling soil was sufficiently moist. For each seedling 1 month, 4 months, and 5 months after transplanting, the seedling length, branch width (branch spread width), base diameter, aboveground weight (fresh weight), and root system development were measured and evaluated (all values ​​were average values ​​for 2 to 4 plants). The root system development was evaluated using the same method as in Experimental Example 2. Note that the seedling length test for seedlings grown in Ca-type (0.5:1) seedling raising soil without chemical fertilizer application 4 months after transplanting was not conducted due to sample size limitations.

[0052] The seedling length of each seedling after transplanting is shown in Figure 13. For seedlings grown in the seedling culture media of the present invention, Ca type (0.5:1), Ca type (1:1), Ca type (1:1), and C, application of chemical fertilizer significantly increased seedling length compared to seedlings grown without chemical fertilizer (fourth and fifth months after transplanting). In contrast, for seedlings grown in the Ca type (1:1), C, and RB seedling culture media containing rice bran, significant increases in seedling length were observed, equivalent to (five months after transplanting) or even greater than (fourth month after transplanting) seedlings grown in Top Coco Peat Old®, even without application of chemical fertilizer. It was demonstrated that rice bran in the seedling culture media of the present invention, which contains rice bran, exhibits effects equivalent to those of chemical fertilizer. Furthermore, since Top Coco Peat Old (registered trademark) contains more fertilizer components than Coco Peat (registered trademark), the seedlings grown using Top Coco Peat Old (registered trademark) grew better than the seedlings grown using Coco Peat (registered trademark) in Experimental Example 2 (comparison of the data 5 months after transplanting in Figure 5 and the data 5 months after transplanting in Figure 13).

[0053] The "seedling length x branch width" values ​​for each seedling 4 and 5 months after transplanting are shown in Figure 14. Figure 14 shows that the seedlings grown in the seedling raising soil of the present invention containing Ca-type bentonite had larger "seedling length x branch width" values ​​than the seedlings grown in the seedling raising soil containing Na-type bentonite. In particular, the seedlings grown in the seedling raising soil containing rice bran (Ca-type (1:1), C, RB) had larger "seedling length x branch width" values, even though no chemical fertilizer was applied. Furthermore, as shown in Figure 15, seedlings grown in seedling soil containing rice bran (Ca type (1:1), C, RB) had a larger base diameter 5 months after transplanting. Furthermore, as shown in Figure 16, seedlings grown in seedling soil containing rice bran (Ca type (1:1), C, RB) had significantly higher aboveground weights five months after transplanting.

[0054] Figure 17 shows the root system development evaluation scores for GSSG seedlings five months after transplanting. In Figure 17, only the Ca type (1:1), C, and RB seedling raising soils were used without chemical fertilizer application. Figure 17 shows that, despite the absence of chemical fertilizer application in the Ca type (1:1), C, and RB seedling raising soils, the root systems were developed to the same extent as seedlings grown in other seedling raising soils of the present invention (Ca type (1:1), Ca type (1:1), and C) to which chemical fertilizer was applied.

Claims

1. Seedling growing soil containing calcium bentonite and grain husks.

2. The seedling soil according to claim 1, wherein the content ratio of the calcium bentonite to the grain husk is, by mass, calcium bentonite:grain husk = 0.5:1 to 3:

1.

3. The seedling raising medium according to claim 2, further comprising a pH adjuster.

4. The seedling raising soil according to claim 3, for growing seedlings of trees selected from the group consisting of trees belonging to the genus Cryptomeria, trees belonging to the genus Chamaecyparis, and trees belonging to the genus Larix.

5. The seedling raising medium according to claim 4, wherein the grain husk is rice husk.

6. A seedling raising method for growing seedlings or seedlings using the seedling raising soil according to any one of claims 1 to 5.

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