JP7301496B2 - Seedling culture soil, method for producing seedling culture soil, and seedling-raising method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a nursery medium for raising seedlings, a method for producing the medium for raising seedlings, and a method for raising seedlings. More specifically, the present invention relates to a nursery soil for raising seedlings, a method for producing the nursery soil for raising seedlings, and a method for raising seedlings, which enables effective use of resources and improvement in labor productivity.

Due to the lack of farmers and successors, the expansion of abandoned farmland and degraded land is progressing. Reasons for this include the aging of the population, abandonment of farming, and low labor productivity.

As a countermeasure against this current situation, expansion of the scale of farmland is progressing by consolidating and consolidating farmland to bearers.

In the field of rice cultivation, along with the expansion of the scale of farmland, the size of agricultural machinery has been increased, the effectiveness of fertilizers has been improved, fertilization techniques have been improved, and further, GPS-based self-driving agricultural machinery has been researched.

As the old saying goes, ``naehan-saku'' means ``naehan-saku'', and ``seedling-making'' is the basis of cultivation. there is As a result, seedlings obtained by inappropriate seedling preparation delay "tilling" and "initial growth", and the yield, quality, taste, etc. It is known to become

In addition, with the expansion of the scale of farmland, a large amount of seedlings are required. From the viewpoint of labor productivity, a direct seeding technique that does not involve transplanting (rice planting) is being introduced. However, there is a problem that it is difficult to maintain an even water level due to the fact that the areas of each field are scattered narrowly and the degree of leveling of the fields is low. Furthermore, due to factors such as poor water availability, the germination rate and initial growth are poor, and the spread of direct seeding technology has been delayed.

Traditionally, seedlings have been grown by filling a nursery box (see Fig. 1) with internal dimensions of 58 cm x 28 cm x 3 cm with potting soil to raise the seedlings. The weight is 7 to 8 kg/sheet, which is heavy.

Here, Japanese Patent Application Laid-Open No. 2013-27365 (Patent No. 5825909) (Patent Document 1) previously proposed by the present inventor discloses a technique aimed at enabling stable production of plants. It is a soil that utilizes the physical properties of the soil by using the curved surface structure of the so-called rice husk as a physical component. That is, the cultivating soil previously proposed by the present inventor is a cultivating soil in which the recessed surface side of rice husks is filled with an organic material and/or an inorganic material, and the resulting product is excellent in both air permeability and water retention.

JP 2013-27365 A

“Minna no Agricultural Square”, “Agricultural Handbook”, rice edition “3. 5th search], Internet <URL: http://www.jeinou.com/benri/rice/2008/04/111130.html> National Federation of Agricultural Cooperatives Tochigi Headquarters, "Basics of Paddy Rice Cultivation", [online], [searched on October 5, 2017], Internet <URL: http://www.tc.zennoh.or.jp/ parts/file/eino/member/suitou.pdf＞ JA ZEN-NOH Saitama, "Farming news", "Points for raising and managing rice seedlings" (May 8, 2009), [online], [searched October 5, 2017], Internet <URL: http:// www.st.zennoh.or.jp/einou_news/2009/einou200905.html> JA ZEN-NOH Saitama, "Farming News", "Points for Raising and Managing Paddy Rice Box Seedlings" (April 1, 2008), [online], [Searched on October 5, 2017], Internet <URL: http:/ /www.st.zennoh.or.jp/einou_news/2008/einou200803.html＞ ZEN-NOH Farming and Technology Center, ``This is the Farming and Technology Center'', ``For producers to raise seedlings with peace of mind-regular inspection of nursery soil-'' (Green Report No. 498 (December 2010 issue)), [ online], [searched on October 5, 2017], Internet <URL: https://www.zennoh.or.jp/eigi/pdf_hiryo/gr498_11.pdf> ZEN-NOH Farming and Technology Center, ``This is the Farming and Technology Center'', ``Recent Trends in Raising Seedling Soil for Paddy Rice and Maintaining and Improving Quality - Holding ``Technical Workshop for Raising Seedling Soil for Paddy Rice'' (Green Report No. 550) (April 2015 issue)), [online], [searched on October 5, 2017], Internet <URL: https://www.zennoh.or.jp/eigi/pdf_hiryo/gr550.pdf> Zen-noh Farming and Technology Center, "Initiatives of the Zen-noh Fertilizer Laboratory to Protect the Quality of Raising Soil for Paddy Rice" (Green Report No. 528 (June 2013 issue)), [online], [searched October 5, 2017 ], Internet <URL: http://www.zennoh.or.jp/eigi/pdf_hiryo/gr528.pdf>

As a result of further intensive research into the functionality of the curved surface structure, which is a physical component of rice husks, the inventors of the present invention found that the concave structure of rice husks has a water retention (water storage) function (hereinafter, sometimes simply referred to as "water retention function"). ), and furthermore, found that the specific shape of rice husks can be a factor in the formation of a gas phase in the soil, and completed the present invention based on this finding.

INDUSTRIAL APPLICABILITY The present invention has been made to overcome the problem of labor productivity in seedling cultivation in rice cultivation and the like. That is, the object is to provide a seedling-raising culture soil, a method for producing the same, and a seedling-raising method that can reduce the labor load in seedling production. Furthermore, the present invention uses rice husks as a raw material, so it is to provide a technique that enables effective utilization of resources.

[1] Raising seedling soil for paddy rice using rice husks obtained by hulling rice,
Having a water retention function and a gas phase on the concave surface side of the curved surface shape of the rice husk ,
At least one of an inorganic material and an organic material is attached to the convex side of the epidermis of the rice husk,
A nursery soil for raising seedlings to which inorganic materials and organic materials are not adhered to the concave surface side .

[ 2 ] The nursery soil according to [1] , which further contains fertilizer.

[ 3 ] A method for producing a seedling culture medium according to [1] or [2] above,
A rice husk preparation step of preparing rice husks;
a mixing step of mixing the prepared rice husks, at least one of an inorganic material and an organic material, a binder, and water to obtain a mixture;
and a heating and drying step of heating and drying the mixture.

[ 4 ] A seedling-raising method using a culture soil consisting of at least upper and lower layers,
The above [1] or [2], wherein the lower layer is a non-fertilizer soil that has a water retention function and a gas phase on the concave surface side of the curved surface shape of the rice husk obtained by hulling rice. A seedling-raising method for raising seedlings using the seedling-raising soil .

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to overcome the problem of labor productivity in seedling cultivation in rice cultivation and the like. That is, it is possible to provide a nursery soil for raising seedlings, a method for producing the same, and a method for raising seedlings, which can reduce the labor load of raising seedlings. Furthermore, according to the present invention, since rice husks are used as a raw material, it is possible to provide a technology that enables effective utilization of resources.

It is a perspective view which shows a nursery box typically. It is an explanatory diagram of young rice and medium rice. FIG. 2 is an explanatory diagram schematically showing seedlings of rice. It is an explanatory view showing a seeding machine for paddy rice typically. It is explanatory drawing which shows a seed rice (left) and its structure (right). BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which expands and shows typically one embodiment of the seedling culture soil of this invention.

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. Therefore, it is understood that the following modifications, improvements, etc., to the following embodiments are also included in the scope of the present invention without departing from the spirit of the present invention, based on the ordinary knowledge of those skilled in the art. should.

(1) Seedling culture soil:
One embodiment of the seedling culture soil of the present invention is a seedling culture soil using rice husks obtained by hulling unhulled rice. It is a seedling culture medium for paddy rice .

The “seedling culture medium using rice husks” is a seedling culture medium using rice husks (rice husks) as a main raw material. However, rice husks may be the entire raw material, or other raw materials may be used in addition to the rice husks, as described later.

Here, the “seedling culture soil” in the specification of the present application refers to culture soil used for raising seedlings of agricultural crops, and is particularly preferably culture soil used for raising seedlings of rice. This is because, when used as a culture soil for raising rice seedlings, it becomes a culture soil having a water retention function and a vapor phase more suitable for raising rice seedlings.

"Rice husk obtained by hulling rice" refers to the rice husk itself generated by hulling rice (or the husk after further heat treatment to sterilize pathogenic bacteria and fungi). In this way, the obtained rice husk has at least a portion of the convex side (skin side) that is the outer surface (surface) before hulling and at least a portion of the concave side that is the inner surface before hulling. , will have a curved surface shape as a whole. However, the shape concerned is not the shape of the whole paddy before hulling, but the shape of "outer hull" and "inner hull" in FIG. Such a shape can be said to be, for example, a Japanese boat shape (vessel shape). In the present specification, rice husks that have been treated to prevent contamination of weed seeds and have been washed and decomposed of germination inhibitors by treatments such as pulverization, water washing, fermentation (composting), carbonization and incineration are used as the above " It is not included in what is obtained by hulling rice. In addition, "hulling" is a process after threshing, and is the work of removing the husk from the paddy to obtain brown rice.

"Having a water retention function" means that at least a part of the concave surface side, which is the inner surface before hulling, of at least each rice husk has a curved surface shape. This means that water is likely to accumulate when water is supplied, and that water is likely to be retained in the potting soil. As the number of rice husks increases, the amount of accumulated water increases accordingly, so that the water retention effect can be improved.

"Has a gas phase" means that at least a part of the recessed surface side, which is the inner surface before hulling, of at least each rice husk has a curved surface shape, so that a space exists in the curved surface shape part. Say things. Incidentally, as the number of rice husks increases, the amount of space increases, so that the gas phase can be increased.

Here, specifically, the seedling culture medium (seedling culture medium 100) of the present invention includes a plurality of rice husks 10 as shown in FIG. The formed space 12 constitutes a part of the gas phase, and furthermore, water accumulates and exhibits a water retention function. Furthermore, the gap 15 between the adjacent rice husks 10, 10 also functions as a gas phase, and furthermore water accumulates to exhibit a water retention function. Here, in FIG. 6, the rice husk 10 indicated by reference numeral "10a" shows a state in which water 17 is stored in its space 12 (that is, as shown in FIG. 6, the space 12 of the rice husk 10a is stored in the water). The rice husk 10a is shown partially transparent to show the moisture 17 in the space 12 thereof. FIG. 6 is an explanatory diagram schematically showing an enlarged embodiment of the seedling culture soil of the present invention. When conventional granular soil is used, the gap between adjacent granular soils is smaller than the gap 15 between the rice husks 10, 10, and is not a region where the roots of plants (especially rice) can fully utilize. In addition, the granular culture soil is spherical, and the pore size of the internal structure is not a diameter that roots can penetrate (that is, it is not water that plants (especially paddy rice) can absorb). For example, the pore size of the internal structure of granular media granulated with particles of 0.1 mm diameter is 7.75 μm.

(Cultivation soil bulk specific gravity)
Conventionally, so-called mountain soil such as brown forest soil, reddish-yellow soil, and black soil is used as a raw material for raising seedlings of paddy rice. Then, using these raw materials (original soil), while considering water permeability and water retention, granulated soil is adjusted to a diameter of about 1 to 4 mm / mm, and the above-mentioned mountain The soil is sieved to adjust the particle size to the above size, and the soil is used. Table 1 shows the "bulk specific gravity of potting soil". In addition, "Example 1" in Table 1 indicates the seedling culture medium of the present invention. From Table 1, it can be seen that the seedling culture soil of Example 1 has a very low bulk specific gravity compared to other culture soils. In general, the original soil is sterilized by heating to prevent contamination with pathogenic bacteria, fungi, and weed seeds.

(fertilizer)
In addition, fertilizers are added to the granular potting soil. The amount of this fertilizer to be added varies depending on the specific components and chemical properties of the mountain soil of the raw material, the time of use of the potting soil, and the characteristics of the cultivation area, such as for warm regions, cold regions, and extreme cold regions. Here, Table 2 shows the "fertilizer addition amount". In Table 2, "N" indicates nitrogen, "P" indicates phosphoric acid, and "K" indicates potassium.

Here, when raising seedlings, the culture soil shown above is filled in a raising seedling box having the dimensions (inner dimensions) shown in FIG. The nursery box used this time was a commonly used nursery box, which had a bottom and a drainage hole on the bottom. The size, shape, and number of holes are not limited to the example of the nursery box used this time. For example, since the size, shape, and number of holes vary depending on the manufacturer of the commercial product, it is desirable to select a nursery box suitable for the usage conditions and the like.

(Procedure for sowing seed rice)
The procedure (method) for sowing seed rice is to evenly fill the hopper 30 with culture soil to a thickness of 2 to 2.5 cm from the bottom of the seedling box 40 (indicated as "<culture soil>" in FIG. 4). ). Here, the culture soil filled in the bottom surface of the nursery box is referred to as the lower layer culture soil (hereinafter, appropriately referred to as the "lower layer culture soil"). After that, the lower culture soil is irrigated (denoted as “<irrigation>” in FIG. 4). After that, the sprouted rice put into the hopper 32 is sown on the watered lower culture soil (indicated as "<sprouted rice>" in FIG. 4). After that, the sown rice is evenly covered with the soil contained in the hopper 34 to a thickness of about 1 to 1.5 cm (denoted as “<covering soil>” in FIG. 4). Here, the culture soil used for cover soil is referred to as cover soil culture (hereinafter referred to as "cover soil culture" as appropriate). Then, the seedling box 40 covered with soil is moved to the nursery.

(Seedling type)
There are three types of seedlings: young seedlings, medium seedlings, and large seedlings. Usually, large seedlings (meaning seedlings of 20 cm or more) are avoided due to the mechanism of transplanters and aging seedlings. Therefore, the amount of seeds to be sown is determined by the type of seedlings to be produced.

Table 3 shows examples of "seedling types and main characteristics." Table 4 shows "seedling types and seeding amounts", and FIG. 2 shows "concepts of young seedlings and medium seedlings".

Here, since the weight of 1,000 grains of unhulled rice is said to be 20 to 25 g, based on the seedling types and seeding amounts shown in Table 4, 7,000 to 10,000 seeds are sown per nursery box. amount. From the above, the seeding density is 6 grains/cm ² . That is, for example, lettuce seedlings have one seed per 6 to 9 cm ² . From this, it can be imagined that the density of seedlings of paddy rice is high in the aboveground part, but the density in the root zone of the underground part is high.

Furthermore, the weight of one seedling grown in a nursery box (hereinafter referred to as "boxed seedling") at the time of transplantation (at the time of rice planting) is as high as 7 to 8 kg. The process from growing paddy rice seedlings to transplanting (rice planting) involves filling nursery boxes with soil and seeding, moving them to the nursery, setting them up, managing their growth, and then loading the boxed seedlings into a vehicle. , moving the seedlings to the paddy field and loading them on the transplanter, etc. At this time, the raising and lowering of the nursery box and moving are performed several times by human power. Therefore, such a heavy nursery box (7 to 8 kg) is a burden on producers.

The number of seedlings required for a 10a (300 tsubo) paddy field is around 20. For example, it is said that an individual farmer can manage up to around 30 ha, which requires 6,000 box seedlings.

In addition, in nursery centers and organized and consolidated management bodies, the scale of management is 700ha or more, and the required number of boxed seedlings reaches 140,000.

Since a large number of seedlings must be raised in this way, the above-mentioned ``simplification and omission of seedling raising'' is progressing, and seedling production with inappropriate seeding amount, seedling raising period, seedling raising management, etc. is spreading.

Furthermore, conventionally used potting soil is manufactured using so-called mountain soil as a raw material, but when using this potting soil, there are problems such as depletion of the above raw materials and an increase in manufacturing costs such as labor costs and fuel costs. There is In addition, recently, soaring freight rates for transporting products to places of demand have also become a problem.

Rice husks have a relatively high C/N ratio (carbon/nitrogen ratio) of 70 degrees and are a material that is resistant to decay. On the other hand, if the rice husk is used as it is, the culture soil becomes nitrogen-starved, and since rice husk contains germination inhibitors such as abscisic acid and momilactone phenol, it causes poor germination and wilting. Therefore, rice husks are usually not used as they are. That is, rice husks are used for cultivation, livestock barn materials, etc. after washing and decomposing germination-inhibiting substances by crushing, washing, fermentation (composting), carbonization, and incineration.

Approximately 2 million tons and 18 million ^cubic meters of rice husk resources (rice husks as resources) are generated with rice cultivation in Japan, but the utilization rate is said to be around 40%.

The effective use of rice husks by using them for power generation is also being considered, but the problem is that when the rice husks are burned, the same level of "crystalline silica" as asbestos is generated. As a result, it has not been used effectively.

(Gap between plant roots and soil particles)
Here, we consider the space between the roots of plants and the soil particles. Plant roots extend through gaps between soil particles and absorb water present in the gaps. This gap is a gap formed by gathering soil particles. In soil science, such gaps (spaces) are called pores, and the water content in the gaps is expressed in pF. Specifically, if the height of the water column is Hcm, pF=logH. p in pF indicates a logarithmic value, and F indicates the free energy of water. Based on its pF value and plant response to water, water in soil is classified as shown in Table 5. Table 5 shows the relationship between pF value, capillary water column height, capillary pore size and particle size.

(plant root)
Next, consider plant roots. The diameter of the roots of general plants is about 60 μm, but the diameter of seed roots and crown roots of Poaceae is said to be 150 to 750 μm.

Here, seed roots and crown roots refer to roots that emerge at the beginning of the growth process of germs and radicles in seeds. From Table 5, this seed root and crown root diameter corresponds to a pore diameter of pF 1.3 or less, and does not correspond to "effective water for normal growth" of general plants. The inventor paid attention to this fact. pF 1.3 is free water (gravity runoff). In other words, it is water that is once saturated by irrigation but is washed away by gravity. Based on this, the water retention capacity of rice husks, which is the base material of the culture soil of Patent Document 1, was compared with the conventionally used granulated culture soil using a conventionally used nursery box. Fig. 3 shows seed roots and crown roots of rice. FIG. 3 shows the “name of seedlings of rice (3.2 leaf-age seedlings)” (excerpt from Non-Patent Document 2 “Fundamentals of Paddy Rice Cultivation”).

The "total amount of pores (pore volume)" is, specifically, the amount of water injected when the potting soil filled with the specified amount in the volumetric gravity measurement container is filled with water up to the specified amount. Formula: column volume - pore volume = solid phase. In other words, the sum of the amount of gas phase and the amount of water is the pore volume. As can be seen from Table 5, the water retained in all pores in pedology includes soil water up to pF7, which is not used by plants.

Here, in order to compare the amount of moisture present in pores generated by aggregation of granulated particles and the amount of moisture present in pores created by aggregation of rice husks, granulated culture soil and rice husks were pre-moisturized. Compare what is included. More specifically, the seedling box was filled with wetness adhering to the surface of the individual, that is, moisture contained inside the granulated particles themselves, and the amount of moisture was compared. Those results are shown in Table 6. Table 6 shows "characteristics of granulated culture soil, rice husks, and rice husks of Example 1 (processed rice husks)". In Table 6, "Example 1" means that the rice husks of Example 1 were used, and "rice husks" indicates dried rice husks.

In Table 6 above, A to F are as follows.
A: Weight (g) per box of granulated culture soil, rice husks, and seedling culture soil of the present invention (Example 1) immediately after opening, filled in the nursery box and measured
B: Weight (g) of each box filled with granulated culture soil, rice husks, and seedling culture soil of the present invention pre-moisturized
C: Weight (g) per box of granulated culture soil, rice husks, and seedling culture soil of the present invention measured after 1 hour after watering from above the nursery box that was left horizontally in the same manner as cultivation.
D: Moisture content (g) in the pores (gap) generated by aggregation of each particle of the granulated culture soil, rice husks, and seedling culture soil of the present invention
E: Gas phase value (%) obtained by determining the gas phase ratio with a volumetric gravimeter
F: Gas phase (cc) 1 hour after irrigation

Here, the gas phase in the granulated soil can be calculated as follows. Formula: 4,872 × 31.5% = 1,534.68 Formula: 1,534.68 - 50 cc = 1,484.68 cc (F: vapor phase (cc) after 1 hour of irrigation) .

The gas phase in the rice husk can be calculated as follows. Formula: 4,872 x 85.5% = 4,165.56 Formula: 4,165.56 - 900 = 3,265.56 cc (F: gas phase (cc) after 1 hour of watering) .

The gas phase in the seedling culture medium of the present invention can be calculated as follows. Formula: 4,872×78%=3,800 Formula: 3,800−350 cc=3,450 cc (F: vapor phase (cc) after 1 hour of irrigation).

As is clear from Table 6 and the above formula, the specific shape of rice hulls can exert a water retention (in other words, water storage) function. Furthermore, it turns out that the specific shape can be a factor in the formation of the gas phase.

(1-1) Inorganic material, organic material:
In the seedling culture soil of the present invention, at least one of the inorganic material and the organic material is attached to the convex side of the surface of the rice husk ( that is, even if both the inorganic material and the organic material are attached) ok, just attach one or the other). By attaching at least one of an inorganic material and an organic material to the convex side of the surface of the rice husk, the effect of increasing the fluidity of the rice husk inside the rice seeder during work using the rice seeder. can be obtained. Work efficiency can be improved by increasing the fluidity in the hopper or the like of the seeding machine for paddy rice.

In the seedling culture medium of the present invention, the method of adhering the inorganic material and the organic material to the convex side of the surface of the rice husk (on the epidermis) is not particularly limited. For example, the method shown in the mixing step in the method for producing seedling culture soil to be described later may be employed to adhere the inorganic material and the organic material.

Inorganic materials include, but are not limited to, clay minerals or their powders, minerals or their powders, and the like. Examples of clay minerals or powders thereof include zeolite, bentonite, kaolinite, and powders thereof. Examples of minerals or powders thereof include igneous rocks, sedimentary rocks, metamorphic rocks, general soils, and the like. In addition, zeolite etc. can be mentioned as a powdery substance of a mineral. When zeolite is used, it is also preferable to use zeolite having a large base exchange capacity in consideration of the addition of fertilizer (that is, use of zeolite or the like improves fertilizer retention). In addition, although the organic material is not particularly limited, fine peat moss and the like can be mentioned. By using such an organic material, it is possible to supplement the water holding capacity.

Here, for example, when using a paddy rice seeding machine 200 as shown in FIG. and checked the fluidity in the hopper 30, it was found that the fluidity of the rice husks in the hopper 30 was low.

Factors for the low fluidity of the rice husks in the hopper 30 include, as shown in FIG. As a countermeasure against these problems, an attempt was made to impregnate rice husks with powdery minerals with a high bulk density using a binder to reduce the protrusion of awns and thorn-like bristles and to increase the bulk density. In addition, FIG. 5 shows a seed rice (left) and its structure (right) (excerpt from Non-Patent Document 2 “Fundamentals of Paddy Rice Cultivation”).

It was found that the rice husks treated as described above (that is, the rice husks that are the raw material for the seedling culture medium of the present invention) have improved fluidity in the hopper.

(Regarding covering soil, etc.)
In addition, in [Quality survey items of kumiai culture soil] (see Non-Patent Document 7), there is an item of "paddy uprooting and exposure" as "seedling performance", but this is the growth of seed roots and crown roots. It is known to be caused by roots, germination, and low or light soil cover. Conventional culture soil with a high bulk density is used as cover soil for seedling raising. Furthermore, as biological properties, there is prevention of mold growth, weeds, and seed contamination.

[Points for Raising and Managing Rice Box Seedlings (Non-Patent Document 4)] includes items for selecting bed soil and culture soil. "It is important to choose a brand with a fertilizer content that matches the type of seedlings to be produced. Normally, the same name is used for young seedlings with high fertilizer content (for cold climates) and medium seedlings with low fertilizer content (for warm climates). If used incorrectly, the seedlings will not grow or cause weak and long seedlings.” In addition, it states that ``Irrigation should be moderate so as not to produce weak and long seedlings. Furthermore, regarding germination, [Fundamentals of Paddy Rice Cultivation (Non-Patent Document 2)] states that "moisture, temperature, and oxygen are necessary for seed rice to germinate." If there is, the radicle appears first, and under oxygen-deficient conditions, the bud (sheath) appears first." Refer to these examples.

Further, no inorganic material is adhered to the recessed surface side ( that is, recesses (spaces) are formed on the recessed surface side, and water is retained in these recesses ) . If there is no filler such as an inorganic material on the concave surface side of the curved surface shape of rice husks, a concave space is formed in the seedling culture soil, and the water retention function on the low pF side (gravitational runoff) and the gas phase can be sufficiently ensured.

(1-2) Other components:
Further, the seedling culture soil of the present invention is preferably a culture soil containing fertilizer. By doing so, the effect of raising seedlings by the fertilizer can be expected. Fertilizers include, for example, fertilizer components such as nitrogen, phosphoric acid, and potassium.

The seedling culture medium of the present invention may contain microorganisms resistant to plant pathogens and ingredients effective for growth.

(2) Method for producing seedling culture soil of the present invention:
The method for producing seedling culture soil of the present invention comprises a rice husk preparation step of preparing rice husks, and mixing to obtain a mixture by mixing the prepared rice husks, at least one of an inorganic material and an organic material, a binder, and water. and a heating and drying step of heating and drying the mixture. This is the method for producing the seedling culture medium described so far. For this reason, overlapping content may be left as an indication to that effect and the explanation may be omitted as appropriate.

As described above, the method for producing seedling culture soil of the present invention is generally produced from the "rice husk preparation step" for preparing rice husks, the "mixing step" for obtaining a mixture, and the heat drying process. is.

Specifically, as the method for producing the seedling culture soil of the present invention, zeolite, which is an inorganic material, is added to rice husks, and PVA (polyvinyl alcohol), which is a binder, and water are added and mixed, and then heated. and dry.

According to the method for producing seedling culture soil of the present invention, it is possible to produce seedling culture soil that can reduce the labor load of seedling making, and since rice husks are used as raw materials, it is a method that enables effective utilization of resources.

(2-1) Rice husk preparation step:
The rice husk preparation step is a step of preparing rice husks. For hulling, conventionally known conditions can be appropriately adopted.

(2-2) Mixing step:
The mixing step is a step of mixing rice husks obtained after the rice husk preparation step, at least one of an inorganic material and an organic material, a binder, and water to obtain a mixture.

Examples of inorganic materials include clay minerals or their powders, minerals, their powders, and the like. Examples of organic materials include organic materials such as fine peat moss.

Binders to be used include known binders that are water-soluble polymer materials that are insolubilized by heating, such as polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, polyacrylamide, polyacrylic acid, and starch. .

(2-3) Heat drying step:
The heat-drying step is a heat-drying step of heating and drying the mixture obtained after the mixing step.

In the heat drying process, each material is mixed and dried. Heat drying can be performed, for example, at a product temperature of 70 to 150 ° C. (preferably 100 to 120 ° C.) and a rotary kiln, granulator, etc. until the water content reaches 10% by weight (wt%), preferably a rotary kiln. can be done with In addition, heat drying can be dried to less than 10% by weight (wt%) of moisture as described above, and in this way, the decomposition and deterioration of fertilizer components and microorganisms are reduced, and the nursery soil is preserved. can be enhanced.

(3) Seedling method:
The seedling-raising method of the present invention is a seedling-raising method using a culture soil consisting of at least upper and lower layers. It is a seedling-raising method for raising seedlings using non-fertilizer culture soil. This seedling-raising method is a method of raising seedlings using the seedling-raising culture soil described above or the seedling-raising culture soil produced by the method for producing a seedling-raising culture soil. For this reason, overlapping content may be left as an indication to that effect and the explanation may be omitted as appropriate.

According to the seedling-raising method of the present invention, it is possible to overcome the problem of labor productivity in seedling cultivation in rice cultivation and the like.

Here, when using a paddy rice sowing machine 200 as shown in FIG. 4, the lower layer of the nursery box 40 is filled with the lower layer culture soil, a layer of seeded unhulled rice is formed, and then the cover soil is filled. The medium can be constructed by At this time, in the seedling-raising method of the present invention, the predetermined non-fertilizer culture soil is used as the lower layer culture soil. By doing so, the control (management) of fertilization becomes easier. In other words, since farm work depends on the weather, there are cases where, for example, rice planting cannot be done as planned. In anticipation of such a situation, if fertilizer is increased in advance, the above-ground parts of the seedlings will prosper and become clustered seedlings. On the other hand, if the non-fertilizer culture soil is used, additional fertilizer can be applied when rice planting cannot be performed as planned, so it is possible to respond according to the situation. In the seedling-raising method of the present invention, while the amount of fertilizer can be reduced, since the seedling-raising culture medium of the present invention is used, a good effect for raising seedlings is exhibited.

EXAMPLES The present invention will be described in more detail below using examples, but the technical scope of the present invention is not limited to these examples.

(Example 1)
To 16 L of rice husks obtained by hulling, 1 kg of zeolite as an inorganic material and 40 g of PVA were added and mixed, and 2 L of water was further added and mixed to obtain a mixture. The resulting mixture was heated and dried using a heat dryer until the product temperature reached 120° C. and the water content reached 10% by weight (wt %), to obtain a nursery soil. Table 1 shows the bulk specific gravity of the obtained seedling culture medium, and Table 6 shows the characteristics.

As shown in Table 1, the seedling culture soil of this example was much lighter than the conventionally used granular culture soil, and had a bulk specific gravity of about 1/5 that of the granular culture soil. In addition, as is clear from Table 6, the gas phase (indicated by "F" in Table 6) is about 2.3 times more 6, indicated by “D”) was also found to be seven times higher.

Here, as described above, moisture, temperature, and oxygen are necessary for seed rice to germinate. In addition, if there is sufficient oxygen, the radicle appears first, and if the oxygen is insufficient, the plumule (sheath leaf) appears first. Non-Patent Document 2, "Fundamentals of Paddy Rice Cultivation," states, "A 'good seedling' is a well-stocked seedling that is easy to transplant and that takes root quickly after transplanting. ] is described. From this fact, the seedling culture medium of the present example meets the conditions of the seedling culture medium for producing good seedlings. The density of roots in seedlings is very high, and oxygen must be supplied in proportion to the density, which requires a high vapor phase rate.

Conventional culture soil contains 20 to 35% by weight (wt%) of water, so the added fertilizer is degraded. The degree of deterioration of the fertilizer is reduced because it has been used for a long time. That is, the preservability of the culture soil can be enhanced. Furthermore, drying by heating is a countermeasure against contamination of weed seeds, generation of mold, and the like. In addition, in the method for producing the seedling culture soil of this example, the fluidity in the hopper was also good.

[Examples of raising seedlings]
Using conventionally used seedling-raising boxes, a conventional granular soil section and a seedling-raising soil section of the present invention were provided to compare the growth of seedlings.

In the conventional seedling raising method, the same brand of soil is used for the lower layer soil and the cover soil soil, but in this comparison, the unique shape of the rice husk can have a water retention (water storage) function. Furthermore, since it was found that the specific shape can be a factor in the formation of the gas phase, the effect of this on root growth was considered.

In addition, in order to determine whether or not the effect depends on the fertilizer, the seedling culture soil of the present invention with "no fertilizer added" was used as the lower layer culture soil, and the cover soil culture soil was for K company warm regions and K company extreme cold regions shown in Table 2. Seedling raising was attempted by setting up two plots, one with the compost.

In raising paddy rice seedlings, the grass vigor was conventionally adjusted by adjusting the amount and frequency of irrigation, so the same amount of water was applied at the same time to avoid the effect of adjusting the grass vigor in each plot.

Germination was delayed by about one day in both the nursery nursery soil of the present invention for warm and extremely cold regions compared to the conventional soil, but root growth was more vigorous than in the conventional soil. This agrees with the fact that the radicle appears first when there is sufficient oxygen, and the plumule (sheath leaf) appears first when the oxygen is insufficient.

Next, as shown in the conceptual diagram of young seedlings and middle seedlings in FIG. Regarding this, as a result of investigating the above-ground part and the underground part, no extreme difference in leaf color was observed in all three cases. The plant height was about 1 cm longer in the conventional granular soil section, but the stem diameter was thicker in both the two sections of the seedling-growing soil section of the present invention, so-called "strong seedlings."

As a result of the above seedling raising, in terms of root growth, both of the two nursery soil plots of the present invention clearly showed more vigorous development and growth than the conventional soil plot, and the amount of roots was large.

As described above, since the seedlings are vigorously growing and have well-developed roots, when raising seedlings using the seedling culture soil of the present invention, the lower layer culture soil may be added with no fertilizer, and the cover soil has different amounts of fertilizer added. It is possible to produce seedlings of the desired type by using , adjusting the amount of irrigation and fertilizing.

Further, when the weight of the box seedlings was compared, it was 7.5 kg in the conventional cultivating section, while it was 4 kg in the seedling cultivating section of the present invention.

As described above, the seedling culture medium of the present invention makes it possible to effectively utilize rice husk resources, and furthermore, it is possible to reduce the labor load and raise seedlings that are said to be "good seedlings" and that can increase productivity. become.

Furthermore, the amount of mountain soil that can be used as a raw material suitable for the production of granular soil is scarce, and the water contained in the mountain soil is removed in the granulation process, but the energy cost in that process is enormous. be. However, according to the method for producing seedling culture medium of the present invention, rice husks are used, so the above problems are alleviated. In addition, since the area where rice husks are generated, that is, the rice-growing area, is the demand area for the culture soil, it is possible to produce the culture soil in the demand area. It becomes possible to use.

The culture soil of the present invention can be used, for example, as a culture soil for raising paddy rice seedlings.

10, 10a: rice husk, 12: space, 15: gap, 17: moisture, 30, 32, 34: hopper, 40: nursery box, 100: nursery soil.

Claims (4)

Raising seedling soil for paddy rice using rice husks obtained by hulling rice,
Having a water retention function and a gas phase on the concave surface side of the curved surface shape of the rice husk ,
At least one of an inorganic material and an organic material is attached to the convex side of the epidermis of the rice husk,
A nursery soil for raising seedlings to which inorganic materials and organic materials are not adhered to the concave surface side . 2. The nursery soil for raising seedlings according to claim 1 , further containing fertilizer. A method for producing the seedling culture soil according to claim 1 or 2,
A rice husk preparation step of preparing rice husks;
a mixing step of mixing the prepared rice husks, at least one of an inorganic material and an organic material, a binder, and water to obtain a mixture;
and a heating and drying step of heating and drying the mixture. A seedling raising method using a culture soil consisting of at least upper and lower layers,
3. The raising seedling culture soil according to claim 1 or 2, wherein the lower layer is a non-fertilizer culture soil having a water retention function and a gas phase on the concave surface side of the curved surface shape of the rice husk obtained by hulling the rice. Seedling raising method to raise seedlings using.

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