JP2006238880A - Nursery bed for paddy rice and method for preparing nursery bed for paddy field - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nursery bed for paddy rice capable of rearing healthy seedlings having good rooting after transplantation, in a method for applying fertilizer to a nursery box in which a fertilizer component necessary for paddy field culture after transplantation to paddy field, etc., can be fed and to provide a method for preparing the nursery bed and a culturing method using the nursery bed. <P>SOLUTION: The nursery bed for paddy rices is obtained by forming a delayed release fertilizer layer by uniformly applying granular fertilizer containing a chemically synthesized delayed release fertilizer as a fertilizer component from the upper part of a bed soil layer, fertilizer and a seed layer and a covering layer. The culturing method is carried out by using the nursery bed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nursery for paddy rice. Specifically, the present invention relates to a paddy rice seedbed having a layered structure that can reduce the amount of fertilization and the number of times of fertilization during the entire cultivation period, a method for preparing the seedbed, and a method for cultivating paddy rice using the seedbed.

  In recent years, new agricultural technologies have been developed, and along with this, technological innovations such as agricultural machinery and agricultural materials have advanced. As a result, significant labor savings in agricultural work have been realized. In paddy rice cultivation, a coated fertilizer having a time-elution type elution function was developed, and a whole-basis fertilization method was put to practical use. Furthermore, a seedling box full-volume fertilization method using a coated fertilizer that minimizes the elution of fertilizer during the seedling period has been newly developed and is becoming widespread (see, for example, Patent Document 1 and Non-Patent Document 1).

  Fertilizers that can be applied at the same time as seeds need to minimize the elution of fertilizers at least during the seedling period. At this time, if the amount of elution exceeds the amount of fertilizer required for raising seedlings, growth delay such as germination failure may occur and the seedlings may die. Even with coated fertilizers that are distributed with a high level of elution function, the elution rate tends to be difficult (slow) even if elution starts because the technology to suppress elution and the elution technology conflict. There is. For this reason, the growth of seedlings during raising seedlings tends to be soft and weak in leaf color as compared with the conventional seedling raising method for topdressing. In addition, even after transplanting, sufficient fertilizer components do not elute from the coated fertilizer immediately, and the state of being weakly susceptible to environmental stress is maintained in a low-nutrient state with little nutrient supply until transplantation before the transplantation. Therefore, it is easy to suffer from cold damage, storm and flood damage, etc.

Japanese Patent Laid-Open No. 7-236352 Edited by Sadao Shoko, Yoshihiro Kaneda, "Challenge to New Farming-Harmony with Production, Resources, and the Environment", Hirotomo, published March 20, 1995, p. 203-220

  The present invention relates to a seedling box fertilization method that can supply fertilizer components necessary for rice cultivation after transplanting to Honda etc., for example, a nursery for paddy rice that can grow healthy seedlings with good survival after transplanting, and its An object is to provide a production method and a cultivation method using the production method.

  The inventors of the present invention have made extensive studies to solve the above-described problems. As a result, (a) containing a chemically synthesized slow-release nitrogen fertilizer, (b) containing 70% by mass or more of particles having a particle size of 0.5 mm or more, and a maximum particle size of 2.0 mm or less, (c) Using a granular fertilizer having a fast-acting nitrogen content of 10% or less with respect to the total nitrogen components in the granular fertilizer, and (d) an average mass per grain of 0.1 to 5 mg, a bed soil layer and a fertilizer -It has been found that the above problems can be solved by a seedbed for paddy rice in which a slow-release fertilizer layer is formed on a layer formed from a seed layer and a cover layer, and a cultivation method using the seedbed, and based on that knowledge The present invention has been completed.

1. A bed soil layer, a fertilizer / seed layer containing a time-dissolved coated nitrogen fertilizer and seeds located on the bed soil layer, a soil covering layer located on the fertilizer / seed layer, and a soil covering layer A nursery for paddy rice, which is a seedbed for cultivating paddy rice having a slow-release fertilizer layer, and the slow-release fertilizer layer is a layer containing granular fertilizer that satisfies the following conditions.
(A) Contains a chemically synthesized slow-release nitrogen fertilizer.
(B) Particles having a particle size of 0.5 mm or more are 70% by mass or more, and the maximum particle size is 2.0 mm or less.
(C) The fast acting nitrogen content is 10% or less with respect to the total nitrogen components in the granular fertilizer.
(D) The average mass per grain is 0.1 to 5 mg.

2. Item 2. The paddy rice nursery according to Item 1, wherein the chemically synthesized slow-release nitrogenous fertilizer is at least one selected from the group consisting of aliphatic aldehyde condensed urea, oxamide, and guanylurea sulfate.
3. The nursery for paddy rice according to Item 1, wherein the chemically synthesized slow-release nitrogenous fertilizer is at least one selected from the group consisting of acetaldehyde condensed urea, isobutyraldehyde condensed urea, formaldehyde processed urea fertilizer, glyoxal condensed urea, and methylol urea polymerized fertilizer. .
4).
Item 2. The paddy rice nursery according to Item 1, wherein the chemically synthesized slow-release nitrogenous fertilizer is acetaldehyde condensed urea.
5. Item 5. The paddy rice nursery according to any one of Items 1 to 4, wherein the granular fertilizer contains a poorly water-soluble phosphate fertilizer and / or a water-repellent substance.

6). The period from when the timed elution-type coated nitrogen fertilizer reaches 10% from the point of application of the cumulative nitrogen component elution rate is d1 (day), and the cumulative nitrogen component elution rate exceeds 10% and reaches 80%. Item 2. The paddy rice nursery according to item 1, wherein the bed has a dissolution pattern in which d1 is equal to the nursery period and d1 / d2 is 0.2 or more, where d2 is the period up to.
7). Item 7. The paddy rice nursery according to any one of Items 1 to 6, wherein the fertilizer / seed layer or the slow-acting fertilizer layer contains a granule having an osmotic and insecticidal action and / or a bactericidal action.

8). A bed soil layer is formed, a fertilizer / seed layer containing a time-dissolved nitrogen fertilizer and seeds is formed on the bed soil layer, a cover layer is formed on the fertilizer / seed layer, and then At any time from immediately after forming the layer to immediately before transplanting the seedling, (a) containing a chemically synthesized slow-release nitrogenous fertilizer, and (b) containing 70% by mass or more of particles having a particle diameter of 0.5 mm or more. The maximum particle diameter is 2.0 mm or less, (c) the fast acting nitrogen content is 10% or less with respect to the total nitrogen components in the granular fertilizer, and (d) the average mass per grain is 0.1 A method for producing a seedbed for paddy rice in which a slow-acting fertilizer layer is formed on a soil covering layer using a granular fertilizer of ˜5 mg.
9. Item 9. The method for producing a paddy rice seedbed according to Item 8, wherein the slow-acting fertilizer layer is formed at any time from 10 days before transplanting of the seedling to immediately before transplanting.
10. Item 10. A method for producing a seedbed for paddy rice according to Item 8 or 9, wherein a slow-acting fertilizer layer is formed using granular fertilizer and a granule having an insecticidal and / or bactericidal activity.
11. Item 8. A method for cultivating paddy rice using the seedbed for paddy rice according to any one of items 1 to 7.

  In the paddy rice nursery of the present invention, fertilizer components necessary for seedling growth and post-transplantation can be applied sufficiently without shifting, so that healthy seedlings with good leaf color can be grown, and post-transplantation is also good In addition, we can expect to secure a tiller. Since the granular fertilizer used in the present invention can maintain a controlled fertilization effect for a long period of time so as not to adversely affect the growth of the seedlings even though it is small, it is difficult for the seedlings to fall down. Furthermore, since the nursery of the present invention can treat fertilizer and agricultural chemicals simultaneously, it is suitable for labor-saving cultivation.

  The seedbed for paddy rice of the present invention is a bed soil layer, a fertilizer / seed layer containing a time-eluting type coated nitrogen fertilizer and seeds located on the bed soil layer, a soil covering layer located on the fertilizer / seed layer And a laminated structure having a slow-acting fertilizer layer located on the soil covering layer. The granular fertilizer used for the slow-release fertilizer layer contains chemically synthesized slow-release nitrogen fertilizer as the main component (most component) of the nitrogen fertilizer component in the granular fertilizer. The granular fertilizer contains 70% by mass or more, preferably 90% by mass or more of particles having a particle size of 0.5 mm or more, and the maximum particle size of the granular fertilizer is 2.0 mm or less, preferably 1.5 mm or less. . When the particle diameter is in the above range, the chemically synthesized slow-release nitrogen fertilizer as the main component is eluted at an appropriate rate and functions as a slow-release fertilizer. Since the granular fertilizer is relatively small and relatively uniform, the number of fertilized grains per seed potato can be secured, and the amount of fertilizer applied is small.

  In the granular fertilizer used in the present invention, after the seedlings are transplanted to Honda, one or more grains per strain are held at the root of the rice, so that the fertilizer components are efficiently absorbed into the rice and can exert a high fertilizing effect. Therefore, the average mass per granular fertilizer is 0.1 to 5 mg, preferably 1 to 3 mg. If the average mass per granular fertilizer is in the above range, fertilization effect control is easy, and it is easy to obtain an appropriate number of applied grains per seedling (or one seed). Difficult to occur and uniform and stable fertilization effect is demonstrated. Here, the average mass per granular fertilizer is an average value obtained by measuring the mass of 100 grains.

  In the present invention, a soil or a culture medium (hereinafter referred to as a culture medium) is used for the floor soil layer and the soil covering layer. As the medium base material (hereinafter referred to as the medium base material), any material can be used as long as it can retain moisture necessary for raising seedlings. Specific examples include vegetable fiber materials and mineral materials that are lightweight and excellent in water retention in addition to soil.

  Examples of soil include natural soil such as alluvial soil, diluvial soil, volcanic soil, Kanuma soil, Bora soil (Hyuga soil), and humus soil, and soil generated from water treatment plants. In the present invention, sterilized soil obtained by sterilizing these with heat or the like is preferable. Examples of such sterilized soil include red ball soil (manufactured by Soyle Co., Ltd., red soil type sterilized soil), black ball soil (manufactured by Soyle Co., Ltd., black soil type sterilized soil), and sterilized bora soil.

  Examples of plant fiber materials include peat moss and coconut husks (residues obtained by removing rigid and medium fibers from the mesocarp obtained by removing the outer skin and inner skin from the palm skin), bark, wood pulp, Rice husks, large sawdust, etc. Examples of the mineral material include calcined vermiculite, bentonite, and zeolite. Moreover, you may use the baking residue which remains when baking a vermiculite. Furthermore, a mixture thereof may be used.

The medium base material can be blended with artificial fibers such as granular cotton, organic carbides such as charcoal and charcoal, and soil improvement materials such as pearlite and urea resin foam as necessary. The ratio of the medium base material contained in the paddy rice seed bed is not particularly limited, but is preferably in the range of 10 to 70% by mass with respect to the seed bed. In addition, although the bulk density of a culture medium base material is not specifically limited, When reducing the weight of a seedling box, it is preferable that it is 0.2-0.7 g / cm < ³ >. The ratio of the bed soil layer and the cover soil layer in the paddy rice seed bed is not particularly limited, but is 5 to 90% by volume and 90 to 5% by volume with respect to the seed bed, respectively, and the sum of the capacity of the bed soil layer and the cover soil layer Is preferably in the range of 50 to 95% by volume.

A fertilizer containing components such as nitrogen (N), phosphoric acid (P ₂ O ₅ ), and potassium (K ₂ O) can be added to the medium base material used in the present invention as necessary. Although the standard of addition amount is based on the customary seedling cultivation soil, the content in the medium base material is 1 g / L or less.

  For the purpose of improving the physical and chemical properties of the medium, the medium base material responds to diseases and pest damage derived from the medium base material during seedling, seeds and plant bodies, suppression of the chief, etc. Appropriate amounts of bactericides, insecticides, plant growth regulators, surfactants, pH regulators and the like can be contained as long as the effects of the present invention are not impaired.

  In the present invention, the fertilizer / seed layer is located on the floor soil layer and contains a time-eluting type coated nitrogen fertilizer and seeds. The fertilizer / seed layer may be formed by any procedure, for example, it may be formed by laminating a mixture of time-eluting type coated nitrogen fertilizer and seed on the floor soil layer. It may be formed by first laminating a time-dissolved coated nitrogen fertilizer and then sowing on it, or by first sowing on the bed soil layer and then time-eluting coated nitrogen It may be formed by laminating fertilizers.

  The time-dissolved coated nitrogen fertilizer used in the present invention is obtained by coating a core material containing nitrogen fertilizer with a coating material containing a resin as an active ingredient. Examples of the resin include olefin resins, diene resins, waxes, polyesters, petroleum resins, natural resins, oils and fats and modified products thereof, and mixtures of two or more selected from the resins, urethane resins. And thermosetting resins such as alkyd resins. An inorganic powder such as talc, an organic powder such as starch, a surfactant, a filler, or an additive may be added to these resins as a coating material.

  Examples of the nitrogen fertilizer of the core material include ammonium sulfate, urea, ammonium nitrate, isobutyraldehyde condensed urea, acetaldehyde condensed urea, and the like. Among these, urea having a low unit price per fertilizer component is preferable. In addition to nitrogen fertilizer, the core material may contain other fertilizer as required. Other fertilizers are, for example, fertilizers containing calcium, magnesium, sulfur, iron, trace elements, silicon, and the like as plant essential elements in addition to phosphate fertilizer and potassium fertilizer. Further, the core material may contain a nitrification inhibitor and an agrochemical.

  Examples of preferable time-dissolved coated nitrogen fertilizers are described in JP-A-6-78684, JP-A-4-202078, JP-A-4-202079, and the like. Specific product names are: Seed box entrusted by Chisso Asahi Fertilizer Co., Ltd., LP Coat S and LP Coat SS, Mitsubishi Chemical Agri Co., Ltd. M Coat S, Sumitomo Chemical Co., Ltd. Super SR Coat, Central Ceracoat U and Ceracoat R manufactured by Joint Fertilizer Co., Ltd., and Ucoat manufactured by Ube Industries, Ltd. A seedling box manufactured by Chisso Asahi Fertilizer Co., Ltd. is particularly preferable.

  The cumulative nitrogen component elution rate of the time-dissolved coated nitrogen fertilizer can be determined by the following method. 10 g of the coated nitrogen fertilizer is immersed in 200 mL of water and allowed to stand at 25 ° C. After a predetermined period of time, the coated nitrogen fertilizer is divided into the coated nitrogen fertilizer and water, and the total elution amount of nitrogen components eluted in the water is determined by quantitative analysis. Further, the total nitrogen amount in 10 g of the coated nitrogen fertilizer is quantified, and the ratio of the cumulative elution amount to the total nitrogen amount as a percentage is defined as the cumulative nitrogen component elution rate. Specifically, the method described in JP-A-2005-319417 can be exemplified.

  The measurement followed this method. That is, 10 g of coated nitrogen fertilizer and 200 mL of distilled water adjusted to 25 ° C. in advance were put into a 250 mL plastic container and left in an incubator set at 25 ° C. Three days later, all the water was extracted from the container, and the total amount of nitrogen components eluted (total amount of nitrogen components eluted) contained in the extracted water was determined by quantitative analysis. Quantitative analysis is, for example, a fertilizer analysis method (for example, “Agricultural Environment Technology Institute, Ministry of Agriculture, Forestry and Fisheries”, “Fertilizer Analysis Method (1992)”, published by Japan Fertilizer Testing Association, December 1992, p. 15). -22, Fumio Yamazoe et al., “Detailed Analysis of Fertilizer Analysis, 1st Edition”, published by Yokendo, January 1973, p.35-62. The rate indicates the percentage of the total amount of the eluted nitrogen component with respect to the total amount of nitrogen in 10 g of the coated nitrogen fertilizer as a percentage.

  The time-dissolved coated nitrogen fertilizer has an elution pattern consisting of an elution suppression period in which elution is suppressed for a certain period from the time it is applied in water or soil, and an elution period in which elution is started immediately after the elapse of the certain period. In the above-mentioned coated nitrogen fertilizer, the period from when the cumulative nitrogen component elution rate is applied (0%) to 10% is d1 (day), until the cumulative nitrogen component elution rate exceeds 10% and reaches 80%. When the period is d2 (days), the elution pattern has d1 / d2 of 0.2 or more. d1 / d2 is preferably 0.3 or more. The cumulative nitrogen component elution rate during the seedling raising period is preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less. When a coated nitrogen fertilizer with a small cumulative nitrogen component elution rate during the seedling period is used, the possibility of occurrence of growth failure or overgrowth in the later stage of seedling is reduced. A coated nitrogen fertilizer with a very low cumulative nitrogen component elution rate is not easy to produce and is likely to be expensive.

  The seedling raising period of paddy rice seedlings is 15 to 25 days when transplanted with young seedlings (2 to 3 leaves), and 30 to 35 days when transplanted with medium seedlings (4 or more leaves), When transplanted with adult seedlings (5 to 6 leaves), it is 35 to 40 days. Since coated nitrogen fertilizer can predict the elution behavior of fertilizer components based on the soil temperature during the seedling period, if there is data on the average soil temperature of the average year, the accumulated nitrogen component elution rate and d1 during the seedling period can be calculated to some extent. Can be predicted. Therefore, if there is data on the elution behavior of the coated nitrogen fertilizer at the average soil temperature, it is possible to select and use the coated nitrogen fertilizer having a desirable cumulative nitrogen component elution rate or d1 during the raising seedling period.

  In the formation of fertilizer / seed layer, the application rate of the above-mentioned coated nitrogen fertilizer is, for example, a standard nursery box (300 mm (vertical) x 600 mm (horizontal) x 30 mm) in the case of coated urea with a nitrogen guarantee component of 40%. 400g to 1200g per (depth) is practically preferable.

Time-eluting coated nitrogen fertilizer is temperature dependent. The coefficient indicating the temperature dependence of d1 is preferably in the range of 1.1 to 3.5, and more preferably in the range of 1.5 to 3.0. The temperature dependence means that d1 fluctuates with a change in temperature, and an index thereof is indicated by a fluctuation ratio (temperature dependence coefficient (Q ₁₀ )) of d1 when the temperature changes by 10 ° C. For example, when the temperature rises or falls by 10 ° C. and d1 becomes ½ or double, the temperature dependence coefficient is said to be 2. Therefore, the minimum value of the temperature dependence coefficient is 1.

  Chemically synthesized slow-release nitrogenous fertilizers are fertilizers whose elution of active ingredients depends on the rate of chemical degradation that the fertilizer undergoes. Specifically, acetaldehyde condensed urea, isobutyraldehyde condensed urea, formaldehyde processed urea fertilizer, glyoxal condensed urea, and methylol urea described in “Pocket Fertilizer Manual 2004” (p.104) published by the Agricultural and Forestry Statistics Association Aliphatic aldehyde condensed urea such as polymer fertilizer, oxamide, guanyl sulfate, and the like. Among these, aliphatic aldehyde condensed urea is preferable.

  The aliphatic aldehyde condensed urea is not particularly limited, and any aliphatic aldehyde condensed urea having any molecular structure such as linear, branched chain, or cyclic can be used. Specifically, acetaldehyde condensed urea (CDU or OMU), isobutyraldehyde condensed urea (IBDU), methylol urea polymerized fertilizer, formaldehyde processed urea fertilizer, glyoxal described in the fertilizer control law (official standard of fertilizer, type of fertilizer) Examples include condensed urea. In the present invention, one or more of these may be arbitrarily selected and used. Preferred are 2-oxo-4-methyl-6-ureidohexahydropyrimidine (hereinafter referred to as “CDU”), which is a kind of acetaldehyde-condensed urea, isobutyraldehyde-condensed urea, and methylol urea polymerized fertilizer, particularly preferably CDU. is there.

  A chemically synthesized slow-release nitrogen fertilizer may contain nitrogen components of ammonia nitrogen, nitrate nitrogen, and urea nitrogen. This nitrogen component is called fast acting nitrogen. The fast acting nitrogen content contained in the granular fertilizer is 10% or less in terms of nitrogen with respect to the total nitrogen components contained in the granular fertilizer. If the content of fast-acting nitrogen is in the above range, even if the amount of granular fertilizer is too much, growth disorders such as growth delay, leaf color abnormality, and death are unlikely to occur. Less damage to the characteristics of nitrogen fertilizer. This tendency is remarkable when an aliphatic aldehyde condensed urea is used as a chemically synthesized slow-release nitrogen fertilizer. Chemically synthesized slow-acting nitrogen fertilizers that do not contain fast-acting nitrogen tend to be costly because a purification step is required after synthesis. Considering this, the ratio of fast-acting nitrogen contained in the granular fertilizer is preferably 0.1 to 10%, more preferably 1 to 10% or 1 to 8%.

  The ratio (percentage) of fast acting nitrogen can be measured and determined according to a known fertilizer analysis method. For example, mention may be made of the method described in “Agricultural Environment Technology Research Institute, Ministry of Agriculture, Forestry and Fisheries”, “Fertilizer Analysis Method (1992)” (published by Japan Fertilizer Examination Association, December 1992, p. 15-22). it can.

The granular fertilizer of the present invention may contain a phosphoric acid component, a potassium component and the like in addition to the chemically synthesized slow-release nitrogenous fertilizer. When chemically synthesized slow-release nitrogenous fertilizer and phosphate fertilizer coexist in the granular fertilizer, the regulation of fertilization may become unstable depending on the phosphoric acid content. This tendency is particularly strong when aliphatic aldehyde condensed urea is used as a chemically synthesized slow-release nitrogen fertilizer. For this reason, the total content of phosphoric acid contained in the granular fertilizer (also referred to as the total phosphoric acid content) is within a range of 0.01 to 5% in terms of P ₂ O _{5 with} respect to the chemically synthesized slow-release nitrogen fertilizer. Preferably there is. If it is this range, the fertilization effect of a chemically synthesized slow-release nitrogen fertilizer can be controlled. The total phosphoric acid content can be measured by the quinoline weight method (the method described in the second revised detailed fertilizer analysis method, published by Yokendo).

  Phosphate fertilizer is preferably less water-soluble than water-soluble. The sparingly water-soluble phosphoric acid component is a component obtained by removing water-soluble phosphoric acid from co-soluble phosphoric acid. Specific examples of fertilizers containing a large amount of the components include phosphorus ore and molten phosphorus fertilizer. Of the phosphoric acid components contained in the organic fertilizer, those that are poorly water-soluble can be preferably used. The above-mentioned soluble phosphoric acid and water-soluble phosphoric acid are fertilizer analysis methods (for example, “Agricultural Environment Technology Research Institute, Ministry of Agriculture, Forestry and Fisheries”, “Fertilizer analysis method (1992 version)”, published by Japan Fertilizer Testing Association, 1992. December, p. 28-37).

If the water-soluble phosphate component is present in excess, fertilization control of the chemically synthesized slow-release nitrogen fertilizer may be impaired. This tendency is particularly strong when aliphatic aldehyde condensed urea is used as a chemically synthesized slow-release nitrogen fertilizer. Therefore, the ratio of the water-soluble phosphate component in the granular fertilizer is preferably 0.5% or less in terms of P ₂ O _{5 with} respect to the chemically synthesized slow-release nitrogenous fertilizer. When using fertilizers such as phosphate fertilizers, ordinary chemical fertilizers, two-component compound fertilizers, advanced chemical fertilizers, and organic fertilizers that contain water-soluble phosphate components for applications such as granulation aids for granular fertilizers, they are water-soluble. It is preferable to use it in consideration of the content of the phosphoric acid component and the solubility in water.

The poorly water-soluble phosphate fertilizer is prepared by immersing the poorly water-soluble phosphate fertilizer in a 2% by mass citric acid aqueous solution at 30 ° C. in a mass ratio represented by the following formula, and 80% of the phosphoric acid component contained in the citric acid aqueous solution. It has elution characteristics in which the time required for elution is in the range of 0.1 to 2000 minutes.
Formula: Slightly water-soluble phosphate fertilizer / 2 mass% citric acid aqueous solution (mass ratio) = 0.013

  Specifically, the elution time can be measured by the following method. In a 300 mL plastic bottle, 2 g of a poorly water-soluble phosphate fertilizer and 150 mL of a 2% by mass citric acid solution heated to 30 ° C. are placed and shaken in a 30 ° C. shaking thermostat. The supernatant of the citric acid aqueous solution is taken little by little over time, diluted with water, and the phosphoric acid component in the diluted solution is quantified by ion chromatography. By creating an elution curve from this measured value, the time required until 80% of the phosphoric acid component contained in the poorly water-soluble phosphate fertilizer is eluted can be obtained.

  If the elution time is in the range of 0.1 to 2000 minutes, the mineralization rate of the chemically-synthesized slow-release nitrogenous fertilizer, particularly the aliphatic aldehyde condensed urea can be easily controlled. In order for the elution time of the poorly water-soluble phosphate fertilizer to be in the range of 0.1 to 2000 minutes, the poorly water-soluble phosphate fertilizer has a low solubility in water and is composed of a single crystal. preferable. Furthermore, when the shape is particulate, it is preferable that there are few voids in the particles.

  Although the method of adjusting the elution time of a slightly water-soluble phosphate fertilizer to the range of 0.1-2000 minutes is not specifically limited, For example, it is the following method. A method of adjusting the particle diameter of the slightly water-soluble phosphate fertilizer in a particulate form, a method of coating the surface of the particulate slightly water-soluble phosphate fertilizer with a water-insoluble or hydrophobic substance, Examples thereof include a method of mixing and granulating powder and water-insoluble or hydrophobic fine powder other than the phosphate fertilizer.

  Among them, the method of adjusting the particle diameter of the poorly water-soluble phosphate fertilizer in a particulate form is preferable because it can be carried out relatively easily. The particle size at that time varies depending on the kind of poorly water-soluble phosphate fertilizer to be used and the required elution time, but from the viewpoint of production or the adjustment of the mineralization rate of the urea-aliphatic aldehyde condensate, 0.01 to A range of 0.5 mm is preferable.

  For the purpose of controlling the fertilization effect of chemically synthesized slow-acting nitrogen fertilizer, a water-repellent substance can be contained in the granular fertilizer. By adding water-repellent substances, it is possible to control the dissolution of chemically synthesized slow-release nitrogenous fertilizer and poorly water-soluble phosphate fertilizer in the soil, and to control the fertilization effect of chemically synthesized slow-release nitrogenous fertilizer in a wide range Become. The effect of adding the granular fertilizer of this water-repellent substance is remarkable when the chemically synthesized slow-release nitrogenous fertilizer is an aliphatic aldehyde condensed urea.

  As the water repellent substance, it is preferable to appropriately use one or more selected from natural wax and synthetic wax. Natural waxes include plant waxes such as cadrine wax, carnauba wax, rice wax, wax, jojoba oil, animal waxes such as beeswax, lanolin and sperm wax, and mineral waxes such as montan wax, ozokerite and ceresin. And petroleum waxes such as paraffin wax, microcrystalline wax and petrolatum. Synthetic waxes include synthetic hydrocarbons such as Fischer-Tropsch wax, polyethylene wax and polypropylene wax, modified waxes such as montan wax derivatives, paraffin wax derivatives and microcrystalline wax derivatives, hydrogenated waxes such as hardened castor oil and hardened castor oil derivatives, Examples thereof include 12-hydroxystearic acid, stearamide, phthalic anhydride imide, and chlorinated hydrocarbon. Among these, hydrogenated castor oil and derivatives thereof are effective in controlling the mineralization rate of chemically synthesized slow-release nitrogenous fertilizer.

  The ratio of the water-repellent substance in the granular fertilizer is 0.1 to 20% by mass with respect to the total mass of the chemically synthesized slow-release nitrogenous fertilizer and the poorly water-soluble phosphate fertilizer and water-soluble components contained as necessary. It is preferable that it is the range of this, More preferably, it is the range of 1-15 mass%. When the ratio of the water repellent material is within the above range, the effect of the water repellent material is sufficient and the manufacturing cost is not increased.

  The granular fertilizer can be produced by a method described in JP2003-212682A, JP2005-67923A, or the like. For example, chemical synthetic slow-release nitrogen fertilizer, phosphoric acid component, potassium component, water-soluble component, water-repellent substance, granulation aid, binder, water, etc. are mixed, rolling granulation method, compression granulation method Granulation is performed using a stirring granulation method, an extrusion granulation method, or the like. If necessary, the granulated particles are dried using a gas having a melting point of not less than 500 and not more than 500? Granule fertilizer can be obtained by classifying the particles thus obtained with a vibration sieve to adjust the particle size distribution.

In the present invention, the granular fertilizer is a fast acting nitrogen, a poorly water-soluble phosphate fertilizer, a water repellent substance, other fertilizers, in addition to the chemically synthesized slow-release nitrogen fertilizer, as long as the effects of the present invention are not impaired. You may contain various granulation adjuvants, binders, etc. Other fertilizers include fertilizers containing phosphoric acid (P ₂ O ₅ ) and potassium (K ₂ O) components, organic fertilizers such as bone meal, oil grounds and meat grounds, calcareous fertilizers, bitter soil fertilizers, siliceous fertilizers And inorganic fertilizers such as trace element fertilizers.

  Granulation aids include bentonite, clay, kaolin, sericite, talc, acid clay, pumice, quartz sand, quartzite, zeolite, perlite, vermiculite and other minerals, rice straw, sawdust, wood flour, pulp floc, soybean flour, etc. Can be mentioned. In the present invention, one or more kinds of granulation aids may be selected and used as necessary.

  Binders include gum arabic, sodium alginate, glycerin, gelatin, molasses, microcrystalline cellulose, pitch, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium polyacrylate, polyvinylpyrrolidone, alumina sol, cement, sodium polyphosphate, lignin Examples thereof include sulfonates, polyvinyl alcohol, polyethylene glycol, surfactants, starch, thermosetting resin raw materials, and the like. In the present invention, one or more of these binders may be selected and used as necessary.

  The paddy rice nursery of the present invention may contain an agrochemical mainly used for pest control after transplanting. Specifically, a fertilizer / seed layer or a slow-release fertilizer layer can contain a granule having an insecticidal action and / or a bactericidal action. The agrochemical may be mixed in advance with the fertilizer / seed layer, or may be applied according to sowing or fertilization. The pesticidal active ingredient is preferably one having osmotic transferability. Specific examples of such agrochemicals are listed below, but these are merely examples and are not limited. The agrochemical active ingredient may be one type or may be composed of two or more composite components. Examples of the pesticidal active ingredient include substances that induce phytoalexin, which is a low-molecular antibacterial substance that is synthesized by a plant and accumulates in the plant body.

  Examples of pesticides with insecticidal action are (E) -N1-[(6-chloro-3-pyridyl) methyl] -N2-cyano-N1-methylacetamidine (generic name: acetamiprid), 1- (6-chloro -3-pyridylmethyl) -N-nitroimidazolidin-2-ylideneamine (generic name: imidacloprid), O, O-diethyl-S-2- (ethylthio) ethyl phosphorodithioate (generic name: ethylthiomethone), 1,3- Bis (carbamoylthio) -2- (N, N-dimethylamino) propane hydrochloride (generic name: Cartap), and the like.

  Another example is 2,3-dihydro-2,2-dimethyl-7-benzo [b] furanyl = N-dibutylaminothio-N-methylcarbamate (generic name: carbosulfan), (2-isopropyl- 4-methylpyrimidyl-6) -diethylthiophosphate (generic name: diazinon), 5-dimethylamino-1,2,3-trithian oxalate (generic name: thiocyclam), (E) -N- (6-chloro -3-pyridylmethyl) -N-ethyl-N′-methyl-2-nitrovinylidenediamine (generic name: nitenpyram), (±) -5-amino-1- (2,6-dichloro-α, α, α -Trifluoro-p-toluyl) -4-trifluoromethylsulfinylpyrazole-3-carbonitrile (generic name: fipronil), O, O-dipropyl-O-4-methylthiol Niruhosufeto (generic name: Purobahosu), and the like.

  Another example is 5-bromo-3-secondary-butyl-6-methyluracil (generic name: bromacil), ethyl = N- [2,3-dihydro-2,2-dimethylbenzofuran-7-yloxycarbonyl ( Methyl) aminothio] -N-isopropyl-β-alaninate (generic name: benfuracarb), 2-chloro-4,6-bis (ethylamino) -1,3,5-triazine (generic name: CAT), 3- ( 3,4-dichlorophenyl) -1,1-dimethylurea (generic name: DCMU), 1-naphthyl-N-methylcarbamate (generic name: NAC), 2-isopropoxyphenyl-N-methylcarbamate (generic name: PHC) ), Etc.

  Examples of pesticides with bactericidal action include diisopropyl-1,3-dithiolane-2-ylidene-malonate (generic name: isoprothiolane), (1RS, 3SR) -2,2-dichloro-N- [1- (4-chlorophenyl) ) Ethyl] -1-ethyl-3-methylcyclopropanecarboxamide (generic name: carpropamide), (RS) -2-cyano-N-[(R) -1- (2,4-dichlorophenyl) ethyl] -3, 3-dimethylbutyramide (generic name: diclocimet), 5-methyl-1,2,4-triazolo [3,4-b] benzothiazole (generic name: tricyclazole), and the like.

  Another example is 2 ′, 6′-dibromo-2-methyl-4-trifluoromethoxy-4-trifluoromethyl-1,3-thiazole-5-carboxanilide (generic name: tifluzamide), 1,2 , 5,6 Tetrahydropyrrolo [3,2,1-ij] quinolin-4-one (generic name: pyroxylone), N- (1-cyano-1,2-dimethylpropyl) -2- (2,4-dichloro) Phenoxy) propionamide (generic name: phenoxanyl), 3-allyloxy-1,2-benzisothiazole-1,1-dioxide (generic name: probenazole), (E) -2-methoxyimino-N-methyl-2- (2-phenoxyphenyl) acetamide (generic name: metminostrobin), and the like.

  The seedbed for paddy rice of the present invention forms a bed soil layer, forms a fertilizer / seed layer containing a time-dissolved nitrogen fertilizer and seeds on the bed soil layer, and covers the soil on the fertilizer / seed layer. Forming a layer, and then immediately after forming the covering layer on the covering layer, immediately before transplanting the seedling, (a) containing chemically synthesized slow-release nitrogenous fertilizer, (b) particles 70% by mass or more of particles having a diameter of 0.5 mm or more, a maximum particle diameter of 2.0 mm or less, and (c) a fast acting nitrogen content of 10% or less with respect to the total nitrogen components in the granular fertilizer (D) It can produce by forming a slow release fertilizer layer using the granular fertilizer whose average mass per grain is 0.1-5 mg.

  As described above, the granular fertilizer may be applied at any time from immediately after the start of raising seedling to immediately before transplanting, but any time from 10 days before transplanting to just before transplanting is preferable, and 10 days before transplanting to the day before transplanting is more preferred. preferable. This is because the work is busy immediately before transplantation and it is difficult to apply uniformly. In addition, the closer to the seedling start date, the shorter the duration of fertilization of the slow-release fertilizer layer in Honda. Since the conventional granule having an insecticidal action and / or bactericidal action for box treatment can be applied at the same time as the granular fertilizer, it takes almost no work time.

  The cultivation method of paddy rice using the seedbed of the present invention can enhance the environmental tolerance of rice seedlings before and after transplanting according to the conventional technique, if cultivated according to the cultivation method in the conventional seedling box full-volume fertilization method, and cultivation management Is preferable because it becomes easier.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The test methods used are as follows.
(1) Elution behavior of coated nitrogen fertilizer 10 g of the coated nitrogen fertilizer of Examples and Comparative Examples and 200 mL of distilled water adjusted to 25 ° C. in advance are put into a 250 mL plastic container with a lid and set at 25 ° C. It was left in an incubator. Seven days later, all the water was extracted from the container, and the amount of urea contained in the extracted water (urea elution amount) was determined by quantitative analysis (dimethylaminobenzaldehyde method “detailed fertilizer analysis method second revised edition” Yokendo). The sample after draining water was put into the container again, and 200 mL of distilled water was put into the container again and left in the same manner. This operation was repeated until the cumulative value of urea elution rate reached 80%.

  Thereafter, the coated nitrogen fertilizer was ground in a mortar, and the content was dissolved in 200 mL of water, and then the amount of urea remaining was quantitatively analyzed in the same manner as described above. The total amount of urea dissolved and the amount of urea remaining is added as the total amount of urea, and the relationship between the total amount of urea eluted in water and the number of days is graphed to create an elution rate curve. Cumulative nitrogen component elution rates are 10% and 80%. The number of days to reach was determined. D1 / d2 was calculated by setting “d1” as the number of days until the cumulative elution rate of nitrogen components reached 10% from the start of elution measurement, and “d2” as the number of days until the dissolution rate reached 80%.

Example of synthesis of aliphatic aldehyde condensate urea (CDU) 60 g of urea was dissolved in 60 mL of water, 8.5 mL of concentrated hydrochloric acid was added, 30 g of acetaldehyde was added dropwise under ice cooling, and the mixture was reacted at 50 ° C. with stirring for 4 hours to precipitate. The obtained crystals were filtered, washed with water, and then dried under reduced pressure to obtain CDU (purity 99.9% by mass or more). The obtained CDU was sieved, and a granular material that passed through a sieve having an opening of 150 μm was used in the following test. The fast acting nitrogen content of the CDU powder was 0.05% by mass or less (by thin layer chromatography).

Production example of granular fertilizers 1 to 6 The above-mentioned CDU granular material and urea (solubility in pure water at 20 ° C. is 107.7 g / 100 mL) so that the total input amount becomes 20 kg at the ratio shown in Table 1. The mixture was put into a spherical mixer with a capacity of 50 L and mixed for 5 minutes to obtain a mixture.
Next, 1 kg of the mixture is put into a rotating dish pan granulator having a diameter of 120 cm, water and the mixture are added little by little while rolling the mixture at a rotation speed of 40 r / min, and the average particle size is 1.3 mm. Granulated to a degree. After granulation, it was dried for 6 hours at 120 ° C. using a hot air circulating drier, and further classified with a vibrating sieve to obtain a granular fertilizer 1 having a particle size of 1.2 to 1.4 mm. Similarly to the case of granular fertilizer 1, granular fertilizers 2 to 4 were obtained so that the total amount of input was 20 kg at the ratio shown in Table 1.
Furthermore, when manufacturing the granular fertilizer 1, the granular fertilizer 5 which was classified with the vibration sieve and the particle diameter was 2.5-4.1 mm, and the granular fertilizer 6 whose particle diameter was less than 0.5 mm were obtained. The granular fertilizers 1 to 6 were prepared using a vibrating sieve (small vibrating sieve VSS-50, manufactured by Tsutsui Scientific Instruments).

Production Example of Granular Fertilizer 7 Commercially available formaldehyde processed urea fertilizer (trade name “Form Nitrogen No. 2”, manufactured by Mitsui Toatsu Fertilizer Co., Ltd.) is sieved to obtain a granular fertilizer 7 having a particle size of 1.0 to 2.0 mm. Obtained. Granular fertilizer 7 had a nitrogen content of 41.3% and a fast acting nitrogen content of 11.1%. The mass per grain (n = 100) was 2.4 mg. The formaldehyde-processed urea fertilizer was adjusted in particle size using a vibrating sieve (compact vibrating sieve VSS-50, manufactured by Tsutsui Chemical).

Production Example of Granular Fertilizer 8 Commercially available methylol urea polymerization fertilizer (trade name “Mikurea”, manufactured by Mitsubishi Rayon Co., Ltd.) was sieved to obtain a granular fertilizer 8 having a particle size of 1.0 to 2.0 mm. Granular fertilizer 8 had a nitrogen content of 29.0% and a fast acting nitrogen content of 1.4%. The mass per grain (n = 100) was 6.2 mg. The methylol urea polymerization fertilizer was prepared with a particle size using a vibrating sieve (small vibrating sieve VSS-50, manufactured by Tsutsui Riken Kikai Co., Ltd.).

  Table 1 summarizes the raw material composition, nitrogen component content, fast-acting nitrogen content, and mass per grain of the granular fertilizers produced in Production Examples 1 to 3. In addition, the granular fertilizers 1-3 were used for the below-mentioned Examples 1-6, and the granular fertilizers 4-8 were used for the below-mentioned Comparative Examples 1-5. Granular fertilizer 1 was also used in Comparative Example 6.

  Footnotes in Table 1: Nitrogen component content is measured by fertilizer analysis (sulfuric acid method). The fast-acting nitrogen content was calculated from the ratio of fast-acting nitrogen (sum of ammonia nitrogen, nitrate nitrogen, and urea nitrogen) to the total nitrogen component of the granular fertilizer. The molten phosphorus fertilizer is a sieving product of Kumiai molten phosphorus 20-15-20 (trade name) manufactured by Minami Kyushu Chemical Co., Ltd. Particles that passed through a sieve having an opening of 180 μm and did not pass through a 150 μm sieve were used. Urea is a reagent grade manufactured by Kanto Chemical Co., Inc. The water repellent material is Custer Wax FP (trade name), manufactured by Ogura Gosei Kogyo Co., Ltd., hardened castor oil, melting point 81 ° C. The mass per grain is an average value obtained from the mass of 100 grains.

Example 1
Commercially available paddy rice seedling boxes (300 mm (vertical) x 600 mm (horizontal) x 30 mm (depth)) as a medium base material (water retaining material), commercially available paddy rice seedling V floor soil (trade name, Chisso Asahi Fertilizer Co., Ltd.) Made of nitrogen, 0 mg / L of nitrogen, 0 mg / L of phosphoric acid, 0 mg / L of potassium, pH 4.5 to 5.5) to a depth of about 2 cm, after forming a floor soil layer, commercially available as coated nitrogen fertilizer 1 Rice seedling box N400 / 100 type (trade name, manufactured by Chisso Asahi Fertilizer Co., Ltd., nitrogen content 40%, d1 = 33 days, d2 = 70 days, d1 / d2 = 0.47) 120 g of seed meal (variety “Hinohikari”) was uniformly applied in order to form a fertilizer / seed layer. Subsequently, after forming a covering layer using the above-mentioned commercially available medium base material, 50 g of granular fertilizer 1 was uniformly applied 7 days before transplantation to form a slow-acting fertilizer layer to obtain a nursery bed of the present invention. The cumulative dissolution rate of the coated nitrogen fertilizer 1 on the 21st day was 2.8%.

Example 2
A nursery of the present invention was obtained in the same manner as in Example 1 except that the granular fertilizer 2 was used instead of the granular fertilizer 1 of Example 1.

Example 3
A nursery of the present invention was obtained in the same manner as in Example 1 except that the granular fertilizer 3 was used in place of the granular fertilizer 1 of Example 1.

Example 4
A nursery of the present invention was obtained in the same manner as in Example 1 except that the granular fertilizer 1 of Example 1 was applied on the 2nd day before transplantation.

Example 5
Same as Example 4 except that 50 g of granular fertilizer 1 and commercially available insecticidal fungicide Wyndmeier box granule (trade name, manufactured by Bayer CropScience Co., Ltd., carpropamide 4%, imidacloprid 2%) were applied. The present invention nursery was obtained.

Example 6
After forming the floor soil layer in Example 1, 50 g of a commercially available insecticidal fungicide, Deleus Prince Granule 10 (trade name, manufactured by Sumitomo Chemical Co., Ltd., diclocimet 3%, fipronil 1%) was applied, and then coated nitrogen A nursery of the present invention was obtained in the same manner except that 600 g of fertilizer 1 and 180 g of paddy rice germination seed varieties (variety “Hinohikari”) were uniformly applied in order to form a fertilizer / seed layer.

Comparative Examples 1-5
Rice seedling beds were produced in the same manner as in Example 1 except that granular fertilizers 4 to 8 were used instead of the granular fertilizer 1 of Example 1, and the results of Comparative Examples 1 to 5 were obtained.

Comparative Example 6
A nursery for paddy rice was produced in the same manner as Example 1 except that the coated nitrogen fertilizer 1 was changed to the coated nitrogen fertilizer 2 in Example 1. Covered nitrogen fertilizer 2 uses commercially available Kumiai LP coat 100 (trade name, manufactured by Chisso Asahi Fertilizer Co., Ltd., nitrogen content 42%, d1 = 12 days, d2 = 88 days, d1 / d2 = 0.14) did.

Cultivation test The seedlings produced in Examples 1 to 6 and Comparative Examples 1 to 6 were grown for 21 days, and the state was investigated. During the seedling period, sufficient irrigation was performed from above the seedling box, and the bottom surface was heated at the same time, and the temperature of the floor soil was controlled so as not to be less than 10 ° C. The seedlings were grown according to the customary method in a greenhouse where an unheated transparent polyolefin film (trade name: Agritop High Power, manufactured by Chisso Corporation) was spread. After raising seedlings, they were transplanted to Honda and cultivated according to the customary method.

The cultivation test results are shown in Table 2. The seedlings grown using the seedbeds of the present invention in Examples 1 to 6 grew well, had good rooting and leaf color, and could be easily transplanted to Honda. Since the survival after transplantation was good, it seems that the fertilization effect derived from granular fertilizer was effective. In particular, Examples 1, 4, 5, and 6 using the granular fertilizer 1 maintained a long-term fertilization effect.

Footnotes in Table 2: Coated nitrogen fertilizer 1 is a seedling box entrusted N400 / 100 type (trade name) manufactured by Chisso Asahi Fertilizer Co., Ltd. The coated nitrogen fertilizer 2 is Kumiai LP Coat 100 (trade name) manufactured by Chisso Asahi Fertilizer Co., Ltd. Application time represents the number of days before transplantation. In Example 5, an insecticide sterilizing granule, Wyner Meyer box granule (trade name) manufactured by Bayer CropScience Co., Ltd. was applied simultaneously with the granular fertilizer. In Example 6, Delousse Prince granule 10 (trade name) manufactured by Sumitomo Chemical Co., Ltd., which is an insecticidal disinfectant granule, was applied simultaneously with the granular fertilizer. As the medium base material (water retaining material), V-bed soil (trade name) for paddy rice raising seedling manufactured by Chisso Asahi Fertilizer Co., Ltd. was used.

  From these, it can be seen that the nursery of the present invention uniformly and sufficiently contains the fertilizer components necessary for seedling growth, and that the fast-acting nitrogen of the nursery does not adversely affect seed germination and seedling growth, Furthermore, it was observed that the examples using the granular fertilizers 1 and 2 controlled the decomposition (mineralization) of the contained aliphatic aldehyde condensed urea. In Examples 5 and 6, the combined use with agricultural chemicals is also good, and labor saving in agricultural work is expected.

  In Comparative Examples 2 and 5 using relatively large granular fertilizers 5 and 8, the growth in the same seedling box was uneven. Measurement of fast-acting nitrogen content in nursery medium ("Soil Nutrient Analysis Method", Yokendo, published in December 1970, simultaneous leaching quantification method of ammonia, nitrite and nitrate nitrogen (p.197-p. 200)), the poorly grown part has a smaller amount of nitrogen component than the good part, which seems to reflect the variation in fertilizer application amount.

  In the test plot where seedlings were grown using the seedbeds of Comparative Examples 1 and 4 using the granular fertilizers 4 and 7 having a high fast-acting nitrogen content, a growth disorder occurred due to a concentration disorder due to the fast-acting nitrogen. Growth failure also occurred in Comparative Example 3 using granular fertilizer 6 close to powder. This is presumably because the fertilizer particles were too small and the decomposition (mineralization) of the CDU was too fast, resulting in a large amount of fast-acting nitrogen. In Comparative Example 6 in which the coated nitrogen fertilizer having no timed elution pattern was used, germination damage occurred.

Claims (11)

A bed soil layer, a fertilizer / seed layer containing a time-dissolved coated nitrogen fertilizer and seeds located on the bed soil layer, a soil covering layer located on the fertilizer / seed layer, and a soil covering layer A nursery for paddy rice, which is a seedbed for cultivating paddy rice having a slow-release fertilizer layer, and the slow-release fertilizer layer is a layer containing granular fertilizer that satisfies the following conditions.
(A) Contains a chemically synthesized slow-release nitrogen fertilizer.
(B) Particles having a particle size of 0.5 mm or more are 70% by mass or more, and the maximum particle size is 2.0 mm or less.
(C) The fast acting nitrogen content is 10% or less with respect to the total nitrogen components in the granular fertilizer.
(D) The average mass per grain is 0.1 to 5 mg.   The seedbed for paddy rice according to claim 1, wherein the chemically synthesized slow-release nitrogenous fertilizer is at least one selected from the group of aliphatic aldehyde condensed urea, oxamide, and guanylurea sulfate.   The chemically synthesized slow-release nitrogenous fertilizer is at least one selected from the group consisting of acetaldehyde condensed urea, isobutyraldehyde condensed urea, formaldehyde processed urea fertilizer, glyoxal condensed urea, and methylol urea polymerized fertilizer. Nursery.   The nursery bed for paddy rice according to claim 1, wherein the chemically synthesized slow-release nitrogenous fertilizer is acetaldehyde condensed urea.   The seedbed for paddy rice according to any one of claims 1 to 4, wherein the granular fertilizer contains a poorly water-soluble phosphate fertilizer and / or a water-repellent substance.   The period from when the timed elution-type coated nitrogen fertilizer reaches 10% from the point of application of the cumulative nitrogen component elution rate is d1 (day), and the cumulative nitrogen component elution rate exceeds 10% and reaches 80%. The seedling bed for paddy rice according to claim 1, which has an elution pattern in which d1 is equal to the seedling raising period and d1 / d2 is 0.2 or more, where d2 (days) is the period up to.   The seedbed for paddy rice according to any one of claims 1 to 6, wherein the fertilizer / seed layer or the slow-acting fertilizer layer contains a granule having an osmotic transfer insecticidal action and / or bactericidal action.   A bed soil layer is formed, a fertilizer / seed layer containing a time-dissolved nitrogen fertilizer and seeds is formed on the bed soil layer, a cover layer is formed on the fertilizer / seed layer, and then At any time from immediately after forming the layer to immediately before transplanting the seedling, (a) containing a chemically synthesized slow-release nitrogenous fertilizer, and (b) containing 70% by mass or more of particles having a particle diameter of 0.5 mm or more. The maximum particle diameter is 2.0 mm or less, (c) the fast acting nitrogen content is 10% or less with respect to the total nitrogen components in the granular fertilizer, and (d) the average mass per grain is 0.1 A method for producing a seedbed for paddy rice in which a slow-acting fertilizer layer is formed on a soil covering layer using a granular fertilizer of ˜5 mg.   The method for producing a paddy rice nursery bed according to claim 8, wherein the slow-acting fertilizer layer is formed at any time from 10 days before transplanting of the seedling to immediately before transplanting.   The method for producing a seedbed for paddy rice according to claim 8 or 9, wherein a slow-acting fertilizer layer is formed using granular fertilizer and a granule having an insecticidal and / or bactericidal action.   The cultivation method of the paddy rice using the seedbed for paddy rice of any one of Claims 1-7.