JP7150877B2 - Fertilizer, method for producing same, method for producing cultivated plant, and method for promoting growth - Google Patents

Description

The present invention relates to methods for producing fertilizers and cultivated plants. More specifically, the present invention provides a fertilizer that promotes the growth of plants, particularly monocotyledonous plants, and increases the yield of their seeds or fruits, typically grains such as rice, wheat, and corn, and cultivated plants using the same. It relates to the production method of

Although silicon is not an essential element for plants, it is an important component in monocotyledonous plants, especially in grasses. The main effects and effects of silicon in plants include, for example, prevention of lodging, alleviation of excessive manganese, and alleviation of disease and pest damage such as suppression of blast and powdery mildew. These disease and insect resistance that silicon brings to plants are not only due to the fact that the silica deposited in the plant body builds a physical barrier against pathogens, but also that the silicon in the plant body has the effect of inducing resistance at the site of infection. was found, and it has been reported that water-soluble silicon plays an important role in this disease and insect resistance (see, for example, Non-Patent Documents 1 and 2).

Originally, soil contains a large amount of silicon, but it exists in the form of poorly soluble aluminum silicate, which is difficult for plants to absorb, and is efficiently used for plant growth. hard to say.

From this point of view, it has been conventional practice to apply silicon-containing fertilizers in paddy field cultivation of rice. Slag (slag) obtained when refining iron and various metals is used as a slag. It cannot be said that it is efficient as a supply source of silicic acid.

Furthermore, in Patent Document 1, crystalline slag, especially slag containing a mineral phase of dicalcium silicate (2CaO.SiO ₂ ), has high silicic acid elution even under pH conditions of about 5 to 7, Although it has been shown that the fertilization effect is improved, it is only an improvement among those using the same slag type, and it is still not sufficient. The composition of the slag in Patent Document 1 is mainly composed of CaO, SiO ₂ , MgO and Al ₂ O ₃ , with 40 to 60% by mass of CaO, 25 to 40% by mass of SiO ₂ and 5% by mass of MgO. ~15% by weight, 0-5% by weight of Al ₂ O ₃ and a CaO/SiO ₂ weight ratio of 1.4-2.0.

Also, in order to facilitate the absorption of silicon by plants, attempts have been made to convert silicon-containing compounds into liquid fertilizers. For example, in Patent Document 2, orthosilicic acid (correct Silicic acid) H ₄ SiO ₄ (Si(OH) ₄ ) has been proposed to produce liquid fertilizers by hydrolyzing orthoalkyl silicates (tetraalkoxysilanes) in aqueous solution under acidic conditions. . However, fertilizers obtained by synthesis using pure chemical raw materials such as tetraalkoxysilane can be expected to be expensive even if the amount added is small, and the flammability of the raw materials, There are also problems such as irritation. For this reason, it remains questionable in terms of commercialization. Furthermore, liquid fertilizers are excellent in terms of immediate effect, but it is well known that orthosilicic acid is generally difficult to maintain as a stable single substance because it quickly undergoes dehydration condensation and becomes silica. It was questionable whether the gelation of the active ingredient would not occur in this method.

In addition, in the above-mentioned Non-Patent Document 2, it is necessary to accumulate a large amount of silicon for healthy growth and stable high yield of rice. Silicic acid (orthosilicic acid) as a molecule is absorbed from the roots and transported to the aerial part, where the silicic acid is gradually concentrated by transpiration, polymerized and deposited as silica. Silicic acid is transported efficiently by the cooperation of the silicic acid inward transporter Lsi1 protein that transports silicic acid from the extracellular to the intracellular and the silicic acid outward transporter Lsi2 protein that transports silicic acid from the intracellular to the extracellular. The idea that there is However, it has also been reported that the expression of Lsi1 and Lsi2 is remarkably suppressed when sufficient silicic acid is continuously given. For this reason, even if the mechanism of silicon accumulation shown in the same document is correct, it is considered to be only a factor that contributes to the growth and high yield of rice, and is not an absolute mechanism. rice field.

Thus far, many studies and proposals have been made regarding the provision of silicon components in hopes of increasing the growth of plants, especially grain yields, but they have not reached a sufficiently satisfactory level. Further investigation and improvement were desired.

Japanese Patent Application Laid-Open No. 2004-218065 JP-A-2005-67996

Eiichi Takahashi, "What is silicic acid for crops? 'Useful elements' that enhance environmental adaptability," 1st edition, Noyama Fishing Village Cultural Association, September 25, 2007, p. 188-189 Jianfeng Ma et al., "Silicon transporter in rice", Protein Nucleic Acid Enzyme Vol. 52 No. 14 pp. 1849-1856 (2007), "Silicon transporters in rice"

Therefore, in view of the problems in the prior art as described above, the present invention provides a stable and economical method for promoting the growth of plants, particularly monocotyledonous plants such as gramineous plants, and effectively increasing the yield of their seeds or fruits. It is an object of the present invention to provide a silicon-containing fertilizer that can be provided at a low cost and a method for producing cultivated plants using the same.

As a result of intensive studies and studies to solve the above problems, the present inventors have found that in the cultivation of grasses such as rice, wheat, and corn, fertilizing the soil with a material that is fired and foamed using waste glass as a raw material. It was found that the grain yield was greatly increased when the grain was cultivated by

Furthermore, when examining the plants grown in this way, it was found that not only the grain yield but also the mass of the whole plant (plant mass) was significantly increased compared to the plants grown in the control plot. However, on the other hand, the silicon concentration in the plant was not much different from that of the plants grown in the control plot, and rather decreased. It has been found that the absorption of silicon in the form of ₄ SiO ₄ (Si(OH) ₄ ) and the need for large amounts of silicon accumulation in the plant are not connected with the theory.

The inventors of the present invention have made further intensive studies to explore the factors behind the increase in yield, and have found that the use of the above-mentioned materials in the hydroponic culture of rice is associated with the concentration of metasilicate ions (SiO ₃ ²⁻ ) in paddy water. It was found that there was a large difference in the given plot compared to the control plot. That is, in the early stage of rice cultivation, the concentration of metasilicate ions (SiO ₃ ^2- ) in the water is slightly higher in the experimental plot than in the control plot, and there is no significant difference. In the control plot, the concentration was significantly reduced, and it was also observed that the expression of the Lsi gene was promoted in rice. did not change significantly, and it was observed that the expression of the Lsi gene was also suppressed in rice.

From these facts, in terms of increasing the grain yield in the cultivation of gramineous plants, as previously reported in Non-Patent Document 2, etc., rice contains silicon as a neutral molecule, orthosilicate H ₄ SiO ₄ (Si ₍ ^OH ) ₄ ) and accumulate a large amount of silicon in the plant body. It is important to have a mechanism of action such as increasing the yield of grains by increasing the amount of photosynthesis and increasing the yield of grains. We have reached the conclusion that silicon can be stably eluted in the form of metasilicate ions (SiO ₃ ^2- ) over a long period of time and have a remarkable effect on the growth of rice and the increase in the yield of grains. It has reached completion.

That is, the present invention for solving the above problems is a fertilizer containing a vitreous foamed sintered body.

As a fertilizer according to the present invention, an embodiment is shown in which the vitreous foamed sintered body has a bulk density of 0.3 to 0.6 g/cm ³ and a water absorption rate of 30 to 35%.

As a fertilizer according to the present invention, the vitreous foam contains 65.0% by mass or more of SiO ₂ and exhibits metasilicate ion (SiO ₃ ²⁻ ) elution in water. Embodiments are shown.

The fertilizer according to the present invention further includes at least one foaming agent selected from the group consisting of silicon carbide, calcium carbonate, aluminum nitride, and Al ash, in addition to the waste glass pulverized raw material in the vitreous foam. is added in an amount of 0.1 to 3% by weight based on the total raw materials and fired.

As a fertilizer according to the present invention, the vitreous foamed sintered body contains SiO ₂ 65.0 to 75.0% by mass, CaO 7.0 to 15.0% by mass, and Na ₂ O 10.0 to 16.0%. 0 to 3.5% by mass of K ₂ O, 0 to 4.5% by mass of MgO, 0 to 2.5% by mass of Al ₂ O ₃ , 0 to 2% by mass of C, and less than 3% by mass of other components Aspects are presented which are intended to

The present invention, which solves the above problems, is also a method for producing a cultivated plant, characterized by placing the fertilizer described above in the vicinity of the root of the plant in the soil culture or hydroponics culture of a monocotyledon.

In the method for producing a cultivated plant according to the present invention, there is shown an aspect in which the plant is particularly a plant of the Gramineae family.

The present invention, which solves the above problems, is also a method for regulating the growth of cultivated plants, characterized by adjusting the concentration of metasilicate ions (SiO ₃ ²⁻ ) near the roots of the plants.

In the method for regulating the growth of cultivated plants according to the present invention, there is shown an embodiment in which the concentration of metasilicate ions (SiO ₃ ²⁻ ) in water given to the cultivated plants is maintained at 20-25 mg/L.

According to the present invention, in growing plants, it is possible to significantly increase the yield of plants, particularly rice and wheat, by a very simple operation of applying a fertilizer made of a vitreous foamed sintered body to the roots of the plants. Since it is effective for all major grains such as corn and maize, it will greatly contribute to solving the food problem. In addition, there is no need for plant breeding, which requires enormous research expenses and time to increase yields, and as a result, it contributes greatly to the reduction of food costs. Furthermore, since the vitreous foamed sintered body according to the present invention is manufactured using waste glass as a raw material, it is low cost and resource-saving. There is no environmental load physically and practically. Furthermore, according to the present invention, the molecular form of silicon taken into the body of plants has been clarified, and is expected to make a great scientific contribution to the elucidation of the evolution of monocotyledonous plants.

2 is a photograph comparing the growth state of (a) rice of the first variety cultivated in an example plot cultivated using the fertilizer of the present invention and (b) rice of the first variety cultivated in a comparative control plot. 4 is a graph showing the intraplant silicon concentration of the first variety rice cultivated in the example plot cultivated using the fertilizer of the present invention and the first variety rice cultivated in the comparative control plot. Fig. 2 is a graph showing the plant weight of the first variety rice cultivated in the example plot cultivated using the fertilizer of the present invention and the first variety rice cultivated in the comparative control plot. 4 is a graph showing the fruit (brown rice) yield of the first variety of rice cultivated in the example plot cultivated using the fertilizer of the present invention and the first variety of rice cultivated in the comparative control plot. Fig. 4 is a graph showing the fruit (brown rice) yield of the second variety of rice cultivated using the fertilizer of the present invention in an example plot of another variety and the second variety of rice cultivated in another comparative control plot. . Metasilicate ion (SiO ₃ ²⁻ ) concentration after 60 days in paddy water in which seedlings were planted in the example plot using the fertilizer of the present invention and in which seedlings were not planted, and seedlings were planted in the control plot, and 4 is a graph showing temporal changes in metasilicate ion (SiO ₃ ²⁻ ) concentration in paddy water after 60 days without planting seedlings. FIG. 2 is a micrograph showing the state of Lis gene expression in rice in an example plot in which rice was cultivated using the fertilizer of the present invention, and a micrograph showing the state of Lis gene expression in rice cultivated in a control plot. (a) A photograph comparing the growth state of wheat cultivated in an example plot cultivated using the fertilizer of the present invention and (b) wheat cultivated in a comparative control plot. 1 is a photograph comparing the growth state of (a) corn grown using the fertilizer of the present invention in an example plot and (b) corn grown in a control plot.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on embodiments.

(fertilizer)
The fertilizer of the present invention contains a vitreous foamed sintered body.

Typically, the vitreous foamed sintered body, as described later, is generally made from waste glass as a raw material, added with a small amount of foaming agent, and heated to a temperature higher than the softening point of glass, generally 750° C. or higher, preferably 750° C. or higher. It is obtained by firing in the range of 840 to 980°C, typically around 880°C.

Therefore, although the composition varies somewhat depending on the type of glass entering the waste glass as a raw material, it contains 65.0% by mass or more of SiO ₂ as a silicon component, and most of the remainder is an alkali or alkaline earth metal. Since it becomes an oxide, it contains a large amount of water-soluble metasilicate in the sintered body phase. Therefore, the vitreous foamed sintered body exhibits metasilicate ion (SiO ₃ ²⁻ ) elution with water. Although it is not particularly limited, specifically, for example, when 100 g of the glassy foamed fired body is put in 1 liter of pure water at a water temperature of 20 ° C. (± 5 ° C.) and left to stand for 3 days, metasilicic acid The ion ion (SiO ₃ ²⁻ ) elution amount is 25 to 50 mg/L, particularly 35 to 45 mg/L, for example 41 mg/L, and particularly preferably the elution amount for 14 days is 50 mg/L or more, especially , 50-70 mg/L, for example 56 mg/L.

In particular, since the main waste glass is soda-lime glass such as glass bottles, plate glass, and window glass, it has a composition relatively close to this, typically SiO ₂ 65.0 to 75.0% by mass. , especially 70.0 to 74.0% by weight, CaO 7.0 to 15.0% by weight, especially 10.0 to 13.0% by weight, Na ₂ O 10.0 to 16.0% by weight, especially 10.0% by weight. 0-13.0% by weight, K ₂ O 0-3.5% by weight, especially 1.0-3.0% by weight, MgO 0-4.5% by weight, especially 1.0-3.0% by weight, Al ₂ O ₃ 0-2.5% by weight, especially less than 1.0% by weight, C 0-2% by weight, especially less than 1.5% by weight, other components less than 3% by weight, especially less than 2% by weight It is a thing. Other components include, but are not limited to, B ₂ O ₃ , Li ₂ O ₃ , TiO ₂ , ZrO ₂ derived from other glasses such as borosilicate glass and crystallized glass, and coloring. Glass-derived Fe ₂ O ₃ , CoO and the like can be mentioned.

Also, the shape of the vitreous foamed sintered body of the fertilizer of the present invention is not particularly limited. It can be placed in the vicinity of the roots or at least in a position in contact with the water supply route to the roots of the plant, as long as it can be in contact with water sufficiently. Desirably, the body has a bulk density of 0.3 to 0.6 g/cm ³ and a water absorption of 30 to 35%. If the bulk density is within such a range, it is lightweight, does not burden the roots of the plant, and has good retention on the roots. It is possible to stably bring about elution of a predetermined metasilicate ion (SiO ₃ ²⁻ ) in a good amount. Also, the average particle size is not particularly limited, but, for example, those having an average particle size of about 10 to 60 mm are preferably used.

In addition, in this specification, the bulk density is measured by the Archimedes method. In addition, the water absorption rate is measured by first measuring the weight W ₀ of the sample to be measured in a dry state, then submerging the sample in water and holding it for 5 minutes, taking it out, wiping the surface with a damp cloth, The weight W ₁ was measured and calculated from the formula (W ₁ -W ₀ )/W ₀ ×100. Furthermore, the average particle size is a value calculated from the results of measuring the specific surface area by an air permeation method according to JIS M-8511.

The method for producing the vitreous foam used as the fertilizer of the present invention is not particularly limited, but for example, it can be produced as follows.

Glass raw materials are various waste glasses. Examples include discarded glass bottles, plate glass, window glass, television and computer front glass panels, and scrap from glassware factories. These waste materials include soda-lime glass, borosilicate glass, borosilicate glass, crystal glass, etc. when viewed as vitreous. , glass bottles, plate glass, and window glass waste are the major ones, are easy to collect, and are available in large quantities, which is advantageous.

It is obtained by pulverizing such waste glass, adding a foaming agent thereto, and firing at a temperature higher than the melting point of glass, preferably at 880°C. As the foaming agent, silicon carbide (SiC), calcium carbonate (CaCO ₃ ), aluminum nitride (AlN), Al ash, etc. can be used. About 1 to 3% by weight is suitable.

More specifically, the manufacturing method thereof will be described with a preferred example. First, waste glass raw materials are crushed using a commercially available glass crusher, for example, an impact crusher such as a hammer mill, and the crushed material is sieved. Mixed glass powder containing 96% or more of coarsely ground glass powder having a particle size distribution of 0.21 mm or more and 2.38 mm or less and 4% or less of fine glass powder having a particle size distribution of less than 0.21 mm is used as a raw material. Although the particle size distribution of the coarsely ground glass powder can be varied, it is preferable to use an average particle size of about 0.5 mm or more.

Coarsely ground glass powder having a particle size exceeding 2.38 mm is ground again and sieved into coarsely ground glass powder and finely ground glass powder within the above particle size distribution range for use. The reason why the upper limit of the particle size distribution of the coarsely pulverized glass powder is set to 2.38 mm is that if glass powder with a particle size exceeding 2.38 mm is used as a raw material, it tends to remain as it is in the product, resulting in a uniform particle size. This is because a foam structure cannot be obtained.

As described above, since the coarsely ground glass powder having a size of 0.21 mm or more accounts for the majority of the mixed glass powder, it is possible to obtain a raw material for grinding at a low cost using a relatively inexpensive grinder capable of coarsely grinding glass waste materials. There is no need to use expensive pulverizers such as ball mills or Reynolds mills that pulverize everything to 0.2 mm or less.

Inorganic incombustible materials such as ceramic pieces, porcelain pieces, metals, soil, sand, gravel, etc., and contaminants such as plastics, paper, wood pieces, etc. mixed in with waste glass raw materials are removed in advance as much as possible. However, as long as it does not affect the production of the vitreous foam for the fertilizer of the present invention, it may be mixed in a very small amount.

As described above, the vitreous blended powder obtained by blending the coarsely ground glass powder with a small amount of the finely ground glass powder is prepared, for example, by not mixing the finely ground glass powder having a particle size of less than 0.21 mm. When only coarsely ground glass powder having a particle size distribution with a diameter of 2 mm or less is used as a raw material and fired by heating, voids formed by being surrounded by coarse particles that are in contact with each other at room temperature before heating are poor in sinterability of the coarse particles. At a sintering temperature of 500 to 600° C., the coarse particles are not yet sintered sufficiently to form closed pores, and during this time the gas generated from the coarse particles escapes to the outside. After that, at a sintering temperature of 700° C., sintering between the coarse particles is sufficiently carried out and the voids are closed to form independent pores, which are very small in size. Furthermore, when the firing temperature is raised to 700° C. or more, the amount of gas in the independent pores is already small, so the pores do not become large and remain small, and large independent pores cannot be obtained. On the other hand, if the heat firing is performed in a state in which the fine crushed glass powder of 0.2 mm or less is interposed between the coarse glass powders of about 2 mm, fine particles are interposed between the coarse particles at room temperature before heating. The relatively large voids that are formed make it easy for the fine particles to be sintered at a sintering temperature of 500 to 600°C. When sintered together, the voids are closed, creating a surrounding wall and creating large closed pores within which the gases generated by these particles are trapped. Sintering at a higher temperature of 700°C further promotes softening sintering, and the coarse grains are fused to form a well-fused wall surrounding the independent pores, thereby enveloping the independent pores and maintaining a large diameter. do. If the temperature is further raised to 700° C. or higher, the gas in the closed pores expands, and thus the closed pores expand, resulting in a foamed glass body that is extremely lightweight and has low water absorption.

0.1 to 3% by weight of silicon carbide is added to the vitreous mixed powder blended as described above to prepare a mixed powder, which is heated to the softening point of the glass or higher at the above firing temperature of 500. ° C or higher, heated as described above, fired at least at 700 ° C or higher, and then cooled by rapid cooling or slow cooling to create countless large closed cells covered with tough vitreous walls. A vitreous foam having a bulk specific gravity of 0.3 to 0.6 g/cm ³ , particularly 0.4 to 0.5 g/cm ³ and a water absorption of 30 to 35% is obtained. Silicon carbide is usually produced from silica sand mainly composed of coke and silicon oxide, but the silicon carbide used for this purpose does not necessarily have to be sufficiently refined. For example, it may have a purity of about 85%, or it may be recovered as a fine powder with a bag filter or the like during production. The reason why the added amount of silicon carbide is limited to 0.1 to 3% by weight with respect to the mixed glass powder is that if the added amount is less than 0.1% by weight, the bulk specific gravity is 0.3 to 0.6 g/cm. ³ and it becomes difficult to make a product with sufficient lightweight properties. On the other hand, even if the added amount exceeds 3% by weight, it is possible to produce a product having sufficient light weight characteristics, but the unit price of the product becomes expensive, which is not preferable. Further, the blended glass powder and the glass are heated and sintered at a temperature higher than the softening point of the glass. In the case of soda-lime glass, the temperature is generally 750°C or higher, and a particularly preferred temperature range is 840-980°C. For example, the time required to raise the temperature to 900° C. depends on the thickness of the layer to be processed, but is preferably about 10 minutes if the thickness is 10 mm, and about 20 minutes if the thickness is 20 mm. As for the high-temperature holding time after reaching the maximum temperature, the lower the maximum temperature, the longer the holding time, and conversely, the higher the maximum temperature, the shorter the holding time. For example, the retention time is generally in the range of 30-0 minutes. Here, 0 minutes means cooling as soon as the maximum temperature is reached. A long holding time of 30 minutes or more is not preferable from the viewpoint of manufacturing costs. If the mixed glass powder contains a large amount of water, the above temperature should be raised after the water is completely evaporated at around 200°C.

The above-mentioned mixed glass powder can be formed into plate-shaped molded articles such as bricks and wall materials by placing it in a predetermined forming mold, heating and firing it, and then slowly cooling it. It is obtained as countless granules that are cracked and broken into irregular masses, for example, amorphous mass vitreous foams with a particle size of 10 to 60 mm. In addition, when making a molded product having a certain shape, such as a brick shape, a plate shape, or any other shape, the product is gradually cooled to 200° C. after the above-mentioned high temperature holding time. In this case, the cooling rate is preferably as slow as possible, most preferably about 2°C/min.
The production method can be either a batch method or a continuous method.

(Method for producing cultivated plants)
The method for producing a cultivated plant of the present invention is characterized in that the fertilizer containing the above-mentioned vitreous foamed sintered body is placed in the vicinity of the root of the plant in the soil or hydroponics of monocotyledonous plants. It is something to do.

The target monocotyledonous plant is not particularly limited. Specifically, for example, rice (Oryza sativa), corn (Zea mays), barley (Hordeum vulgare), wheat (Triticum aestivum), rye (Secale cereale), pearl barley (Coix lacryma-jobi var. ma-yuen), Bamboo (Phyllostachys), Sugarcane (Saccharum officinarum), Foxtail (Setaria italica), Japanese barnyard (Echinochloa esculenta), Sorghum (Sorghum bicolor), Napier grass (Pennisetum pupureum), Erianthus (Erianthus ravenae), Miscanthus (Miscanthus) virgatum), sorghum, switchgrass (Panicum), oat (Avena fatua); nucifera), date palm (Phoenix dactylifera), wax palm (Copernicia), and the like, but are not limited to these. Among these, it is particularly preferable for Poaceae plants because excellent effects can be expected.

The fertilization method, timing and amount of the vitreous foamed sintered body for monocotyledonous plants are not particularly limited. It is acceptable as long as the eluate from the vitreous foamed calcined body, especially the metasilicate ion, can reliably migrate into the moisture absorbed by the roots of the target plant. It can be placed in a site, and in hydroponics, it can be placed in the vicinity of the root of the plant or at least in contact with the water supply route to the root of the plant. Further, in the cultivation of plants, the above-mentioned vitreous foamed sintered body can be used as base fertilizer or top dressing. In any case, it is desirable to allow the vitreous foamed sintered body to exist during the growing period of the plant, for example, during the period including the tillering period in the case of paddy field cultivation of rice. Furthermore, the amount used is also not particularly limited because it depends on the target plant species, cultivation method, etc., but typically, for example, about 2 to 3 kg is supplied per 1 m ² of the cultivation area. A good yield increasing effect can be expected.

Note that, for example, in paddy field cultivation, when the fertilizer according to the present invention is applied to the soil, the metasilicate ion (SiO ₃ ²⁻ ) concentration in paddy water typically reaches a significant level in about 3 days. Changes have occurred, and it seems that the same is happening in the case of soil cultivation.

Furthermore, in growing plants, particularly monocotyledonous plants and gramineous plants, the concentration of metasilicate ions (SiO ₃ ²⁻ ) in the water supplied to the roots of the plants is controlled so as to be maintained at a predetermined level or higher. can promote plant growth and increase seed or fruit yield.

The optimum concentration of metasilicate ions (SiO ₃ ²⁻ ) is thought to vary to some extent depending on the type of plant, so it cannot be defined unconditionally. Although it seems that it can be determined relatively easily by cultivating in several test plots, typically, for example, in paddy field hydroponics of rice, the metasilicate ion (SiO ₃ ^2- ) concentration in water is 20 to 25 mg/L in the soil culture of wheat, the metasilicate ion (SiO ₃ ²⁻ ) concentration in the water is 20 to 25 mg/L in the soil culture of corn wheat, metasilicic acid in the water By setting the ion (SiO ₃ ²⁻ ) concentration to 20 to 25 mg/L, a significant increase in yield can be expected.

In addition, the period for maintaining such a metasilicate ion (SiO ₃ ²⁻ ) concentration at a predetermined amount or more is not particularly limited, and can be appropriately selected according to the growth period of each plant, but at least 60 days or more. It is desirable to establish a continuous period of

Hereinafter, the present invention will be described more specifically based on specific examples. The examples shown below are disclosed only for the purpose of facilitating the understanding of the content of the present invention, and the present invention is not limited to the content of these examples. do not have.

Synthesis Example Waste glass raw materials, mainly waste bottles, are sufficiently washed and dried, then pulverized using a hammer mill, and the particle size distribution of 0.21 mm or more and 2.38 mm or less obtained by sieving the pulverized material is determined. 96% by mass of coarsely pulverized glass powder having a particle size distribution of less than 0.21 mm and 4% by mass or less of fine glass powder having a particle size distribution of less than 0.21 mm. A mixed powder was prepared by adding and mixing 3% by mass of silicon carbide to this blended glass powder. This mixed powder was heated to 880° C. and cooled to room temperature in the atmosphere to obtain an irregular bulk vitreous foamed sintered body having a particle size of 10 to 60 mm.
This product has a _bulk specific gravity of _{0.3 g} /cm ³ and a water absorption rate of 30%. .98 wt%, MgO 0.42 wt% _{, Al2O3} 1.57 wt%, C 0.4 wt%, balance 0.53 wt%.

Example 1
About 1,620 g of commercially available black soil in terms of dry weight was placed in a pot without a hole in the bottom, and 180 g of the vitreous foamed sintered body obtained in the above synthesis example was evenly sprinkled on the bottom of the pot. Then, city water was used as irrigation water, and water was added so that the water depth was about 5 cm. After supplying the vitreous foamed sintered body to the soil, Koshihikari seedlings were planted and rice was grown according to the usual paddy field cultivation method. During the cultivation period, the water in the pots was appropriately replenished with the same city water to maintain substantially the same water depth.

After 180 days from the planting of rice, when the ear of rice matured, cultivation was finished, and the degree of maturity of the rice was observed externally. Concentration was measured. The silicon concentration in the plant body was measured by the nitric acid decomposition weight method. The results obtained are shown in FIGS. 1 to 4, respectively.

In addition, the ion concentration in the paddy water of the example plot was measured 60 days after the start of cultivation for both the pots in which the seedlings were not planted and the pots in which the seedlings were planted. In addition, the measurement after 60 days was performed after 7 days had passed since the last replenishment of water to the example plot. Also, regarding the pots in which the seedlings were not planted, the water in the pots was replenished in the same cycle as the pots in which the seedlings were planted. FIG. 6 shows the SO ₃ ^2- ion concentration among the measured ion concentrations.

Furthermore, rice plants raised for 14 days were collected, and the degree of expression of Lsi transcripts in the individuals was examined by RT-PCR using rice Lsi gene-specific primers. The primer sequences are FW: 5'-GAGAACAAAACTCCAGGGCGA-3', RV: 5'-CGAGCGTGACGAACATCATG-3'. The results obtained are shown in FIG. This measurement was performed by a procedure called ethidium bromide staining.

Comparative example 1
For comparison, Koshihikari was cultivated in the same manner as in Example 1 except that the vitreous foamed sintered body was not mixed with the soil and an equal amount of soil was added. The degree of maturity of rice was observed externally, the mass of individual plants was measured, the yield of brown rice was measured, the silicon concentration in the plant was measured, and differences from Example 1 were observed. The results obtained are shown in FIGS. 1 to 4, respectively.

In addition, the ion concentration in the paddy water was measured 60 days after the start of cultivation for both the pots in which the seedlings were not planted and the pots in which the seedlings were planted. In addition, the measurement after 60 days was performed after 7 days had passed since the last replenishment of water to the comparative plot. As in the case of the above example plot, the water in the pots without seedlings was replenished in the same cycle as the pots with seedlings. FIG. 6 shows the SO ₃ ^2- ion concentration among the measured ion concentrations.

Furthermore, rice plants raised for 14 days were collected, and the degree of Lsi protein expression in the individuals concerned was examined by RT-PCR method. The results obtained are shown in FIG.

(Experimental result)
As a result, as shown in FIG. 1, the growth of the cultivated rice plants in Example 1 was clearly better in terms of leaf attachment, rice ear attachment, etc., and as shown in FIG. As shown in FIG. 4, the yield of brown rice in particular was increased by 208% compared to the comparative example.

On the other hand, as shown in FIG. 2, the silicon concentration in the plant is not much different in Example 1 from that in Comparative Example 1, and on the contrary, it is slightly lower. The results showed that the degree of silicon accumulation in rice grains was not directly related to the increase in brown rice yield and the improvement of plant growth.

Here, as shown in FIG. 6, when looking at the SiO ₃ ^2- ion concentration in the paddy water during the rice cultivation period, the metasilicate ion (SiO ₃ ^2- ) concentration in the water was higher than that of the seedlings not planted. is slightly higher in the experimental plot than in the control plot, and there is not much difference, but in the planted seedlings, the concentration decreased significantly in the control plot during the vegetative growth period. observed. Furthermore, at that time, as shown in FIG. 7, in the comparative example, it was observed that the expression of the Lsi gene was promoted in rice, whereas in the experimental plot where seedlings were planted, no seedlings were planted. Although the concentration was slightly lower than that in the experimental plot, the concentration did not change so much, and as shown in FIG. 7, it was observed that the expression of the Lsi gene was also suppressed in rice. From this, it can be ^{concluded that, in the example group, SiO 2-} _{ions were} stably and continuously supplied as silicon content from the vitreous foam to the water throughout the rice cultivation period ^. It was considered that ions were taken into the body, which promoted growth, increased the amount of photosynthesis, and consequently greatly improved the yield of seeds or fruits. On the other hand, in the comparative plot, the supply of SiO 3 2- ions from the soil could not keep up with the amount of SiO ₃ ^2- ions taken into the body by the rice plants from the water throughout the rice cultivation period, and the ions were nearly deficient in the later stage of cultivation. As a result, it was considered that no further improvement in growth could be seen.

Example 2 and Comparative Example 2
Rice was cultivated in the same manner as in Example 1 and Comparative Example 1, except that the rice variety to be cultivated was changed from Koshihikari to Hitomebore, and the brown rice yield of each individual was measured. The results obtained are shown in FIG.
As shown in FIG. 5, even if the rice variety is changed, in Example 2 according to the present invention, the yield is higher than in Comparative Example 2, as in the comparison results of Example 1 and Comparative Example 1. was done.

Example 3 and Comparative Example 3
About 1,620 g of commercially available black soil in terms of dry weight was placed in a pot having a hole at the bottom, and 180 g of the vitreous foamed sintered body obtained in the above synthesis example was evenly spread on the bottom of the pot. After supplying the vitreous foamed sintered body to the soil, about 500 ml of city water was supplied at intervals of 7 days. Of the supplied water, the amount of water not retained in the soil drained from the bottom of the pot in about 1 minute.
After disposing the vitreous foamed sintered body, wheat seedlings were planted, and thereafter, the wheat was cultivated for 90 days while being watered according to the above cycle (Example 3). After the cultivation period was over, the degree of growth of wheat was visually observed. The results obtained are shown in FIG.
On the other hand, for comparison, wheat was cultivated in the same manner as in Example 3, except that the vitreous foam sintered body was not mixed with the soil and an equal amount of soil was added. finished (Comparative Example 3). After the cultivation period was over, the degree of growth of wheat was visually observed. The results obtained are shown in FIG.

As is clear from the results shown in FIG. 8, in Example 3, in which the vitreous foamed sintered body according to the present invention was placed in the soil, the growth rate of wheat was significantly accelerated compared to Comparative Example 3. was seen.

Example 4 and Comparative Example 4
About 1,620 g of commercially available black soil in terms of dry weight was placed in a pot having a hole at the bottom, and 180 g of the vitreous foamed sintered body obtained in the above synthesis example was evenly spread on the bottom of the pot. After supplying the vitreous foamed sintered body to the soil, about 500 ml of city water was supplied at intervals of 7 days. Of the supplied water, the amount of water not retained in the soil drained from the bottom of the pot in about 1 minute.
After disposing the vitreous foamed sintered body, corn seedlings were planted, and thereafter, corn was cultivated for 90 days while watering according to the above cycle (Example 3). After the cultivation period was over, the degree of growth of the corn was visually observed. The results obtained are shown in FIG.
On the other hand, for comparison, corn was cultivated in the same manner as in Example 4 except that the vitreous foamed sintered body was not mixed with the soil and the same amount of soil was supplemented, and cultivated for the same period as in Example 4. finished (Comparative Example 4). After the cultivation period was over, the degree of growth of the corn was visually observed. The results obtained are shown in FIG.

As is clear from the results shown in FIG. 9, in Example 4, in which the vitreous foamed sintered body according to the present invention was placed in the soil, the growth rate of corn was remarkably accelerated compared to Comparative Example 4. was seen.

Claims (10)

A fertilizer comprising a vitreous foamed sintered body exhibiting metasilicate ion (SiO ₃ ²⁻ ) elution in water and having an average particle diameter in the range of 10 to 60 mm. A fertilizer comprising a vitreous foamed sintered body,
The vitreous foamed sintered body has an average particle diameter in the range of 10 to 60 mm, and 100 g of the vitreous foamed sintered body is placed in 1 liter of water and stored statically for 3 days. A fertilizer having a (SiO ₃ ²⁻ ) concentration of 25 mg/L or more and exhibiting a metasilicate ion (SiO ₃ ²⁻ ) elution property in water. 3. A metasilicate ion (SiO ₃ ²⁻ ) concentration of 50 mg/L or more when 100 g of the vitreous foamed sintered body is placed in 1 liter of water and left to stand for 14 days, is 50 mg/L or more. fertilizer. 4. A method for producing a cultivated plant, wherein the fertilizer according to any one of claims 1 to 3 is placed in the vicinity of the root of the cultivated plant in soil culture or hydroponics of the cultivated plant. A method for producing the fertilizer according to any one of claims 1 to 3,
0.1 to 3% by mass of a foaming agent is added to a glass pulverization raw material obtained by pulverizing a glass pulverization raw material containing 65.0% by mass or more of SiO ₂ with respect to 100% by mass of the glass pulverization raw material to obtain the glass. A step of mixing the pulverized raw material and the foaming agent to prepare a mixed powder;
a sintering and foaming step of heating the mixed powder at a softening point or higher of the glass pulverization raw material;
and a cooling step to obtain a vitreous foamed sintered body by cooling after the sintering and foaming step. 6. The method for producing a fertilizer according to claim 5, wherein the cooling in the cooling step is quenched to obtain a plurality of vitreous foamed sintered bodies having a particle size of 10 to 60 mm. The method for producing a fertilizer according to claim 5 or 6, wherein the frit is soda-lime glass. The glass raw material contains 65.0 to 75.0% by mass of SiO ₂ , 7.0 to 15.0% by mass of CaO, 10.0 to 16.0% by mass of Na ₂ O, and 0 to 0% by mass of K ₂ O. 3.5% by mass, 0 to 4.5% by mass of MgO, 0 to 2.5% by mass of Al ₂ O ₃ , 0 to 2% by mass of C, and less than 3% by mass of other components. Item 7. A method for producing a fertilizer according to Item 5 or 6. The fertilizer according to any one of claims 1 to 3 is placed in the soil or on the surface of the ground in the case of soil culture of cultivated plants, and in the case of hydroponics of cultivated plants, the cultivated plants or at least a position in contact with the water supply route to the root of the cultivated plant, and the metasilicate ion (SiO ₃ ^2- ) concentration at the position near the root of the cultivated plant is measured. A method for promoting the growth of cultivated plants, characterized by adjusting. 10. The method for promoting the growth of cultivated plants according to claim 9, wherein the concentration of metasilicate ions (SiO ₃ ^2- ) in water given to the cultivated plants is maintained at 20 mg/L or more.

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