JP6037807B2 - Plant growth promoter - Google Patents

Description

  The present invention provides a plant growth promoter containing a large amount of soluble silica that is inexpensive, has a low environmental impact, and is effective for plant growth, and a method for producing the same. Here, hereinafter, “soluble silica” represents monosilicic acid and polysilicic acid having a polymerization degree of 2 to 8.

  In recent years, the United Nations has reported that the Earth is heading for food and environmental crises due to population growth and water resources issues, and the view that improving agricultural technology is indispensable to solve these problems. Indicated. Even in Japan, where water resources are abundant, this is not an exception, and more efficient and less environmental impact crop and plant growing methods are desired.

  Fertilizer is an important factor that increases the growth efficiency in plant growth, and contains N, P, K, Ca, Mg, S, Fe, Mn, B, Zn, Mo, Cu, Cl, which are essential elements of plants Many chemical fertilizers have been proposed. While these chemical fertilizers have a great effect on plant growth, there are problems with environmental load such as acidification of soil due to overuse and the occurrence of red sea urchins and red tides due to runoff into rivers.

  Therefore, Si has been attracting attention as an element that has little environmental impact and has an effect of promoting plant growth. Si is known as a useful component that helps plant growth, and has been recognized as effective in strengthening plant cell walls, promoting photosynthesis, activating roots, improving lodging resistance, and increasing resistance to disease and insect damage. Yes. Si is universally present in natural water as silicic acid, has a low environmental load, and is harmless even if contained in food and drinking water. Furthermore, the amount of Si crustal reserves is the second largest after oxygen, and the cost performance is very high. From these characteristics, various plant growth promoters containing Si, such as Patent Document 1 or Patent Document 2, have been proposed.

According to Non-Patent Document 1, it has been reported that the form of a silicon compound in which plants are most likely to absorb Si is monosilicate Si (OH) ₄ , and the monosilicate is an equilibrium represented by the following formula [1] from polysilicate. Produced by reaction.

According to Non-Patent Document 2 and Non-Patent Document 3, the solubility of polysilicic acid varies depending on the pH and particle size, and the solubility increases when the pH is 9 or more. When the pH is the same, the smaller the particle size, the higher the solubility. Reported to be higher. Further, according to Non-Patent Document 4, the amount is increased or decreased depending on the type and concentration of the coexisting salts. Patent Document 3 proposes a method for producing an aqueous silicic acid solution containing 100 ppm or more of monosilicic acid in terms of SiO ₂ by adjusting the type and molar ratio of the coexisting salt. However, in this method, when the silicic acid concentration is increased, the silicic acid does not dissolve and settles, so it is recommended to use it in the range of 100 to 300 ppm, and there is a problem that it cannot be used at a high concentration. On the other hand, Patent Document 4 proposes a plant growth promoter that regulates the size of the silica colloid particles contained in the plant growth promoter, thereby suppressing sedimentation of the particles and increasing the solubility of silicic acid. It can be used at a solid content concentration of 10,000 ppm or less. However, the plant growth promotion effect is not always satisfactory, and even if the particle size is reduced to increase the growth promotion effect and the solubility is increased, the colloidal solution is unstable and gelled when the average particle size is 3 nm or less. There was a problem that the absorption into the plant worsened.

JP 2009-73771 A JP 2005-67996 A Japanese Patent Laid-Open No. 7-69964 JP-A-8-81317

Published by Eiichi Takahashi, “Soil Fertilizer Science Magazine”, Volume 49, No. 5, p.357, 1978 Published by M.E.Nordberg "Journal of the American Ceramic Society" Vol.41, p.517, 1958 "The Journal of Physical Chemistry" by G.B.Alexamder, Vol.61, p.1563, published in 1957

  An object of the present invention is to provide a plant growth promoter that has a low environmental load, is inexpensive, and has a high plant growth promoting effect.

  As a result of intensive efforts to solve the above problems, the present inventors have found that soluble silica having a small particle size and high solubility is present in an amount of 10 to 80% by mass based on the total amount of silica, and further monosilicic acid is present relative to the soluble silica. It has been found that a significant plant growth promoting effect can be obtained by allowing a silica sol that is stably present at 30 to 80% by mass to act on plants, and the present invention has been completed.

  ADVANTAGE OF THE INVENTION According to this invention, the plant growth promoter with a high plant growth effect, such as reinforcement | strengthening of the cell wall of a plant, acceleration | stimulation of photosynthesis, activation of a root, improvement of lodging resistance, and resistance to a disease and insect damage, is provided. .

The plant growth promoter in the present invention is a silica sol (silica fine particle concentration of 10 to 40% by mass) in which silica fine particles are dispersed in a dispersion medium, and is based on the total silica amount (SiO ₂ equivalent) of the silica fine particles. The soluble silica contains 10 to 80% by mass in terms of SiO ₂ , and the soluble silica is composed of monosilicic acid and polysilicic acid having a polymerization degree of 2 to 8, and the total amount of the soluble silica (in terms of SiO ₂ ) the monosilicic acid is intended, characterized by containing 30 to 80 wt% in terms of SiO _2.

  The plant is preferably a gramineous plant, and in particular, a turfaceous plant.

  For example, water such as pure water, ultrapure water, or ion exchange water is preferably used as the dispersion medium. When the dispersion medium contains an organic substance such as an organic solvent or a chelating agent, for example, when used in a paddy field, the BOD may increase.

The concentration of the silica fine particles contained in the silica sol is 10 to 40% by mass, preferably 20 to 40% by mass in terms of SiO ₂ . When the solid content concentration is less than 10% by mass, the storage container becomes large and the transportation cost becomes high, which is not practical. In addition, when the solid content concentration exceeds 40% by mass, the silica fine particles are polymerized, and precipitates and gels are easily generated during storage, and there is a problem that scales are easily formed during drying.

Non-Patent Document 1 shows that monosilicic acid contained in the silica sol is Si (OH) ₄ , which is a form of a silicon compound that is most easily absorbed by plants. In this invention, it is 30-80 mass% with respect to the whole quantity of a soluble silica component, Preferably it is in the range of 40-80 mass%. If the monosilicic acid content is too low, the absorption of Si into the plant becomes poor, so that the expected growth promoting effect of the plant cannot be obtained. On the other hand, if the content of monosilicic acid is too high, silica fine particles are polymerized and precipitates and gels are easily generated, which is not preferable.

Soluble silica contained in the silica sol is composed of monosilicic acid and polysilicic acid having a polymerization degree of 2 to 8. In the present invention, the silicon compound that the plant is most likely to absorb Si is monosilicic acid, which is produced by an equilibrium reaction represented by the formula [1]. This equilibrium reaction is a reaction that requires water, and the reaction takes place from the portion where the silica fine particles and water are in contact with each other. Therefore, the silica fine particles preferably have a small particle size and a large surface area. That is, a silica sol containing a large amount of silica fine particles having a small particle diameter easily produces monosilicic acid and is effective as a plant growth promoter. The particle diameter of the silica fine particles becomes smaller as the degree of polymerization of polysilicic acid becomes smaller, and monosilicic acid can be efficiently generated by containing many particles having a small degree of polymerization of polysilicic acid. On the other hand, if the degree of polymerization of the polysilicic acid is too large, the particle diameter increases as the degree of polymerization increases, which is not preferable because monosilicic acid cannot be efficiently generated. However, it is difficult to detect particles having a small degree of polymerization by a general particle size distribution measurement method such as a dynamic light scattering method or a laser diffraction method. Detected by the method.
The soluble silica contained in the silica sol is preferably in the range of 10 to 80% by mass, and preferably in the range of 50 to 80% by mass, based on the total amount of silica in the silica fine particles. If the soluble silica component is too low, the amount of monosilicic acid produced is reduced. When the amount of monosilicic acid decreases, the absorption of Si into the plant is deteriorated, so that the expected growth promoting effect of the plant cannot be obtained. On the other hand, if the soluble silica component is too high, there is a problem that silica fine particles are polymerized and precipitates and gels are easily generated, which is not preferable.

  The silica sol can be prepared by hydrothermally treating a slurry obtained by mixing silica powder and silicate in an aqueous solvent, and performing ion exchange and concentration as necessary. The hydrothermal treatment is preferably performed at 130 to 150 ° C.

  The silica powder is preferably fumed silica. Hydrophobic fumed silica is particularly preferable, and AEROSIL (registered trademark): RX300 is preferable.

  The silicate is preferably a highly soluble substance, and lithium silicate, sodium silicate, sodium metasilicate, potassium silicate, and the like are preferable.

The silica sol can be prepared by various methods in addition to the production method, but can be used in the present invention as long as it can produce a silica sol that satisfies the predetermined requirements. Typically, the following production methods can be mentioned.
1) A silicate solution obtained by dealkalizing a water-soluble silicate selected from alkali metal silicate, tertiary ammonium silicate, quaternary ammonium silicate or guanidine silicate is alkalinized. A method for producing a silica sol comprising a step of polymerizing silicic acid by heating in the presence.
2) A method for producing a silica sol, comprising washing a silica hydrogel obtained by neutralizing a silicate with an acid to remove salts, adding an alkali, and then heating the silica hydrogel by heating.
3) A method for producing a silica sol, comprising a step of hydrothermally treating a slurry obtained by mixing fumed silica and silicate in an aqueous solvent.
In addition, if it is a commercially available silica sol and the silica sol satisfy | fills the said predetermined requirement, it can be used for this invention.

  In this invention, a fertilizer component can be mixed or used together with a plant growth promoter.

  The fertilizer component is an inorganic or organic substance that is a source of N, P, K, Ca, O, H, C, Mg, S, Fe, Mn, B, Zn, Mo, Cu, and Cl, which are essential elements of plants. Can be used. Examples of such inorganic substances include ammonium sulfate, ammonium chloride, urea, ammonium nitrate, ammonium phosphate, sodium nitrate, lime nitrogen, superphosphate lime, heavy superphosphate, molten phosphorus fertilizer, calcined phosphorus fertilizer, potassium chloride, Examples include potassium sulfate, potassium phosphate, potassium silicate, magnesium sulfate, magnesium nitrate, and magnesium chloride, but the substance is not particularly limited. Examples of the organic substance include chicken dung, cow dung, bark compost, peptone, Mieki, fermented extract, calcium salt of organic acid, and the like, but the substance is not particularly limited. By mixing or using in combination with these fertilizer components, a more prominent plant growth effect can be obtained.

The above-mentioned plant growth promoter may be used after planting a plant after adding an appropriate amount to the soil and mixing well, or may be used directly on the root of the plant. Moreover, it can also use together with the above-mentioned fertilizer component in that case. The amount of application is desirably about 0.5 g / m ^{2 with} respect to the medium.

  The aforementioned plant growth promoter can be used after diluting with water to an appropriate solid content concentration. The solid content concentration of the commercially available silica sol is usually 10 to 60% by mass, but in the case of the plant growth promoter of the present invention, the solid content concentration is 1% by mass or less, preferably 0.01 to 0%. It is preferable to use it diluted with water in the range of 0.5 mass%.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated in detail, this invention is not limited to these Examples.

  Methods for analysis or quantification in Examples and Comparative Examples are shown below.

[Silica fine particle concentration measurement method]
2 ml of a 50% by volume sulfuric acid aqueous solution is added to 10 g of silica sol, evaporated to dryness on a platinum dish, and the obtained solid content is baked at 1000 ° C. for 1 hour, then cooled and weighed. Next, the weighed solid is dissolved in a small amount of 50% by volume sulfuric acid solution, and further 20 ml of hydrofluoric acid is added, and then evaporated to dryness on a platinum dish, baked at 1000 ° C. for 15 minutes, and then cooled. Weigh. The concentration of the silica fine particles in the silica sol was determined from these weight differences.

[Method for measuring soluble silica content and monosilicic acid content]
After adding 6 ml of methanol dehydrated with CaO to 3 ml of trimethylsilyl and stirring, 9 ml of hexamethyldisiloxane was added and stirred for 5 minutes. While maintaining stirring, 100 ml of silica sol was added and stirred for 20 minutes or more. The entire amount of the prepared sample was collected and the supernatant was separated. Then, 2 g of ion exchange resin (Amberlite 15 (registered trademark)) was added and stirred for 1.5 hours. The ion exchange resin was separated from the obtained sample, washed with water, added again with 2 g of the same ion exchange resin, and stirred for 1.5 hours. The ion exchange resin was separated from the obtained sample and used as a sample for gas chromatography.
Next, the sample was analyzed using a gas chromatograph mass spectrometer using a flame ionization detector as a detector. The column used was a 2 mm diameter, 1 m long stainless steel tube filled with Dexsil 400 (registered trademark) and Chromosolv W as fillers, the carrier gas used argon, and the temperature of the sample inlet and detector was 400 ° C. Set to. The column temperature was analyzed while increasing the temperature from 70 ° C. to 350 ° C. at a rate of 0.125 ° C./s.
As a result of the analysis, the peaks of monosilicic acid and soluble silica are assigned from the detection temperature and mass-to-charge ratio m / e in Table 1, and the ratio of each peak area is obtained from the total area of all obtained peaks. The amount of monosilicic acid and the amount of soluble silica were calculated.

  Using the values obtained from [Method for measuring concentration of silica fine particles] and [Method for measuring amount of soluble silica and amount of monosilicic acid], the values of soluble silica amount / total silica amount and monosilicic acid amount / soluble silica amount were calculated.

  The following examples illustrate the present invention more specifically.

[Example 1]
[Preparation of spray liquid]
995 g of water was mixed with 70 g of commercially available silica powder (AEROSIL (registered trademark): RX300), 100 g of sodium metasilicate and 5 g of sodium hydroxide to prepare a solution having a SiO ₂ equivalent concentration of 8.3 mass%. This solution was heated at 150 ° C. for 5 hours, and concentrated with a vacuum evaporator until the SiO ₂ equivalent concentration became 40% by mass, to obtain a plant growth promoter. As a result of measuring the soluble silica component content and the monosilicic acid content for 100 g of the plant growth promoter, the total silica content was 40 g, the soluble silica content was 31.7 g, and the monosilicic acid content in the soluble silica content was 15 0.5 g. Moreover, although the silica sol was stored at room temperature for 60 days, no precipitate was formed or gelled. 50 g of the silica sol and 12 g of fertilizer (trademark: fine powder Hyponex) were mixed with 5938 g of water to obtain a spray solution.

[Plant growth test]
Bent turf stocks were cut and planted in a medium consisting of upland soil. On the day when the turf was planted, the spray solution was sprayed so that the amount of SiO ₂ sprayed was 0.5 g / m ^{2 on} the grass of each medium. 30 days after the planting date, only water was sprayed once a day except that the sprayed liquid fertilizer was sprayed again.

[Confirmation of training effect]
The amount of bent turf grown as described above was measured 60 days after the date of turf planting. In the measurement, first, 10 pieces of 10 cm × 10 cm turf were cut out, and the attached matter was washed and removed, and the plant height and root length of the above-ground part were measured. Subsequently, after drying at room temperature all day, the leaf part and the root part were separated, and the respective weights were measured. Further, after the separated leaf and root were dissolved in acid, the Si content was measured by inductively coupled plasma emission spectrometry. Each measurement result is shown in Table 1. Each measured value is an average value.

[Example 2]
995 g of water was mixed with 70 g of commercially available silica powder (AEROSIL (registered trademark): RX300), 100 g of sodium metasilicate and 5 g of sodium hydroxide to prepare a solution having a SiO ₂ equivalent concentration of 8.3 mass%. This solution was heated at 150 ° C. for 5 hours, and concentrated with a vacuum evaporator until the SiO ₂ equivalent concentration became 20% by mass to obtain silica sol. As a result of measuring the soluble silica component content and the monosilicic acid content for 100 g of the silica sol, the total silica amount was 20 g, the soluble silica amount was 15.7 g, and the monosilicic acid amount in the soluble silica amount was 7.5 g. It was. Moreover, although the silica sol was stored at room temperature for 60 days, no precipitate was formed or gelled. 150 g of the silica sol and 12 g of fertilizer (trademark: fine powder Hyponex) were mixed with 5838 g of water to obtain a spray solution. [Plant growth test] and [Confirmation of growth effect] were carried out under the same conditions as in Example 1.

[Example 3]
70 g of commercially available silica powder (AEROSIL (registered trademark): RX300) and 100 g of sodium metasilicate were mixed with 1000 g of water to prepare a solution having a SiO ₂ equivalent concentration of 8.3 mass%. This solution was heated at 150 ° C. for 5 hours, and concentrated with a vacuum evaporator until the SiO ₂ equivalent concentration became 20% by mass to obtain silica sol. As a result of measuring the soluble silica component content and the monosilicic acid content for 100 g of the silica sol, the total silica amount was 20 g, the soluble silica amount was 11.0 g, and the monosilicic acid amount in the soluble silica amount was 5.1 g. there were. Moreover, although the silica sol was stored at room temperature for 60 days, no precipitate was formed or gelled. 150 g of the silica sol and 12 g of fertilizer (trademark: fine powder Hyponex) were mixed with 5838 g of water to obtain a spray solution. [Plant growth test] and [Confirmation of growth effect] were carried out under the same conditions as in Example 1.

[Example 4]
40 g of commercially available silica powder (AEROSIL (registered trademark): RX300) and 160 g of sodium metasilicate were mixed with 1000 g of water to prepare a solution having a SiO ₂ equivalent concentration of 8.3 mass%. This solution was heated at 150 ° C. for 5 hours, and concentrated with a vacuum evaporator until the SiO ₂ equivalent concentration became 20% by mass to obtain silica sol. As a result of measuring the soluble silica component content and the monosilicic acid content for 100 g of the silica sol, the total silica amount was 20 g, the soluble silica amount was 12.2 g, and the monosilicic acid amount in the soluble silica amount was 9.5 g. It was. Moreover, although the silica sol was stored at room temperature for 60 days, no precipitate was formed or gelled. 150 g of the silica sol and 12 g of fertilizer (trademark: fine powder Hyponex) were mixed with 5838 g of water to obtain a spray solution. [Plant growth test] and [Confirmation of growth effect] were carried out under the same conditions as in Example 1.

[Example 5]
1000 g of water was mixed with 100 g of commercially available silica powder (AEROSIL (registered trademark): RX300) and 40 g of sodium metasilicate to prepare a solution having a SiO ₂ equivalent concentration of 8.3 mass%. This solution was heated at 150 ° C. for 5 hours, and concentrated with a vacuum evaporator until the SiO ₂ equivalent concentration became 20% by mass to obtain silica sol. As a result of measuring the soluble silica component content and the monosilicic acid content for 100 g of the silica sol, the total silica amount was 20 g, the soluble silica amount was 3.8 g, and the monosilicic acid amount in the soluble silica amount was 1.4 g. It was. Moreover, although the silica sol was stored at room temperature for 60 days, no precipitate was formed or gelled. 150 g of the silica sol and 12 g of fertilizer (trademark: fine powder Hyponex) were mixed with 5838 g of water to obtain a spray solution. [Plant growth test] and [Confirmation of growth effect] were carried out under the same conditions as in Example 1.

[Comparative Example 1]
260 g of sodium metasilicate was mixed with 1000 g of water to prepare a solution having a SiO ₂ equivalent concentration of 10% by mass. When this solution was heated at 150 ° C. for 5 hours, it gelled.

[ Comparative Example 2 ]
12 g of fertilizer (trademark: fine powder Hyponex) was mixed with 5988 g of water to obtain a spray solution. [Plant growth test] and [Confirmation of growth effect] were carried out under the same conditions as in Example 1.

The turf of Example 1 to which the plant growth promoter was applied had remarkable root growth and high leaf growth density compared to the turf of Comparative Example 2 to which the plant growth promoter was not applied. it is obvious. These effects are also confirmed from the turf height, root length, leaf weight, root weight, leaf Si content, and root Si content shown in Table 1.

Claims (6)

A plant growth promoter comprising a silica sol in which silica fine particles are dispersed in a dispersion medium, the silica sol satisfying the following conditions 1), 2) , 3) and 4) .
1) Silica fine particles are contained in the silica sol in an amount of 10 to 40% by mass in terms of SiO ₂ .
2) 10-80 mass% of the silica fine particles is soluble silica composed of monosilicic acid and polysilicic acid having a polymerization degree of 2-8.
3) 30-80 mass% of the soluble silica is monosilicic acid.
4) A fertilizer component containing at least one element selected from the group consisting of N, P, K, Ca, O, H, C, Mg, S, Fe, Mn, B, Zn, Mo, Cu, and Cl is included. The plant growth promoter according to claim 1, wherein 50 to 80% by mass of the silica fine particles is soluble silica composed of monosilicic acid and polysilicic acid having a polymerization degree of 2 to 8. The plant growth promoter according to claim 1 or 2, wherein 40-80% by mass of the soluble silica is monosilicic acid. A silica sol in which silica fine particles are dispersed in a dispersion medium, which is a method for producing a silica sol that satisfies the following conditions 1), 2) and 3), wherein fumed silica and sodium metasilicate are mixed in an aqueous solvent. A method for producing a silica sol, comprising the steps of: preparing a raw material slurry mixed in step 1 and hydrothermally treating the raw material slurry.
1) Silica fine particles are contained in the silica sol in a SiO ₂ equivalent concentration of 10 to 40% by mass.
2) 10-80% by mass of the silica fine particles is soluble silica composed of monosilicic acid and polysilicic acid having a polymerization degree of 2-8.
3) 30-80% by mass of the soluble silica is monosilicic acid. The method for producing a silica sol according to claim 4, wherein the raw material slurry contains sodium hydroxide. The method for producing a silica sol according to claim 4 or 5, wherein the raw slurry is hydrothermally treated at 130 to 150 ° C.