JP2015117154A - Slowly available liquid fertilizer and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slowly available liquid fertilizer including guanylurea and capable of reducing additional fertilization workload by reducing a number of addition of fertilizer.SOLUTION: The slowly available liquid fertilizer comprises guanylurea obtained by reaction of 7 mass parts or more and 35 mass parts or less of dicyandiamide with respect to 100 mass parts of solution including phosphoric acid of 40 mass% or more and less than 85 mass% at 70°C or less, in which a ratio of the guanylurea derived nitrogen component with respect to the total nitrogen is 10% or more.

Description

  The present invention relates to a slow-acting liquid fertilizer and a method for producing the same.

  In recent years, with the aging of farmers, slow-acting fertilizers are widely used so that the number of additional fertilizations can be reduced in order to reduce the physical burden of fertilization work as much as possible. As slow-release nitrogenous fertilizers, coated fertilizers coated with chemically synthesized slow-release nitrogenous fertilizers and fertilizer components such as guanyl urea, acetaldehyde condensed urea, isobutyraldehyde condensed urea, oxamide, glyoxal condensed urea, formaldehyde processed urea fertilizer, etc. It has been known. However, after the coated fertilizer is applied, the coated material may remain on the farmland for a long time, or may be washed away from the farmland, resulting in environmental problems. In addition, chemical fertilizers containing chemically synthesized slow-release fertilizers are considered insufficient to supply the nutrients necessary for field crops with a long cultivation period by applying the whole amount of basic fertilizer, and several additional fertilizers are performed in addition to the basic fertilizer. ing. In particular, the cultivation environment under abnormal weather in recent years is strongly stressed by crops such as high temperature, low temperature, overhumidity, drying, lack of sunlight, etc. Diligent fertilizer management is necessary to ensure topdressing so that it does not hang.

  However, at the production site of agricultural products where the aging of farmers is further advanced, there are scenes of paddy rice cultivation where field crop cultivation, either open field cultivation or facility cultivation, and traditional fertilization such as pantilization and actual fertilization has been carried out However, there is a strong demand for a slow-acting fertilizer that can reduce the number of times of topdressing that can contribute to reducing the burden of topdressing work. In particular, the fertilizer for top fertilization in paddy rice cultivation needs to be applied to the entire field in the case of granular products, and the fertilization work for the top fertilization is a considerable burden in the current situation where the farmer is aging. Moreover, even if granular fertilizers such as fine grains are applied at the water inlet for the purpose of reducing the burden of fertilizing work, there is a drawback that the fertilizer nutrients are difficult to diffuse throughout the field. From this point of view, a liquid slow-acting fertilizer that can be applied at the mouth is strongly desired.

  As a solution to the above problems, Patent Document 1 describes a slow-acting liquid fertilizer comprising a cyanamide acidic aqueous solution containing dicyandiamide, but the quality is not constant, such as an increase in dicyandiamide during the storage period. There was a problem. Caution should be exercised because increasing the content of dicyandiamide may cause harmful effects on crops.

  In addition, the methods for producing guanylurea are disclosed in Patent Documents 2 and 3, both of which are methods for producing and recovering guanylurea as powdered crystals, the purpose of which is completely different from the present invention. The molar ratio of acid to dicyandiamide is also different.

JP 2000-302583 A Japanese Examined Patent Publication No. 45-7730 Japanese Patent Publication No. 47-48375

  An object of the present invention is to provide a slow-acting liquid fertilizer containing guanylurea that can reduce the number of times of topdressing and reduce the topdressing work burden.

  As a result of intensive studies to solve the above problems, the present inventors have added dicyandiamide at a predetermined ratio to a solution containing a predetermined concentration of phosphoric acid and allowed to react at 70 ° C. or lower to obtain a guanyl urea solution. As a result, it has been found that the number of additional fertilization in open field cultivation, facility cultivation, and paddy rice cultivation of field crops can be reduced, and that the paddy rice cultivation can be applied to water lip application, and the present invention has been completed.

That is, the present invention includes the following inventions.
(1) Production of a guanylurea solution comprising adding 7 parts by weight or more and 35 parts by weight or less of dicyandiamide to 100 parts by volume of a solution containing 40% by weight or more and less than 85% by weight of phosphoric acid and reacting at 70 ° C. or less Method.
(2) A slow-acting liquid fertilizer containing a guanylurea solution obtained by the production method according to (1).
(3) The slow-acting liquid fertilizer according to (2), containing at least one selected from a nitrogen source other than guanylurea, a phosphate source, and a potassium source.
(4) The slow-acting liquid fertilizer according to (2) or (3), wherein the ratio of the nitrogen component derived from guanylurea to the total nitrogen of the slow-acting liquid fertilizer is 10% or more.

  According to the present invention, a liquid containing guanylurea can be efficiently produced, and by using a slow-acting liquid fertilizer containing the produced guanylurea liquid, the number of times of topdressing during crop cultivation can be reduced. It is possible to reduce the burden on fertilization work accompanying the aging of farmers in Japan.

First, the manufacturing method of the guanyl urea liquid of this invention is demonstrated.
In the method for producing a guanylurea solution of the present invention, it is produced by reacting 100 parts by volume of a solution containing 40% by weight or more and less than 85% by weight of phosphoric acid at 70 ° C. or less with 7 to 35 parts by weight of dicyandiamide. And obtained in a liquid state.

  As the solution containing phosphoric acid, a phosphoric acid aqueous solution is usually used, but a phosphoric acid aqueous solution containing at least one component selected from bitter earth, boron, manganese, iron, zinc, molybdenum and the like is used. Also good.

  When a solution containing phosphoric acid with a concentration of less than 40% by weight is used, the reactivity with dicyandiamide is poor, and guanylurea exceeding the target concentration cannot be obtained, or phosphoric acid with a concentration of 85% by weight or more cannot be obtained. When the contained solution is used, problems such as gelation and solidification of the solution occur. Therefore, the concentration of the phosphoric acid solution to be used is 40% by weight or more and less than 85% by weight, preferably 40% by weight or more and 83% by weight or less, and more preferably 60% by weight or more and 80% by weight or less. The amount of dicyandiamide added to the phosphoric acid solution having a predetermined concentration is 7 parts by weight or more and 35 parts by weight or less, preferably 17 parts by weight or more and 32 parts by weight or less with respect to 100 parts by volume of the phosphoric acid solution. .

  In addition, when the temperature in the case of reacting a solution containing phosphoric acid with dicyandiamide exceeds 70 ° C., the generated guanylurea is not only denatured into guanidine, but further decomposes into ammonia and vaporizes at a temperature exceeding 100 ° C. Nitrogen component is lost. Therefore, it is necessary to keep the temperature at which the solution containing phosphoric acid and dicyandiamide are reacted at 70 ° C. or lower. The reaction vessel may be cooled to keep the reaction temperature at 70 ° C. or lower. However, in order to reduce the cooling cost, a method of adding dicyandiamide to the phosphoric acid solution little by little is recommended.

  The guanylurea solution prepared as described above may be used as a slow-acting liquid fertilizer as it is, but if necessary, such as the target crop to be used and the application time, other fertilizer raw materials are added to the prepared guanylurea solution, Water or the like may be added and dissolved so that the amount of nitrogen component derived from guanylurea with respect to the total amount of nitrogen is 10% or more to obtain a slow-release liquid fertilizer.

  The content of guanylurea in the slow-release liquid fertilizer of the present invention is usually 10 in terms of the total nitrogen amount derived from guanylurea relative to the total nitrogen amount in the liquid fertilizer from the viewpoint of the fertilizer effect on the crop and the storage stability of the liquid fertilizer. % Or more, preferably 30% or more and 60% or less. If the guanylurea content is less than 10%, the slow effect of nitrogen fertilization is small and the effect of reducing the number of topdressing is reduced. On the other hand, if the content exceeds 60%, it is a problem to use in a short period after production. However, when it is stored for a long time in a low temperature environment or the like, problems such as precipitation of crystals and precipitates are likely to occur.

  Examples of raw materials other than guanylurea to be mixed with the slow-acting liquid fertilizer of the present invention include the following.

  Nitrogen sources include urea, ammonium sulfate, ammonium chloride, ammonium nitrate, sodium nitrate, and phosphoric acid sources include phosphoric acid, monoammonium phosphate, diammonium phosphate, triammonium phosphate, monopotassium phosphate, diphosphate Examples of potassium and potassium sources include potassium sulfate, potassium chloride, nitrate, and hydroxide.

  If necessary, surfactants such as secondary higher alcohol ethoxylates and dialkyl ester sulfonates and thickeners such as gum arabic, guar gum, xanthan gum and succinoglycan may be added.

  EXAMPLES Hereinafter, although this invention is explained in full detail according to an Example and a comparative example, this invention is not limited by these Examples.

[Addition of phosphoric acid concentration and dicyandiamide on the production rate of guanylurea in the production of 1-1 guanylurea solution]
A mixture of Comparative Examples 1 to 3 and Examples 1 to 8 shown in Table 1 to which the amount of dicyandiamide added with respect to 100 ml of phosphoric acid aqueous solution having a phosphoric acid concentration of 20 to 85% by weight was added was a constant temperature bath at a temperature of 20 ° C. After stirring for 24 hours, the content of guanylurea nitrogen in the filtered filtrate was analyzed by high performance liquid chromatography (HPLC 2080 manufactured by JASCO Corporation) to calculate the production rate of guanylurea nitrogen. The results are shown in Table 1.

  As shown in Table 1, in Comparative Examples 1 and 2, the content of guanylurea nitrogen was 2% or less and the production rate was as low as 60% or less. In Comparative Example 3, the product was solidified. . On the other hand, in Examples 1 to 8, the content of guanylurea nitrogen was 2% or more and the production rate was 60% or more, and the guanylurea liquid could be efficiently prepared by the method of the present invention. .

[Effect of reaction temperature on production of 1-2 guanylurea solution]
Example 9
In a 3000 ml glass beaker, 2000 ml of a phosphoric acid aqueous solution having a phosphoric acid concentration of 75% by weight was put into a 3000 ml glass beaker, and 600 g of dicyandiamide was added in three portions of 200 g while stirring with a three-one motor. The reaction temperature after the addition of dicyandiamide at that time and the contents of guanylurea nitrogen and guanidine nitrogen in the prepared solution after 24 hours were analyzed by high performance liquid chromatography (HPLC 2080 manufactured by JASCO Corporation), and guanylurea state The results of calculating the nitrogen production rate are shown in Table 2.

(Comparative Example 4)
In a 3000 ml glass beaker, 2000 ml of a phosphoric acid aqueous solution having a phosphoric acid concentration of 75% by weight was put into a 3000 ml glass beaker, and 600 g of dicyandiamide was added and reacted at one time. The reaction temperature after the addition of dicyandiamide at that time and the contents of guanylurea nitrogen and guanidine nitrogen in the prepared solution after 24 hours were analyzed by high performance liquid chromatography (HPLC 2080 manufactured by JASCO Corporation), and guanylurea state The results of calculating the nitrogen production rate are shown in Table 2.

  As shown in Table 2, Comparative Example 4 in which the reaction temperature exceeded 70 ° C. caused nitrogen volatilization loss, and the total amount of nitrogen in the liquid fertilizer produced compared to Example 9, the content of guanylurea nitrogen The production rate was low and guanidine nitrogen was also produced. On the other hand, Example 9 prepared by controlling the reaction temperature to 70 ° C. or lower has a high guanylurea nitrogen content and production rate, and no guanidine nitrogen is produced. According to the method of the present invention, A guanylurea solution could be prepared efficiently.

[Production of 1-3 slow-release liquid fertilizer (TN of GuN 3% -WP13% -WK 5%)]
(Example 10)
16 L of phosphoric acid aqueous solution having a phosphoric acid concentration of 75% by weight was placed in a 30 L plastic container, and 4.8 kg of dicyandiamide was added in 5 portions of 960 g while being cooled with cold water, and the mixture was stirred and reacted with a three-one motor. 25 kg of this reaction solution was added to 37.5 kg of tap water in a 150 L plastic container, and further 13.5 kg of urea and 8 kg of potassium chloride were dissolved to obtain a slow-acting liquid fertilizer.

[Production of 1-4 liquid fertilizer (TN15% -WP5% -WK5%)]
(Comparative Example 5)
A liquid fertilizer was prepared by dissolving 33.5 kg of urea, 10 kg of an aqueous phosphoric acid solution having a phosphoric acid concentration of 75% by weight, and 9 kg of potassium chloride in 47.5 kg of water placed in a 150 L plastic container.

[Efficacy test of 1-5 slow-acting liquid fertilizer (Example 10)]
40 kg of chemical fertilizer (TN10% -CP15% -WK13%) was applied as a basic fertilizer to each of two adjacent paddy fields (one area of 1500 m ² ), and paddy rice (variety: Koshihikari) was planted on May 5 . Sixty days after rice planting, 21 kg of slow-acting liquid fertilizer prepared in Example 10 was added to a single paddy field (1500 m ² ) for additional fertilizer application. On the same day, 14 kg of the liquid fertilizer prepared in Comparative Example 5 was added to the other paddy field (1500 m ² ) for additional fertilization. The growth situation of paddy rice was investigated and compared 8 days before the fertilization of liquid fertilizer, the day of fertilization, 20 days, 40 days and 48 days after fertilization. On August 27, plowing was carried out, and the yield was investigated and compared. The results are shown in Tables 3 and 4.

  As shown in Table 3, as for the number of stems, the comparative example 5 ward is superior to the example 10 ward 20 days after fertilization and 40 days later, but the decrease is severe after 48 days after fertilization. Less than 10 wards. In comparison, in Example 10 ward, the number of stems after 40 days of fertilization was secured, and the effective stem ratio was high. The leaf color of Table 3 was clearly ensured in Example 10 ward as compared with Comparative Example 5 ward, with less decrease in leaf color 40 days after fertilization 20 days after fertilization and 48 days after fertilization.

  In addition, as shown in Table 4, the paddy rice applied with Example 10 was superior in yield to the paddy rice applied with Comparative Example 5.

  Thus, in the liquid fertilizer section of Comparative Example 5, additional fertilization is required, but by using the slow-acting liquid fertilizer of the present invention (Example 10), it can be handled by a single additional fertilizer, It was possible to reduce the burden.

Claims (4)

  A method for producing a guanylurea solution, comprising adding 7 parts by weight or more and 35 parts by weight or less of dicyandiamide to 100 parts by volume of a solution containing 40% by weight or more and less than 85% by weight of phosphoric acid, and reacting them at 70 ° C. or less.   The slow release liquid fertilizer containing the guanyl urea liquid obtained by the manufacturing method of Claim 1.   The slow-acting liquid fertilizer according to claim 2, comprising at least one selected from a nitrogen source other than guanylurea, a phosphate source, and a potassium source.   The slow-release liquid fertilizer according to claim 2 or 3, wherein the ratio of the nitrogen component derived from guanylurea to the total nitrogen of the slow-release liquid fertilizer is 10% or more.