JP2000143378A - Porous compound fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a quick-acting homogeneous porous fertilizer of low bulk density and high instantaneous solubility by including nitrogen ingredients and a specific amount of a potassium ingredient as fertilizer ingredients, with the nitrogen ingredients containing a nitrate-nitrogen ingredient at a specific level. SOLUTION: This porous compound fertilizer is such one as to essentially contain >=8 wt.% of a potassium ingredient and nitrogen ingredients and also contain <9 wt.% of a phosphate ingredient; wherein a nitrate-nitrogen ingredient accounts for >=5 wt.% of the total nitrogen ingredients, and it is preferable that the nitrogen, phosphate and potassium ingredients total >=30 wt.%. This fertilizer is obtained by spraying an acidic solution containing sulfuric acid, nitric acid or potassium nitrate, potassium sulfate, and as necessary, phosphoric acid into an ammonia gas flow. For applying this fertilizer to a paddy field, it is directly charged together with irrigation water via an inlet for the paddy field thereinto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a uniform porous synthetic fertilizer having a low bulk density, a high solubility, a rapid action, and a method for top-fertilizing rice, vegetables, fruit trees, rush, etc. It relates to the fertilization method.

[0002]

2. Description of the Related Art Conventionally, as a fertilizer for topdressing in paddy rice cultivation, vegetables, fruit trees, grass cultivation, and the like, chemical fertilizers and nitrogen having a low phosphate component among nitrogen components, phosphate components, and potassium components which are three components of the fertilizer component. So-called NK fertilizers, which contain only components and potash components, have been used. On the other hand, a porous chemical fertilizer is a foamed fertilizer having voids therein. Due to this, the bulk density is as low as about 0.2 to 0.8, and it has the features of being rapidly soluble and being fast-acting. As a method for producing this porous chemical fertilizer, a method of producing an acidic solution comprising sulfuric acid and phosphoric acid in ammonia gas by spraying the same has been conventionally known. A manufacturing method for performing the above is disclosed. However, even if these techniques are used, it is difficult to make the porous fertilizer uniformly porous when the phosphate component in the porous chemical fertilizer is reduced. Especially when it contains a certain amount or more of potash component, it is difficult to make it porous,
It is very difficult to make the porous material uniform because it is easily powdered.

Japanese Patent Application Laid-Open No. Sho 60-180984 discloses that if potassium nitrate is contained in an acidic solution composed of phosphoric acid and sulfuric acid which is sprayed into ammonia gas, the viscosity of the acidic solution becomes high and the acid solution is easily made porous. Is disclosed. However, there is no mention of the case where the content of the phosphoric acid component, which makes it difficult to produce a uniform porous chemical fertilizer, is low. Furthermore, the case where a certain amount of potassium component is contained and a phosphate component is not contained, which is almost impossible to produce a uniform porous chemical fertilizer, is not included in this technology.

[0004] Non-uniform porous fertilizers have problems such as difficulty in spraying with a machine or the like due to uneven shape and size, and problems in handling dust and the like. Furthermore, the rapid effect originally expected of a porous fertilizer is derived from the fact that the fertilizer is easily soluble in water due to its low bulk density and large specific surface area. However, if the shells of the fertilizer grains are uneven in thickness, the thicker portions are less soluble in water than the thinner portions, and there is a major problem that the rapid effect cannot be sufficiently exhibited. Therefore, for fertilizer such as vegetables, fruit trees, paddy rice, rush, etc., chemical fertilizers with low phosphate content or NK chemical fertilizers containing only nitrogen and potash are used. Although sought, it was virtually impossible to produce it industrially. That is, such fertilizers did not exist on the market.

In recent years, in particular, as a method of saving fertilization in paddy fields, a solid fertilizer which is rapidly dissolved in water, particularly a porous or granular fertilizer, is directly injected into a paddy field together with irrigation water from a water mouth of the paddy field. Japanese Patent Application Laid-Open No. 5-103521 has proposed a method of pouring and applying fertilizer, but does not particularly describe the composition of fertilizer components. However, since this fertilization method is mainly suitable for topdressing of paddy rice, rush, lotus root, etc., especially as a fertilizer suitable for this fertilization method,
Chemical fertilizers with low phosphate content and NK containing only nitrogen and potassium
There has been a strong demand for uniform fertilizers, which are highly soluble and have rapid efficiencies and uniform porosity.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to a compound fertilizer containing only a small amount of phosphoric acid or an NK compound fertilizer containing only nitrogen and potassium for topdressing of vegetables, fruit trees, paddy rice, rush and the like. It is an object of the present invention to provide a uniform porous chemical fertilizer which is highly soluble and has a rapid effect.

[0007]

The uniform porous chemical fertilizer referred to in the present invention is formed of particles having a thin shell having a uniform thickness and foamed into a hollow sphere, and has a substantially uniform particle size. . Non-uniform porous synthetic fertilizers have a relatively large flat shape and some air bubbles are dispersed unevenly, so that there are grains with thick and thin parts in the shell thickness. Such as those that contain a large amount of powder or a large amount of powder such as thin shell debris that seems to have been formed by bursting of the fertilizer that was hollowed out in the process of manufacturing porous chemical fertilizer , Non-uniform shapes and sizes.

[0008] In studying the above problems, the present inventors first studied a measure of uniformity. As a result, the central value varies depending on the manufacturing conditions, and it is difficult to express the uniformity quantitatively in a straightforward manner. When the weight% of the value in the range of ± 0.75 mm is 70% by weight or more, and 50 g of the porous synthetic fertilizer is dissolved in 1 L of water at 25 ° C. while stirring at 200 rpm, It has been found that the time required for the chemical fertilizer to be dissolved is 10 minutes or less, which can be an evaluation criterion for uniformity.

In order to achieve the above-mentioned object, the present inventors have further developed a porous chemical fertilizer by spraying an acidic solution into a nitrogen component, a phosphoric acid component, a potassium component, or an ammonia gas stream. As a result of intensive studies on ammonia gas concentration, reaction temperature, acid gas spraying conditions and the like when producing the chemical fertilizer, the phosphoric acid component in the porous chemical fertilizer was less than 9% by weight, and the potassium component in the porous chemical fertilizer was 8% by weight. Even with the above, it has been found that if the ratio of the nitrate nitrogen component in the nitrogen component to the total nitrogen component is 5% by weight or more, a uniform porous chemical fertilizer can be obtained, and the present invention is made based on these findings. Reached.

That is, the present invention is as follows. 1) The fertilizer component contains at least a nitrogen component and a potash component, the potash component is 8% by weight or more, and the ratio of the nitrate nitrogen component in the nitrogen component to the total nitrogen component is 5% by weight or more, and phosphoric acid A porous chemical fertilizer, wherein the component is less than 9% by weight. 2) The porous chemical fertilizer according to the above 1), wherein the total of the nitrogen component, the phosphate component, and the potash component as the fertilizer components is 30% by weight or more. 3) The method for producing a porous chemical fertilizer according to the above 1), wherein an acidic solution comprising sulfuric acid, nitric acid or potassium nitrate, potassium sulfate, and, if necessary, phosphoric acid is sprayed into an ammonia gas stream. 4) A fertilization method characterized in that the porous chemical fertilizer described in 1) above is directly introduced into a paddy field together with irrigation water from a water port of the paddy field.

Hereinafter, the present invention will be described in more detail. In the present invention, the weight percentages of the nitrogen component, the phosphate component, and the potassium component, which are the fertilizer components in the porous chemical fertilizer, are expressed as N, P ₂ O ₅ , and K ₂ O, respectively. It is a percentage by weight based on the total weight of the porous chemical fertilizer of each component. Since the porous chemical fertilizer of the present invention is for topdressing, the content of the phosphoric acid component may be less than 9% by weight. Phosphoric acid components are easily adsorbed to soil and are less likely to run off due to water. Therefore, if fertilized with base fertilizer, it is less necessary to apply fertilizer by top-end fertilization than nitrogen and potassium components. In some cases, no fertilization is required. When the content of the phosphoric acid component is less than 9% by weight, it is very difficult to produce a uniform porous chemical fertilizer. However, as disclosed in the present invention, a specific amount of the nitrate nitrogen component is used as the fertilizer component. Can be easily manufactured. If the content of the phosphoric acid component is less than 9% by weight,
Although it can be set according to the purpose, it is preferably 2 to 7% by weight in a normal case. When the necessity of the phosphoric acid component is small, it is preferable that the phosphoric acid component is smaller in consideration of cost.

The porous chemical fertilizer of the present invention contains, as fertilizer components, at least a nitrogen component and a potassium component, which are important components as topdressing. The content of potash is 8% by weight
That is all. When the content of the potash component is less than 8% by weight, it is not preferable because the topdressing as a chemical fertilizer becomes meaningless. Normally, when the content of the phosphoric acid component is less than 9% by weight and the content of the potassium component is 8% by weight or more, it is almost impossible to produce a uniform porous chemical fertilizer. As disclosed, the fertilizer can be produced by including a specific amount of a nitrate nitrogen component as a fertilizer component. The potash content is 8
If it is not less than weight%, it can be set according to the purpose, but usually, it is preferably 10 to 24 weight%.
When the content of the potash component is more than 24% by weight, the production of the porous chemical fertilizer becomes difficult because it becomes easy to powder.

Although the content of the nitrogen component can be freely set according to the purpose, it is usually 10 to 25.
% By weight. If the content of the nitrogen component is less than 10% by weight, it is not preferable because the meaning of topdressing as a chemical fertilizer is lost. The gist of the present invention resides in that a nitrate nitrogen component is contained as a nitrogen component in the porous chemical fertilizer in an amount of 5% by weight or more based on the total nitrogen component. In the normal case, particularly when the content of potassium component is 8% by weight or more, if the content of the phosphoric acid component is less than 9% by weight, it is almost impossible to produce a uniform porous chemical fertilizer, but it is surprising. To
By including a specific amount of nitrate nitrogen component in this way, it is possible to produce a uniform porous chemical fertilizer.

When a nitrate nitrogen component is contained in the porous chemical fertilizer as a nitrogen component in an amount of 5% by weight or more based on the total nitrogen component, the content of the phosphoric acid component is less than 9% by weight, and
It is not clear why even if the potassium component is contained in an amount of 8% by weight or more, a uniform porous chemical fertilizer is obtained, but a specific amount is contained in an acidic solution sprayed into an ammonia gas stream at the time of producing the porous chemical fertilizer. When the acid solution contains nitrate nitrogen, the potassium in the acid solution dissolves or disperses uniformly in the acid solution. It is considered that when moisture is lost due to heat, a uniform film is formed on the surface, and the film easily expands into a hollow sphere.

[0015] The total of the three components of the fertilizer components of the porous chemical fertilizer of the present invention, namely, the nitrogen component, the phosphate component and the potash component, depends on the purpose of use of the fertilizer as long as the above conditions are satisfied. Although it can be set, it is preferably 30% by weight or more in order to increase the value as a chemical fertilizer. By the way, the sum of these three components is 3
Chemical fertilizers of 0% by weight or more are called advanced chemical fertilizers. A fertilizer component or additive other than these three components may be contained as needed, as long as the chemical fertilizer does not prevent uniform porosity.

One example of the method for producing the porous chemical fertilizer of the present invention is described below. Usually, an acidic solution comprising sulfuric acid, nitric acid or potassium nitrate, potassium sulfate and, if necessary, phosphoric acid is added to an ammonia gas stream. It is produced by spraying into the solution and reacting the acidic solution with ammonia. The acid solution is mixed with a predetermined amount of sulfuric acid, nitric acid, potassium sulfate and, if necessary, phosphoric acid, etc., so that the composition corresponds to the target porous chemical fertilizer composition, and is inconvenient when spraying a uniform solution or spraying. It is manufactured by heating and stirring to obtain a uniform slurry that does not contain large insolubles. Potassium nitrate may be used instead of nitric acid. Although the phosphoric acid is not particularly limited, it is common to use sulfuric acid or one produced by subjecting phosphate rock to wet decomposition using sulfuric acid and nitric acid.

The water content in the acidic solution is preferably in the range of 25 to 40% by weight. If the water content is too small, porosity does not progress, and potassium sulfate having low solubility becomes difficult to uniformly disperse in the solution, so that uniform porosity becomes difficult. Conversely, if the water content is too high, drying will not proceed sufficiently and the water content in the porous chemical fertilizer will increase. The acidic solution is sprayed or dropped from the upper portion of the reaction tower through which the ammonia gas flows, reacting the falling acidic solution droplets with the ammonia and making the water porous by volatilizing the water. As a result, a desired dry and uniform porous chemical fertilizer can be obtained.

The device for spraying the acidic solution is as follows:
Any type can be used as long as the acidic solution can be sprayed to a desired droplet diameter, and a pressure spray nozzle, a rotary perforated plate, or the like is used. The desired droplet size is
Depending on the type of product after the reaction, the average particle size is 7
It is about 00 μm. The height of the reaction tower cannot be unconditionally specified because the optimum height varies depending on the droplet diameter and the production amount, but is about 5 to 25 m.

Ammonia gas is introduced into the reaction tower from the lower part of the reaction tower, and unreacted ammonia gas is discharged out of the reaction system from an ammonia gas exhaust line at the upper part of the reaction tower. The discharged ammonia gas containing water and the like is recovered and regenerated by an ammonia recovery device, and is recycled and used. It is preferable that the supply rate of the ammonia gas is about twice or more excess of the theoretical neutralization equivalent of the supplied acidic solution. In this case, the exhaust gas concentration of ammonia gas is about 30% by volume or more. When the exhaust concentration of the ammonia gas is 0% by volume, it means that the acidic solution and the neutralization equivalent of the ammonia gas have been supplied. In this case, the required height of the reaction tower becomes extremely high, which is not preferable.

For the purpose of accelerating the reaction, the ammonia gas is preferably preheated and supplied. The reaction tower itself is preferably heated by a jacket or the like, and a preferable reaction temperature range is about 70 to 170 ° C. If the temperature is too low, the reaction between the acidic solution and the ammonia gas does not proceed sufficiently, and the moisture content in the obtained fertilizer is undesirably high. Conversely, if the temperature is too high, it is not preferable because the ammonium phosphate is decomposed into ammonium phosphate. As the moisture content of the obtained uniform porous chemical fertilizer,
Less than 1.5% by weight is preferred. If the water content is too high, it is not preferable because the porous chemical fertilizer easily blocks.

[0021] The porous chemical fertilizer of the present invention is a chemical fertilizer having a low phosphate component or an NK chemical fertilizer containing only nitrogen and potash. Since it is a chemical fertilizer, it is optimal to use a method of pouring and fertilizing rice into a paddy field, which is suitable for a method of top-fertilizing rice and the like. The method of pouring and applying fertilizer to a paddy field is, specifically, by pouring the porous synthetic fertilizer of the present invention into a place where irrigation water is flowing from a water mouth of the paddy field, the porous chemical fertilizer is quickly applied to the irrigation water. This is a fertilization method in which the irrigation water that flows into the paddy field while dissolving moves in the paddy field and is uniformly fertilized. As a method of putting the porous compound fertilizer, a hole is made in the corner of the fertilizer bag, and the fertilizer bag is hung at the water opening so that the hole is at the bottom, so as to save labor. It is also possible to make it in the form that is done.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples and comparative examples.

Example 1 96% by weight sulfuric acid 27.8 parts by weight, 61% by weight nitric acid 17.7 parts by weight, 85% by weight phosphoric acid 8.8 parts by weight,
After mixing 20.0 parts by weight of potassium sulfate and 25.7 parts by weight of water,
The mixture was stirred at 90 ° C, and 26.7 parts by weight of sulfuric acid and 10.
An acidic solution comprising 8 parts by weight, 7.5 parts by weight of phosphoric acid, 20.0 parts by weight of potassium sulfate, and 35 parts by weight of water was prepared. This acidic solution was sprayed from the upper part of the reaction tower having a height of 10 m using a pressure spray nozzle to form droplets having an average particle diameter of 700 μm. Then, a gas having an ammonia gas concentration of 95% by volume is supplied from the lower portion of the reaction tower, and an ammonia gas outlet concentration of 7
Discharged as 0% by volume gas. At this time, ammonia gas was supplied four times in excess of the neutralization equivalent of the supplied acidic solution. The temperature of the reaction tower was 135 ° C.

As described above, a uniform porous chemical fertilizer was obtained. Most of these have a shape in which each particle is foamed into a hollow sphere, and some have some foamed particles attached to them, but it seems to be composed of a shell that burst when foaming etc. Powder contained little. The quality of the obtained homogeneous porous chemical fertilizer was 15.0% by weight of ammonia nitrogen component, 2.6% by weight of nitrate nitrogen component, 6.8% by weight of phosphoric acid component, and 12.2% by weight of potassium component. ,
The ratio of the nitrate nitrogen component to the total nitrogen component was 14.8% by weight. The bulk density was 0.62. Further, the water content was 0.23% by weight, which was sufficiently dried.

As an index of the uniformity of the obtained porous chemical fertilizer, the particle size and the dissolution time in water were measured. The particle size was determined by sieving a 5 kg sample using a standard sieve and measuring the weight% of particles having a particle size in the range of 0.5 mm to 2.0 mm with respect to the total weight, and was 79% by weight. The dissolution time in water is as follows.
g of sample and stirring at 200 rpm,
The time until the sample dissolved was measured. Immediately after addition, the sample settled out of the water and dissolved in 8 minutes.

[0025]

Example 2 96 weight% sulfuric acid 26.0 weight parts, 61 weight% nitric acid 16.4 weight parts, potassium sulfate 30 weight parts, water 27.
After mixing 6 parts by weight, the mixture was stirred at 90 ° C. to obtain 25.0 parts by weight of sulfuric acid.
An acidic solution was prepared by weight, 10.0 parts by weight of nitric acid, 30.0 parts by weight of potassium sulfate, and 35.0 parts by weight of water. This acidic solution was reacted with ammonia gas under the same conditions as in Example 1 to obtain a uniform porous chemical fertilizer.
Most of the obtained uniform porous synthetic fertilizers had a shape in which each grain was foamed into a hollow sphere, and some had some foamed grains attached to them. The powder which seems to consist of ruptured shells contained only trace amounts.

The quality of the obtained homogeneous porous chemical fertilizer is as follows:
The ammonia nitrogen component was 12.3% by weight, the nitrate nitrogen component was 2.9% by weight, and the potash component was 21.2% by weight. The ratio of the nitrate nitrogen component to the total nitrogen component was 19.1% by weight. The bulk density was 0.52. Further, the moisture content was 0.21% by weight, which was sufficiently dried. In the same manner as in Example 1, the particle size and the dissolution time in water were measured. The particle size in the range of 0.5 mm to 2.0 mm was 76% by weight. The behavior upon dissolution in water was the same as in Example 1, and the dissolution time was 6 minutes.

[0027]

Example 3 32.3 parts by weight of 96% by weight sulfuric acid, 7.1 parts by weight of 61% by weight nitric acid, 9.4 parts by weight of 85% by weight phosphoric acid, 20.0 parts by weight of potassium sulfate, and 31.2 parts by weight of water After mixing, 9
The mixture was stirred at 0 ° C. to prepare an acidic solution comprising 31.0 parts by weight of sulfuric acid, 6.0 parts by weight of nitric acid, 8.0 parts by weight of phosphoric acid, 20.0 parts by weight of potassium sulfate, and 35 parts by weight of water. This acidic solution was reacted with ammonia gas under the same conditions as in Example 1 to obtain a uniform porous chemical fertilizer. Most of the obtained uniform porous synthetic fertilizers had a shape in which each grain was foamed into a hollow sphere, and some had some foamed grains attached to them. The powder which seems to consist of ruptured shells contained only trace amounts.

The quality of the obtained uniform porous chemical fertilizer is as follows:
11.14.9% by weight of ammonia nitrogen component, 1.2% by weight of nitrate nitrogen component, 7.2% by weight of phosphoric acid component, 12.
It was 5% by weight, and the ratio of the nitrate nitrogen component to the total nitrogen component was 7.5% by weight. The bulk density is 0.60
Met. Further, the water content was 0.40% by weight, which was sufficiently dried. In the same manner as in Example 1, the particle size and the dissolution time in water were measured. 0.5mm-2.0m
Those with a particle size in the range of m were 72% by weight. The behavior upon dissolution in water was the same as in Example 1, and the dissolution time was 9 minutes. The particle size and dissolution time in water were measured as indices of uniformity of the obtained porous chemical fertilizer.

[0029]

Comparative Example 1 96% by weight sulfuric acid 38.5 parts by weight, 85% by weight phosphoric acid 10.6 parts by weight, potassium sulfate 19.0 parts by weight, water 3
After mixing 1.9 parts by weight, the mixture was stirred at 90 ° C.
An acidic solution comprising 7.0 parts by weight, 9.0 parts by weight of phosphoric acid, 19.0 parts by weight of potassium sulfate, and 35.0 parts by weight of water was prepared.
This acidic solution was reacted with ammonia gas under the same conditions as in Example 1 to obtain a heterogeneous porous chemical fertilizer. The resulting porous chemical fertilizer was non-uniform, mostly in a relatively large, flat shape, with some bubbles in the non-uniform shape. The powder contained a small amount of powder which seems to consist of shells that burst during foaming.

The quality of the obtained heterogeneous porous chemical fertilizer is as follows: 15.5% by weight of ammoniacal nitrogen component, 0.0% by weight of nitrate nitrogen component, 8.2% by weight of phosphoric acid component, 1% by weight of potassium component.
2.9% by weight, and the ratio of the nitrate nitrogen component to the total nitrogen component was 0.0% by weight. Further, the bulk density is 0.
It was relatively high at 78. Further, the water content is 2.1% by weight.
And drying was also insufficient. In the same manner as in Example 1, the particle size and the dissolution time in water were measured. 0.5mm
Those with a particle size in the range of ２．０2.0 mm were 60% by weight. Further, the behavior upon dissolution in water is different from that of Example 1,
The particles of the sample embraced the air and repeatedly settled from the water surface and floated to the water surface, and the dissolution time was 15 minutes.

[0031]

COMPARATIVE EXAMPLE 2 38.5 parts by weight of 96% by weight sulfuric acid, 28.0 parts by weight of potassium sulfate, and 31.5 parts by weight of water were mixed and stirred at 90 ° C. to obtain 37.0 parts by weight of sulfuric acid and 37.0 parts by weight of potassium sulfate. An acidic solution consisting of 28.0 parts by weight and 35.0 parts by weight of water was prepared.
This acidic solution was reacted with ammonia gas under the same conditions as in Example 1 to obtain a heterogeneous porous chemical fertilizer. The resulting porous chemical fertilizer is non-uniform, in addition to flat-shaped particles containing a number of irregularly dispersed bubbles and particles that are foamed into a hollow sphere, when it consists of shells that burst at the time of foaming, etc. Probably powder contained a large amount.

The quality of the obtained heterogeneous porous chemical fertilizer was 13.5% by weight of an ammonia nitrogen component, 0.0% by weight of a nitrate nitrogen component, and 19.5% by weight of a potassium component. Component is 0.0% by weight based on total nitrogen
Met. The bulk density was 0.34. The water content was 1.6% by weight, and drying was slightly insufficient. In the same manner as in Example 1, the particle size and the dissolution time in water were measured. 0.5m
Particle sizes ranging from m to 2.0 mm were 49% by weight. The behavior upon dissolution in water was almost the same as in Example 1, and the dissolution time was 11 minutes.

[0033]

Comparative Example 3 96% by weight sulfuric acid 37.0 parts by weight, 61% by weight nitric acid 2.5 parts by weight, potassium sulfate 28.0 parts by weight, water 3
After mixing 2.5 parts by weight, the mixture was stirred at 90 ° C.
An acidic solution consisting of 5.5 parts by weight, 1.5 parts by weight of nitric acid, 28.0 parts by weight of potassium sulfate, and 35.0 parts by weight of water was prepared.
This acidic solution was reacted with ammonia gas under the same conditions as in Example 1 to obtain a heterogeneous porous chemical fertilizer. The obtained porous chemical fertilizer is non-uniform, and in addition to flat-shaped particles containing several bubbles that are unevenly dispersed and particles that are foamed into a hollow sphere, when they consist of shells that burst at the time of foaming, etc. It contained a considerable amount of powder that could be.

The grade of the obtained heterogeneous porous chemical fertilizer was 13.5% by weight of an ammonia nitrogen component, 0.3% by weight of a nitrate nitrogen component, and 19.0% by weight of a potash component. The ratio of the components to the total nitrogen components is 2.2% by weight.
Met. The bulk density was 0.48. The water content was 1.5% by weight. In the same manner as in Example 1, the particle size and the dissolution time in water were measured. Those having a particle size in the range of 0.5 mm to 2.0 mm were 55% by weight. The behavior upon dissolution in water was almost the same as in Example 1, and the dissolution time was 11 minutes.

[0035]

Industrial Applicability The porous chemical fertilizer of the present invention has a low bulk density, is rapidly soluble, and has a rapid effect despite the fact that the phosphoric acid component is less than 9% by weight and the potassium component is 8% by weight or more. It is a uniform porous fertilizer having properties, and is suitable for top-fertilization of vegetables, fruit trees, rice, rush and the like. In particular, it is most suitable for fertilizing by a method of pouring into a paddy field, which is a fertilization method suitable for topdressing of paddy rice and the like which is labor-saving.

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Claims (4)

[Claims] 1. A fertilizer component comprising at least a nitrogen component and a potash component, wherein the potash component is at least 8% by weight, and the ratio of the nitrate nitrogen component in the nitrogen component to the total nitrogen component is at least 5% by weight. Wherein the phosphoric acid component is less than 9% by weight. 2. The porous chemical fertilizer according to claim 1, wherein the total of the nitrogen component, the phosphate component and the potash component as the fertilizer components is 30% by weight or more. 3. The production of a porous chemical fertilizer according to claim 1, wherein an acidic solution comprising sulfuric acid, nitric acid or potassium nitrate, potassium sulfate and, if necessary, phosphoric acid is sprayed into the ammonia gas stream. Law. 4. A fertilization method, wherein the porous chemical fertilizer according to claim 1 is directly fed into a paddy field together with irrigation water from a water port of the paddy field.