JP7768580B2 - Granular fertilizer and method for producing granular fertilizer - Google Patents

Description

The present invention relates to an invention in the field of fertilizers and their manufacturing technology.

Livestock manure compost, an organic matter derived from animals, is used as organic fertilizer because it contains nitrogen, phosphorus, and potassium, the three major elements that have a significant impact on crop growth. The amounts of nitrogen, phosphorus, and potassium contained in compost are greatest for chickens, followed by pigs and cows, but the amount of organic matter needed for soil improvement is greatest for cows, pigs, and chickens, in that order. Furthermore, while the amount of nitrogen in cow manure compost that can be used by crops in the year of application is low, its high content of sparingly soluble nitrogen accumulates in the soil, and the nitrogen accumulated in the soil is continuously supplied to subsequent crops. In other words, with repeated application, in addition to the nitrogen supplied from the compost applied in the current year, nitrogen is also supplied from compost applied up to the previous year. Therefore, it is said that repeated application of cow manure compost increases soil fertility and produces a repeated application effect, increasing the amount of nitrogen supplied (Non-Patent Document 1).

A method for producing organic fertilizer is known in which fertilizer raw materials such as livestock waste are adjusted to a moisture content of 40 to 60% by weight, and then sheared and kneaded under pressure to produce a mixture heated to 40 to 90°C by the frictional heat of the pressurization and kneading. This processed material is then crushed into granules using a screw-type granulator while ozone ( _O3 ) is supplied to oxidize the surface of the processed granules with the ozone, thereby creating conditions that suppress the activity of thermophilic anaerobic bacteria and promote the activation of thermophilic aerobic bacteria, and the processed material is then fermented (Patent Document 1).However, while one effect of this method is that odor caused by ozone can be suppressed, the fertilizer produced by this method is in the form of pellets, and no description is given of its effectiveness as a fertilizer.

A method for granulating organic fertilizer from fermented chicken manure, etc., is known (Patent Document 2), in which powdered organic raw materials, such as fermented chicken manure, are fed from above into a cylindrical housing with rotors rotating at high speed. The powder is suspended within the housing, rotated vertically and circumferentially, and rotated on its axis. Numerous water droplets are sprayed into the housing to agglomerate the powder. After a required time has elapsed, a powdered coating agent is fed into the housing, coating the surfaces of the agglomerated powder granules with the coating agent. This method, however, is limited to certain powdered raw materials, such as chicken manure, and cannot be used as compost raw materials with a moisture content exceeding 50%. Furthermore, the coating process is laborious and costly. Furthermore, changes in active ingredients such as phosphate, nitrogen, and potassium, as well as granule shape, have not been investigated.

A granular organic fertilizer composition (Patent Document 3) is known in which dried fermented chicken manure is sieved and granulated using a screw-type extrusion granulator, during which a small amount of water is added to the fermented chicken manure to form granules, and the surface of each granule is coated with a powder that enhances fertilizer efficacy, resulting in the individual granules being separated from one another. However, this composition is limited to powdered chicken manure and requires a coating process, and does not disclose any changes in active ingredients such as phosphate, nitrogen, and potassium.

Unlike the organic fertilizer manufacturing methods using the screw-type extrusion granulator or high-speed rotary granulator described above, a method for manufacturing low-density porous carbon granules is known in which plant-based powder is granulated in a pin-type granulator with an aqueous solution of a binder component consisting of lignin, starch, or a mixture of these, and the granules are then dried while tumbling in a rotating drum at 50 to 300°C, and then calcined and carbonized. However, this method is complicated in that it uses powder as a raw material, requires the addition of a binder, and requires the granules to be treated by high heat after granulation, and the pin-type granulator is only described as being suitable for mass production (Patent Document 4).

One known method for producing granules using a pin-type granulator involves mixing and stirring powdered carbon black and granulation water inside the granulator while transporting them in the axial direction of the granulator, and then removing the granular carbon black from the outlet at the end of the granulator. This method sprays granulation water in the direction opposite to the direction in which the carbon black is transported within the granulator, setting the droplet diameter during spraying to 50 to 1000 μm. This method is known to result in 92% of granules having a particle size of 1 mm or less (Patent Document 5).

Japanese Patent Application Publication No. 8-183684 Special Publication No. 6-79998 Special Publication No. 3-75513 Special Publication No. 6-45445 JP 2004-182803 A

"Chapter 3: Current Status and Fertilizer Efficiency of Livestock Manure Compost," Guide to Proper Application of Livestock Manure Compost, pp. 19-27, March 2014, published by the Okayama Prefectural Department of Agriculture, Forestry and Fisheries

As livestock farms expand in scale, the amount of livestock manure and compost produced is increasing. However, using it directly as organic fertilizer poses many problems, such as the fact that consumption areas are far away and demand is concentrated in the spring. There are also environmental hygiene issues, such as odors that occur during storage. Therefore, there is a need to develop technology to process these materials into organic fertilizers that have less odor and higher levels of active fertilizer ingredients such as nitrogen, phosphoric acid, and potassium salts. Organic fertilizers made from cow manure, in particular, have the problem of having low concentrations of phosphoric acid, nitrogen, and potassium.

Furthermore, conventional organic fertilizers made from livestock manure and other raw materials are mainly produced using a screw-type extrusion granulation method, which means that only large pellet-shaped organic fertilizers can be produced. When blended with chemical fertilizers with smaller particle sizes of 2-8 mm, problems exist, such as the inability to spread the fertilizer on fields depending on the type of fertilizer spreader. Another drawback is that chemical fertilizers are usually spherical, while pellets are cylindrical, making them difficult to mix evenly. Even when other granulation methods are used, such as those using pin-type agitation granulators, which are suitable for producing small granules with a particle size of 1 mm or less, it is difficult to grow them to the size of chemical fertilizer granules.

The inventors conducted extensive research into the production of granular organic fertilizers that have higher blending rates of phosphorus, nitrogen, potassium, etc. than the raw materials and have a shape similar to that of chemical fertilizers. As a result, they confirmed that it is possible to obtain granular organic fertilizers that are odorless and rich in active ingredients without the use of binders, coating agents, etc.

The present invention provides
[1] A granular organic fertilizer using organic raw materials of animal origin and having a particle size of 2 to 8 mm, characterized in that the nitrogen content is 1.5 times or more that of the organic raw materials, the phosphorus content is 1.5 times or more that of the organic raw materials, and the potassium content is 1.3 times or more that of the organic raw materials.
[2] The fertilizer according to [1], wherein the animal-derived organic raw material is livestock manure compost or livestock manure.
[3] The organic fertilizer according to [1] or [2], characterized in that the nitrogen content is 1.5 to 4 times that of the organic raw material, the phosphorus content is 1.5 to 3.5 times that of the organic raw material, and the potassium content is 1.3 to 4 times that of the organic raw material.
[4] The organic fertilizer according to [2], characterized in that the livestock manure compost or livestock excrement is cow manure compost or cow manure, and has a nitrogen component content of 1.5 to 4.5%, a phosphorus component content of 1.5 to 5%, and a potassium component content of 2.5 to 6%.
[5] The organic fertilizer according to [4], characterized in that the nitrogen content is 1.5 to 2.5% as a component, the phosphoric acid content is 1.5 to 3% as a component, and the potassium content is 3 to 5% as a component.
[6] The organic fertilizer according to [2], characterized in that the livestock manure compost or livestock excrement is swine manure compost or swine manure, and has a nitrogen content of 3 to 9%, a phosphorus content of 3 to 12%, and a potassium content of 2 to 7%.
[7] The organic fertilizer according to [6], characterized in that the nitrogen content is 3 to 4.5%, the phosphoric acid content is 3 to 5%, and the potassium content is 2 to 5%.
[8] The organic fertilizer according to [2], characterized in that the livestock manure compost or livestock excrement is chicken manure compost or chicken manure, and the component content of nitrogen is 3 to 9%, the component content of phosphorus is 3 to 15%, and the component content of potassium is 2 to 10%.
[9] The organic fertilizer according to [8], characterized in that the nitrogen content is 4 to 6%, the phosphorus content is 3 to 5%, and the potassium content is 2.5 to 4%.
[10] A step of injecting an animal-derived organic raw material into a stirring and mixing granulator characterized by a pin shape to granulate it;
A step of drying the granules obtained in the granulation step; and
a step of separating the dried granules obtained in the drying step into granular organic fertilizers having particle sizes of 2 to 8 mm using a sieve;
[11] The manufacturing method according to [10], wherein the moisture content of the animal-derived organic raw material is 50 to 64%.
[12] The production method according to [11], characterized in that the input amount of organic raw materials of animal origin is 1 ton/hour or less.
[13] The manufacturing method according to [12], characterized in that the rotation speed of the stirring/mixing granulator is 100 to 300 rpm.
[14] The manufacturing method according to [13], wherein the drying step is drying in the sun or using a dryer.
[15] The manufacturing method according to [14], wherein the amount of the dried granules rejected by sieving is 35% or less.
[16] The manufacturing method according to [15], wherein the animal-derived organic raw material is livestock manure compost or livestock manure.
[17] The manufacturing method according to any one of [10] to [16], characterized in that the pin shape of the stirring/mixing granulator is such that a large number of pins of the same size are arranged spirally at equal intervals on the rotation shaft.
[18] A step of granulating an animal-derived organic raw material using a stirring and mixing granulator characterized by having a large number of pins of the same size arranged spirally at equal intervals on a rotating shaft;
A step of drying the granules obtained in the granulation step; and
The dry granules obtained in the drying step are separated into granular organic fertilizers having a particle size of 2 to 8 mm using a sieve.
a method for producing an organic fertilizer, characterized in that the nitrogen content is 1.5 times or more that of the organic raw material, the phosphorus content is 1.5 times or more that of the organic raw material, and the potassium content is 1.3 times or more that of the organic raw material;
[19] A method for producing an organic fertilizer according to [10] or [18], characterized in that the animal-derived organic raw material is cow dung or cow dung compost, and the component content of nitrogen is 1.5 to 4.5%, the component content of phosphorus is 1.5 to 5%, and the component content of potassium is 2.5 to 6%.
[20] The method for producing an organic fertilizer according to [10] or [18], characterized in that the animal-derived organic raw material is swine manure or swine manure compost, and has a component content of 3 to 9% nitrogen, 3 to 12% phosphoric acid, and 2 to 7% potassium; and [21] the method for producing an organic fertilizer according to [10] or [18], characterized in that the animal-derived organic raw material is chicken manure or chicken manure compost, and has a component content of 3 to 9% nitrogen, 3 to 15% phosphoric acid, and 2 to 10% potassium.

The present invention provides a granular organic fertilizer that is odorless, rich in active ingredients, and can be mixed with chemical fertilizers for spraying, as well as a method for producing the granular organic fertilizer.

Perspective view of the external and internal structure of a pin-type agitation mixer granulator Vertical (A) and horizontal (B) views of the internal structure of a pin-type agitation mixer granulator A diagram showing the relationship between the moisture content of cow manure compost raw material and the particle size distribution of the granulated material Comparison photograph of conventional granular product (pellets) and the product of this invention Nitrogen, phosphorus, and potassium (potassium) contents (%) in the raw compost used in the production of the present invention under various drying conditions and in the granular compost (granular organic fertilizer) that is the product of the present invention The concentration ratio of nitrogen, phosphorus, and potassium in the granular compost (granular organic fertilizer) that is the product of this invention compared to the raw compost used in the production of this invention under various drying conditions.

In the present invention, animal-derived organic raw materials refer to organic substances produced and excreted by animals that are typically used as fertilizers, and livestock manure or livestock manure compost can preferably be used.

Examples of livestock manure include cow manure, pig manure, chicken manure, etc. The present invention is a technology that can handle the treatment of these livestock manures, and therefore any livestock manure raw material can be used to produce granular organic fertilizer, but since the blending ratios of phosphorus, nitrogen, potassium, etc. vary depending on the type of livestock, for example, chicken manure or pig manure is preferably used as the raw material to produce a fertilizer rich in phosphorus and nitrogen, and cow manure is preferably used as the raw material to produce a fertilizer rich in potassium.
Compost is, for example, a material made by piling up organic materials, fermenting them, and then applying them to the soil and allowing them to decompose until they no longer cause damage to agricultural crops.

In this invention, organic fertilizer refers to organic fertilizers specified in the official specifications of the Act on Assurance of Fertilizer Quality, as well as sludge fertilizers and special fertilizers specified in the Act on Assurance of Fertilizer Quality. Examples of special fertilizers include animal waste, ash from the combustion of animal waste, and compost. With regard to special fertilizers in particular, there is a notice from the Ministry of Agriculture, Forestry and Fisheries designating special fertilizers, which specifies the specific fertilizers that can be used. For example, rice bran, fermented rice bran, vegetable oil cake and its powder (vegetable oil cake and its powder made from plant seed waste), herbaceous plant seed shell oil cake and its powder, nut oil cake and its powder (excluding kapok oil cake and its powder; the same applies below), coffee grounds, soybean waste and its powder (soybean waste or soybeans that have been deteriorated by wetting, etc., heated and then compressed, and its powder), tobacco waste fertilizer and its powder (excluding undenatured tobacco waste fertilizer powder), dried algae and its powder, cottonseed dregs fertilizer, mugwort dregs, wood ash (excluding earthen ash), charcoal fertilizer, clay residue, glue residue (excluding dried residue from extracting gelatin from ossein, and only those that have undergone control measures when using raw materials derived from cattle, etc., and for those made from parts of cattle, etc., These include fertilizers manufactured using a process confirmed by the Minister of Agriculture, Forestry and Fisheries as being free of spinal columns and other materials, fish scales (excluding steamed fish scales and their powder), poultry processing waste fertilizers (excluding steamed feather meal (including steamed feathers)), fermented dried manure fertilizers (obtained by anaerobic fermentation of human waste), ash from the combustion of animal waste, and compost (straw, rice husks, bark, animal waste, and other organic matter of plant and animal origin (excluding sludge and fish and shellfish organs) piled or stirred and allowed to rot (including those using urea, ammonium sulfate, and other materials that promote rot). In the case of using raw materials derived from cattle and other animals, only those that have undergone control measures must be used, and in the case of using parts of cattle and other animals, only those manufactured using a process confirmed by the Minister of Agriculture, Forestry and Fisheries as being free of spinal columns and other materials). Organic fertilizers specified in official specifications and sludge fertilizers must be mixed with special fertilizers.

Organic fertilizers are generally converted into a form that can be used by plants and into a form that can be used by plants in the soil. In particular, the latter form is thought to be converted into a form that can be used by crops by being mineralized in the soil by the action of microorganisms, etc.

The organic fertilizer of the present invention is a granular organic fertilizer with a particle size of 2 to 8 mm, and is circular rather than pellet-shaped. Because the organic fertilizer of the present invention has such a shape and size, it can be mixed with a chemical fertilizer and sprayed mechanically. While any method can be used to measure the particle size of the granular fertilizer, sieving is preferred for its simplicity. The chemical fertilizer to be sprayed in combination with the organic fertilizer of the present invention refers to ordinary fertilizers defined in the Fertilizer Control Act, excluding organic fertilizers (including sludge compost). Nitrogen-based chemical fertilizers include ammonia-based fertilizers such as ammonium sulfate, ammonium chloride, and ammonium phosphate, which are produced using ammonia synthesized from atmospheric nitrogen as a raw material; nitrate-based fertilizers such as ammonium nitrate, calcium nitrate, and potassium nitrate; amide-based fertilizers such as urea and urea-aldehyde condensates; and calcium nitrous oxide synthesized from atmospheric nitrogen. Compound fertilizers and compound fertilizers formed by reacting or blending these fertilizers are also included in the chemical fertilizer of the present invention.

The organic fertilizer of the present invention is characterized by its improved three fertilizer elements compared to organic raw materials derived from animals, and its compact granular fertilizer can supply the soil with more of these three fertilizer elements than organic raw materials derived from animals. The three fertilizer elements are nitrogen, phosphorus, and potassium.

Nitrogen is an essential element for plants, and is found in a variety of plant compounds, including the amino acids that make up proteins, the nucleic acid bases that make up nucleotides, the membrane lipid phosphatidylethanolamine, amino sugars such as glucosamine, and secondary metabolites such as alkaloids and lignin. Within the appropriate range, the more nitrogen is provided, the more chloroplasts there are and the higher the yield.

In the organic fertilizer of the present invention, the nitrogen content increases by at least 1.5 times, preferably 1.5 to 4 times, and more preferably 1.5 to 3 times, compared to the organic raw material.

Specifically, when cow manure is used as the raw material, the nitrogen content is 1.5-4.5%, preferably 1.5-3%, and more preferably 1.5-2.5%. When pig manure is used as the raw material, the nitrogen content is 3-9%, preferably 3-6%, and more preferably 3-4.5%. When chicken manure is used as the raw material, the nitrogen content is 3-9%, preferably 3-7%, and more preferably 4-6%.

Plant compounds that contain phosphate include nucleic acids, phospholipids that form cell membranes, adenosine triphosphate, the energy currency of living organisms, and ribulose-1,5-bisphosphate, which is involved in photosynthesis. Many proteins are phosphorylated and dephosphorylated by kinases and phosphatases, controlling reactions within the body. Because of these important functions within the body, phosphorus is important for plant growth, seed germination, and flowering.

In the organic fertilizer of the present invention, the amount of phosphorus increases by at least 1.5 times, preferably 1.5 to 3.5 times, and more preferably 1.5 to 3 times, compared to the organic raw material.

Specifically, when cow manure is used as the raw material, the phosphoric acid content is 1.5-5%, preferably 1.5-3.5%, and more preferably 1.5-3%. When pig manure is used as the raw material, the phosphoric acid content is 3-12%, preferably 3-8%, and more preferably 3-5%. When chicken manure is used as the raw material, the phosphoric acid content is 3-15%, preferably 3-8%, and more preferably 3-5%.

Unlike other macronutrients, potassium does not become a constituent element of metabolic biomolecules within plants, but functions as an inorganic salt dissolved in plant fluids. When potassium ions move through ion channels to other cells, the water potential of that cell decreases, causing water movement. Plants maintain a lower water potential in their leaf blades relative to the rhizosphere, and absorb water based on this difference. In komatsuna and spinach, there is a positive correlation between the amount of water and potassium content per dry leaf weight. Potassium also activates plant enzymes, promoting the synthesis of carbohydrates and proteins, regulating the amount of water within the plant, and the synthesis of chlorophyll precursors required for photosynthesis. It also determines the color and shape of fruit and promotes an increase in Brix sugar content. Therefore, high-quality fruit is produced in potassium-rich soil.

In the organic fertilizer of the present invention, potassium is increased by at least 1.3 times, preferably 1.3 to 4 times, and more preferably 1.3 to 3 times, compared to the organic raw material.

Specifically, when cow manure is used as the raw material, the potassium content is 2.5-6%, preferably 2.5-5%, and more preferably 3-5%. When pig manure is used as the raw material, the potassium content is 2-7%, preferably 2-5%. When chicken manure is used as the raw material, the potassium content is 2-10%, preferably 2-7%, and more preferably 2.5-4%.

In the method for producing granular organic fertilizer of the present invention, the step of injecting animal-derived organic raw materials into a pin-shaped agitation mixer granulator to granulate them comprises the steps of preparing the animal-derived organic raw materials and injecting them into the pin-shaped agitation mixer granulator, and granulating the animal-derived organic raw materials injected into the granulator.

The animal-derived organic raw materials used in the manufacturing method of the present invention have the same meaning as above, and refer to organic substances produced and excreted by animals that are typically used as fertilizers, preferably livestock manure or livestock manure compost.

Examples of livestock manure include cow manure, pig manure, chicken manure, etc. The present invention is a technology that can handle the treatment of these livestock manures, and therefore any livestock manure raw material can be used to produce granular organic fertilizer, but since the blending ratios of phosphorus, nitrogen, potassium, etc. vary depending on the type of livestock, for example, chicken manure or pig manure is preferably used as the raw material to produce a fertilizer rich in phosphorus and nitrogen, and cow manure is preferably used as the raw material to produce a fertilizer rich in potassium.
Compost is, for example, a material made by piling up organic materials, fermenting them, and then applying them to the soil and allowing them to decompose until they no longer cause damage to agricultural crops.

Animal-derived organic raw materials should have a moisture content of 50-64%, preferably 58-64% when using cow manure or cow manure compost, and 52-64% when using chicken manure compost or pig manure compost. For animal-derived organic raw materials with low moisture content, simply add water to adjust the moisture content to 50-64%, and for raw materials with a moisture content of 64% or more, the moisture content can be adjusted by heating or other methods. The raw materials adjusted in this way are then fed into the granulator.

The input rate should be 2 tons/hour or less, preferably 1 ton/hour or less, and more preferably 0.5 tons/hour or less.

In this invention, the stirring/mixing granulator characterized by its pin shape is preferably a granulator with a structure in which a large number of pins of the same size are arranged spirally and at equal intervals on the rotating shaft of the stirring/mixing granulator. A specific example is shown in Figure 1, which shows a perspective view of the internal and external structure, and Figure 2, which shows the vertical (A) and horizontal (B) views of the internal structure, of the stirring/mixing granulator, in which pin-shaped protrusions are arranged spirally on the rotating shaft. The pins are all the same shape and are arranged at equal intervals.

The granulation temperature is 20°C to 60°C, and the granulation humidity is 80% or higher. The rotation speed needs to be adjusted depending on the motor output of the granulator, and granulation can be carried out at, for example, 100 to 300 rpm, preferably 150 to 300 rpm, and more preferably 180 to 260 rpm.
The resulting granules are sized using a size sizing machine, if necessary.

In the method for producing a granular organic fertilizer of the present invention, the step of drying the granules obtained in the granulation step refers to a step of evaporating the moisture from the granules obtained in the granulation step by natural sun drying or using a dryer.

Natural sun drying is a device that uses natural energy such as solar energy and wind to dry out the moisture in compost. If the amount of compost is small, granular organic compost can be piled up in trays in a plastic greenhouse to a depth of about 2-4 cm and left to dry for 4-10 days. For larger scale compost facilities, it is preferable to attach a fan or other ventilation device to the greenhouse to speed up drying and to install a self-propelled agitator to ensure uniform drying. Under these conditions, drying can be carried out for 7-30 days, preferably 10-17 days.

Drying can be done using any dryer used for industrial purposes, such as a rotary drum dryer, a rotary triple screw dryer, or a rotary kiln, as long as it is suitable for drying large quantities of granules. However, a rotary kiln is preferred. The drying temperature and time will vary depending on the amount of granules being processed, but for approximately 15 kg of granules, heating at a temperature of 150°C to 250°C for 15 to 80 minutes, or preferably at a temperature of 180°C to 220°C for 20 to 50 minutes, will suffice.

At the end of the drying process, granules that do not meet the particle size standard for granular organic fertilizer of 2 to 8 mm will account for 35% or less of the total granules, preferably 25% or less. These non-standard granules can be removed by sieving. Specifically, the dried granules can be sieved in a sieving machine that complies with the sieving test method of the Japanese Industrial Standards to produce circular granular organic fertilizer with a particle size of 2 to 8 mm.

Industrially, sieving machines are mainly divided into vibrating and rotary types. Vibrating machines sift the input materials by vibrating a sieve mesh up and down. There may also be multiple sieve meshes, allowing for step-by-step sieving. Rotary machines are also called trommels, and sift the input materials by rotating a cylindrical sieve. Another advantage is that, because the input materials are sieved inside the machine, they produce less noise than vibrating screens, etc.

The method for producing granular organic fertilizer of the present invention provides a granular organic fertilizer made from animal-derived organic raw materials, having a particle size of 2 to 8 mm, characterized by a nitrogen content of at least 1.5 times that of the organic raw materials, a phosphorus content of at least 1.5 times that of the organic raw materials, and a potassium content of at least 1.3 times that of the organic raw materials.

In the granular fertilizer obtained by the manufacturing method of the present invention, the three major elements of the fertilizer change as follows:

(1) The nitrogen content increases by 1.5 times or more, preferably 1.5 to 4 times, more preferably 1.5 to 3 times, compared to the organic raw material.
Specifically, when cow manure is used as the raw material, the nitrogen content is 1.5 to 4.5%, preferably 1.5 to 3%, and more preferably 1.5 to 2.5%. When pig manure is used as the raw material, the nitrogen content is 3 to 9%, preferably 3 to 6%, and more preferably 3 to 4.5%. When chicken manure is used as the raw material, the nitrogen content is 3 to 9%, preferably 3 to 7%, and more preferably 4 to 6%.

(2) The amount of phosphoric acid increases by 1.5 times or more, preferably 1.5 to 3.5 times, more preferably 1.5 to 3 times, compared to the amount of organic raw material.
Specifically, when cow manure is used as the raw material, the phosphoric acid content is 1.5 to 5%, preferably 1.5 to 3.5%, and more preferably 1.5 to 3%. When pig manure is used as the raw material, the phosphoric acid content is 3 to 12%, preferably 3 to 8%, and more preferably 3 to 5%. When chicken manure is used as the raw material, the phosphoric acid content is 3 to 15%, preferably 3 to 8%, and more preferably 3 to 5%.

(3) The amount of potassium increases by 1.3 times or more, preferably 1.3 to 4 times, more preferably 1.3 to 3 times, compared to the amount of the organic raw material.
Specifically, when cow manure is used as the raw material, the potassium content is 2.5 to 6%, preferably 2.5 to 5%, and more preferably 3 to 5%. When pig manure is used as the raw material, the potassium content is 2 to 7%, preferably 2 to 5%. When chicken manure is used as the raw material, the potassium content is 2 to 10%, preferably 2 to 7%, and more preferably 2.5 to 4%.

Example 1
Using cow dung compost produced on a farm as the organic raw material, the following production study was carried out using a stirring and mixing granulator (manufactured by Zhangjiagang MG Machinery Co., Ltd.) whose internal and external structures are shown in perspective in Figure 1 and whose internal structure is shown in vertical (A) and horizontal (B) views in Figure 2, and which has pin-shaped protrusions arranged spirally on the rotating shaft.

(1) Preliminary test on the relationship between the amount of organic raw material input and the particle size of the granulated product. Using organic raw material made from cow manure compost, the relationship between the amount of organic raw material input into the granulator and the particle size of the granulated product was confirmed. When the relationship between the input amount and particle size was examined under conditions of a rotation speed of 213 rpm, a granulation temperature of 37 to 41°C, and a granulation humidity of 96 to 99% RH, it was found that at an input rate of 1.5 tons/hour, more than 50% of the particles were 2 mm or less in diameter, whereas at an input rate of 1 ton/hour, the rate of fine particles with a particle size of 2 mm or less was approximately 35%, and at an input rate of 0.5 tons/hour, the rate of fine particles with a particle size of 2 mm or less decreased to less than 30%.

(2) Preliminary test on the relationship between the rotation speed of the granulator and the particle size of the granulated material. The relationship between the rotation speed of the granulator and the particle size of the granulated material was examined when using organic raw material made from cow manure compost. The rotation speed was examined under the conditions of a granulation temperature of 38-42°C, a granulation humidity of 96-99% RH, and a dosage of 1 ton/hour. As a result, when the rotation speed was 235 rpm, fine particles with a particle size of 2 mm or less accounted for approximately 35%, and granules with a particle size of 8 mm or more accounted for approximately 10%. However, when the rotation speed was reduced to 213 rpm, fine particles with a particle size of 2 mm or less remained at approximately 35%, but granules with a particle size of 8 mm or more decreased to approximately 1%.

(3) Relationship between moisture content of organic raw material and particle size of granulated product Cow manure compost, which has a viscosity slightly different from that of chicken manure compost and swine manure compost, was used as the organic raw material and granulated at various moisture contents from 56% to 65% under the conditions of granulator rotation speed of 213 rpm, input amount of 1.0 ton/hour, granulation temperature of 23°C to 42°C, and granulation humidity of 94 to 99% RH. The relationship between the moisture content and particle size distribution of the resulting granular fertilizer was investigated. The results are shown in Figure 3.

The results in Figure 3 confirm that when cow manure compost is used, granular organic fertilizer with a particle size of 2 to 8 mm can be produced at a rate of nearly 70% when the moisture content of the organic raw material is between 58% and 64%.

In the production of organic fertilizer using conventional extrusion granulation methods, the moisture content of the organic raw materials needs to be reduced to approximately 30-40%, which requires heating to evaporate the moisture (Patent Document 1, Patent Document 3). However, the production method of the present invention does not require heating, which has been confirmed to help reduce production costs and prevent unpleasant odors.

The granules obtained in the granulation process were dried in the sun until all moisture was removed, and granular organic fertilizer with a particle size of 2 to 8 mm was collected using a standard sieve mesh specified in JIS Z8801.

Figure 4 shows a photograph comparing the shapes of the resulting granular organic fertilizer and organic fertilizer pellets obtained using conventional extrusion granulation methods.

From the comparison photograph in Figure 4, it can be seen that the granular organic fertilizer of the present invention has a shape and size that allows it to be mixed with chemical fertilizer, and is in a form that is suitable for mechanical application to fields.

Furthermore, the granular fertilizer of this invention had significantly improved odor compared to conventional fertilizers made from cow manure compost.

Example 2 (Production of granular organic fertilizer using cow dung compost as a raw material)
Using cow dung compost with a moisture content of 62% as the raw material, organic fertilizer was granulated using the same granulator as used in Example 1 under the following conditions: granulator rotation speed: 213 rpm, raw material input rate: 1.0 ton/hour, granulation temperature: 14.6°C, granulation humidity: 92.2% RH (temperature and humidity logger: SK-L754, SKL-754 sensor: SK-L754-2, manufactured by Sato Keiryoki Mfg. Co., Ltd.).

The granules obtained from the granulation process were divided into four groups, A to D, to examine the effect of the drying method. Samples A and B were dried in the sun, and samples C and D were dried using a dryer. Samples A and B were stored in a greenhouse for eight days to produce granular fertilizer samples A and B. Sample C was produced by drying 16 kg of granules at 200°C for 40 minutes using a rotary kiln (manufactured by Zhangjiagang MG Machinery Co., Ltd.) as the dryer, producing granular fertilizer sample C. Sample D was produced by drying 16 kg of granules at 200°C for 20 minutes using a rotary kiln (manufactured by Zhangjiagang MG Machinery Co., Ltd.).

The content of nitrogen, phosphorus, and potassium, which are active ingredients in fertilizer, was measured for the resulting granular fertilizer and the cow manure compost used as a raw material. The measurement method was as follows, in accordance with the Fertilizer Testing Methods (2021) of the Food and Agricultural Materials Inspection Center (FAMIC).

To measure the nitrogen content, sulfuric acid, potassium sulfate, and copper (II) sulfate pentahydrate were added to the analytical sample, and the sample was pretreated using the Kjeldahl method to convert all nitrogen to ammonium ions. Sodium hydroxide solution was then added and the sample was subjected to steam distillation. The separated ammonia was collected with sulfuric acid, and the excess sulfuric acid was neutralized and titrated with sodium hydroxide solution to determine the total amount of nitrogen in the analytical sample, using the Kjeldahl method (4.1.1.a).

The phosphate content was measured using the ammonium vanadomolybdate spectrophotometric method (4.2.1.a), in which sulfuric acid, potassium sulfate, and copper (II) sulfate pentahydrate were added to the analytical sample, followed by Kjeldahl digestion to convert all phosphorus to phosphate ions, and the absorbance of the phosphorus vanadomolybdate produced by reaction with ammonium vanadate (V), hexaammonium heptamolybdate, and nitric acid was measured to determine the total amount of phosphate in the analytical sample.

The potassium content was measured using flame photometry (4.3.1.a), in which the analytical sample was pretreated by ashing and boiling in hydrochloric acid to convert all potassium to potassium ions, and the intensity of the emission line at a wavelength of 766.5 nm generated in the flame was measured to determine the total amount of potassium in the analytical sample. The results are shown in Table 1 and Figure 5.

From the results in Table 1 and Figure 5, it can be seen that the nitrogen content of the raw compost was 0.91%, but increased to 2.31% and 2.24% in sun-dried Samples A and B, respectively, while Sample C, obtained by mechanical drying, increased to 2.03%, and Sample D to 1.79%, both of which increased by approximately or more than double. This confirmed that the nitrogen content was significantly higher than the 1.1% of the known cow manure compost described in Non-Patent Document 1.

Regarding the phosphorus content, the nitrogen content, which was 0.98% in the raw compost, increased to 2.65% and 2.37% in sun-dried samples A and B, respectively, while sample C, obtained by mechanical drying, increased to 2.28% and sample D to 1.94%, both of which increased by approximately two to more than two times. This confirmed that the phosphorus content was significantly higher than the 1.1% phosphorus content of the publicly known cow manure compost described in Non-Patent Document 1.

Furthermore, the potassium content of the raw compost was 1.97%, but increased to 4.6% and 4.23% in sun-dried samples A and B, respectively, while sample C, obtained by mechanical drying, had a potassium content of 3.7%, and sample D had a potassium content of 3.17%, both of which increased by more than 1.5 times. This confirmed that the potassium content was significantly higher than the 2.1% of the known cow manure compost described in Non-Patent Document 1.

To confirm the relative concentration effect of the components, the nitrogen, phosphate, and potassium content of each sample A, B, C, and D was calculated relative to the raw compost, assuming that the nitrogen, phosphate, and potassium content of the raw compost was 1. The results are shown in Table 2 and Figure 6.

According to Table 2 and Figure 6, the granular organic fertilizer obtained by the manufacturing method of the present invention, Sample D, dried at 200°C for 40 minutes, had 1.97 times the nitrogen, 1.98 times the phosphorus, and 1.61 times the potassium of the raw compost. Sample C, dried at 200°C for 20 minutes, had 2.23 times the nitrogen, 2.33 times the phosphorus, and 1.88 times the potassium of the raw compost. In comparison, of the sun-dried granular organic fertilizers, Sample B had 2.46 times the nitrogen, 2.42 times the phosphorus, and 2.15 times the potassium of the raw compost, and Sample A had 2.54 times the nitrogen, 2.71 times the phosphorus, and 2.34 times the potassium of the raw compost, meaning that all of the fertilizer's major active ingredients were more than double those of the raw compost.

Example 3 (Production of granular organic fertilizer using chicken manure compost)
Poultry manure compost with a moisture content of 52.7% was used as the raw material, and granulation was carried out using the same granulator as used in Example 1 under the following conditions: granulator rotation speed: 213 rpm, raw material input rate: 1.0 ton/hour, granulation temperature: 37.0°C, granulation humidity: 98.0% RH (temperature and humidity logger: SK-L754, SKL-754 sensor: SK-L754-2, manufactured by Sato Keiryoki Mfg. Co., Ltd.).

The granules obtained in the granulation process were naturally dried in the sun (stored in a greenhouse for 8 days) to obtain granular fertilizer. It was visually observed that approximately 60 to 70% of the granulated fertilizer had been produced, with a size of 2 to 8 mm.
The content of nitrogen, phosphorus, and potassium, which are active ingredients in the fertilizer, was measured for the obtained granular fertilizer and the chicken manure compost used as a raw material. The measurement method was as follows, in accordance with the Fertilizer Testing Method (2021) of the Food and Agricultural Materials Inspection Center (FAMIC).

To measure the nitrogen content, sulfuric acid, potassium sulfate, and copper (II) sulfate pentahydrate were added to the analytical sample, and the sample was pretreated using the Kjeldahl method to convert all nitrogen to ammonium ions. Sodium hydroxide solution was then added and the sample was subjected to steam distillation. The separated ammonia was collected with sulfuric acid, and the excess sulfuric acid was neutralized and titrated with sodium hydroxide solution to determine the total amount of nitrogen in the analytical sample, using the Kjeldahl method (4.1.1.a).

The content of phosphoric acid was measured by the ammonium vanadomolybdate absorptiometry method (4.2.1.a), in which sulfuric acid, potassium sulfate, and copper (II) sulfate pentahydrate were added to the analytical sample, followed by Kjeldahl decomposition to convert total phosphorus to phosphate ions, which reacted with ammonium vanadate (V), hexaammonium heptamolybdate, and nitric acid to produce phosphorus vanadomolybdate, and the absorbance of this product was measured to determine the total amount of phosphoric acid in the analytical sample.
The results are shown in Table 3.

Compared to cow manure, chicken manure is rich in nitrogen and phosphorus at the raw compost stage, but when it is made into granular fertilizer, these components are further concentrated, with extremely high contents of 5.04% nitrogen and 3.84% phosphorus. Potassium was 1.58% in chicken manure raw compost, which was lower than the 1.97% found in cow manure compost, but this increased to 3.33% when made into granular fertilizer.

To confirm the relative concentration effect of the components, the nitrogen, phosphorus, and potassium content of the granular chicken manure fertilizer was calculated relative to the raw compost, assuming that the nitrogen, phosphorus, and potassium content of the raw compost was set to 1, and the results are shown in Table 4.

It was confirmed that by making the granular fertilizer, each component was concentrated 1.95 to 2.11 times, making it possible to produce a granular fertilizer rich in nitrogen and phosphorus that takes advantage of the properties of the chicken manure compost raw material.

Example 4 (Production of granular organic fertilizer using pig manure compost as a raw material)
Pig manure compost with a moisture content of 53.2% was used as the raw material, and granulation was carried out using the same granulator as used in Example 1 under the following conditions: granulator rotation speed: 213 rpm, input rate: 1.0 ton/hour, granulation temperature: 37.5°C, granulation humidity: 98.9% RH (temperature and humidity logger: SK-L754, SKL-754 sensor: SK-L754-2, manufactured by Sato Keiryoki Seisakusho Co., Ltd.). It was visually observed that approximately 70% of granulated fertilizer with a size of 2 to 8 mm was produced. The granules obtained from the granulation process (same as for cow manure compost) were naturally dried in the sun.

The content of nitrogen, phosphorus, and potassium, which are active ingredients in fertilizer, was measured for the resulting granular fertilizer and the pig manure compost used as a raw material. The measurement method was as follows, in accordance with the Fertilizer Testing Methods (2021) of the Food and Agricultural Materials Inspection Center (FAMIC).

To measure the nitrogen content, sulfuric acid, potassium sulfate, and copper (II) sulfate pentahydrate were added to the analytical sample, and the sample was pretreated using the Kjeldahl method to convert all nitrogen to ammonium ions. Sodium hydroxide solution was then added and the sample was subjected to steam distillation. The separated ammonia was collected with sulfuric acid, and the excess sulfuric acid was neutralized and titrated with sodium hydroxide solution to determine the total amount of nitrogen in the analytical sample, using the Kjeldahl method (4.1.1.a).

The phosphate content was measured using the ammonium vanadomolybdate spectrophotometric method (4.2.1.a), in which sulfuric acid, potassium sulfate, and copper (II) sulfate pentahydrate were added to the analytical sample, followed by Kjeldahl digestion to convert all phosphorus to phosphate ions, and the absorbance of the phosphorus vanadomolybdate produced by reaction with ammonium vanadate (V), hexaammonium heptamolybdate, and nitric acid was measured to determine the total amount of phosphate in the analytical sample.

The potassium content was measured by flame photometry (4.3.1.a), in which the analytical sample was pretreated by ashing and boiling in hydrochloric acid to convert the total amount of potassium into potassium ions, and the intensity of the emission line at a wavelength of 766.5 nm generated in the flame was measured to determine the total amount of potassium in the analytical sample.
The results are shown in Table 5.

Compared to cow manure, pig manure is also rich in nitrogen and phosphorus at the raw compost stage, but when it is made into granular fertilizer, these components are further concentrated, with extremely high contents of 3.99% nitrogen and 3.81% phosphorus. Potassium was 1.34% in the pig manure raw compost compared to 1.97% in the cow manure compost, but this increased to 2.69% when made into granular fertilizer.

To confirm the relative concentration effect of the components, the nitrogen, phosphorus, and potassium content of the granular swine manure fertilizer was calculated relative to the raw compost, assuming that the nitrogen, phosphorus, and potassium content of the raw compost was set to 1, and the results are shown in Table 6.

It was confirmed that by making the granular fertilizer, each component was concentrated 1.84 to 2.05 times, making it possible to produce a granular fertilizer rich in nitrogen and phosphorus that takes advantage of the properties of the swine manure compost raw material.

As described above, in a method for producing organic fertilizer using animal-derived organic raw materials, it has been confirmed that by carrying out granulation using an agitation/mixing granulator characterized by a large number of pins of the same size arranged at equal intervals in a spiral, it is possible to produce a granular fertilizer that, unlike conventional organic fertilizers, is easy to blend with chemical fertilizers. Furthermore, by examining the moisture content of the animal-derived organic raw materials, it has been confirmed that it is possible to produce granules containing 65% or more of granular organic fertilizer with a particle size of 2 to 8 mm, which makes it easy to blend with chemical fertilizers, and it has been confirmed that this manufacturing method has high product production efficiency.

The granular organic fertilizer, with a particle size of 2-8 mm, obtained using this production method contains roughly twice as much of the three main components of fertilizer: nitrogen, phosphorus, and potassium, and is expected to have significantly superior fertilizing effects. It also has less of the odor characteristic of organic fertilizers than conventional organic fertilizers. In particular, cow manure fertilizer, which has traditionally been known to accumulate in soil but is said to contain less of the three main elements than other livestock, has been confirmed to be a beneficial fertilizer without any of these drawbacks.

1. Granulator 2. Rotating shaft 3. Inlet 4. Outlet 5. Pin 6. Screw blade 7. Flange 8. Motor

Claims (2)

A granular organic fertilizer that is made from cow dung compost or cow dung raw material (excluding those containing other fertilizer components) and has a particle size of 2 to 8 mm and is circular rather than pellet-shaped , characterized in that the nitrogen content is 1.5 times or more that of the cow dung compost or cow dung raw material , with a component content of 1.5 to 2.5% , the phosphorus content is 1.5 times or more that of the cow dung compost or cow dung raw material, with a component content of 1.5 to 3%, and the potassium content is 1.3 times or more that of the cow dung compost or cow dung raw material, with a component content of 3 to 5% . 2. The organic fertilizer according to claim 1, wherein the component contents are 1.79 to 2.5% for nitrogen, 1.94 to 3% for phosphorus, and 3.17 to 5% for potassium.