Compound fertilizer for improving pH value of soil and preparation method thereof

Abstract

The invention relates to the technical field of compound fertilizer production, in particular to a compound fertilizer for improving the pH value of soil and a preparation method of the compound fertilizer. The component A comprises the following components in parts by weight: 10-20 parts of a porous carrier, 0.03-0.05 part of aspergillus niger and 1-2 parts of a water-soluble polymer, the aspergillus niger is loaded in pore channels of the porous carrier, and the surface of the porous carrier is coated with the water-soluble polymer; the component B comprises the following components in parts by weight: 1-2 parts of bagasse and 1-2 parts of bean dregs, and is used for providing necessary nitrogen source and carbon source for the propagation of aspergillus niger and promoting the growth of aspergillus niger; the component C comprises the following components in parts by weight: 20-30 parts of a phosphorus source fertilizer, 10-15 parts of a potassium source fertilizer and 30-40 parts of a nitrogen source fertilizer. The alkaline soil can be modified, the effect of improving the soil for a long time is achieved, and the soil improvement cost is saved.

Description

Technical Field

[0001] The invention relates to the technical field of compound fertilizer production, and in particular to a compound fertilizer for improving soil pH value and a preparation method thereof. Background Art

[0002] Alkaline soil refers to soil with a pH value greater than 7, that is, the hydroxide ions (OH - ) concentration is greater than the hydrogen ion (H + ) concentration. In practical applications, soils with a pH value above 7.3 are usually considered alkaline soils.

[0003] The soil is alkaline, and this environment with a pH value of >7.3 will have many effects on crop planting, such as reducing nutrient absorption and affecting soil nutrient effectiveness, such as affecting soil structure and soil permeability, which in turn affects crop planting and reduces crop yields.

[0004] In the prior art, the following improvement measures are generally taken to address the problem of excessive soil alkalinity: (1) The application of organic fertilizer can increase the organic matter content in the soil and improve the physical and chemical properties of the soil. However, the physical and chemical properties of organic fertilizer are unstable, and it is difficult to effectively improve soils with high alkalinity.

[0005] (2) The application of acidic fertilizers, such as azurite, phosphotyrite, ferrous sulfate and other acidic fertilizers, can neutralize the alkaline substances in the soil and lower the pH value of the soil. However, its disadvantage is that the amount of fertilizer applied is limited. After the acidic substances react completely, they need to be applied for a long time and have no long-term improvement effect. It is especially not suitable for soils that are prone to alkalinity.

[0006] (3) Planting alkaline-tolerant crops: Select crops that are suitable for growing in alkaline soils. These crops usually have strong alkaline resistance and can grow normally in alkaline soils and obtain higher yields. However, the disadvantage is that the types of alkaline resistance are limited and the cost is high. Summary of the invention

[0007] In view of the technical problem that alkaline soil is difficult to improve, the present invention provides a compound fertilizer for improving soil pH value and a preparation method thereof, wherein Aspergillus niger is loaded in the pores of a porous carrier, and acidic substances such as citric acid produced by the metabolism of Aspergillus niger are used to modify the alkaline soil, and at the same time, the Aspergillus niger loaded in the pores of the porous carrier is slowly released to allow the active Aspergillus niger to gradually multiply, thereby achieving the effect of long-term soil improvement and saving costs.

[0008] In a first aspect, the present invention provides a compound fertilizer for improving soil pH, comprising component A, component B and component C; Component A includes the following components in parts by weight: 10-20 parts of a porous carrier, 0.03-0.05 parts of Aspergillus niger, and 1-2 parts of a water-soluble polymer, wherein the Aspergillus niger is loaded in the pores of the porous carrier, and the water-soluble polymer is coated on the surface of the porous carrier; Component B includes the following components in parts by weight: 1-2 parts of bagasse and 1-2 parts of bean dregs, which provide the necessary nitrogen and carbon sources for the reproduction of Aspergillus niger and promote the growth of the fungus; Component C includes the following components in parts by weight: 20-30 parts of phosphorus source fertilizer, 10-15 parts of potassium source fertilizer, and 30-40 parts of nitrogen source fertilizer.

[0009] Furthermore, the porous carrier is one of biochar, porous silica, and zeolite powder, and the particle size of the porous carrier is 2-5 mm.

[0010] Furthermore, the water-soluble polymer is one of sodium alginate, sodium carboxymethyl cellulose and polyvinyl alcohol.

[0011] Furthermore, the phosphorus source fertilizer is at least one of diammonium phosphate, triammonium phosphate, monoammonium phosphate, and calcium phosphate.

[0012] Furthermore, the potassium source fertilizer is at least one of potassium chloride, potassium sulfate, and potassium dihydrogen phosphate.

[0013] Furthermore, the nitrogen source fertilizer is at least one of urea, ammonium bicarbonate, ammonium sulfate, and ammonium chloride.

[0014] In a second aspect, the present invention provides a method for preparing a compound fertilizer for improving soil pH, comprising the following steps: S1, preparing Aspergillus niger fermentation liquid, immersing the porous carrier in the Aspergillus niger fermentation liquid, and drying to obtain a porous carrier with Aspergillus niger loaded in the pores; S2, adding a water-soluble polymer into water and stirring to obtain an aqueous solution of the water-soluble polymer, using the aqueous solution of the water-soluble polymer as a coating material, and using a porous carrier with Aspergillus niger loaded in the pores as a core material, using a coating machine to coat the water-soluble polymer on the surface of the porous carrier, and drying to form a film of the water-soluble polymer on the surface of the porous carrier to block the pores on the surface of the biochar, thereby obtaining component A; S3, mixing component A, component B and component C and stirring them uniformly to obtain a finished product.

[0015] Furthermore, in step S1, the porous carrier is pre-treated by crushing.

[0016] Furthermore, in step S2, drying includes low-temperature drying or natural drying.

[0017] The beneficial effects of the present invention are: (1) The present invention loads Aspergillus niger in the pores of a porous carrier. Only when it is applied to the soil, the water-soluble polymer film dissolves in the presence of water, and external water enters the pores to provide conditions for the reproduction of Aspergillus niger. The alkaline soil is modified by using acidic substances such as citric acid produced by the metabolism of Aspergillus niger. The modification effect is good and the invention is suitable for the modification of soil with high alkalinity.

[0018] (2) The Aspergillus niger loaded in the pores of the porous carrier of the present invention is slowly released, so that the active Aspergillus niger gradually multiplies, thereby achieving the effect of long-term soil improvement.

[0019] (3) The present invention can improve alkaline soil by fertilizing, eliminating the need to plant alkali-resistant crops, thus saving costs. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0021] Example 1 A method for preparing a compound fertilizer for improving soil pH value comprises the following steps: S1, preparing Aspergillus niger fermentation liquid, soaking 10 parts of crushed pretreated biochar (particle size of 2-5 mm) in the Aspergillus niger fermentation liquid, and drying to obtain biochar loaded with Aspergillus niger in the pores, wherein the loading amount of Aspergillus niger is 0.03 parts; S2, adding 1 part of sodium alginate into water and stirring to obtain a sodium alginate aqueous solution with viscosity, using sodium alginate as a coating material, using biochar with Aspergillus niger loaded in the pores as a core material, using a coating machine to coat the sodium alginate on the surface of the biochar, and drying to remove moisture so that the sodium alginate forms a film on the surface of the biochar; S3. The product obtained in step (2) is mixed with 1 part of bagasse, 1 part of bean dregs, 20 parts of diammonium phosphate, 10 parts of potassium chloride and 30 parts of urea, and stirred to obtain a finished product.

[0022] Example 2 A method for preparing a compound fertilizer for improving soil pH value comprises the following steps: S1. Prepare Aspergillus niger fermentation liquid, soak 15 parts of crushed pretreated biochar (particle size of 2-5 mm) in the Aspergillus niger fermentation liquid, and dry to obtain biochar loaded with Aspergillus niger in the pores, wherein the loading amount of Aspergillus niger is 0.04 parts; S2, adding 1.5 parts of sodium carboxymethyl cellulose into water and stirring to obtain a sodium carboxymethyl cellulose aqueous solution with viscosity, using sodium carboxymethyl cellulose as a coating material, using biochar with Aspergillus niger loaded in the pores as a core material, using a coating machine to coat the sodium carboxymethyl cellulose on the surface of the biochar, and drying to remove moisture so that the sodium carboxymethyl cellulose forms a film on the surface of the biochar; S3. The product obtained in step (2) is mixed with 2 parts of bagasse, 2 parts of bean dregs, 25 parts of triammonium phosphate, 13 parts of potassium sulfate and 35 parts of urea, and stirred to obtain a finished product.

[0023] Example 3 A method for preparing a compound fertilizer for improving soil pH value comprises the following steps: S1, preparing Aspergillus niger fermentation liquid, soaking 20 parts of crushed pre-treated zeolite powder (particle size of 2-5 mm) in the Aspergillus niger fermentation liquid, and drying to obtain zeolite powder loaded with Aspergillus niger in the pores, and the loading amount of Aspergillus niger is 0.05 parts; S2, putting 2 parts of sodium carboxymethyl cellulose into water and stirring to obtain a sodium carboxymethyl cellulose aqueous solution with viscosity, using sodium carboxymethyl cellulose as a coating material, using zeolite powder loaded with Aspergillus niger in the pores as a core material, using a coating machine to coat the sodium carboxymethyl cellulose on the surface of the zeolite powder, drying to remove moisture so that the sodium carboxymethyl cellulose forms a film on the surface of the zeolite powder; S3. The product obtained in step (2) is mixed with 1.5 parts of bagasse, 1.5 parts of bean dregs, 30 parts of monoammonium phosphate, 15 parts of potassium sulfate and 40 parts of ammonium bicarbonate, and stirred to obtain a finished product.

[0024] Test example: Soil improvement experiment The experimental area selected was a 60-square-meter saline-alkali land experimental field in the coastal area. According to measurements, the average salt content in the area was 0.46%, the average pH value was 8.9, the soil moisture content was 8%-10%, and the organic matter content in the soil was 7.1~7.5g / kg.

[0025] The test area was divided into three parts according to the area, marked as test field I, test field II, and test field III, and samples were taken 5 times at different locations in each test field. The pH value was measured using pH test paper, and the average pH value of each test field was calculated. The compound fertilizer for improving the soil pH value obtained in Examples 1-3 was applied to test field I, test field II, and test field III respectively. The fertilizer was applied in March at a dosage of 0.6 kg per square meter, and then the soil was deep plowed once to a depth of 30 cm. Every other month, the average pH value of each test field was calculated according to the above method for 5 months. The specific pH value data are shown in Table 1.

[0026] Table 1 pH value change data of each experimental field

[0027] It can be seen from Table 1 that the present invention achieves the effect of long-term soil improvement, which can last for a growth cycle of general crops.

[0028] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily conceive of changes or substitutions within the technical scope disclosed by the present invention, and such changes or substitutions shall be within the scope of protection of the present invention.

Claims

1. A compound fertilizer for improving soil pH, characterized in that: Comprising component A, component B and component C; Component A includes the following components in parts by weight: 10-20 parts of a porous carrier, 0.03-0.05 parts of Aspergillus niger, and 1-2 parts of a water-soluble polymer, wherein the Aspergillus niger is loaded in the pores of the porous carrier, and the water-soluble polymer is coated on the surface of the porous carrier; Component B comprises the following components in parts by weight: 1-2 parts of bagasse and 1-2 parts of bean dregs; Component C includes the following components in parts by weight: 20-30 parts of phosphorus source fertilizer, 10-15 parts of potassium source fertilizer, and 30-40 parts of nitrogen source fertilizer.

2. A compound fertilizer for improving soil pH as claimed in claim 1, characterized in that: The porous carrier is one of biochar, porous silica and zeolite powder, and the particle size of the porous carrier is 2-5 mm.

3. The compound fertilizer for improving soil pH value according to claim 1, characterized in that: The water-soluble polymer is one of sodium alginate, sodium carboxymethyl cellulose and polyvinyl alcohol.

4. The compound fertilizer for improving soil pH value according to claim 1, characterized in that: The phosphorus source fertilizer is at least one of diammonium phosphate, triammonium phosphate, monoammonium phosphate, and calcium phosphate.

5. The compound fertilizer for improving soil pH value according to claim 1, characterized in that: The potassium source fertilizer is at least one of potassium chloride, potassium sulfate, and potassium dihydrogen phosphate.

6. A compound fertilizer for improving soil pH as claimed in claim 1, characterized in that: The nitrogen source fertilizer is at least one of urea, ammonium bicarbonate, ammonium sulfate and ammonium chloride.

7. A method for preparing the compound fertilizer for improving soil pH as claimed in claim 1, characterized in that: The steps include: S1, preparing Aspergillus niger fermentation liquid, immersing the porous carrier in the Aspergillus niger fermentation liquid, and drying to obtain a porous carrier with Aspergillus niger loaded in the pores; S2, adding a water-soluble polymer into water and stirring to obtain an aqueous solution of the water-soluble polymer, using the aqueous solution of the water-soluble polymer as a coating material, using a porous carrier with Aspergillus niger loaded in the pores as a core material, using a coating machine to coat the water-soluble polymer on the surface of the porous carrier, and drying to form a film of the water-soluble polymer on the surface of the porous carrier, to obtain component A; S3, mixing component A, component B and component C and stirring them uniformly to obtain a finished product.

8. The method for preparing the compound fertilizer for improving soil pH value according to claim 7, characterized in that: In step S1, the porous carrier is pre-treated by crushing.

9. The method for preparing the compound fertilizer for improving soil pH value according to claim 7, characterized in that: In step S2, drying includes low-temperature drying or natural drying.

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