Soil-improving disease-resistant controlled-release fertilizer and preparation method thereof

Abstract

The invention relates to the technical field of sustained and controlled release fertilizers, in particular to a soil-improving disease-resistant sustained and controlled release fertilizer and a preparation method thereof. The preparation method comprises the following steps: (1) preparation of the nutrient core: weighing an organic fertilizer, an ammonium nitrogen fertilizer, a phosphate fertilizer, a potash fertilizer, a biological regulator, chelated medium trace elements and modified attapulgite, uniformly mixing, and granulating to obtain the nutrient core; (2) covering an organic polymer coating layer: dissolving polylactic acid in a solvent to form a composite solution, spraying the composite solution on the surface of the nutrient core, and drying to obtain an organic polymer coated nutrient core; and (3) covering a mineral coating layer. The outermost layer of the soil-improving disease-resistant controlled-release fertilizer provided by the invention is the mineral coating layer, the mineral coating layer can be gradually disintegrated after being applied to soil, mineral components can improve the physical structure of the soil, regulate the acid-base property of the soil and increase the content of organic matters in the soil after entering the soil, and inorganic and organic nutrients are slowly released into the soil through the organic polymer coating layer; nutrient substances are continuously supplied, and common diseases of the corn are prevented and controlled.

Description

Technical Field

[0001] The invention relates to the technical field of slow-release fertilizers, and in particular to a soil-improving and disease-resistant slow-release fertilizer and a preparation method thereof. Background Art

[0002] Improper fertilization is one of the key factors causing land degradation. Excessive use of chemical fertilizers not only causes non-point source pollution, but also accelerates the decomposition of soil organic matter, destroys the composition ratio of soil components, causes soil structure damage, causes soil compaction, decreased fertilizer efficiency, short fertilizer effect and other obstacle factors, affects the absorption of water and mineral nutrients by crop roots, and causes a decrease in crop yields.

[0003] Applying soil conditioner products is one of the main means of soil repair. At present, commonly used soil conditioner products include acidic soil conditioners, saline-alkali soil conditioners, heavy metal contaminated soil conditioners, etc. However, the results of long-term soil improvement practice show that the single application of soil conditioners cannot improve soil texture and structure in the long run. Only by using soil conditioners in combination with organic fertilizers, inorganic fertilizers and other fertilizers can the physical and chemical properties of the soil be effectively improved, the soil organic matter content can be increased, and the soil organic matter content can be improved to achieve the result of long-term soil improvement. However, applying different products in batches will increase labor costs, so there is an urgent need for a new product that efficiently combines fertilizers and soil conditioners. Summary of the invention

[0004] In view of the problem of increased labor costs caused by the separate application of soil conditioners and different products such as organic fertilizers and inorganic fertilizers, the present invention provides a soil-improving and disease-resistant slow-release fertilizer and a preparation method thereof. The soil-improving and disease-resistant slow-release fertilizer has a double-layer coating structure, which comprises, from the outside to the inside, a mineral coating layer, an organic polymer coating layer and a nutrient core. The mineral coating layer contains a variety of natural ingredients, which can improve the soil structure, adjust the soil acidity and alkalinity, and increase the soil organic matter content. After the mineral coating layer disintegrates, inorganic and organic nutrients are slowly released into the soil through the organic polymer coating layer, continuously supplying the nutrients required for crop growth, and playing a role in preventing and treating common corn diseases (corn leaf spot disease, corn stalk rot).

[0005] In a first aspect, the present invention provides a method for preparing a soil-improving disease-resistant slow-release fertilizer, comprising the following steps: (1) Preparation of nutrient core: weigh 20-30 parts of organic fertilizer, 20-25 parts of ammonium nitrogen fertilizer, 15-20 parts of phosphate fertilizer, 10-15 parts of potash fertilizer, 3-5 parts of biological regulator, 5-10 parts of chelated trace elements and 0-10 parts of modified attapulgite, mix well and granulate to prepare nutrient core; (2) Covering with an organic polymer coating layer: dissolving polylactic acid in a solvent to form a composite solution, spraying it on the surface of the nutrient core, and drying it to obtain an organic polymer coated nutrient core; (3) Covering with a mineral coating layer: Expanded perlite, vermiculite, biochar and shell powder are mixed evenly to obtain mineral material powder, and organic polymer coated nutrient cores are mixed evenly with the mineral material powder and granulated to obtain soil-improving and disease-resistant slow-release fertilizer granules.

[0006] Furthermore, in step (1), the organic fertilizer is prepared by composting one or more of silkworm manure, earthworm manure, peanut meal, soybean meal, bone meal, and chicken feathers; The ammonium nitrogen fertilizer is one or more of ammonium chloride, ammonium sulfate, ammonium bicarbonate, and ammonium nitrate; The phosphate fertilizer is one or more of monoammonium phosphate, diammonium phosphate, ammonium phosphate, and ammonium polyphosphate; Potash fertilizer is one or two of potassium chloride and potassium sulfate; The biological regulator is one or more of Bacillus subtilis, Bacillus megaterium, Bacillus gelatinus, Trichoderma, and Rhodopseudomonas palustris; The trace elements in the chelate are one or more of EDDHA chelated magnesium, EDDHA chelated iron, EDDHA chelated manganese, EDDHA chelated copper, and EDDHA chelated zinc; The preparation method of modified attapulgite is as follows: (a) Acid modification: The attapulgite was crushed and ground, and then passed through a 150-mesh sieve. Subsequently, 5 mol / L H3PO4 was added at a liquid-to-solid ratio of 5 mL / g. The mixture was heated in a water bath at 80 °C for 2 h, filtered, washed with distilled water, dried, and passed through a 150-mesh sieve to obtain the acidified modified attapulgite. (b) Organic modification: The acidified modified attapulgite prepared in step (a) was added to 0.05 mol / L of a surfactant at a liquid-to-solid ratio of 10 mL / g. After stirring and dispersing, the mixture was shaken and reacted at 25°C and 200 rpm for 24 h. The mixture was filtered, washed with distilled water, dried, and passed through a 150-mesh sieve to obtain modified attapulgite.

[0007] Furthermore, in step (b), the surfactant is hexadecyltrimethylammonium chloride.

[0008] Furthermore, step (2) further comprises adding sodium alginate to the prepared composite solution and stirring to mix well.

[0009] Furthermore, in step (2), the mass ratio of polylactic acid to sodium alginate is 90-95:5-10.

[0010] Furthermore, in step (2), the solvent is chloroform and methanol in a volume ratio of 10 to 15:1.

[0011] Furthermore, in the mineral material powder of step (3), the amount of expanded perlite is 40wt%~50wt%, the amount of vermiculite is 25wt%~35wt%, the amount of biochar is 15wt%~20wt%, and the amount of shell powder is 5wt%~10wt%.

[0012] Furthermore, in step (3), the biochar is one or more of corn cob biochar, peanut shell biochar, and straw biochar; The shell powder is one or more of oyster shell powder, mussel shell powder, pearl shell powder and scallop shell powder.

[0013] In a second aspect, the present invention provides a soil-improving and disease-resistant slow-release fertilizer prepared by the above-mentioned preparation method.

[0014] Furthermore, the particle size of the soil-improving disease-resistant slow-release fertilizer is 4.5-5 mm, the particle size of the organic polymer-coated nutrient core inside it is 3-3.5 mm, and the particle size of the nutrient core is 2-2.5 mm.

[0015] The beneficial effects of the present invention are: 1. The soil-improving disease-resistant slow-release fertilizer provided by the present invention has a double-layer coating structure, the outermost layer of which is a mineral coating layer. After being applied to the soil, it will gradually disintegrate. After the mineral components enter the soil, they can improve the physical structure of the soil and adjust the soil pH. The biochar component has the characteristics of large specific surface area and rich pore structure, which can provide a microenvironment for the reproduction of soil microorganisms and improve the biological properties of the soil. After the mineral coating layer disintegrates, the inorganic nutrients and organic nutrients in the nutrient core can be slowly released outward through the organic polymer coating layer, providing the nutrients required for crop growth for a long time. The bioregulator can activate nutrients such as phosphorus and potassium in the soil, and at the same time improve the stress resistance of crops.

[0016] 2. The soil-improving and disease-resistant slow-release fertilizer provided by the present invention uses environmentally friendly polylactic acid as the main coating material. After the internal nutrients are released, they will not cause pollution to the soil environment. The use of sodium alginate as a coating additive further enhances the nutrient slow-release performance.

[0017] 3. Adding modified attapulgite to the nutrient core of the soil-modified disease-resistant slow-release fertilizer provided by the present invention can adsorb nutrient ions in the nutrients and reduce the nutrient release rate.

[0018] 4. The soil-improving and disease-resistant slow-release fertilizer provided by the present invention adds a variety of beneficial microorganisms to the nutrient core, which can activate inorganic nutrients in the soil and improve crop resistance. DETAILED DESCRIPTION

[0019] 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.

[0020] Unless otherwise mentioned, the organic fertilizer used in the specific embodiment of the present invention is made by composting silkworm manure, earthworm manure and peanut meal in a mass ratio of 1:1:1; Ammonium nitrogen fertilizers are ammonium chloride and ammonium sulfate, with a mass ratio of 1:1; phosphate fertilizers are monoammonium phosphate; and potash fertilizers are potassium sulfate. The biological regulators are Bacillus subtilis powder, Bacillus megaterium powder, Bacillus gelatinus powder, Trichoderma powder and Rhodopseudomonas palustris powder in a live bacteria count ratio of 1:1:1:1:1; Among them, Bacillus subtilis powder was purchased from Shandong Weilan Biotechnology Co., Ltd., with a viable count of 10 billion CFU / g; Bacillus megaterium powder was purchased from Weifang Yihao Biotechnology Co., Ltd., with a viable bacterial count of 10 billion CFU / g; Bacillus jelly was purchased from Weifang Yihao Biotechnology Co., Ltd., with a viable count of 10 billion CFU / g; The Trichoderma powder was Trichoderma aspergillus, purchased from Shandong Qilu Chemical Technology Co., Ltd., with a viable count of 10 billion CFU / g; Rhodopseudomonas palustris was purchased from Cangzhou Zhongxin Biotechnology Co., Ltd., with a viable count of 10 billion CFU / g; The trace elements in the chelate are EDDHA chelated magnesium, EDDHA chelated iron, EDDHA chelated manganese, EDDHA chelated copper and EDDHA chelated zinc in a mass ratio of 10:10:10:3:1; The preparation method of modified attapulgite is as follows: (a) Acid modification: The attapulgite was crushed and ground, and then passed through a 150-mesh sieve. Then, 5 mol / L H3PO4 was added according to a liquid-to-solid ratio of 5 mL / g. The mixture was heated in a water bath at 80 °C for 2 h, filtered, washed with distilled water for 3 to 5 times, dried at 100 °C, and passed through a 150-mesh sieve to obtain acid-modified attapulgite. (b) Organic modification: the acidified modified attapulgite prepared in step (a) was added to 0.05 mol / L hexadecyltrimethylammonium chloride at a liquid-to-solid ratio of 10 mL / g, and the mixture was stirred and dispersed, and then shaken and reacted at 25° C. and 200 rpm for 24 h, filtered, washed with distilled water for 3 to 5 times, dried at 100° C., and sieved through a 150-mesh sieve to obtain modified attapulgite; Polylactic acid was purchased from Zhongshan Dixin Chemical Co., Ltd.; Sodium alginate had a viscosity of 150 and was purchased from Wuhan Jiyesheng Chemical Co., Ltd.; The expanded perlite uses 300 mesh expanded perlite powder purchased from Xinyang Houpu Mining Co., Ltd. Vermiculite was 150 mesh vermiculite powder purchased from Lingshou County Yongqi Mineral Products Co., Ltd. The biochars were corn cob biochar, peanut shell biochar and straw biochar in a mass ratio of 1:1:1; The shell powder is oyster shell powder and mussel shell powder in a mass ratio of 1:1.

[0021] Example 1 A soil-improving disease-resistant slow-release fertilizer is a granular fertilizer, which comprises a nutrient core, an organic polymer coating layer and a mineral coating layer from the inside to the outside, and is prepared by the following method: (1) Preparation of nutrient core: weigh 20 parts of organic fertilizer, 25 parts of ammonium nitrogen fertilizer, 20 parts of phosphate fertilizer, 15 parts of potash fertilizer, 5 parts of biological regulator, 10 parts of chelated trace elements and 5 parts of modified attapulgite, mix them evenly and granulate them to obtain nutrient core with a particle size of 2.5 mm; (2) Covering with an organic polymer coating layer: polylactic acid was dissolved in a chloroform / methanol solvent with a volume ratio of 12:1 to form a composite solution, sodium alginate was added, and the mass ratio of polylactic acid to sodium alginate was 90:10. The mixture was stirred and mixed, and then sprayed on the surface of the nutrient core, and dried at 100°C for 8 hours to obtain an organic polymer coated nutrient core with a particle size of 3 mm. (3) Covering with a mineral coating layer: Expanded perlite, vermiculite, biochar and shell powder are mixed evenly according to a mass percentage of 40wt%, 35wt%, 15wt% and 10wt% to obtain mineral material powder. The organic polymer coated nutrient core and the mineral material powder are mixed evenly, and then granulated with water as a wetting agent to restore some viscosity of the organic polymer coated material. The mineral material powder is adhered to the surface of the organic polymer coated nutrient core to obtain soil-improving and disease-resistant slow-release fertilizer granules with a particle size of 4.5 mm.

[0022] Example 2 A soil-improving disease-resistant slow-release fertilizer is a granular fertilizer, which comprises a nutrient core, an organic polymer coating layer and a mineral coating layer from the inside to the outside, and is prepared by the following method: (1) Preparation of nutrient core: 30 parts by weight of organic fertilizer, 20 parts by weight of ammonium nitrogen fertilizer, 15 parts by weight of phosphate fertilizer, 10 parts by weight of potash fertilizer, 3 parts by weight of biological regulator, 5 parts by weight of chelated trace elements and 10 parts by weight of modified attapulgite are mixed evenly and granulated to obtain a nutrient core with a particle size of 2 mm; (2) Covering with an organic polymer coating layer: polylactic acid was dissolved in a chloroform / methanol solvent with a volume ratio of 15:1 to form a composite solution, sodium alginate was added, and the mass ratio of polylactic acid to sodium alginate was 95:5. The mixture was stirred and mixed, and then sprayed on the surface of the nutrient core, and dried at 100°C for 8 hours to obtain an organic polymer coated nutrient core with a particle size of 3.5 mm. (3) Covering with a mineral coating layer: Expanded perlite, vermiculite, biochar and shell powder are uniformly mixed according to a mass percentage of 50wt%, 25wt%, 20wt% and 5wt% to obtain a mineral material powder; the organic polymer coated nutrient core and the mineral material powder are uniformly mixed; granulation is performed using water as a wetting agent to restore some viscosity of the organic polymer coated material; the mineral material powder is adhered to the surface of the organic polymer coated nutrient core to obtain soil-improving and disease-resistant slow-release fertilizer granules with a particle size of 5 mm.

[0023] Example 3 A soil-improving disease-resistant slow-release fertilizer is a granular fertilizer, which comprises a nutrient core, an organic polymer coating layer and a mineral coating layer from the inside to the outside, and is prepared by the following method: (1) Preparation of nutrient core: weigh 20 parts of organic fertilizer, 25 parts of ammonium nitrogen fertilizer, 20 parts of phosphate fertilizer, 15 parts of potash fertilizer, 5 parts of biological regulator, 10 parts of chelated trace elements and 5 parts of modified attapulgite, mix them evenly and granulate them to obtain nutrient core with a particle size of 2.5 mm; (2) Covering with an organic polymer coating layer: polylactic acid was dissolved in a chloroform / methanol solvent with a volume ratio of 12:1 to form a composite solution, which was then sprayed on the surface of the nutrient core and dried at 100°C for 8 hours to obtain an organic polymer coated nutrient core with a particle size of 3 mm; (3) Covering with a mineral coating layer: Expanded perlite, vermiculite, biochar and shell powder are mixed evenly according to a mass percentage of 40wt%, 35wt%, 15wt% and 10wt% to obtain mineral material powder. The organic polymer coated nutrient core and the mineral material powder are mixed evenly, and then granulated with water as a wetting agent to restore some viscosity of the organic polymer coated material. The mineral material powder is adhered to the surface of the organic polymer coated nutrient core to obtain soil-improving and disease-resistant slow-release fertilizer granules with a particle size of 4.5 mm.

[0024] Example 4 A soil-improving disease-resistant slow-release fertilizer is a granular fertilizer, which comprises a nutrient core, an organic polymer coating layer and a mineral coating layer from the inside to the outside, and is prepared by the following method: (1) Preparation of nutrient core: weigh 20 parts of organic fertilizer, 25 parts of ammonium nitrogen fertilizer, 20 parts of phosphate fertilizer, 15 parts of potassium fertilizer, 5 parts of biological regulator and 10 parts of chelated trace elements by weight, mix them evenly and granulate them to obtain nutrient core with a particle size of 2.5 mm; (2) Covering with an organic polymer coating layer: polylactic acid was dissolved in a chloroform / methanol solvent with a volume ratio of 12:1 to form a composite solution, sodium alginate was added, and the mass ratio of polylactic acid to sodium alginate was 90:10. The mixture was stirred and mixed, and then sprayed on the surface of the nutrient core, and dried at 100°C for 8 hours to obtain an organic polymer coated nutrient core with a particle size of 3 mm. (3) Covering with a mineral coating layer: Expanded perlite, vermiculite, biochar and shell powder are mixed evenly according to a mass percentage of 40wt%, 35wt%, 15wt% and 10wt% to obtain mineral material powder. The organic polymer coated nutrient core and the mineral material powder are mixed evenly, and then granulated with water as a wetting agent to restore some viscosity of the organic polymer coated material. The mineral material powder is adhered to the surface of the organic polymer coated nutrient core to obtain soil-improving and disease-resistant slow-release fertilizer granules with a particle size of 4.5 mm.

[0025] Example 5 A soil-improving disease-resistant slow-release fertilizer is a granular fertilizer, which comprises a nutrient core, an organic polymer coating layer and a mineral coating layer from the inside to the outside, and is prepared by the following method: (1) Preparation of nutrient core: weigh 20 parts of organic fertilizer, 25 parts of ammonium nitrogen fertilizer, 20 parts of phosphate fertilizer, 15 parts of potash fertilizer, 5 parts of biological regulator, 10 parts of chelated trace elements and 5 parts of modified attapulgite, mix them evenly and granulate them to obtain nutrient core with a particle size of 2.5 mm; The bioregulator is composed of Bacillus subtilis, Bacillus megaterium and Bacillus gelatinus in a ratio of 1:1:1; (2) Covering with an organic polymer coating layer: polylactic acid was dissolved in a chloroform / methanol solvent with a volume ratio of 12:1 to form a composite solution, sodium alginate was added, and the mass ratio of polylactic acid to sodium alginate was 90:10. The mixture was stirred and mixed, and then sprayed on the surface of the nutrient core, and dried at 100°C for 8 hours to obtain an organic polymer coated nutrient core with a particle size of 3 mm. (3) Covering with a mineral coating layer: Expanded perlite, vermiculite, biochar and shell powder are mixed evenly according to a mass percentage of 40wt%, 35wt%, 15wt% and 10wt% to obtain mineral material powder. The organic polymer coated nutrient core and the mineral material powder are mixed evenly, and then granulated with water as a wetting agent to restore some viscosity of the organic polymer coated material. The mineral material powder is adhered to the surface of the organic polymer coated nutrient core to obtain soil-improving and disease-resistant slow-release fertilizer granules with a particle size of 4.5 mm.

[0026] Comparative Example 1 Di Zengwang compound fertilizer (N-P2O5-K2O15-15-15) and Bacillus megaterium powder with a live bacteria count of 10 billion CFU / g.

[0027] Test Example 1 The effects of the soil-improving disease-resistant slow-release fertilizer provided by the present invention on soil physicochemical properties, nutrient release rate, corn diseases and yield were determined by field tests. The corn variety is "Xiangyu 655", the test site is selected in Jingmen City, Hubei Province, each test group has an area of ​​1 mu, and the basic physicochemical properties of the soil are: pH 8.56, organic matter 21.72g / kg, total nitrogen 151.26mg / kg, available phosphorus 25.74mg / kg, and available potassium 82.71mg / kg. Corn was sown on April 18, 2024 and harvested on August 22, 2024. Examples 1 to 5 adopt base application, and the fertilizer application rate is 50kg / mu. Comparative Example 1 adopts base application, the application rate of ground-enhanced compound fertilizer is 47.5kg / mu, the application rate of Bacillus megaterium powder is 2.5kg / mu, and other field measures such as sowing, irrigation, and weeding are consistent.

[0028] Table 1 Effects of Examples and Comparative Examples on Soil Physical and Chemical Properties

[0029] It can be seen from Table 1 above that, compared with Comparative Example 1, after applying the soil-improving and disease-resistant slow-release fertilizer of the present invention, the soil porosity, water retention rate, and organic matter content are increased, and the soil pH value is decreased.

[0030] Table 2 Nutrient release rates of examples and comparative examples

[0031] As shown in Table 2 above, compared with Comparative Example 1, after applying the soil-modified disease-resistant slow-release fertilizer of the present invention, the nutrient release rate is significantly reduced. By comparing the nutrient release rates of Example 1 and Example 3, it can be found that adding sodium alginate to the organic polymer coating layer is conducive to further reducing the nutrient release rate. By comparing the nutrient release rates of Example 1 and Example 4, it can be found that adding modified attapulgite to the nutrient core can further reduce the nutrient release rate.

[0032] Table 3 The control effect of the embodiments and comparative examples on corn leaf blight and stalk rot

[0033] As shown in Table 3 above, compared with Comparative Example 1, after applying the soil-improving disease-resistant slow-release fertilizer of the present invention, the disease index of corn leaf blight and stem rot decreased, and the control effect was significant. By comparing the control effects of corn leaf blight and stem rot in Example 1 and Example 5, it can be found that the control effect of the five microorganisms of Bacillus subtilis, Bacillus megaterium, Bacillus jelly, Trichoderma and Rhodopseudomonas palustris is better, which is better than the control effect of using three microorganisms in combination or using Bacillus megaterium alone. Therefore, the biological regulator in the nutrient core is preferably Bacillus subtilis, Bacillus megaterium, Bacillus jelly, Trichoderma, and Rhodopseudomonas palustris with a live bacteria ratio of 1:1:1:1:1.

[0034] Table 4 Effect of Examples and Comparative Examples on Corn Yield

[0035] It can be seen from Table 4 above that, compared with Comparative Example 1, after applying the soil-improving and disease-resistant slow-release fertilizer of the present invention, the number of kernels per ear, thousand-kernel weight and corn yield are significantly improved.

[0036] In summary, the soil-improving disease-resistant slow-release fertilizer provided by the present invention has the ability to improve soil structure, adjust soil pH, and increase soil organic matter content, the ability to release nutrients over a long period of time and at a slow rate, the ability to prevent and control crops and improve stress resistance, and the ability to promote growth by increasing the number of grains per ear, thousand-grain weight, and yield of crops. The soil-improving disease-resistant slow-release fertilizer provided by the present invention is conducive to reducing labor costs and has good prospects for application and promotion.

[0037] 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 method for preparing a soil-improving disease-resistant slow-release fertilizer, characterized in that: The steps include: (1) Preparation of nutrient core: weigh 20-30 parts of organic fertilizer, 20-25 parts of ammonium nitrogen fertilizer, 15-20 parts of phosphate fertilizer, 10-15 parts of potash fertilizer, 3-5 parts of biological regulator, 5-10 parts of chelated trace elements and 0-10 parts of modified attapulgite, mix well and granulate to prepare nutrient core; (2) Covering with an organic polymer coating layer: dissolving polylactic acid in a solvent to form a composite solution, spraying it on the surface of the nutrient core, and drying it to obtain an organic polymer coated nutrient core; (3) Covering with a mineral coating layer: Expanded perlite, vermiculite, biochar and shell powder are mixed evenly to obtain mineral material powder, and organic polymer coated nutrient cores are mixed evenly with the mineral material powder and granulated to obtain soil-improving and disease-resistant slow-release fertilizer granules.

2. The preparation method according to claim 1, characterized in that In step (1), the bioregulator is one or more of Bacillus subtilis, Bacillus megaterium, Bacillus gelatinosa, Trichoderma, and Rhodopseudomonas palustris; The trace elements in the chelate are EDDHA chelated magnesium, EDDHA chelated iron, EDDHA chelated manganese, EDDHA chelated copper and EDDHA chelated zinc.

3. The preparation method according to claim 1, characterized in that: The preparation method of modified attapulgite is as follows: (a) Acid modification: The attapulgite was crushed and ground, and then passed through a 150-mesh sieve. Subsequently, 5 mol / L H3PO4 was added at a liquid-to-solid ratio of 5 mL / g. The mixture was heated in a water bath at 80 °C for 2 h, filtered, washed with distilled water, dried, and passed through a 150-mesh sieve to obtain the acidified modified attapulgite. (b) Organic modification: The acidified modified attapulgite prepared in step (a) was added to 0.05 mol / L of surfactant at a liquid-to-solid ratio of 10 mL / g, and the mixture was stirred, dispersed and shaken for 24 h. The mixture was filtered, washed with distilled water, dried, and passed through a 150-mesh sieve to obtain modified attapulgite.

4. The preparation method according to claim 3, characterized in that: In step (b), the surfactant is hexadecyltrimethylammonium chloride.

5. The preparation method according to claim 1, characterized in that: Step (2) also includes adding sodium alginate to the prepared composite solution and stirring to mix.

6. The preparation method according to claim 5, characterized in that: In step (2), the mass ratio of polylactic acid to sodium alginate is 90-95:5-10.

7. The preparation method according to claim 1, characterized in that: In step (2), the solvent is a mixed solvent of chloroform and methanol.

8. The preparation method according to claim 1, characterized in that: In the mineral material powder of step (3), the amount of expanded perlite is 40wt%~50wt%, the amount of vermiculite is 25wt%~35wt%, the amount of biochar is 15wt%~20wt%, and the amount of shell powder is 5wt%~10wt%.

9. A soil-improving and disease-resistant slow-release fertilizer prepared by the preparation method according to any one of claims 1 to 8.

10. The soil-improving and disease-resistant slow-release fertilizer according to claim 9, characterized in that: The particle size of the soil-improving and disease-resistant slow-release fertilizer is 4.5~5mm, the particle size of the organic polymer-coated nutrient core inside it is 3~3.5mm, and the particle size of the nutrient core is 2~2.5mm.

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