A soil improving fertilizer suitable for Jianghuai region and its production method

Abstract

The invention discloses a soil improvement fertilizer suitable for Jianghuai region and a production method thereof, belonging to the technical field of soil improvement fertilizer. Peat soil, crop straw, fly ash, livestock excrement and microbial agent are stirred and mixed, composted and fermented to obtain fermented organic fertilizer, the fermented organic fertilizer, coated urea particles, humic acid and sodium carboxymethyl cellulose are stirred and mixed, and transferred to a granulator for granulation to obtain the soil improvement fertilizer suitable for Jianghuai region; amino acid powder provides organic cementing material to aggregates in soil, the released urea can increase the solubility of the amino acid powder, the released furfural is cross-linked with the dissolved amino acid powder, the stability of the organic cementing material is improved, the transformation of large aggregates in the deep tillage layer of soil into micro aggregates is avoided, the stability of soil structure is improved, and the addition of fermented organic fertilizer and humic acid helps to reduce the bulk density of the deep tillage layer of soil, increase soil porosity, improve the soil structure of paddy soil, and increase rice yield.

Description

Technical Field

[0001] The invention belongs to the technical field of soil improvement fertilizers, and in particular relates to a soil improvement fertilizer suitable for the Jianghuai region and a production method thereof. Background Art

[0002] The zonal soils in the Jianghuai region are mainly yellow-brown soil and yellow-brown soil developed from the Xiashu loess parent material. Rice-wheat rotation is the main cropping system in the area, and the cultivated area accounts for more than 50% of the total cultivated land area in the Jianghuai region.

[0003] In order to increase rice yields, traditional chemical fertilizers, compound fertilizers or unprocessed organic fertilizers are generally applied to rice fields. Not only do these fertilizers have low utilization rates, but they are also prone to environmental pollution. Therefore, a number of new fertilizers have appeared on the market. New fertilizers generally refer to fertilizers produced using new methods and processes that have the characteristics of composite high efficiency, slow release / controlled release, and environmental friendliness, such as coated slow-release nitrogen fertilizers and green smart fertilizers. The application of new fertilizers can meet the nutrient demand patterns for high yield and high quality of crops of different seasonal types and the timeliness and turnover patterns of soil annual nutrient supply through methods such as local nutrient regulation in the rhizosphere, construction of healthy soil microorganisms, bio-organic-inorganic composites, slow-controlled / fast-acting nutrient combinations, and synergistic enhancement of trace elements and macroelements. It is one of the key technologies to solve problems such as soil nutrient imbalance, low effectiveness, and unstable crop yields.

[0004] In view of the characteristics of soil obstacles, planting systems and farming habits in the Jianghuai region, from the perspective of building a high-quality plow layer structure, achieving soil carbon, nitrogen and phosphorus nutrient balance, and regulating soil nutrient turnover and effective supply, the soil sub-plow layer bulk density is reduced and the nutrient storage capacity is expanded through plowing at an appropriate depth; on this basis, new fertilizers are applied to improve the physical and chemical properties such as nutrient balance, physical properties, and aggregate structure of the deep plow layer soil, and enhance the soil's water and fertilizer retention capacity, which can effectively improve the soil quality and crop productivity in the Jianghuai region. Summary of the Invention

[0005] The purpose of the present invention is to provide a soil improvement fertilizer suitable for the Jianghuai region and a production method thereof, which provides an organic binder to the deep plowing layer of paddy soil by containing amino acid powder, cross-links with the released furfural, increases the proportion of soil macroaggregates, and improves the soil performance of the deep plowing layer.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for producing soil-improving fertilizer suitable for the Jianghuai region comprises the following steps:

[0008] Peat soil, crop straw, fly ash, livestock manure and microbial agents are stirred and mixed, and the moisture content is adjusted to 40-50%. After composting, the compost is fermented at 45-55°C for 6-7 days. During the composting process, the compost is turned over every 24 hours and the moisture content is adjusted to 25-40% to obtain fermented organic fertilizer. The fermented organic fertilizer, coated urea granules, humic acid and sodium carboxymethyl cellulose are stirred and mixed, and the mixture is transferred to a granulator for granulation to obtain a soil improvement fertilizer suitable for the Jianghuai region.

[0009] Furthermore, the mass ratio of peat soil, crop straw, fly ash, livestock manure and microbial agent is 60-80:30-40:15-20:20-25:0.04-0.06.

[0010] Furthermore, the microbial agent is prepared by mixing Bacillus subtilis, Bacillus mucilaginosus and Bacillus megaterium in a mass ratio of 2:1:1.

[0011] Furthermore, the usage ratio of fermented organic fertilizer, coated urea granules, humic acid and sodium carboxymethyl cellulose is 80-100:30-40:30-40:5-10.

[0012] Furthermore, the coated urea granules are prepared by the following steps:

[0013] Step 1: Add polylactic acid, succinic anhydride and chloroform to a reactor, react at 100-105°C for 2-2.5 hours, then transfer the reaction product to anhydrous ethanol for precipitation, filter, wash the filter cake with anhydrous ethanol 2-3 times, and vacuum dry at 40-60°C to obtain carboxylated polylactic acid.

[0014] Step 2: Add carboxylated polylactic acid, polyethylene glycol with a molecular weight of 400 and dichloromethane to a reactor, stir for 20-30 minutes at 20-25°C and 200-300r / min, then add 4-dimethylaminopyridine and dicyclohexylcarbodiimide to the reactor, continue stirring for 6-8 hours, transfer the reaction product to n-heptane, stir and disperse for 10-15 minutes, filter, wash the filter cake with a hydrochloric acid solution with a molar concentration of 0.1mol / L and deionized water for 2-3 times, and dry in vacuo at 40-60°C to obtain block-modified polylactic acid.

[0015] Step 3: Filter the food waste through a grid, remove impurities, and transfer it to a pulping tank for pulping and crushing. After solid-liquid separation, the filter cake is sterilized at high temperature to obtain pretreated food waste; the pretreated food waste and soybean meal are evenly mixed in a mass ratio of 6-7:3-4, ground and crushed to obtain a solid phase material, and then transferred to a hydrolysis tank, and then a sulfuric acid solution with a molar concentration of 4-4.2 mol / L is added to the hydrolysis tank, and acid-hot hydrolysis is carried out at 95-100°C for 100-120 minutes, and then calcium hydroxide is added to adjust the pH value to 9.5-10, and the insoluble matter is removed by plate and frame filtration, and spray drying is obtained to obtain amino acid-containing powder.

[0016] Step 4: Add the amino acid powder and deionized water into the reactor and stir to mix, dissolve the block-modified polylactic acid with dichloromethane to form a 2% film-forming agent solution, add the film-forming agent solution to the reactor, stir at 8000-10000 r / min for 5-8 minutes, then add a 1% polyvinyl alcohol aqueous solution as a stabilizer to the reactor, stir at 8000-10000 r / min for 5-8 minutes, then adjust the speed to 400-500 r / min and stir for 8-10 hours, centrifuge and concentrate, freeze-dry the precipitate to obtain amino acid-containing microcapsules.

[0017] Step 5: Stir and mix the epoxy soybean oil, isocyanate, furfural and amino acid-containing microcapsules to obtain a coating liquid, add the urea granules into the coating machine, preheat at a speed of 35-40r / min and a temperature of 60-70°C for 20-30min, spray the coating liquid into the coating machine, the mass ratio of urea granules to the coating liquid is 10:5-8, and after the coating liquid is sprayed, the coating machine continues to work for 10-15min to solidify the coating liquid to obtain coated urea granules.

[0018] Furthermore, the usage ratio of polylactic acid, succinic anhydride and chloroform is 250 g:10 g:500 mL.

[0019] Furthermore, the usage ratio of carboxylated polylactic acid, polyethylene glycol, dichloromethane, 4-dimethylaminopyridine and dicyclohexylcarbodiimide is 5g:1-1.2g:50-60mL:1g:1.6g.

[0020] Furthermore, the usage ratio of the solid phase material and the sulfuric acid solution is 1 g:5 mL.

[0021] Furthermore, the usage ratio of the amino acid powder, deionized water, film-forming agent solution and polyvinyl alcohol aqueous solution is 2 g:10 mL:100 mL:5 mL.

[0022] Furthermore, the mass ratio of the epoxy soybean oil, isocyanate, furfural and amino acid-containing microcapsules is 12-14.5:10-12:3.5-4:4-5.5.

[0023] Beneficial effects of the present invention:

[0024] The soil-improving fertilizer of the present invention is suitable for improving paddy soil in the Jianghuai region and increasing rice yield. The addition of fermented organic fertilizer and humic acid helps reduce the bulk density of the deep-ploughed soil layer, increase soil porosity, and improve the soil structure of paddy soil. Sodium carboxymethyl cellulose facilitates the disintegration of the soil-improving fertilizer, and the coated urea granules help increase soil nitrogen content.

[0025] The coated urea granules in the soil-improving fertilizer of the present invention utilize a high proportion of coating liquid during their preparation. Epoxidized soybean oil and isocyanate in the coating liquid are cross-linked to form a film layer containing amino acid-containing microcapsules and furfural. The shell membrane of the amino acid-containing microcapsules is primarily composed of a polylactic acid block copolymer. This polylactic acid block copolymer is modified by carboxylation and grafted with polyvinyl alcohol to enhance its water solubility, thereby facilitating the release and dissolution of the amino acid-containing powder.

[0026] The amino acid powder is produced by combining food waste and soybean meal and then subjecting them to acid and hot hydrolysis, reducing resource waste. The product contains a large amount of soluble protein, peptides, and amino acids, which help provide organic binders to soil aggregates. The released urea increases the solubility of the amino acid powder, while the amino acids, in turn, increase soil microbial activity, accelerate the mineralization of organic nitrogen, and reduce nitrogen loss. The released furfural cross-links with the dissolved amino acid powder, improving the stability of the organic binder, preventing the conversion of macroaggregates into microaggregates in the deep tillage layer of soil, improving soil structural stability, and increasing the water and fertilizer retention capacity of the deep tillage layer of paddy soil. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0028] Example 1: This example provides a soil-improving fertilizer suitable for the Jianghuai region, which is obtained by a production method:

[0029] S1: Add 250 kg of polylactic acid, 10 kg of succinic anhydride, and 500 L of chloroform to a reactor, react at 100 ° C for 2 hours, then transfer the reaction product to anhydrous ethanol for precipitation, filter, wash the filter cake twice with anhydrous ethanol, and vacuum dry at 40 ° C to obtain carboxylated polylactic acid.

[0030] S2: 200 kg of carboxylated polylactic acid, 40 kg of polyethylene glycol with a molecular weight of 400 and 2000 L of dichloromethane were added to the reactor, stirred at 20 ° C and 200 r / min for 20 min, and then 40 kg of 4-dimethylaminopyridine and 64 kg of dicyclohexylcarbodiimide were added to the reactor, and stirring was continued for 6 h. The reaction product was transferred to n-heptane and stirred and dispersed for 10 min. Filtered, the filter cake was washed twice with a hydrochloric acid solution with a molar concentration of 0.1 mol / L and deionized water, and dried in vacuo at 40 ° C to obtain block-modified polylactic acid.

[0031] S3: The kitchen waste is filtered through a grid, and after removing impurities, it is transferred to a pulping tank for pulping and crushing. After solid-liquid separation, the filter cake is sterilized at high temperature to obtain pretreated kitchen waste; the pretreated kitchen waste and soybean meal are mixed evenly in a mass ratio of 6:3, ground and crushed to obtain a solid phase material, and then transferred to a hydrolysis tank, and then a sulfuric acid solution with a molar concentration of 4 mol / L is added to the hydrolysis tank. The amount ratio of the solid phase material and the sulfuric acid solution is 1g:5mL. Acid-hot hydrolysis is carried out at 95°C for 100 minutes, and then calcium hydroxide is added to adjust the pH value to 9.5. The insoluble matter is removed by plate and frame filtration, and spray drying is obtained to obtain amino acid-containing powder.

[0032] S4: Add 20 kg of amino acid powder and 100 L of deionized water into a reactor and stir to mix. Dissolve the block-modified polylactic acid with dichloromethane to form a film-forming agent solution with a mass fraction of 2%. Add 1000 L of the film-forming agent solution into the reactor and stir at 8000 r / min for 5 minutes. Then add 50 L of a 1% polyvinyl alcohol aqueous solution as a stabilizer into the reactor and stir at 8000 r / min for 5 minutes. Then adjust the speed to 400 r / min and stir for 8 hours. Centrifuge and concentrate. Freeze-dry the precipitate to obtain amino acid-containing microcapsules.

[0033] S5: 24 kg of epoxy soybean oil, 20 kg of isocyanate, 7 kg of furfural and 8 kg of amino acid microcapsules were stirred and mixed to obtain a coating liquid. The urea granules were added to a coating machine, preheated at a speed of 35 r / min and a temperature of 60°C for 20 min, and the coating liquid was sprayed into the coating machine. The mass ratio of urea granules to the coating liquid was 10:5. After the coating liquid was sprayed, the coating machine continued to operate for 10 min to solidify the coating liquid to obtain coated urea granules.

[0034] S6: 60 kg of peat soil, 30 kg of crop straw, 15 kg of fly ash, 20 kg of poultry and livestock manure and 0.04 kg of microbial agent were stirred and mixed, and the moisture content was adjusted to 40% and then composted at 45°C. The microbial agent included Bacillus subtilis, Bacillus mucilaginosus and Bacillus megaterium mixed in a mass ratio of 2:1:1; the compost was turned over every 24 hours during the composting process, and the moisture content was adjusted to 25% after 6 days of composting to obtain fermented organic fertilizer; 80 kg of fermented organic fertilizer, 30 kg of coated urea granules, 30 kg of humic acid and 5 kg of sodium carboxymethyl cellulose were stirred and mixed, and transferred to a granulator for granulation to obtain a soil improvement fertilizer suitable for the Jianghuai region.

[0035] Example 2: This example provides a soil-improving fertilizer suitable for the Jianghuai region, which is obtained by a production method:

[0036] S1: Add 250 kg of polylactic acid, 10 kg of succinic anhydride, and 500 L of chloroform to a reactor, react at 102°C for 2.2 hours, then transfer the reaction product to anhydrous ethanol for precipitation, filter, wash the filter cake twice with anhydrous ethanol, and vacuum dry at 50°C to obtain carboxylated polylactic acid.

[0037] S2: 200 kg of carboxylated polylactic acid, 44 kg of polyethylene glycol with a molecular weight of 400 and 2200 L of dichloromethane were added to the reactor, stirred at 22 ° C and 250 r / min for 25 min, and then 40 kg of 4-dimethylaminopyridine and 64 kg of dicyclohexylcarbodiimide were added to the reactor, and stirring was continued for 7 h. The reaction product was transferred to n-heptane and stirred and dispersed for 12 min, filtered, and the filter cake was washed twice with a hydrochloric acid solution with a molar concentration of 0.1 mol / L and deionized water, respectively, and dried in vacuo at 50 ° C to obtain block-modified polylactic acid.

[0038] S3: The kitchen waste is filtered through a grid, and after removing impurities, it is transferred to a pulping tank for pulping and crushing. After solid-liquid separation, the filter cake is sterilized at high temperature to obtain pretreated kitchen waste; the pretreated kitchen waste and soybean meal are mixed evenly in a mass ratio of 6.5:3.5, ground and crushed to obtain a solid phase material, and then transferred to a hydrolysis tank, and then a sulfuric acid solution with a molar concentration of 4.1 mol / L is added to the hydrolysis tank. The amount ratio of the solid phase material and the sulfuric acid solution is 1g:5mL. Acid-hot hydrolysis is carried out at 98°C for 110min, and then calcium hydroxide is added to adjust the pH value to 9.8. The insoluble matter is removed by plate and frame filtration, and spray drying is obtained to obtain amino acid-containing powder.

[0039] S4: Add 20 kg of amino acid powder and 100 L of deionized water into a reactor and stir to mix. Dissolve the block-modified polylactic acid with dichloromethane to form a film-forming agent solution with a mass fraction of 2%. Add 1000 L of the film-forming agent solution into the reactor and stir at 9000 r / min for 6 minutes. Then add 50 L of a 1% polyvinyl alcohol aqueous solution as a stabilizer into the reactor and stir at 9000 r / min for 6 minutes. Then adjust the speed to 450 r / min and stir for 9 hours. Centrifuge and concentrate. Freeze-dry the precipitate to obtain amino acid-containing microcapsules.

[0040] S5: 26.5 kg of epoxy soybean oil, 22 kg of isocyanate, 7.5 kg of furfural and 8.5 kg of amino acid microcapsules were stirred and mixed to obtain a coating liquid. The urea granules were added to the coating machine, preheated at a speed of 38 r / min and a temperature of 65°C for 25 minutes, and the coating liquid was sprayed into the coating machine. The mass ratio of urea granules to the coating liquid was 10:7. After the coating liquid was sprayed, the coating machine continued to operate for 13 minutes to solidify the coating liquid to obtain coated urea granules.

[0041] S6: 70 kg of peat soil, 35 kg of crop straw, 18 kg of fly ash, 23 kg of poultry and livestock manure and 0.05 kg of microbial agent were stirred and mixed, and the moisture content was adjusted to 45% and then composted at 50°C. The microbial agent included Bacillus subtilis, Bacillus mucilaginosus and Bacillus megaterium mixed in a mass ratio of 2:1:1; the compost was turned over every 24 hours during the composting process, and the moisture content was adjusted to 30% after 7 days of composting to obtain fermented organic fertilizer; 90 kg of fermented organic fertilizer, 35 kg of coated urea granules, 35 kg of humic acid and 8 kg of sodium carboxymethyl cellulose were stirred and mixed, and transferred to a granulator for granulation to obtain a soil improvement fertilizer suitable for the Jianghuai region.

[0042] Example 3: This example provides a soil-improving fertilizer suitable for the Jianghuai region, which is obtained by a production method:

[0043] S1: Add 250 kg of polylactic acid, 10 kg of succinic anhydride, and 500 L of chloroform to a reactor, react at 105°C for 2.5 hours, then transfer the reaction product to anhydrous ethanol for precipitation, filter, wash the filter cake with anhydrous ethanol three times, and vacuum dry at 60°C to obtain carboxylated polylactic acid.

[0044] S2: 200 kg of carboxylated polylactic acid, 48 kg of polyethylene glycol with a molecular weight of 400 and 2400 L of dichloromethane were added to the reactor and stirred at 25 ° C and 300 r / min for 30 min. Then, 40 kg of 4-dimethylaminopyridine and 64 kg of dicyclohexylcarbodiimide were added to the reactor and stirred for 8 h. The reaction product was transferred to n-heptane and stirred and dispersed for 15 min. After filtration, the filter cake was washed three times with a hydrochloric acid solution with a molar concentration of 0.1 mol / L and deionized water, and dried in vacuo at 60 ° C to obtain block-modified polylactic acid.

[0045] S3: The kitchen waste is filtered through a grid, and after removing impurities, it is transferred to a pulping tank for pulping and crushing. After solid-liquid separation, the filter cake is sterilized at high temperature to obtain pretreated kitchen waste; the pretreated kitchen waste and soybean meal are mixed evenly in a mass ratio of 7:4, ground and crushed to obtain a solid phase material, and then transferred to a hydrolysis tank, and then a sulfuric acid solution with a molar concentration of 4.2 mol / L is added to the hydrolysis tank. The amount ratio of the solid phase material and the sulfuric acid solution is 1g:5mL. Acid-hot hydrolysis is carried out at 100°C for 120 minutes, and then calcium hydroxide is added to adjust the pH value to 10. The insoluble matter is removed by plate and frame filtration, and spray drying is carried out to obtain amino acid-containing powder.

[0046] S4: Add 20 kg of amino acid powder and 100 L of deionized water into a reactor and stir to mix. Dissolve the block-modified polylactic acid with dichloromethane to form a film-forming agent solution with a mass fraction of 2%. Add 1000 L of the film-forming agent solution into the reactor and stir at 10,000 r / min for 8 minutes. Then add 50 L of a 1% polyvinyl alcohol aqueous solution as a stabilizer into the reactor and stir at 10,000 r / min for 8 minutes. Then adjust the speed to 500 r / min and stir for 10 hours. Centrifuge and concentrate. Freeze-dry the precipitate to obtain amino acid-containing microcapsules.

[0047] S5: 29 kg of epoxy soybean oil, 24 kg of isocyanate, 8 kg of furfural and 9 kg of amino acid microcapsules were stirred and mixed to obtain a coating liquid. The urea granules were added to the coating machine, preheated at a speed of 40 r / min and a temperature of 70°C for 30 min, and the coating liquid was sprayed into the coating machine. The mass ratio of urea granules to the coating liquid was 10:8. After the coating liquid was sprayed, the coating machine continued to operate for 15 min to solidify the coating liquid to obtain coated urea granules.

[0048] S6: 80 kg of peat soil, 40 kg of crop straw, 20 kg of fly ash, 25 kg of poultry and livestock manure and 0.06 kg of microbial agent were stirred and mixed, and the moisture content was adjusted to 50% and then composted at 55°C. The microbial agent included Bacillus subtilis, Bacillus mucilaginosus and Bacillus megaterium mixed in a mass ratio of 2:1:1; the compost was turned over every 24 hours during the composting process, and the moisture content was adjusted to 40% after 7 days of composting to obtain fermented organic fertilizer; 100 kg of fermented organic fertilizer, 40 kg of coated urea granules, 40 kg of humic acid and 10 kg of sodium carboxymethyl cellulose were stirred and mixed, and transferred to a granulator for granulation to obtain a soil improvement fertilizer suitable for the Jianghuai region.

[0049] Comparative Example 1: Based on Example 3, furfural and amino acid-containing microcapsules are not added during the preparation of coated urea in step S5, and then used in subsequent steps, while the remaining steps remain unchanged to prepare a soil improvement fertilizer.

[0050] Comparative Example 2: Based on Example 3, the block-modified polylactic acid in step S4 was replaced with commercially available polylactic acid, and the remaining steps remained unchanged to prepare a soil improvement fertilizer.

[0051] Comparative Example 3: Based on Example 3, the urea granules in step S5 are replaced with ammonium nitrate granules with the same average particle size to prepare coated ammonium nitrate granules and replace the coated urea granules. The remaining steps remain unchanged to prepare a soil improvement fertilizer.

[0052] The raw material bacterial agents in the examples and comparative examples were purchased from Shandong Yihao Biotechnology Co., Ltd.; the kitchen waste was provided by Suzhou Haichuang Environmental Energy Co., Ltd.; and the remaining raw materials were conventional commercial products.

[0053] Performance tests were conducted on Examples 1-3 and Comparative Examples 1-3 in Changfeng County, Anhui Province, where the paddy soil type is white soil. Five adjacent test plots of equal area were selected, one of which served as a blank control. In March 2023, the soil-improving fertilizers described in Example 3 and Comparative Examples 1-3 were applied, using a rotary tiller to deeply plow the soil at an application rate of 2500 kg / hm2. 2 The working depth was 18-20 cm. The seedlings were raised in late April. The variety was "Xiang Liang You 5398". In early June, the experimental fields were irrigated and transplanted. The seedlings were transplanted using a transplanter at a density of 250,000 holes / hm2. 2 , the field management methods in the later period will be the same, and rice will be harvested in October 2023 to examine the effects of different soil improvement fertilizers on rice yield.

[0054] The number of effective rice panicles, number of grains per panicle, and 1000-grain weight in different experimental fields were recorded. The results are shown in Table 1:

[0055] Table 1

[0056]

[0057] As can be seen from Table 1, applying the soil improvement fertilizer in the embodiment during deep plowing can increase the effective ears, number of grains per ear and 1000-grain weight of rice, and significantly increase the rice yield compared with Comparative Examples 1 to 3 and the blank control.

[0058] After the rice was harvested, 10 samples of soil with a thickness of 10-20 cm were randomly collected from each experimental field. The soil was in the form of cylinders with a diameter of 5 cm, packaged and ensured not to be squeezed. After being brought back to the laboratory and naturally air-dried, different samples were obtained. Each group of 5 samples was tested using a strain-controlled unconfined pressure instrument (Yuzhan Instrument) to test the maximum axial stress of different samples at the time of collapse, thereby evaluating the stability of each group of samples. The other 5 different samples in each group were gently broken into small pieces along the natural fracture surface, and debris such as plant roots and stones were removed. After passing through a 10mm sieve, they were air-dried and the distribution of water-stable aggregates at various levels was determined: 50g of air-dried soil was weighed, soaked in distilled water for 10 minutes, and then placed from top to bottom on 2mm, 0.25mm and 0.053mm soil sieves. The soil was run in a particle analyzer for 10 minutes. The aggregates on the sieves at various levels were collected and transferred to beakers respectively, dried at 60°C, and the aggregates of different particle sizes were weighed. The mass percentage of aggregates at various levels was calculated, and the components <0.053mm were calculated by subtraction. Aggregates >0.25mm are large aggregates, aggregates 0.053-0.25mm are microaggregates, and components <0.053mm are clay particles. The average value of 5 samples was taken for each group of data. The results are shown in Table 2:

[0059] Table 2

[0060]

[0061] It can be seen from Table 2 that after applying the soil improving fertilizers in Examples 1 to 3, the maximum axial stress of the samples increased, and the large aggregates (R 0.25 ) content is significantly increased because the amino acid microcapsules in the coated urea granules release soluble proteins, polypeptides and amino acids after dissolution, providing organic binders to the aggregates in the soil, and the furfural released from the coated urea granules is cross-linked with the dissolved amino acid powder to avoid the transformation of large aggregates in the deep plowing layer of the soil into microaggregates, thereby improving the stability of the soil structure; Comparative Example 2 shows that the use of block-modified polylactic acid to prepare amino acid microcapsules can increase the release rate of organic binders and facilitate the cross-linking of furfural with corresponding substances; Comparative Example 3 shows that urea can increase the solubility of amino acid powder and improve the cross-linking effect.

[0062] It should be noted that, in this document, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0063] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing soil improving fertilizer suitable for Jianghuai region, characterized in that: The steps include: The peat soil, crop straw, fly ash, livestock manure and microbial agent are stirred and mixed, the water content is adjusted to 40-50%, and the composting is fermented at 45-55°C for 6-7 days. During the composting process, the compost is turned once every 24 hours, and the water content is adjusted to 25-40% to obtain fermented organic fertilizer. The fermented organic fertilizer, coated urea granules, humic acid and sodium carboxymethyl cellulose are stirred and mixed, and transferred to a granulator for granulation to obtain a soil improvement fertilizer suitable for the Jianghuai region; The mass ratio of the fermented organic fertilizer, the coated urea granules, the humic acid and the sodium carboxymethyl cellulose is 80-100:30-40:30-40:5-10; The coated urea granules are prepared by the following steps: filtering the food waste through a grid, removing impurities, beating and crushing, separating solid and liquid, sterilizing the filter cake at high temperature, obtaining pretreated food waste and mixing it evenly with soybean meal in a mass ratio of 6-7:3-4, grinding and crushing to obtain a solid phase material, adding the solid phase material and a sulfuric acid solution with a concentration of 4-4.2 mol / L into a hydrolysis tank in a dosage ratio of 1 g:5 mL, performing acid-thermal hydrolysis at 95-100° C. for 100-120 min, adjusting the pH value to 9.5-10 with calcium hydroxide, removing insoluble matter by plate-frame filtration, and spray drying to obtain an amino acid-containing powder; The amino acid powder and deionized water are added to a reactor and stirred and mixed, the block-modified polylactic acid is dissolved in dichloromethane to form a 2wt% film-forming agent solution, the film-forming agent solution is added to the reactor, stirred at 8000-10000 r / min for 5-8 min, and then a 1wt% polyvinyl alcohol aqueous solution is added to the reactor, stirred at 8000-10000 r / min for 5-8 min, stirred at 400-500 r / min for 8-10 h, centrifuged and concentrated, and the precipitate is freeze-dried to obtain amino acid-containing microcapsules; Epoxidized soybean oil, isocyanate, furfural and amino acid-containing microcapsules are stirred and mixed to obtain a coating liquid, urea granules are added into a coating machine, preheated at 35-40r / min and 60-70°C for 20-30min, and the coating liquid is sprayed into the coating machine. The mass ratio of urea granules to the coating liquid is 10:5-8. After spraying, the coating machine is continuously operated for 10-15min to solidify the coating liquid to obtain coated urea granules.

2. The method for producing a soil improving fertilizer suitable for the Jianghuai region according to claim 1, characterized in that: The mass ratio of the peat soil, crop straw, fly ash, livestock manure and microbial agent is 60-80:30-40:15-20:20-25:0.04-0.

06.

3. The method for producing a soil improving fertilizer suitable for the Jianghuai region according to claim 1, characterized in that: The microbial inoculant is prepared by mixing Bacillus subtilis, Bacillus mucilaginosus and Bacillus megaterium in a mass ratio of 2:1:

1.

4. The method for producing a soil improving fertilizer suitable for the Jianghuai region according to claim 1, characterized in that: The mass ratio of the epoxy soybean oil, isocyanate, furfural and amino acid-containing microcapsules is 12-14.5:10-12:3.5-4:4-5.

5.

5. The method for producing a soil improving fertilizer suitable for Jianghuai region according to claim 1, characterized in that: The dosage ratio of the amino acid powder, deionized water, film-forming agent solution and polyvinyl alcohol aqueous solution is 2g:10mL:100mL:5mL.

6. The method for producing soil improving fertilizer suitable for Jianghuai region according to claim 1, characterized in that: The block-modified polylactic acid is prepared by the following steps: Add carboxylated polylactic acid, polyethylene glycol with a molecular weight of 400 and dichloromethane into a reactor, stir at 20-25°C and 200-300 r / min for 20-30 min, then add 4-dimethylaminopyridine and dicyclohexylcarbodiimide into the reactor, continue stirring for 6-8 h, transfer the reaction product into n-heptane, stir and disperse for 10-15 min, filter by suction, wash the filter cake with 0.1 mol / L hydrochloric acid solution and deionized water for 2-3 times respectively, and dry under vacuum at 40-60°C to obtain block-modified polylactic acid; The usage ratio of the carboxylated polylactic acid, polyethylene glycol, dichloromethane, 4-dimethylaminopyridine and dicyclohexylcarbodiimide is 5g:1-1.2g:50-60mL:1g:1.6g.

7. The method for producing soil improving fertilizer suitable for Jianghuai region according to claim 6, characterized in that: The carboxylated polylactic acid is prepared by the following steps: Add polylactic acid, succinic anhydride and chloroform into a reaction kettle, react at 100-105° C. for 2-2.5 hours, transfer the reaction product to anhydrous ethanol for precipitation, filter, wash the filter cake with anhydrous ethanol 2-3 times, and vacuum dry at 40-60° C. to obtain carboxylated polylactic acid; The usage ratio of the polylactic acid, succinic anhydride and chloroform is 250g:10g:500mL.

8. A soil improving fertilizer suitable for the Jianghuai region, characterized in that: It is prepared by the production method according to any one of claims 1 to 7.

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