Ecological slow-release fertilizer and preparation method thereof

Abstract

The present invention discloses an ecological slow-release fertilizer and a preparation method thereof, comprising the following steps: preparing a slow-release compound fertilizer: mixing the compound fertilizer with a filler, heating and stirring, then adding modified porous biochar and continuing stirring, and granulating after completion to obtain the slow-release compound fertilizer; preparing a microbial organic fertilizer: inoculating agricultural and animal husbandry waste with fermentation microorganisms for fermentation; and granulating after completion to obtain the microbial organic fertilizer; mixing: uniformly mixing the slow-release compound fertilizer with the microbial organic fertilizer. The ecological slow-release fertilizer of the present invention has high utilization rate and lasting fertility, can effectively promote crop growth, and improve crop yield and quality.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizers, and in particular relates to an ecological slow-release fertilizer and a preparation method thereof. Background Art

[0002] Fertilizer, as the "food" of crops, is crucial to improving crop yield and quality. However, traditional chemical fertilizers are expensive, and large-scale fertilization has a greater adverse effect on the soil environment. Slow-release fertilizers can achieve the slow release of fertilizer nutrients, effectively control fertility, improve fertilizer utilization, and reduce the amount of fertilizer application to a certain extent. Common slow-release fertilizers such as nitrification inhibitor fertilizers, urea formaldehyde fertilizers, polymer coated fertilizers, etc. are generally divided into two categories: coated slow-release fertilizers and non-filmed slow-release fertilizers. The disadvantage of coated slow-release fertilizers is that the preparation process is complicated, and the polymers used are often non-degradable high-molecular materials, which are not suitable for large-scale farmland planting; non-filmed slow-release fertilizers generally use fertilizers as carriers and then add slow-release materials, which are easily affected by external conditions such as temperature, pH, and humidity.

[0003] Chinese patent CN111662130A discloses a slow-release ecological fertilizer and a preparation method thereof, comprising the following steps: mixing and granulating the raw materials to obtain an inner core; adding a water-retaining agent and water to the coating material and stirring to obtain a coating liquid; mixing the coating liquid and the inner core and drying; the raw materials are nitrogen, phosphorus and potassium fertilizers, organic fertilizers, diatomaceous earth, zeolite powder, water-retaining agent, and coating material. The slow-release ecological fertilizer can improve the utilization rate and make the soil less likely to compact. Chinese patent CN103183573A discloses a polymerized amino acid ecological slow-release fertilizer, comprising a nitrogen, phosphorus and potassium compound fertilizer and an additive, wherein the additive is a mixture of polyaspartic acid, polyglutamic acid and a nitrification inhibitor. The ecological slow-release fertilizer has a long nutrient release period, and the additive belongs to a biological material, which has little impact on the environment. The present invention aims to provide an ecological slow-release fertilizer, which not only has a high fertilizer utilization rate and a long slow-release period, but also reduces damage to the soil environment. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides an ecological slow-release fertilizer and a preparation method thereof. By applying the ecological slow-release fertilizer of the present invention, the crop growth rate, fertilizer nutrient utilization rate and soil ventilation porosity are all improved, and no secondary pollution is caused to the soil.

[0005] The technical solution adopted by the present invention is:

[0006] A method for preparing an ecological slow-release fertilizer comprises the following steps:

[0007] S1: preparing a slow-release compound fertilizer: mixing 70-80 parts by weight of the compound fertilizer and 1-3 parts by weight of the filler, heating and stirring, then adding 20-30 parts by weight of the modified porous biochar and continuing to stir, and then granulating, drying and cooling to obtain the slow-release compound fertilizer;

[0008] S2: preparing microbial organic fertilizer: adjusting the water content of agricultural and animal husbandry waste, inoculating fermentation microorganisms for fermentation; after fermentation, granulating and drying to obtain the microbial organic fertilizer;

[0009] S3 mixing: 60-70 parts by weight of the slow-release compound fertilizer and 20-30 parts by weight of the microbial organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer.

[0010] The ecological slow-release fertilizer of the present invention is obtained by using slow-release compound fertilizer as the main component and supplemented with a certain amount of microbial organic fertilizer. Compared with the simple use of compound fertilizer (chemical fertilizer), the ecological slow-release fertilizer can realize the gradual and slow release of compound fertilizer, and the crops can continuously absorb and balance nutrients, thereby improving the utilization rate of fertilizer, not only realizing the increase of crop yield and quality, but also reducing the application amount of fertilizer, and avoiding the influence of excessive use of chemical fertilizer on the soil environment.

[0011] Preferably, the specific method for preparing the slow-release compound fertilizer in S1 is: 70-80 parts by weight of compound fertilizer and 1-3 parts by weight of filler are evenly mixed, and then stirred at 105-120°C for 15-20 minutes, and then 20-30 parts by weight of modified porous biochar are added and stirred for 10-15 minutes. After the mixture is granulated, dried and cooled, the slow-release compound fertilizer is obtained.

[0012] The slow-release compound fertilizer of the present invention is rich in nitrogen, phosphorus, potassium, carbon and silicon elements, can promote crop photosynthesis and nutrient absorption, improve crop stress resistance, inhibit pathogens and promote organic matter decomposition.

[0013] The preparation method of the modified porous biochar is:

[0014] The rice husk is washed and dried, and then carbonized at 550-650°C under nitrogen for 30-50 minutes, cooled, and crushed through a 50-80 mesh sieve to obtain porous biochar; the porous biochar is added to a 0.5-2wt% chitosan oligosaccharide aqueous solution at a solid-liquid ratio of 1kg:2-5L, and soaked for 12-18h, filtered, and dried to obtain pretreated porous biochar;

[0015] 2-3 parts by weight of methacryloxypropylmethyldiethoxysilane, 1-2 parts by weight of allyltrimethoxysilane, and 3-8 parts by weight of γ-polyglutamic acid are added to 100-150 parts by weight of 40-45wt% ethanol aqueous solution and mixed evenly, and then 60-70 parts by weight of pretreated porous biochar are added, and microwave treatment is performed at 100-300W and 1500-2500MHz for 5-15min, and the biochar is filtered and dried to obtain the modified porous biochar.

[0016] In the preparation of slow-release compound fertilizer, modified porous biochar is used as a slow-release carrier. The modified porous biochar uses rice husk as a raw material, making full use of the characteristic that rice husk contains a high content of silicon. The modified porous biochar prepared by the present invention uses a carbon chain as a basic skeleton and absorbs silicon to form a carbon-silicon porous composite material. The internal atomic bonding force is strong, the structural elasticity is high, and the chemical stability is good, so that the prepared slow-release compound fertilizer has a large loading capacity for the compound fertilizer and good adsorption capacity, and can firmly adsorb and lock the nutrient elements of the compound fertilizer, thereby realizing the slow release of nutrients and improving the release efficiency.

[0017] Pretreatment of porous biochar with chitosan oligosaccharide aqueous solution can first load chitosan oligosaccharide on its surface, and then work with γ-polyglutamic acid in subsequent treatment to finally form an external film-forming and internal porous structure, further enhancing the slow-release and water-retention functions, and greatly adsorbing and locking fertilizer nutrients and moisture; and the modification of porous biochar with methacryloxypropylmethyldiethoxysilane and allyltrimethoxysilane not only helps its external film formation, but also modifies the internal porous structure, making the nutrient adsorption and binding effect stronger, which is beneficial to control the release rate of fertilizer nutrients.

[0018] In addition, the biomass organic carbon and silicon components contained in the modified porous biochar itself can also loosen the soil and improve the soil structure, providing a suitable environment for the growth and reproduction of beneficial microorganisms. Especially in the preparation process of modified porous biochar, after a series of treatments, the silicon contained in rice husks has been converted into silicon nutrients that are more easily absorbed by crops. After being absorbed by crops, the hardness of crop stems is improved, making it difficult for pests and pathogens to eat and digest them, thereby improving the crops' ability to resist diseases and pests and to withstand temperature changes.

[0019] Preferably, the preparation method of the modified porous biochar may also be:

[0020] The rice husk is washed and dried, and then carbonized at 550-650°C under nitrogen for 30-50 minutes, cooled, and crushed through a 50-80 mesh sieve to obtain porous biochar; the porous biochar is added to a 0.5-2wt% chitosan oligosaccharide aqueous solution at a solid-liquid ratio of 1kg:2-5L, and soaked for 12-18h, filtered, and dried to obtain pretreated porous biochar;

[0021] 2-3 parts by weight of methacryloxypropylmethyldiethoxysilane, 1-2 parts by weight of allyltrimethoxysilane, 3-5 parts by weight of γ-polyglutamic acid, and 1-3 parts by weight of polyacrylamide are added to 100-150 parts by weight of 40-45wt% ethanol aqueous solution and mixed evenly, and then 60-70 parts by weight of pretreated porous biochar are added, and microwave treatment is performed at 100-300W, 1500-2500MHz for 5-15min, and the biochar is filtered and dried to obtain the modified porous biochar.

[0022] The present invention can also simultaneously use γ-polyglutamic acid and polyacrylamide in the preparation of modified porous biochar. γ-polyglutamic acid can enhance the effect of enriching and storing nutrients, increase the retention of nitrogen, phosphorus, potassium, carbon and silicon in compound fertilizer in the soil, and promote crop absorption and utilization, while polyacrylamide has a good water retention effect, can slowly release water, and assist γ-polyglutamic acid in extending the retention time of fertilizer nutrients and water in the soil.

[0023] The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate in a mass ratio of 3-5:3-5:1-3:1-3:1-3.

[0024] The filler is a mixture of kaolin and bentonite in a mass ratio of 3:1-2. The present invention selects kaolin and bentonite as fillers, wherein kaolin is a clay mineral with good plasticity, the main components of which are SiO2 and Al2O3, and bentonite is a natural mineral material that can be used as a binder and stabilizer. The addition of the filler can improve the cohesiveness and particle strength of the slow-release compound fertilizer and prevent agglomeration.

[0025] Preferably, the specific method for preparing microbial organic fertilizer in S2 is: taking corn stalks, rice stalks, sheep manure, chicken manure, and peanut shells in a mass ratio of 7-10:7-10:3-7:3-7:1-3, mixing them, and crushing them through a 20-50 mesh sieve to obtain agricultural and animal husbandry waste; adjusting the water content of the agricultural and animal husbandry waste to 40-50wt%, and then inoculating 0.2-0.5wt% of the mass of the agricultural and animal husbandry waste with fermentation microorganisms, and then placing them in an environment of 28-37°C for fermentation for 10-20d, turning the materials every 1-2d, and after the fermentation is completed, granulating and drying, and adjusting the water content to 3-7wt% to obtain the microbial organic fertilizer.

[0026] The fermentation microorganism is a mixture of Bacillus amyloliquefaciens and Trichoderma harzianum in a mass ratio of 3:1-2.

[0027] The ecological slow-release fertilizer of the present invention also includes microbial organic fertilizer, which is prepared by using a mixture of agricultural and animal husbandry waste materials such as corn stalks, rice stalks, sheep manure, chicken manure and peanut shells as raw materials and inoculating specific fermentation microorganisms for fermentation and composting. Among the fermentation microorganisms, Bacillus amyloliquefaciens has a good fermentation and composting effect on agricultural and animal husbandry waste materials, and its metabolites have a certain promoting effect on the root growth of crops. African Trichoderma harzianum can antagonize crop pathogens, prevent and control soil-borne diseases, promote crop growth, and increase crop yields.

[0028] Beneficial effects of the present invention: The ecological slow-release fertilizer of the present invention has a slow-release compound fertilizer as the main component and is supplemented with a certain amount of microbial organic fertilizer. It has the advantages of high utilization rate and lasting fertility, and can effectively promote crop growth and improve crop yield and quality. In the preparation of the slow-release compound fertilizer, modified porous biochar is used as a slow-release carrier. The modified porous biochar is a carbon-silicon porous composite material with a carbon chain as the basic skeleton and absorbs silicon. It has strong internal atomic bonding force, high structural elasticity, and good chemical stability. The prepared slow-release compound fertilizer has a large load capacity for compound fertilizer and good adsorption capacity. It can firmly adsorb and lock the nutrient elements of the compound fertilizer, achieve the slow release of nutrients, and improve the release efficiency. In addition, the biomass organic carbon and silicon components contained in the modified porous biochar itself can also loosen the soil and improve the soil structure. Especially in the preparation process of the modified porous biochar, after a series of treatments, the silicon contained in the rice husk has been converted into silicon nutrients that are more easily absorbed by crops. After being absorbed by the crops, the hardness of the crop stems is improved, making it difficult for pests and pathogens to eat and digest, thereby improving the crop's ability to resist diseases and pests and to withstand temperature changes. DETAILED DESCRIPTION

[0029] Some of the raw materials in this application are introduced as follows:

[0030] Bacillus amyloliquefaciens was purchased from China Agricultural Microbiological Culture Collection Center, with the number: ACCC 19745.

[0031] Trichoderma harzianum was purchased from China Agricultural Microbiological Culture Collection Center, with the number: ACCC 33109.

[0032] Kaolin, purchased from Jiaze Mineral Products Processing Plant in Lingshou County, calcined, 325 mesh.

[0033] Bentonite, purchased from Hebei Mingzhe Mineral Products Co., Ltd., sodium base, 200 mesh.

[0034] γ-Polyglutamic acid was purchased from Shaanxi Saier Biotechnology Co., Ltd., product number: SR0257, molecular weight: 700,000-1.1 million.

[0035] Polyacrylamide was purchased from Henan Hongshengyuan Environmental Protection Technology Co., Ltd., model: HSY116, molecular weight: 8 million.

[0036] Chitosan oligosaccharide was purchased from Xi'an Wenzhu Biotechnology Co., Ltd., product number: ZT-0080, molecular weight: 2000.

[0037] Example 1

[0038] A method for preparing an ecological slow-release fertilizer comprises the following steps:

[0039] S1. Preparation of slow-release compound fertilizer: 75 parts by weight of compound fertilizer and 2 parts by weight of filler were mixed evenly, and then stirred at 115° C. for 18 minutes, and then 25 parts by weight of modified porous biochar were added and stirred for 12 minutes. After the mixture was granulated, dried, and cooled, the slow-release compound fertilizer was obtained;

[0040] S2 prepares microbial organic fertilizer: corn stalks, rice stalks, sheep manure, chicken manure, and peanut shells are mixed in a mass ratio of 10:10:6:6:3 and crushed through a 30-mesh sieve to obtain agricultural and animal husbandry waste; the moisture content of the agricultural and animal husbandry waste is adjusted to 45wt%, and then 0.3wt% of the mass of the agricultural and animal husbandry waste is inoculated with fermentation microorganisms and then placed in an environment of 33°C for fermentation for 14 days, and the material is turned over every 2 days, wherein the fermentation microorganism is a mixture of Bacillus amyloliquefaciens and Trichoderma harzianum in a mass ratio of 3:2; after the fermentation is completed, the water content is adjusted to 6wt% after granulation and drying to obtain the microbial organic fertilizer;

[0041] S3 mixing: 65 parts by weight of the slow-release compound fertilizer and 25 parts by weight of the microbial organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer.

[0042] The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate in a mass ratio of 5:5:3:3:3.

[0043] The filler is a mixture of kaolin and bentonite in a mass ratio of 3:1.

[0044] The preparation method of the modified porous biochar is:

[0045] The rice husk was washed and dried, and then carbonized at 600°C under nitrogen for 35 minutes, cooled, and crushed through a 60-mesh sieve to obtain porous biochar; the porous biochar was added to a 1wt% chitosan oligosaccharide aqueous solution at a solid-liquid ratio of 1kg:3L, and soaked for 15 hours, filtered, and dried to obtain pretreated porous biochar;

[0046] 2.5 parts by weight of methacryloxypropylmethyldiethoxysilane, 1.5 parts by weight of allyltrimethoxysilane, and 8 parts by weight of γ-polyglutamic acid are added to 120 parts by weight of 42wt% ethanol aqueous solution and mixed evenly, and then 65 parts by weight of pretreated porous biochar are added, and microwave treatment is performed at 200W and 2450MHz for 10 minutes. The modified porous biochar is obtained after filtration and drying.

[0047] Example 2

[0048] A method for preparing an ecological slow-release fertilizer comprises the following steps:

[0049] S1. Preparation of slow-release compound fertilizer: 75 parts by weight of compound fertilizer and 2 parts by weight of filler were mixed evenly, stirred at 115° C. for 18 minutes, and then 25 parts by weight of porous biochar were added and stirred for 12 minutes. After the mixture was granulated, dried and cooled, the slow-release compound fertilizer was obtained;

[0050] S2 prepares microbial organic fertilizer: corn stalks, rice stalks, sheep manure, chicken manure, and peanut shells are mixed in a mass ratio of 10:10:6:6:3 and crushed through a 30-mesh sieve to obtain agricultural and animal husbandry waste; the moisture content of the agricultural and animal husbandry waste is adjusted to 45wt%, and then 0.3wt% of the mass of the agricultural and animal husbandry waste is inoculated with fermentation microorganisms and then placed in an environment of 33°C for fermentation for 14 days, and the material is turned over every 2 days, wherein the fermentation microorganism is a mixture of Bacillus amyloliquefaciens and Trichoderma harzianum in a mass ratio of 3:2; after the fermentation is completed, the water content is adjusted to 6wt% after granulation and drying to obtain the microbial organic fertilizer;

[0051] S3 mixing: 65 parts by weight of the slow-release compound fertilizer and 25 parts by weight of the microbial organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer.

[0052] The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate in a mass ratio of 5:5:3:3:3.

[0053] The filler is a mixture of kaolin and bentonite in a mass ratio of 3:1.

[0054] The preparation method of the porous biochar is:

[0055] The rice husk is washed and dried, and then carbonized at 600° C. under nitrogen for 35 minutes, cooled, and crushed to pass through a 60-mesh sieve to obtain the porous biochar.

[0056] Example 3

[0057] A method for preparing an ecological slow-release fertilizer comprises the following steps:

[0058] S1. Preparation of slow-release compound fertilizer: 75 parts by weight of compound fertilizer and 2 parts by weight of filler were mixed evenly, and then stirred at 115° C. for 18 minutes, and then 25 parts by weight of modified porous biochar were added and stirred for 12 minutes. After the mixture was granulated, dried, and cooled, the slow-release compound fertilizer was obtained;

[0059] S2 prepares microbial organic fertilizer: corn stalks, rice stalks, sheep manure, chicken manure, and peanut shells are mixed in a mass ratio of 10:10:6:6:3 and crushed through a 30-mesh sieve to obtain agricultural and animal husbandry waste; the moisture content of the agricultural and animal husbandry waste is adjusted to 45wt%, and then 0.3wt% of the mass of the agricultural and animal husbandry waste is inoculated with fermentation microorganisms and then placed in an environment of 33°C for fermentation for 14 days, and the material is turned over every 2 days, wherein the fermentation microorganism is a mixture of Bacillus amyloliquefaciens and Trichoderma harzianum in a mass ratio of 3:2; after the fermentation is completed, the water content is adjusted to 6wt% after granulation and drying to obtain the microbial organic fertilizer;

[0060] S3 mixing: 65 parts by weight of the slow-release compound fertilizer and 25 parts by weight of the microbial organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer.

[0061] The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate in a mass ratio of 5:5:3:3:3.

[0062] The filler is a mixture of kaolin and bentonite in a mass ratio of 3:1.

[0063] The preparation method of the modified porous biochar is:

[0064] The rice husk is washed and dried, and then carbonized at 600°C under nitrogen for 35 minutes, cooled, and crushed through a 60-mesh sieve to obtain porous biochar; 2.5 parts by weight of methacryloxypropylmethyldiethoxysilane, 1.5 parts by weight of allyltrimethoxysilane, and 8 parts by weight of γ-polyglutamic acid are added to 120 parts by weight of a 42wt% ethanol aqueous solution and mixed evenly, and then 65 parts by weight of the porous biochar are added, and microwave treatment is performed at 200W and 2450MHz for 10 minutes, and the modified porous biochar is obtained after filtering and drying.

[0065] Example 4

[0066] A method for preparing an ecological slow-release fertilizer comprises the following steps:

[0067] S1. Preparation of slow-release compound fertilizer: 75 parts by weight of compound fertilizer and 2 parts by weight of filler were mixed evenly, and then stirred at 115° C. for 18 minutes, and then 25 parts by weight of modified porous biochar were added and stirred for 12 minutes. After the mixture was granulated, dried, and cooled, the slow-release compound fertilizer was obtained;

[0068] S2 prepares microbial organic fertilizer: corn stalks, rice stalks, sheep manure, chicken manure, and peanut shells are mixed in a mass ratio of 10:10:6:6:3 and crushed through a 30-mesh sieve to obtain agricultural and animal husbandry waste; the moisture content of the agricultural and animal husbandry waste is adjusted to 45wt%, and then 0.3wt% of the mass of the agricultural and animal husbandry waste is inoculated with fermentation microorganisms and then placed in an environment of 33°C for fermentation for 14 days, and the material is turned over every 2 days, wherein the fermentation microorganism is a mixture of Bacillus amyloliquefaciens and Trichoderma harzianum in a mass ratio of 3:2; after the fermentation is completed, the water content is adjusted to 6wt% after granulation and drying to obtain the microbial organic fertilizer;

[0069] S3 mixing: 65 parts by weight of the slow-release compound fertilizer and 25 parts by weight of the microbial organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer.

[0070] The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate in a mass ratio of 5:5:3:3:3.

[0071] The filler is a mixture of kaolin and bentonite in a mass ratio of 3:1.

[0072] The preparation method of the modified porous biochar is:

[0073] The rice husk was washed and dried, and then carbonized at 600°C under nitrogen for 35 minutes, cooled, and crushed through a 60-mesh sieve to obtain porous biochar; the porous biochar was added to a 1wt% chitosan oligosaccharide aqueous solution at a solid-liquid ratio of 1kg:3L, and soaked for 15 hours, filtered, and dried to obtain pretreated porous biochar;

[0074] 8 parts by weight of γ-polyglutamic acid are added to 120 parts by weight of 42 wt% ethanol aqueous solution and mixed evenly, and then 65 parts by weight of pretreated porous biochar are added, and microwave treatment is performed at 200 W and 2450 MHz for 10 minutes, and the modified porous biochar is obtained after filtration and drying.

[0075] Example 5

[0076] A method for preparing an ecological slow-release fertilizer comprises the following steps:

[0077] S1. Preparation of slow-release compound fertilizer: 75 parts by weight of compound fertilizer and 2 parts by weight of filler were mixed evenly, and then stirred at 115° C. for 18 minutes, and then 25 parts by weight of modified porous biochar were added and stirred for 12 minutes. After the mixture was granulated, dried, and cooled, the slow-release compound fertilizer was obtained;

[0078] S2: preparing organic fertilizer: mixing corn stalks, rice stalks, sheep manure, chicken manure and peanut shells in a mass ratio of 10:10:6:6:3, crushing and passing through a 30-mesh sieve to obtain agricultural and animal husbandry waste; adjusting the moisture content of the agricultural and animal husbandry waste to 45wt%, placing the agricultural and animal husbandry waste to ferment naturally for 14 days at 33°C, and turning the material every 2 days; after the fermentation is completed, granulating and drying, adjusting the moisture content to 6wt%, and obtaining the organic fertilizer;

[0079] S3 mixing: 65 parts by weight of the slow-release compound fertilizer and 25 parts by weight of the organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer.

[0080] The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate in a mass ratio of 5:5:3:3:3.

[0081] The filler is a mixture of kaolin and bentonite in a mass ratio of 3:1.

[0082] The preparation method of the modified porous biochar is:

[0083] The rice husk was washed and dried, and then carbonized at 600°C under nitrogen for 35 minutes, cooled, and crushed through a 60-mesh sieve to obtain porous biochar; the porous biochar was added to a 1wt% chitosan oligosaccharide aqueous solution at a solid-liquid ratio of 1kg:3L, and soaked for 15 hours, filtered, and dried to obtain pretreated porous biochar;

[0084] 2.5 parts by weight of methacryloxypropylmethyldiethoxysilane, 1.5 parts by weight of allyltrimethoxysilane, and 8 parts by weight of γ-polyglutamic acid are added to 120 parts by weight of 42wt% ethanol aqueous solution and mixed evenly, and then 65 parts by weight of pretreated porous biochar are added, and microwave treatment is performed at 200W and 2450MHz for 10 minutes. The modified porous biochar is obtained after filtration and drying.

[0085] Example 6

[0086] A method for preparing an ecological slow-release fertilizer comprises the following steps:

[0087] S1. Preparation of slow-release compound fertilizer: 75 parts by weight of compound fertilizer and 2 parts by weight of filler were mixed evenly, and then stirred at 115° C. for 18 minutes, and then 25 parts by weight of modified porous biochar were added and stirred for 12 minutes. After the mixture was granulated, dried, and cooled, the slow-release compound fertilizer was obtained;

[0088] S2 prepares microbial organic fertilizer: corn stalks, rice stalks, sheep manure, chicken manure, and peanut shells are mixed in a mass ratio of 10:10:6:6:3 and crushed through a 30-mesh sieve to obtain agricultural and animal husbandry waste; the moisture content of the agricultural and animal husbandry waste is adjusted to 45wt%, and then 0.3wt% of the mass of the agricultural and animal husbandry waste is inoculated with fermentation microorganisms and then placed in an environment of 33°C for fermentation for 14 days, and the material is turned over every 2 days, wherein the fermentation microorganism is a mixture of Bacillus amyloliquefaciens and Trichoderma harzianum in a mass ratio of 3:2; after the fermentation is completed, the water content is adjusted to 6wt% after granulation and drying to obtain the microbial organic fertilizer;

[0089] S3 mixing: 65 parts by weight of the slow-release compound fertilizer and 25 parts by weight of the microbial organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer.

[0090] The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate in a mass ratio of 5:5:3:3:3.

[0091] The filler is a mixture of kaolin and bentonite in a mass ratio of 3:1.

[0092] The preparation method of the modified porous biochar is:

[0093] The rice husk was washed and dried, and then carbonized at 600°C under nitrogen for 35 minutes, cooled, and crushed through a 60-mesh sieve to obtain porous biochar; the porous biochar was added to a 1wt% chitosan oligosaccharide aqueous solution at a solid-liquid ratio of 1kg:3L, and soaked for 15 hours, filtered, and dried to obtain pretreated porous biochar;

[0094] 2.5 parts by weight of methacryloxypropylmethyldiethoxysilane, 1.5 parts by weight of allyltrimethoxysilane, and 8 parts by weight of polyacrylamide are added to 120 parts by weight of 42wt% ethanol aqueous solution and mixed evenly, and then 65 parts by weight of pretreated porous biochar are added, and microwave treatment is performed at 200W and 2450MHz for 10 minutes. The modified porous biochar is obtained after filtration and drying.

[0095] Example 7

[0096] A method for preparing an ecological slow-release fertilizer comprises the following steps:

[0097] S1. Preparation of slow-release compound fertilizer: 75 parts by weight of compound fertilizer and 2 parts by weight of filler were mixed evenly, and then stirred at 115° C. for 18 minutes, and then 25 parts by weight of modified porous biochar were added and stirred for 12 minutes. After the mixture was granulated, dried, and cooled, the slow-release compound fertilizer was obtained;

[0098] S2 prepares microbial organic fertilizer: corn stalks, rice stalks, sheep manure, chicken manure, and peanut shells are mixed in a mass ratio of 10:10:6:6:3 and crushed through a 30-mesh sieve to obtain agricultural and animal husbandry waste; the moisture content of the agricultural and animal husbandry waste is adjusted to 45wt%, and then 0.3wt% of the mass of the agricultural and animal husbandry waste is inoculated with fermentation microorganisms and then placed in an environment of 33°C for fermentation for 14 days, and the material is turned over every 2 days, wherein the fermentation microorganism is a mixture of Bacillus amyloliquefaciens and Trichoderma harzianum in a mass ratio of 3:2; after the fermentation is completed, the water content is adjusted to 6wt% after granulation and drying to obtain the microbial organic fertilizer;

[0099] S3 mixing: 65 parts by weight of the slow-release compound fertilizer and 25 parts by weight of the microbial organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer.

[0100] The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate in a mass ratio of 5:5:3:3:3.

[0101] The filler is a mixture of kaolin and bentonite in a mass ratio of 3:1.

[0102] The preparation method of the modified porous biochar is:

[0103] The rice husk was washed and dried, and then carbonized at 600°C under nitrogen for 35 minutes, cooled, and crushed through a 60-mesh sieve to obtain porous biochar; the porous biochar was added to a 1wt% chitosan oligosaccharide aqueous solution at a solid-liquid ratio of 1kg:3L, and soaked for 15 hours, filtered, and dried to obtain pretreated porous biochar;

[0104] 2.5 parts by weight of methacryloxypropylmethyldiethoxysilane, 1.5 parts by weight of allyltrimethoxysilane, 5 parts by weight of γ-polyglutamic acid, and 3 parts by weight of polyacrylamide are added to 120 parts by weight of 42wt% ethanol aqueous solution and mixed evenly, and then 65 parts by weight of pretreated porous biochar are added, and microwave treatment is carried out at 200W and 2450MHz for 10 minutes. The modified porous biochar is obtained after filtration and drying.

[0105] Test Example 1

[0106] Evaluation of crop growth performance: A cucumber planting test field was divided into 35 equal parts, 5 parts were randomly selected as 1 group, and a total of 7 groups were divided, and the ecological slow-release fertilizer prepared in Examples 1-7 of the present invention was applied at a fertilizer rate of 45 kg / mu. The same planting management method was adopted during the growth period of the cucumber, the growth of the cucumber was recorded, and the yield and pest and disease situation of the cucumber were counted and calculated.

[0107] Table 1 Effects of ecological slow-release fertilizer on crop growth performance

[0108]

[0109] Test Example 2

[0110] Evaluation of crop quality: Cucumbers harvested from Test Example 1 were measured for V C Ten samples were randomly selected from each group and the average value was taken.

[0111] Table 2 Effects of ecological slow-release fertilizer on crop quality

[0112]

[0113] As can be seen from the results of Tables 1 and 2, the ecological slow-release fertilizer of the present invention can effectively promote the growth of crops, reduce the occurrence of pests and diseases, and improve the yield and quality of crops. The ecological slow-release fertilizer of the present invention uses slow-release compound fertilizer as the main component and is supplemented with a certain amount of microbial organic fertilizer, which can realize the gradual and slow release of compound fertilizer, and crops can continuously absorb and balance nutrients, thereby improving the utilization rate of fertilizer. One of the slow-release compound fertilizers uses modified porous biochar as a slow-release carrier in the preparation of the slow-release compound fertilizer. The modified porous biochar is a carbon-silicon porous composite material formed by absorbing silicon with a carbon chain as the basic skeleton, and its internal atomic binding force is strong, the structural elasticity is high, and the chemical stability is good, so that the obtained slow-release compound fertilizer has a large load capacity for compound fertilizer and good adsorption capacity, and can firmly adsorb and lock the nutrient elements of the compound fertilizer, so as to realize the slow release of nutrients and improve the release efficiency. Pretreatment of porous biochar with chitosan oligosaccharide aqueous solution can first load chitosan oligosaccharide on its surface, and then work with γ-polyglutamic acid in the subsequent treatment to finally form an external film-forming and internal porous structure, further enhancing the slow release and water retention functions, greatly adsorbing and locking fertilizer nutrients and water; and the modification of porous biochar with methacryloxypropylmethyldiethoxysilane and allyltrimethoxysilane not only helps its external film formation, but also modifies the internal porous structure, making the adsorption and binding of nutrients stronger, which is conducive to controlling the release rate of fertilizer nutrients. In addition, the biomass organic carbon and silicon components contained in the modified porous biochar itself can also play a role in loosening the soil and improving the soil structure, providing a suitable environment for the growth and reproduction of beneficial microorganisms. In particular, in the preparation process of modified porous biochar, after a series of treatments, the silicon contained in rice husks has been converted into silicon nutrients that are easier for crops to absorb, and then absorbed by crops to improve the hardness of crop stems, making it difficult for pests and pathogens to eat and digest, and improving the crop's ability to resist pests and diseases and temperature changes. Two of the microbial organic fertilizers use a mixture of agricultural and animal husbandry waste materials such as corn stalks, rice stalks, sheep manure, chicken manure, and peanut shells as raw materials, and are prepared by inoculating specific fermentation microorganisms for fermentation and composting. Among the fermentation microorganisms, Bacillus amyloliquefaciens has a good fermentation and composting effect on agricultural and animal husbandry waste materials, and its metabolites have a certain promoting effect on the root growth of crops. African Trichoderma harzianum can antagonize crop pathogens, prevent and control soil-borne diseases, promote crop growth, and increase crop yields.

Claims

1. A method for preparing an ecological slow-release fertilizer, characterized in that: The steps include: S1: preparing a slow-release compound fertilizer: mixing 70-80 parts by weight of the compound fertilizer and 1-3 parts by weight of the filler, heating and stirring, then adding 20-30 parts by weight of the modified porous biochar and continuing to stir, and then granulating, drying and cooling to obtain the slow-release compound fertilizer; S2: preparing microbial organic fertilizer: adjusting the water content of agricultural and animal husbandry waste, inoculating fermentation microorganisms for fermentation; after fermentation, granulating and drying to obtain the microbial organic fertilizer; S3 mixing: 60-70 parts by weight of the slow-release compound fertilizer and 20-30 parts by weight of the microbial organic fertilizer are uniformly mixed to obtain the ecological slow-release fertilizer; The fermentation microorganism is a mixture of Bacillus amyloliquefaciens and Trichoderma harzianum; The preparation method of the modified porous biochar is: The rice husk is washed and dried, and then carbonized at 550-650°C under nitrogen for 30-50 minutes, cooled, and crushed through a 50-80 mesh sieve to obtain porous biochar; the porous biochar is added to a 0.5-2wt% chitosan oligosaccharide aqueous solution at a solid-liquid ratio of 1kg:2-5L, and soaked for 12-18 hours, filtered, and dried to obtain pretreated porous biochar; 2-3 parts by weight of methacryloxypropylmethyldiethoxysilane, 1-2 parts by weight of allyltrimethoxysilane, 3-5 parts by weight of γ-polyglutamic acid, and 1-3 parts by weight of polyacrylamide are added to 100-150 parts by weight of 40-45wt% ethanol aqueous solution and mixed evenly, and then 60-70 parts by weight of pretreated porous biochar are added, and microwave treatment is performed at 100-300W and 1500-2500MHz for 5-15min, and the biochar is filtered and dried to obtain the modified porous biochar.

2. The method for preparing the ecological slow-release fertilizer according to claim 1, characterized in that: The compound fertilizer is a mixture of ammonium bicarbonate, urea, potassium dihydrogen phosphate, superphosphate and diammonium phosphate.

3. The method for preparing the ecological slow-release fertilizer according to claim 1, characterized in that: The filler is kaolin, bentonite or a mixture of the two.

4. The method for preparing the ecological slow-release fertilizer according to claim 1, characterized in that: The agricultural and animal husbandry waste is prepared by mixing corn stalks, rice stalks, sheep manure, chicken manure and peanut shells, and then crushing and sieving them.

5. The method for preparing the ecological slow-release fertilizer according to claim 1, characterized in that: The inoculation amount of the fermentation microorganism is 0.2-0.5wt% of the mass of the agricultural and animal husbandry waste; the fermentation conditions are specifically as follows: adjusting the water content of the agricultural and animal husbandry waste to 40-50wt%, fermenting at 28-37°C for 10-20 days, and turning the material every 1-2 days.

6. An ecological slow-release fertilizer, characterized in that: The method is prepared according to any one of claims 1 to 5.

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