Preparation method of water-retaining slow-release bio-organic fertilizer

Abstract

The invention relates to the technical field of organic fertilizers, and discloses a preparation method of a water-retaining slow-release bio-organic fertilizer, which is characterized in that water-retaining material powder is prepared from nano silicon dioxide, gamma-methacryloxypropyltrimethoxysilane, acrylic acid, attapulgite and the like as raw materials. The preparation method comprises the following steps: blending furfural residues and pig manure biogas residues into a mixed matrix according to a certain proportion, adding a microbial decomposition bacterium agent, nitrogen-fixing bacteria, phosphate solubilizing bacteria and the like into the mixed matrix, fermenting, crushing, drying and sieving to obtain bio-organic fertilizer particles. The water-retaining slow-release bio-organic fertilizer is obtained by taking the bentonite as an inner core carrier, taking a bentonite slow-release material as an inner coating film and taking water-retaining material powder as an outer coating film through a rotary drum coating process, and the prepared bio-organic fertilizer has relatively good water-retaining performance and slow-release performance.

Description

Technical Field

[0001] The invention relates to the technical field of organic fertilizers, in particular to a method for preparing a water-retaining slow-release biological organic fertilizer. Background Art

[0002] my country is a major agricultural country. Water and fertilizer are necessary input factors in agricultural production and important factors affecting crop growth. However, drought, water shortage and low water and fertilizer utilization rate are important limiting factors affecting my country's food security and sustainable agricultural development. Therefore, improving water and fertilizer utilization efficiency and reducing environmental pollution caused by waste of water and fertilizer resources have always been the focus of agricultural science and technology workers.

[0003] Bio-organic fertilizer refers to a type of fertilizer that combines the effects of microorganisms and organic fertilizers, which are made from microorganisms with specific functions and organic materials that are mainly derived from animal and plant residues and have been harmlessly treated and decomposed. It is rich in nutrients, can improve the utilization rate of chemical fertilizers and the disease resistance of crops, and is widely used in fertilizers.

[0004] Furfural residue and pig manure residue are by-products of biogas projects and are also one of the raw materials of biological organic fertilizers. They contain a lot of organic matter. If they are not utilized, they will cause secondary pollution to the environment. The common way to deal with the residue is to apply it directly to farmland after simple composting. However, this method has a low utilization rate of resources, so it needs to be processed to increase its utilization rate. Summary of the invention

[0005] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a method for preparing a water-retaining and slow-release bio-organic fertilizer. The prepared bio-organic fertilizer has good water-retaining effect and slow-release effect.

[0006] (II) Technical solution A method for preparing a water-retaining slow-release biological organic fertilizer, the preparation method is as follows: (1) Add furfural residue, pig manure sludge and microbial decomposition agent CM to the fermentation tank, mix them evenly, adjust the moisture content to 60-70%, control the carbon-nitrogen ratio to 20-30:1, use a chain plate turning machine to turn the residue once a day, ferment it in the fermentation tank for 30 days, then add nitrogen-fixing bacteria and phosphate-dissolving bacteria, continue fermentation for 7 days, crush, dry, and pass through a 2-5 mm sieve to obtain biological organic fertilizer granules.

[0007] (2) Add the bio-organic fertilizer particles into a disc granulator, spray the organic binder thereon until a layer of mucus is formed on the surface, add the bentonite slow-release material that has passed through a 0.1-0.2 mm sieve thereon, rotate until the slow-release material completely covers the surface of the bio-organic fertilizer particles, spray the organic binder thereon again until a layer of mucus is formed on the surface, add the water-retaining material powder that has passed through a 0.25 mm sieve thereon until the water-retaining material powder completely covers the fertilizer surface, and dry to obtain a water-retaining slow-release bio-organic fertilizer.

[0008] Preferably, in (1), the mass ratio of furfural residue to pig manure residue is 1:1-3.

[0009] Preferably, in (1), the microbial decomposing agent CM accounts for 0.5-1% of the total mass of furfural residue and pig manure biogas residue; the nitrogen-fixing bacteria and phosphate-solubilizing bacteria account for 0.2-0.8% of the total mass of furfural residue and pig manure biogas residue, respectively.

[0010] Preferably, in (2), the organic binder is epoxy resin E-44, and its concentration is 30%.

[0011] Preferably, in (2), the mass ratio of the biological organic fertilizer particles, the bentonite slow-release material, and the water-retaining material powder is 1:0.2-0.4:0.25-0.4.

[0012] Preferably, in (2), the preparation method of the water-retaining material powder is: S1. Add the dried nano-silica to deionized water containing γ-methacryloxypropyltrimethoxysilane, stir and disperse, react at 100-110° C. for 6-10 hours, filter after the reaction, wash with toluene, and dry to obtain olefinated nano-silica.

[0013] S2. At 0-5°C, add acrylic acid to a 10% sodium hydroxide solution, control the neutralization degree to 70-80%, add acrylamide, olefinic nano-silica, and a cross-linking agent, stir and disperse, then add attapulgite, stir and disperse, finally add an initiator, react at 30-45°C for 30-60 minutes, and after the reaction is completed, dry, crush, and pass through a 0.25 mm sieve to obtain a water-retaining material powder.

[0014] Preferably, in S1, the mass of γ-methacryloxypropyltrimethoxysilane is 5-15% of the nano-silicon dioxide.

[0015] Preferably, in S2, the mass ratio of acrylic acid, acrylamide and olefinic nano-silica is 1:0.2-0.5:0.1-0.3.

[0016] Preferably, in S2, the crosslinking agent is N,N-methylenebisacrylamide, and its usage is 0.03-0.05% of the total mass of acrylic acid, acrylamide, and olefinic nano-silica; the initiator is potassium persulfate, and its usage is 1-1.5% of the total mass of acrylic acid, acrylamide, and olefinic nano-silica; the usage of attapulgite is 2-5% of the total mass of acrylic acid, acrylamide, and olefinic nano-silica.

[0017] 3. Beneficial technical effects The present invention uses nano silicon dioxide to react with γ-methacryloxypropyltrimethoxysilane to obtain olefinated nano silicon dioxide, which is used as a raw material, and N,N-methylenebisacrylamide is used as a crosslinking agent, potassium persulfate is used as an initiator, and acrylic acid and acrylamide are copolymerized, and attapulgite is added thereto to prepare a water-retaining material powder. Furfural residue and pig manure biogas residue are prepared into a mixed matrix in a certain proportion, and then microbial decomposing bacteria, nitrogen-fixing bacteria, phosphate-dissolving bacteria and the like are added thereto for fermentation, crushed, dried, and sieved to obtain biological organic fertilizer particles, which are then added to a disc granulator, and epoxy resin E-44 is used as an organic binder, bentonite is used as a slow-release material, and the water-retaining material is used as an outer coating material. A rotary drum coating process is adopted to obtain a water-retaining slow-release biological organic fertilizer.

[0018] The water-retaining material prepared by the present invention contains a siloxane structure, which is easily hydrolyzed to generate a cross-linked network structure, thereby increasing the cross-linking density of the water-retaining material, and the nano silicon dioxide therein acts as a grid point of the cross-linked network structure in the water-retaining material, which can further increase the water-retaining specific surface area, and the carboxyl and amide groups contained therein can generate hydrogen bonds with water molecules, thereby further increasing the water absorption and water-retaining performance of the water-retaining material. The attapulgite coating used therein is rich in polar groups, which can also increase the water-retaining performance of the water-retaining material, and the attapulgite rich in polar groups can form a strong hydrogen bond with the carboxyl and amide groups, thereby extraordinarily increasing the polymerization network points, increasing the water-retaining performance of the water-retaining material, and using it as an outer coating material for fertilizers can increase the water-retaining performance of the fertilizers.

[0019] The water-retaining slow-release biological organic fertilizer prepared by the present invention has a three-layer structure, with biological organic fertilizer particles as the inner core carrier, the inner coating is bentonite slow-release material, and the outer coating is water-retaining material powder, which is applied to the soil, and the outer layer of water-retaining material absorbs water and swells to form a thick gel, which retains a large amount of nutrients in the water-retaining layer, on the one hand, inhibits the nutrient diffusion outward, and on the other hand, reduces the osmotic pressure difference between the inner and outer coating layers, reduces the nutrient release rate, and increases the slow-release performance of the biological organic fertilizer. In addition, the present invention uses wastes such as furfural residues and pig manure biogas residues to reduce their pollution to the environment, and realizes waste resource utilization and harmless treatment. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are provided. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Example

[0021] (1) Add 10 g of dried nano-silica to deionized water containing 1.5 g of γ-methacryloxypropyltrimethoxysilane, stir and disperse, and react at 120° C. for 10 h. After the reaction is completed, filter, wash with toluene, and dry to obtain olefinated nano-silica.

[0022] (2) At 0°C, add 20 g of acrylic acid to a 10% sodium hydroxide solution, control the degree of neutralization to 80%, add 4 g of acrylamide, 2 g of olefinated nano-silica, and 0.008 g of N,N-methylenebisacrylamide crosslinker, stir and disperse, then add 1 g of attapulgite, stir and disperse, and finally add 0.54 g of potassium persulfate initiator, react at 45°C for 40 min, and after the reaction is completed, dry, crush, and pass through a 0.25 mm sieve to obtain a water-retaining material powder.

[0023] (3) Add 1000 g of furfural residue, 1000 g of pig manure sludge, and 30 g of microbial decomposition agent CM into the fermentation tank, mix them evenly, adjust the moisture content to 65%, control the carbon-nitrogen ratio to 30:1, use a chain plate turning machine to turn the residue once a day, ferment it in the fermentation tank for 30 days, then add 30 g of nitrogen-fixing bacteria and 32 g of phosphate-solubilizing bacteria, continue fermentation for 7 days, crush, dry, and pass through a 5 mm sieve to obtain biological organic fertilizer granules.

[0024] (4) Add 1000 g of bio-organic fertilizer granules into a disc granulator, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 200 g of bentonite slow-release material that has passed a 0.1 mm sieve, rotate until the slow-release material completely covers the surface of the bio-organic fertilizer granules, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 250 g of water-retaining material powder that has passed a 0.25 mm sieve until the water-retaining material powder completely covers the fertilizer surface, and dry to obtain a water-retaining slow-release bio-organic fertilizer. Example

[0025] (1) Add 10 g of dried nano-silica to deionized water containing 1 g of γ-methacryloxypropyltrimethoxysilane, stir and disperse, and react at 110° C. for 8 h. After the reaction is completed, filter, wash with toluene, and dry to obtain olefinated nano-silica.

[0026] (2) At 5°C, add 20 g of acrylic acid to a 10% sodium hydroxide solution, control the degree of neutralization to 70%, add 6 g of acrylamide, 3 g of olefinated nano-silica, and 0.018 g of N,N-methylenebisacrylamide crosslinker, stir and disperse, then add 0.52 g of attapulgite, stir and disperse, finally add 0.4 g of potassium persulfate initiator, react at 35°C for 60 min, and after the reaction is completed, dry, crush, and pass through a 0.25 mm sieve to obtain a water-retaining material powder.

[0027] (3) Add 1000 g of furfural residue, 3000 g of pig manure sludge, and 10 g of microbial decomposition agent CM into the fermentation tank, mix well, adjust the moisture content to 70%, control the carbon-nitrogen ratio to 25:1, use a chain plate turning machine to turn the residue once a day, ferment in the fermentation tank for 30 days, then add 10 g of nitrogen-fixing bacteria and 30 g of phosphate-solubilizing bacteria, continue fermentation for 7 days, crush, dry, and pass through a 2 mm sieve to obtain biological organic fertilizer granules.

[0028] (4) Add 1000 g of bio-organic fertilizer granules into a disc granulator, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 250 g of bentonite slow-release material that has passed a 0.2 mm sieve, rotate until the slow-release material completely covers the surface of the bio-organic fertilizer granules, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 300 g of water-retaining material powder that has passed a 0.25 mm sieve, until the water-retaining material powder completely covers the fertilizer surface, and dry to obtain a water-retaining slow-release bio-organic fertilizer. Example

[0029] (1) Add 10 g of dried nano-silica to deionized water containing 0.5 g of γ-methacryloxypropyltrimethoxysilane, stir and disperse, and react at 100° C. for 6 h. After the reaction is completed, filter, wash with toluene, and dry to obtain olefinated nano-silica.

[0030] (2) At 0°C, add 20 g of acrylic acid to a 10% sodium hydroxide solution, control the degree of neutralization to 80%, add 6 g of acrylamide, 4 g of olefinated nano-silica, and 0.006 g of N,N-methylenebisacrylamide crosslinking agent, stir and disperse, then add 1.8 g of attapulgite, stir and disperse, finally add 0.26 g of potassium persulfate initiator, react at 30°C for 30 min, and after the reaction is completed, dry, crush, and pass through a 0.25 mm sieve to obtain a water-retaining material powder.

[0031] (3) Add 1000 g of furfural residue, 2000 g of pig manure sludge, and 40 g of microbial decomposition agent CM into the fermentation tank, mix well, adjust the moisture content to 68%, control the carbon-nitrogen ratio to 27:1, use a chain plate turning machine to turn the residue once a day, ferment in the fermentation tank for 30 days, then add 4 g of nitrogen-fixing bacteria and 30 g of phosphate-solubilizing bacteria, continue fermentation for 7 days, crush, dry, and pass through a 5 mm sieve to obtain biological organic fertilizer granules.

[0032] (4) Add 1000 g of bio-organic fertilizer granules into a disc granulator, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 300 g of bentonite slow-release material that has passed a 0.2 mm sieve, rotate until the slow-release material completely covers the surface of the bio-organic fertilizer granules, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 350 g of water-retaining material powder that has passed a 0.25 mm sieve until the water-retaining material powder completely covers the fertilizer surface, and dry to obtain a water-retaining slow-release bio-organic fertilizer. Example

[0033] (1) Add 10 g of dried nano-silica to deionized water containing 1.2 g of γ-methacryloxypropyltrimethoxysilane, stir and disperse, and react at 105° C. for 8 h. After the reaction is completed, filter, wash with toluene, and dry to obtain olefinated nano-silica.

[0034] (2) At 0°C, add 20 g of acrylic acid to a 10% sodium hydroxide solution, control the degree of neutralization to 75%, add 8 g of acrylamide, 5 g of olefinated nano-silica, and 0.015 g of N,N-methylenebisacrylamide crosslinker, stir and disperse, then add 1.8 g of attapulgite, stir and disperse, finally add 0.5 g of potassium persulfate initiator, react at 35°C for 50 min, and after the reaction is completed, dry, crush, and pass through a 0.25 mm sieve to obtain a water-retaining material powder.

[0035] (3) Add 1000 g of furfural residue, 2500 g of pig manure sludge, and 20 g of microbial decomposition agent CM into the fermentation tank, mix well, adjust the moisture content to 65%, control the carbon-nitrogen ratio to 24:1, use a chain plate turning machine to turn the residue once a day, ferment in the fermentation tank for 30 days, then add 32 g of nitrogen-fixing bacteria and 4 g of phosphate-solubilizing bacteria, continue fermentation for 7 days, crush, dry, and pass through a 2 mm sieve to obtain biological organic fertilizer granules.

[0036] (4) Add 1000 g of bio-organic fertilizer granules into a disc granulator, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 350 g of bentonite slow-release material that has passed a 0.2 mm sieve, rotate until the slow-release material completely covers the surface of the bio-organic fertilizer granules, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 400 g of water-retaining material powder that has passed a 0.25 mm sieve until the water-retaining material powder completely covers the fertilizer surface, and dry to obtain a water-retaining slow-release bio-organic fertilizer. Example

[0037] (1) Add 10 g of dried nano-silica to deionized water containing 1.2 g of γ-methacryloxypropyltrimethoxysilane, stir and disperse, and react at 110° C. for 7 h. After the reaction is completed, filter, wash with toluene, and dry to obtain olefinated nano-silica.

[0038] (2) At 0°C, add 20 g of acrylic acid to a 10% sodium hydroxide solution, control the degree of neutralization to 80%, add 10 g of acrylamide, 6 g of olefinated nano-silica, and 0.016 g of N,N-methylenebisacrylamide crosslinker, stir and disperse, then add 1.5 g of attapulgite, stir and disperse, finally add 0.4 g of potassium persulfate initiator, react at 45°C for 50 min, and after the reaction is completed, dry, crush, and pass through a 0.25 mm sieve to obtain a water-retaining material powder.

[0039] (3) Add 1000 g of furfural residue, 3000 g of pig manure sludge, and 30 g of microbial decomposition agent CM into the fermentation tank, mix them evenly, adjust the moisture content to 70%, control the carbon-nitrogen ratio to 20:1, use a chain plate turning machine to turn the residue once a day, ferment it in the fermentation tank for 30 days, then add 20 g of nitrogen-fixing bacteria and 30 g of phosphate-solubilizing bacteria, continue fermentation for 7 days, crush, dry, and pass through a 4 mm sieve to obtain biological organic fertilizer granules.

[0040] (4) Add 1000 g of bio-organic fertilizer granules into a disc granulator, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 400 g of bentonite slow-release material that has passed a 0.1 mm sieve, rotate until the slow-release material completely covers the surface of the bio-organic fertilizer granules, spray 30% epoxy resin E-44 organic binder thereto until a layer of mucus is formed on the surface, add 400 g of water-retaining material powder that has passed a 0.25 mm sieve until the water-retaining material powder completely covers the fertilizer surface, and dry to obtain a water-retaining slow-release bio-organic fertilizer.

[0041] Water retention capacity test of water-retaining slow-release biological organic fertilizer: Mix 0.5 kg of dry soil and 2 g of fertilizer evenly, add them to a beaker, add deionized water until there is no water on the soil surface, and when the beaker is tilted, water seeps out between the inner wall of the beaker and the soil. Place it in an oven, dry it, weigh the mass, and calculate the water retention rate. Water retention rate (%) = (total mass of soil and fertilizer - mass of dry soil and fertilizer) / (total mass of fertilizer and soil when fully absorbed and saturated - mass of dry soil and fertilizer) × 100%.

[0042] Table 1: It can be seen from the table that the water-retaining slow-release biological organic fertilizer prepared by the present invention has good water-retaining performance, with the highest water-retaining rate reaching 83.4% in 10 days and the highest water-retaining rate reaching 70.1% in 25 days.

[0043] Test of slow-release ability of water-retaining slow-release biological organic fertilizer: Add 5g of water-retaining slow-release bio-organic fertilizer to a 0.15mm nylon bag, place it in a plastic bottle filled with 100mL of deionized water, seal it, and place it in a constant temperature and humidity incubator at 30℃. After 24h, take out the plastic bottle, measure 10mL of the solution, and use p-dimethylaminobenzaldehyde to test the nitrogen release, and record the time required for the cumulative nitrogen release to reach 80%.

[0044] Table 2: It can be seen from the table that with the increase of water-retaining materials and bentonite materials, the time required for the cumulative release of nitrogen to reach 80% is also increasing, indicating that the slow-release performance of the water-retaining slow-release biological organic fertilizer is jointly determined by the inner increasing material and the outer layer material. Therefore, the water-retaining slow-release biological organic fertilizer prepared by the present invention has a good slow-release effect.

[0045] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a water-retaining slow-release biological organic fertilizer, characterized in that: The preparation method is as follows: (1) Add furfural residue, pig manure sludge, and microbial decomposition agent CM to a fermentation tank, mix them evenly, adjust the moisture content to 60-70%, control the carbon-nitrogen ratio to 20-30:1, use a chain plate turning machine to turn the residue once a day, ferment it in the fermentation tank for 30 days, then add nitrogen-fixing bacteria and phosphate-dissolving bacteria, continue fermenting for 7 days, crush, dry, and pass through a 2-5 mm sieve to obtain biological organic fertilizer particles; (2) Add the bio-organic fertilizer particles into a disc granulator, spray the organic binder thereon until a layer of mucus is formed on the surface, add the bentonite slow-release material that has passed through a 0.1-0.2 mm sieve thereon, rotate until the slow-release material completely covers the surface of the bio-organic fertilizer particles, spray the organic binder thereon again until a layer of mucus is formed on the surface, add the water-retaining material powder that has passed through a 0.25 mm sieve thereon until the water-retaining material powder completely covers the fertilizer surface, and dry to obtain a water-retaining slow-release bio-organic fertilizer.

2. The method for preparing the water-retaining slow-release biological organic fertilizer according to claim 1, characterized in that: In the above (1), the mass ratio of furfural residue to pig manure residue is 1:1-3.

3. The preparation method of the water-retaining slow-release biological organic fertilizer according to claim 1, characterized in that: In the above (1), the microbial decomposing agent CM accounts for 0.5-1% of the total mass of furfural residue and pig manure biogas residue; the nitrogen-fixing bacteria and phosphate-solubilizing bacteria account for 0.2-0.8% of the total mass of furfural residue and pig manure biogas residue, respectively.

4. The method for preparing the water-retaining slow-release biological organic fertilizer according to claim 1, characterized in that: In the above (2), the organic binder is epoxy resin E-44, and its concentration is 30%.

5. The method for preparing the water-retaining slow-release biological organic fertilizer according to claim 1, characterized in that: In the above (2), the mass ratio of the biological organic fertilizer particles, the bentonite slow-release material, and the water-retaining material powder is 1:0.2-0.4:0.25-0.

4.

6. The method for preparing the water-retaining slow-release biological organic fertilizer according to claim 1, characterized in that: In (2), the preparation method of the water-retaining material powder is: S1. Add the dried nano-silica to deionized water containing γ-methacryloxypropyltrimethoxysilane, stir and disperse, react at 100-110° C. for 6-10 hours, filter after the reaction, wash with toluene, and dry to obtain olefinated nano-silica; S2. At 0-5°C, add acrylic acid to a 10% sodium hydroxide solution, control the neutralization degree to 70-80%, add acrylamide, olefinic nano-silica, and a cross-linking agent, stir and disperse, then add attapulgite, stir and disperse, finally add an initiator, react at 30-45°C for 30-60 minutes, and after the reaction is completed, dry, crush, and pass through a 0.25 mm sieve to obtain a water-retaining material powder.

7. The method for preparing the water-retaining slow-release biological organic fertilizer according to claim 6, characterized in that: In the S1, the mass of γ-methacryloxypropyltrimethoxysilane is 5-15% of the nano-silicon dioxide.

8. The method for preparing the water-retaining slow-release biological organic fertilizer according to claim 6, characterized in that: In the S2, the mass ratio of acrylic acid, acrylamide and olefinic nano-silica is 1:0.2-0.5:0.1-0.

3.

9. The method for preparing the water-retaining slow-release biological organic fertilizer according to claim 6, characterized in that: In S2, the crosslinking agent is N,N-methylenebisacrylamide, and its usage is 0.03-0.05% of the total mass of acrylic acid, acrylamide, and olefinic nano-silica; the initiator is potassium persulfate, and its usage is 1-1.5% of the total mass of acrylic acid, acrylamide, and olefinic nano-silica; the usage of attapulgite is 2-5% of the total mass of acrylic acid, acrylamide, and olefinic nano-silica.