Fertilizer synergist and preparation method thereof

Abstract

The invention discloses a fertilizer synergist and a preparation method thereof, and belongs to the technical field of fertilizer synergists. The invention relates to a modified meerschaum adsorbent, which is composed of 0.1-0.3 part of a urease inhibitor, 0.3-0.5 part of a nitrification inhibitor, 5-10 parts of an active agent, 30-40 parts of modified meerschaum powder, and 5-8 parts of fatty alcohol-polyoxyethylene ether. The active agent is composed of a sludge extract and a rice bran extract according to a mass ratio of 2: 1. Active components are further extracted from the residual sludge of the sewage treatment plant and the agricultural waste rice bran, and are reasonably matched with other components to form the stable and efficient fertilizer synergist, so that the use of chemical raw material synergists is remarkably reduced, the production cost is reduced, the nitrogen fertilizer utilization rate is increased, the plant growth is promoted, and the plant stress resistance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizer synergists, in particular to a fertilizer synergist and a preparation method thereof. Background Art

[0002] Nitrogen fertilizer is an indispensable element for crop growth and is the main component of protein, chlorophyll and enzymes. Chemical nitrogen fertilizer is mainly amide nitrogen fertilizer (urea). If crops lack nitrogen during growth, they need to be supplemented by applying nitrogen fertilizer. However, farmers have the following technical problems in the use of nitrogen fertilizer: (1) low nitrogen utilization rate; (2) short fertilizer effect, it is difficult to meet the fertilizer requirements of crops throughout the growth period, and multiple topdressing is required; (3) damage to the soil and environment.

[0003] Urea is a common nitrogen fertilizer with a low utilization rate, usually only 30%-40%. In order to improve the utilization rate of urea, the existing technology has widely adopted methods such as adding urease inhibitors and nitrification inhibitors to slow down the urea hydrolysis and nitrification process. Urease inhibitors can delay the process of urea hydrolysis to ammonium nitrogen by inhibiting urease activity and reducing ammonia volatilization. Nitrification inhibitors can delay the conversion of ammonium nitrogen to nitrate nitrogen by inhibiting the activity of nitrifying bacteria, reducing nitrification-denitrification losses and nitrate leaching. However, some urease inhibitors (such as NBPT) are easily decomposed under high temperature, high humidity or strong light conditions, resulting in a decrease in their inhibitory effect; and the effect of urease inhibitors is greatly affected by environmental factors such as soil pH, temperature, and humidity, and the performance is inconsistent under different soil and climatic conditions; the production cost of efficient urease inhibitors (such as NBPT) is high, which increases the total cost of fertilizers and may affect their large-scale promotion; long-term and large-scale use of urease inhibitors may have a negative impact on soil microbial communities and destroy the ecological balance of the soil. The effect of nitrification inhibitors is also greatly affected by factors such as soil type, temperature, and humidity. For example, DCD works better under low temperature conditions, but degrades faster under high temperature conditions; some nitrification inhibitors (such as DCD) may remain in the soil for a long time, potentially affecting subsequent crops or soil microorganisms; high-efficiency nitrification inhibitors (such as DMPP, Nitrapyrin) have high production costs, which limits their widespread application in field crops. It is difficult to fully solve the problem of urea nitrogen loss by using urease inhibitors or nitrification inhibitors alone, and the synergistic effect between the two has not been fully explored. Therefore, providing a more efficient, more stable, and more environmentally friendly fertilizer enhancer to achieve the dual goals of nitrogen fertilizer efficiency and environmental protection is a technical problem that needs to be solved urgently in the existing technology. Summary of the invention

[0004] The object of the present invention is to provide a fertilizer synergist, which further extracts active ingredients from sewage treatment plant sludge and agricultural waste rice bran, and forms a stable and efficient fertilizer synergist through reasonable proportioning with other components, significantly reducing the use of chemical raw material synergists, reducing production costs, improving nitrogen fertilizer utilization rate, promoting plant growth, and enhancing plant stress resistance.

[0005] To achieve the above technical object, the technical solution adopted by the present invention is as follows: A fertilizer synergist is composed of 0.1 - 0.3 parts of urease inhibitor, 0.3 - 0.5 parts of nitrification inhibitor, 5 - 10 parts of activator, 30 - 40 parts of modified sepiolite powder, and 5 - 8 parts of fatty alcohol polyoxyethylene ether; the activator is composed of sludge extract and rice bran extract according to a mass ratio of 2:1.

[0006] Preferably, the sludge extract is prepared by the following method: Step 1, take the surplus sludge, dry it until the water content is lower than 10%, and then crush it into sludge particles with a particle size of 1 mm. Step 2, mix the sludge particles with a sulfuric acid solution with a mass concentration of 3% according to a ratio of 1 g:5 ml, heat to 80 - 90 °C, stir and react for 3 - 4 h, then perform solid-liquid separation, and wash the solid to neutrality to obtain filter residue I and acidolysis solution. Step 3, mix filter residue I with a sodium hydroxide solution with a mass concentration of 5% according to a ratio of 1 g:5 ml, heat to 90 - 100 °C, stir and react for 3 - 4 h, after completion, perform solid-liquid separation, and wash the solid to neutrality to obtain filter residue II and alkalolysis solution. Step 4, add deionized water to filter residue II according to a ratio of 1 g:10 ml, stir evenly, then add a 1.5 wt% complex enzyme solution, heat to 55 - 60 °C and enzymolyze for 3 - 4 h, after completion, inactivate the enzyme, perform solid-liquid separation, and obtain filter residue III and enzymolysis solution. Step 5, mix the obtained acidolysis solution, alkalolysis solution, and enzymolysis solution according to a volume ratio of 1:1:2 to obtain a mixed solution, add 10% of the total weight of activated carbon to the mixed solution, stir at room temperature for 1 h, then filter to obtain the filtrate, further concentrate the filtrate to one-tenth of the original volume, and spray dry it into powder to obtain the sludge extract.

[0007] Preferably, the surplus sludge is from a sewage treatment plant that treats sewage by biological methods.

[0008] Preferably, in step 5, the complex enzyme solution contains 30 - 40 g / L of cellulase, 5 - 10 g / L of laccase, and 15 - 20 g / L of α-amylase.

[0009] Preferably, the enzyme activity of the cellulase is 100,000 u / g, the enzyme activity of the laccase is 100,000 u / g, and the enzyme activity of the α-amylase is 30,000 u / g.

[0010] Preferably, the rice bran extract is prepared by the following method: (1) Dissolve defatted rice bran in deionized water at a solid-liquid ratio of 1:10. After stirring at room temperature for 1 h, adjust the pH of the mixture to 9-10 with NaOH. Heat the mixture to 50 °C and react with magnetic stirring for 2 h. Then, centrifuge and separate to obtain the supernatant. Add 1 mol / L HCl solution to the supernatant to adjust its pH to 4.0, let it stand for 40-45 min, then centrifuge and separate to obtain the solid. Wash the solid product with deionized water 3-4 times, and dry it to obtain solid A; (2) Dissolve 1 g of solid A in 100 ml of deionized water. After mixing evenly, add neutral protease and enzymolyze at room temperature for 3-4 h. Then, adjust the pH of the enzymolyzed solution to 6.0-6.5. Add complex enzyme and enzymolyze at 50-55 °C for 2-3 h to inactivate the enzyme. Adjust the enzymolyzed solution to neutral, centrifuge and separate, and take the supernatant to spray dry into powder to obtain the rice bran extract.

[0011] Preferably, the complex enzyme is composed of papain and bromelain according to a mass ratio of 2:1; the dosage of neutral protease is 1% of the mass of solid A, and the dosage of complex enzyme is 1.5% of the mass of solid A; the enzyme activities of neutral protease, papain and bromelain are all 100,000 u / g.

[0012] Preferably, the modified sepiolite is prepared by the following method: (a) Add sepiolite powder to 2 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:15, heat to 80 °C, and react with magnetic stirring for 10 h. Then, filter, and repeatedly wash the solid until the surface is neutral, and dry to obtain acid-modified sepiolite powder; (b) Mix the acid-modified sepiolite powder with 1 mol / L ferrous chloride solution at a solid-liquid ratio of 1:10, react with magnetic stirring at room temperature for 1 h, let it stand for 24 h, then filter. Place the solid precipitate in an oven to dry and grind it into powder to obtain the modified sepiolite powder.

[0013] Preferably, the urease inhibitor is N-butyl thiophosphoryl triamide or N-propyl thiophosphoryl triamide; the nitrification inhibitor is dicyandiamide.

[0014] The present invention also provides a preparation method of the above fertilizer synergist, which includes the following steps: S1: Prepare sludge extract and rice bran extract respectively, and then form an active agent according to the mass ratio; S2: Prepare modified sepiolite powder; S3: Dissolve fatty alcohol polyoxyethylene ether in water with a mass 10 times that of the fatty alcohol polyoxyethylene ether, then add the modified sepiolite powder and the surfactant component thereto. After high-speed stirring and mixing for 30 min, add the urease inhibitor and the nitrification inhibitor. After stirring and mixing evenly, dry to obtain the fertilizer synergist.

[0015] The fertilizer synergist prepared in the present invention is used simultaneously with urea, and the dosage is 2% of the mass of urea.

[0016] Excess sludge, as the main by-product in the process of sewage biological treatment, has been regarded as waste in traditional concepts. In the process of the world's efforts to improve the performance of sewage treatment facilities and expand their coverage in developing countries, the sludge production has continued to increase significantly, and the economic and environmental problems related to its treatment and disposal have become increasingly prominent. The sludge contains a variety of unique energy and nutrients, and if it can be reasonably utilized, the resource utilization rate can be improved. The sludge extract obtained by acid treatment, alkali treatment and enzyme treatment of the sludge prepared in the present invention contains a variety of bioactive components such as polysaccharides, organic acids, amino acids secreted by microorganisms under specific conditions, as well as inorganic components of various medium and trace elements such as calcium, magnesium and silicon; the active substances of the sludge extract have the ability to form gels, and after being applied to the soil with fertilizers, they interact with the nutrients in the soil to form a stable matrix network, which can adsorb more urea to form a stable complex, further delaying the hydrolysis of urea. At the same time, the organic substances in the sludge extract can provide a carbon source for soil microorganisms, promote the utilization of urea by microorganisms, reduce the direct hydrolysis of urea, and can also improve the soil structure, enhance the water and fertilizer retention capacity of the soil, and achieve long-term slow release of nutrients. The rice bran extract prepared in the present invention is rich in a variety of active components such as small molecule peptides, amino acids, and organic acids, and can provide a rapid and effective nitrogen source for plants, promoting the development of plant roots and nutrient absorption. The present invention mixes the two in the best ratio to prepare a surfactant, and the combination of the two forms a "fast-slow combination" nutrient supply system, and this synergistic effect can meet the nutrient requirements of plants at different growth stages and improve the nitrogen fertilizer utilization rate.

[0017] Urease inhibitors (such as N-butyl thiophosphoryl triamide) can inhibit the activity of urease in the soil, slow down the hydrolysis rate of urea, and reduce the volatilization loss of ammonium nitrogen. Nitrification inhibitors (such as dicyandiamide) can inhibit the activity of nitrifying bacteria in the soil, slow down the conversion of ammonium nitrogen to nitrate nitrogen, and reduce the leaching and denitrification losses of nitrate nitrogen. The organic substances in the surfactant prepared in the present invention can form a stable complex with ammonium nitrogen, reducing the nitrification of ammonium nitrogen. At the same time, the organic substances in the surfactant can provide a carbon source for soil microorganisms, promoting the fixation of ammonium nitrogen by microorganisms and reducing the occurrence of nitrification.

[0018] The modified sepiolite powder can be used as a carrier to load urease inhibitors, nitrification inhibitors and activators, prolong their action time and improve the fertilizer utilization rate. At the same time, the ferrous ions in the modified sepiolite powder and the active small molecule peptides in the activator can interact with each other to form stable chelates, further enhancing the slow-release effect of the fertilizer and providing more abundant nutrients for plants.

[0019] As a surfactant, fatty alcohol polyoxyethylene ether can improve the dispersibility and adsorbability of fertilizers, enhance their permeability and stability in the soil, and ensure the effects of fertilizer synergists under different soil conditions.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Through the synergistic effect of a small amount of urease inhibitor and nitrification inhibitor, the volatilization, nitrification-denitrification loss and leaching of urea nitrogen are reduced, and the nitrogen fertilizer utilization rate is significantly improved. Moreover, in the combined use of the activator, urease inhibitor and nitrification inhibitor of the present invention, the organic substances in the activator can delay the hydrolysis of urea and the nitrification of ammonium nitrogen, while the urease inhibitor and nitrification inhibitor can further inhibit the volatilization and leaching of nitrogen. (2) The sludge extract and rice bran extract in the activator not only provide nutrients for plants and prolong the release time of nutrients, but also improve the soil environment, promote the development of plant roots and nutrient absorption. (3) By using waste resources such as sludge and rice bran, the use of urease inhibitors and nitrification inhibitors is reduced, the production cost is lowered, and at the same time, the dependence on chemically synthesized synergists is reduced, with significant environmental protection benefits. Description of the Drawings

[0021] Figure 1 It is the test result of the dry matter accumulation amount of the above-ground part of corn in the test example of the present invention; Figure 2 It is the test result of the ammonium nitrogen content in the soil of corn at the jointing stage and maturity stage in the test example of the present invention; Figure 3 It is the test result of the nitrate nitrogen content in the soil of corn at the jointing stage and maturity stage in the test example of the present invention. Detailed Embodiments

[0022] The technical solutions of the present invention will be further described below in conjunction with specific embodiments, but are not limited thereto.

[0023] Example 1 A fertilizer synergist is composed of 0.1 part of urease inhibitor, 0.3 part of nitrification inhibitor, 5 parts of activator, 30 parts of modified sepiolite powder and 5 parts of fatty alcohol polyoxyethylene ether; the activator is composed of sludge extract and rice bran extract according to a mass ratio of 2:1.

[0024] The sludge extract is prepared by the following method: Step 1: Take the excess sludge, dry it until the water content is less than 10%, and then crush it into sludge particles with a particle size of 1 mm. Step 2: Mix the sludge particles with a sulfuric acid solution with a mass concentration of 3% at a ratio of 1 g:5 ml, heat to 80 - 90 °C, stir and react for 3 - 4 h, then perform solid-liquid separation, and wash the solid to neutrality to obtain filter residue I and acidolysis solution. Step 3: Mix filter residue I with a sodium hydroxide solution with a mass concentration of 5% at a ratio of 1 g:5 ml, heat to 90 - 100 °C, stir and react for 3 - 4 h, after completion, perform solid-liquid separation, and wash the solid to neutrality to obtain filter residue II and alkalolysis solution. Step 4: Add deionized water to filter residue II at a ratio of 1 g:10 ml, stir evenly, then add a 1.5 wt% complex enzyme solution, heat to 55 - 60 °C and perform enzymatic hydrolysis for 3 - 4 h, after completion, inactivate the enzyme, and perform solid-liquid separation to obtain filter residue III and enzymatic hydrolysis solution. Step 5: Mix the obtained acidolysis solution, alkalolysis solution, and enzymatic hydrolysis solution according to a volume ratio of 1:1:2 to obtain a mixed solution, add activated carbon accounting for 10% of the total weight to the mixed solution, stir at room temperature for 1 h, then filter to obtain the filtrate, further concentrate the filtrate to one-tenth of the original volume, and spray-dry it into powder to obtain the sludge extract.

[0025] The excess sludge is from a sewage treatment plant that uses a biological method to treat sewage.

[0026] In the complex enzyme solution in Step 5, it contains 30 g / L of cellulase, 5 g / L of laccase, and 15 g / L of α-amylase.

[0027] The enzyme activity of the cellulase is 100,000 u / g, the enzyme activity of the laccase is 100,000 u / g, and the enzyme activity of the α-amylase is 30,000 u / g.

[0028] The rice bran extract is prepared by the following method: (1) Dissolve defatted rice bran in deionized water at a solid-liquid ratio of 1:10, stir at room temperature for 1 h, then adjust the pH of the mixed solution to 9 - 10 with NaOH, heat the mixed solution to 50 °C, magnetically stir and react for 2 h, then perform centrifugal separation to take the supernatant, add 1 mol / L HCl solution to the supernatant to adjust its pH to 4.0, let it stand for 40 - 45 min, then perform centrifugal separation to take the solid, wash the solid product with deionized water 3 - 4 times, and dry it to obtain solid A. (2) Dissolve 1 g of solid A in 100 ml of deionized water. After mixing evenly, add neutral protease and enzymolyze at room temperature for 3 - 4 h. Then adjust the pH of the enzymolysis solution to 6.0 - 6.5. Add complex enzyme and enzymolyze at 50 - 55 °C for 2 - 3 h to inactivate the enzyme. Adjust the enzymolysis solution to neutral, centrifuge and separate, and take the supernatant to spray dry into powder to obtain rice bran extract.

[0029] The complex enzyme is composed of papain and bromelain according to the mass ratio of 2:1; the dosage of neutral protease is 1% of the mass of solid A, and the dosage of complex enzyme is 1.5% of the mass of solid A; the enzyme activities of neutral protease, papain and bromelain are all 100,000 u / g.

[0030] The modified sepiolite is prepared by the following method: (a) Add sepiolite powder to 2 mol / L hydrochloric acid solution according to the solid-liquid ratio of 1:15, heat to 80 °C, react for 10 h under magnetic stirring, filter, repeatedly rinse the solid until the surface is neutral, and dry to obtain acid-modified sepiolite powder; (b) Mix the acid-modified sepiolite powder with 1 mol / L ferrous chloride solution according to the solid-liquid ratio of 1:10, react under magnetic stirring at room temperature for 1 h, stand for 24 h and then filter. Place the solid precipitate in an oven to dry and then grind into powder to obtain modified sepiolite powder.

[0031] The urease inhibitor is N-butyl thiophosphoryl triamide; the nitrification inhibitor is dicyandiamide.

[0032] A preparation method of the above fertilizer synergist, which includes the following steps: S1: Prepare sludge extract and rice bran extract respectively, and then form an active agent according to the mass ratio; S2: Prepare modified sepiolite powder; S3: Dissolve fatty alcohol polyoxyethylene ether in 10 times its mass of water, then add the modified sepiolite powder and the active agent component into it, stir and mix at high speed for 30 min, then add the urease inhibitor and the nitrification inhibitor, stir and mix evenly, and dry to obtain the fertilizer synergist.

[0033] Example 2 A fertilizer synergist is composed of 0.3 parts of urease inhibitor, 0.5 parts of nitrification inhibitor, 10 parts of active agent, 40 parts of modified sepiolite powder, and 8 parts of fatty alcohol polyoxyethylene ether; the active agent is composed of sludge extract and rice bran extract according to the mass ratio of 2:1.

[0034] The sludge extract is prepared by the following method: Step 1, take the excess sludge, dry it until the water content is less than 10%, and then crush it into sludge particles with a particle size of 1 mm; Step 2: Mix sludge particles with a sulfuric acid solution with a mass concentration of 3% at a ratio of 1 g:5 ml, heat to 80 - 90 °C, stir and react for 3 - 4 h, then perform solid-liquid separation, wash the solid to neutrality to obtain filter residue I and acidolysis solution; Step 3: Mix filter residue I with a sodium hydroxide solution with a mass concentration of 5% at a ratio of 1 g:5 ml, heat to 90 - 100 °C, stir and react for 3 - 4 h, after completion, perform solid-liquid separation, wash the solid to neutrality to obtain filter residue II and alkalolysis solution; Step 4: Add deionized water to filter residue II at a ratio of 1 g:10 ml, stir evenly, then add a 1.5 wt% composite enzyme solution, heat to 55 - 60 °C and enzymolyze for 3 - 4 h, after completion, inactivate the enzyme, perform solid-liquid separation to obtain filter residue III and enzymolysis solution; Step 5: Mix the obtained acidolysis solution, alkalolysis solution, and enzymolysis solution according to a volume ratio of 1:1:2 to obtain a mixed solution, add 10% of the total weight of activated carbon to the mixed solution, stir at room temperature for 1 h, then filter to obtain the filtrate, further concentrate the filtrate to one-tenth of the original volume, and spray dry it into powder to obtain the sludge extract.

[0035] The excess sludge is from a sewage treatment plant that uses biological methods to treat sewage.

[0036] In the composite enzyme solution in Step 5, it contains 40 g / L of cellulase, 10 g / L of laccase, and 20 g / L of α-amylase.

[0037] The enzyme activity of the cellulase is 100,000 u / g, the enzyme activity of the laccase is 100,000 u / g, and the enzyme activity of the α-amylase is 30,000 u / g.

[0038] The rice bran extract is prepared by the following method: (1) Dissolve defatted rice bran in deionized water at a solid-liquid ratio of 1:10, stir at room temperature for 1 h, then adjust the pH of the mixed solution to 9 - 10 with NaOH, heat the mixed solution to 50 °C, stir magnetically and react for 2 h, then perform centrifugal separation to take the supernatant, add 1 mol / L HCl solution to the supernatant to adjust its pH to 4.0, let it stand for 40 - 45 min, then perform centrifugal separation to take the solid, wash the solid product with deionized water 3 - 4 times, and dry it to obtain solid A; (2) Dissolve 1 g of solid A in 100 ml of deionized water, mix evenly, then add neutral protease and enzymolyze at room temperature for 3 - 4 h, then adjust the pH of the enzymolysis solution to 6.0 - 6.5, add a composite enzyme and enzymolyze at 50 - 55 °C for 2 - 3 h to inactivate the enzyme, adjust the enzymolysis solution to neutrality, perform centrifugal separation, and take the supernatant and spray dry it into powder to obtain the rice bran extract.

[0039] The composite enzyme is composed of papain and bromelain at a mass ratio of 2:1; the dosage of neutral protease is 1% of the mass of solid A, and the dosage of the composite enzyme is 1.5% of the mass of solid A; the enzyme activities of the neutral protease, papain and bromelain are all 100,000 u / g.

[0040] The modified sepiolite is prepared by the following method: (a) Add sepiolite powder to 2 mol / L hydrochloric acid solution according to a solid-liquid ratio of 1:15, heat to 80 °C, react for 10 h under magnetic stirring, then filter, repeatedly wash the solid until the surface is neutral, and dry to obtain acid-modified sepiolite powder; (b) Mix the acid-modified sepiolite powder with 1 mol / L ferrous chloride solution according to a solid-liquid ratio of 1:10, react under magnetic stirring at room temperature for 1 h, then let stand for 24 h and filter. Place the solid precipitate in an oven to dry and then grind it into powder to obtain the modified sepiolite powder.

[0041] The urease inhibitor is N-butyl thiophosphoryl triamide or N-propyl thiophosphoryl triamide; the nitrification inhibitor is dicyandiamide.

[0042] A preparation method of the above fertilizer synergist includes the following steps: S1: Prepare sludge extract and rice bran extract respectively, and then form an active agent according to the mass ratio; S2: Prepare modified sepiolite powder; S3: Dissolve fatty alcohol polyoxyethylene ether in 10 times its mass of water, then add the modified sepiolite powder and the active agent component thereto, stir and mix at high speed for 30 min, then add the urease inhibitor and the nitrification inhibitor, stir and mix evenly, and dry to obtain the fertilizer synergist.

[0043] Example 3 A fertilizer synergist is composed of 0.2 parts of urease inhibitor, 0.4 parts of nitrification inhibitor, 8 parts of active agent, 35 parts of modified sepiolite powder, and 6 parts of fatty alcohol polyoxyethylene ether; the active agent is composed of sludge extract and rice bran extract at a mass ratio of 2:1.

[0044] The sludge extract is prepared by the following method: Step 1, take the excess sludge, dry it until the water content is less than 10%, and then crush it into sludge particles with a particle size of 1 mm; Step 2, take the sludge particles and mix them with a 3% sulfuric acid solution according to a ratio of 1 g:5 ml, heat to 80 - 90 °C, stir and react for 3 - 4 h, then perform solid-liquid separation, and wash the solid to neutral to obtain filter residue I and acidolysis solution; Step 3: Take the filter residue I and mix it with a sodium hydroxide solution with a mass concentration of 5% at a ratio of 1 g: 5 ml, heat it to 90 - 100 °C, stir and react for 3 - 4 h. After completion, perform solid-liquid separation, and wash the solid to neutrality to obtain filter residue II and an alkali hydrolysis solution; Step 4: Take the filter residue II and add deionized water to it at a ratio of 1 g: 10 ml. After stirring evenly, add a 1.5 wt% composite enzyme solution, heat it to 55 - 60 °C and then perform enzymatic hydrolysis for 3 - 4 h. After completion, inactivate the enzyme, perform solid-liquid separation, and obtain filter residue III and an enzymatic hydrolysis solution; Step 5: Mix the obtained acid hydrolysis solution, alkali hydrolysis solution, and enzymatic hydrolysis solution according to a volume ratio of 1: 1: 2 to obtain a mixed solution. Add activated carbon with a total weight of 10% to the mixed solution, stir at room temperature for 1 h, then filter to obtain the filtrate. Further concentrate the filtrate to one-tenth of the original volume, and spray-dry it into powder to obtain the sludge extract.

[0045] The surplus sludge is from a sewage treatment plant that uses a biological method to treat sewage.

[0046] In the composite enzyme solution in Step 5, it contains 35 g / L of cellulase, 8 g / L of laccase, and 16 g / L of α-amylase.

[0047] The enzyme activity of the cellulase is 100,000 u / g, the enzyme activity of the laccase is 100,000 u / g, and the enzyme activity of the α-amylase is 30,000 u / g.

[0048] The rice bran extract is prepared by the following method: (1) Dissolve defatted rice bran in deionized water at a solid-liquid ratio of 1: 10. After stirring at room temperature for 1 h, adjust the pH of the mixed solution to 9 - 10 with NaOH. Heat the mixed solution to 50 °C, stir magnetically and react for 2 h, then perform centrifugal separation to take the supernatant. Add 1 mol / L HCl solution to the supernatant to adjust its pH to 4.0, let it stand for 40 - 45 min, then perform centrifugal separation to take the solid, wash the solid product with deionized water 3 - 4 times, and dry it to obtain solid A; (2) Dissolve 1 g of solid A in 100 ml of deionized water. After mixing evenly, add neutral protease and perform enzymatic hydrolysis at room temperature for 3 - 4 h. Then adjust the pH of the enzymatic hydrolysis solution to 6.0 - 6.5, add composite enzyme and perform enzymatic hydrolysis at 50 - 55 °C for 2 - 3 h to inactivate the enzyme. Adjust the enzymatic hydrolysis solution to neutrality, perform centrifugal separation, and take the supernatant and spray-dry it into powder to obtain the rice bran extract.

[0049] The composite enzyme is composed of papain and bromelain according to a mass ratio of 2: 1; the dosage of the neutral protease is 1% of the mass of solid A, and the dosage of the composite enzyme is 1.5% of the mass of solid A; the enzyme activities of the neutral protease, papain, and bromelain are all 100,000 u / g.

[0050] The modified sepiolite is prepared by the following method: (a) Add sepiolite powder to 2 mol / L hydrochloric acid solution according to a solid-liquid ratio of 1:15, heat to 80 °C, react for 10 h under magnetic stirring, then filter, repeatedly rinse the solid until the surface is neutral, and dry to obtain acid-modified sepiolite powder; (b) Mix the acid-modified sepiolite powder with 1 mol / L ferrous chloride solution according to a solid-liquid ratio of 1:10, react under magnetic stirring at room temperature for 1 h, let stand for 24 h and then filter, dry the solid precipitate in an oven and grind it into powder to obtain the modified sepiolite powder.

[0051] The urease inhibitor is N-propylthiophosphoric triamide; the nitrification inhibitor is dicyandiamide.

[0052] A preparation method of the above fertilizer synergist includes the following steps: S1: Prepare sludge extract and rice bran extract respectively, and then form an active agent according to the mass ratio; S2: Prepare modified sepiolite powder; S3: Dissolve fatty alcohol polyoxyethylene ether in 10 times its mass of water, then add the modified sepiolite powder and the active agent component thereto, stir and mix at high speed for 30 min, then add the urease inhibitor and the nitrification inhibitor, stir and mix evenly, and dry to obtain the fertilizer synergist.

[0053] Comparative Example 1 A fertilizer synergist, whose principle composition is basically the same as that of Example 3, the only difference being that the active agent only contains sludge extract.

[0054] Comparative Example 2 A fertilizer synergist, whose principle composition is basically the same as that of Example 3, the only difference being that the active agent only contains rice bran extract.

[0055] Comparative Example 3 A fertilizer synergist, whose principle composition is basically the same as that of Example 3, the only difference being that it does not contain an active agent.

[0056] Comparative Example 4 A fertilizer synergist, whose principle composition is basically the same as that of Example 3, the only difference being that it does not contain the urease inhibitor N-propylthiophosphoric triamide.

[0057] Comparative Example 5 A fertilizer synergist, whose principle composition is basically the same as that of Example 3, the only difference being that it does not contain the nitrification inhibitor dicyandiamide.

[0058] Comparative Example 6 A fertilizer synergist, whose principle composition is basically the same as that of Example 3, the only difference being that it does not contain the nitrification inhibitor dicyandiamide and the urease inhibitor N-propylthiophosphoric triamide.

[0059] Test Example Test site: It was selected to be carried out at the Shikefeng agricultural planting test base in the Economic Development Zone of Linyi City, Shandong Province. The soil type is loam with medium fertility. The basic physical and chemical properties of the 0-20 cm soil are as follows: pH value is 5.89, organic matter is 20.89 g / kg, available nitrogen is 93.9 mg / kg, available phosphorus is 23.4 mg / kg, and available potassium is 208 mg / kg.

[0060] Test crop variety: Maize, Xianyu 335, with a planting density of 4000 plants per mu. The planting time is sowing in the middle and late June every year and harvesting in the middle of October.

[0061] Test design: A total of 9 treatment groups were set up in this test, namely treatment groups 1-9. Among them, 1 is the treatment group of Example 3, 2-7 are the treatment groups of Comparative Examples 1-6, 8 is the control group of conventional fertilizer without any synergist, and 9 is the control group without any nitrogen fertilizer. The test plot area is 45 m 2 , with 3 replicates for each treatment, and the average value was taken for the experimental results. All treatment group fertilizers were applied as a one-time base application, and the fertilizer application rates were N 200 kg / hm 2 , P2O5 100 kg / hm 2 , K2O 100 kg / hm 2 , and nitrogen fertilizer, phosphate fertilizer and potassium fertilizer were provided by urea (containing 46% N), triple superphosphate (P2O5 45%) and potassium sulfate (K2O 60%) respectively. The dosage of the fertilizer synergist was 2% of the urea quality, which was mixed with urea and also applied as a base fertilizer once. After broadcasting, it was turned into the soil. Other field management measures were the same as the local conventional management.

[0062] Determination items and methods: Above-ground dry matter accumulation: At the maturity stage, in each treatment, 10 representative plants were selected, blanched at 105 °C for 30 min, dried to a constant weight at 80 °C, and weighed to calculate the above-ground dry matter accumulation. As Figure 1 shown.

[0063] From Figure 1 it can be seen that the dry matter accumulation of maize in Example 3 of the present invention is significantly higher than that of other comparative examples, indicating that the fertilizer synergist prepared by the present invention significantly promotes the dry matter accumulation of maize after use.

[0064] At the jointing stage and the maturity stage, 20 g of 0-20 cm plough layer soil was taken from each plot by the 5-point sampling method. After the soil samples were mixed, impurities were removed, and after sieving, they were respectively put into self-sealing bags and stored at -20 °C. The soil samples were extracted with 1 M KCL solution, and then the ammonium nitrogen (NH4 +-N) and nitrate nitrogen (NO3 - -N) content. The results are shown in Figure 2 and Figure 3 . From Figure 2 and Figure 3 , it can be seen that as the corn grows, from the jointing stage to the maturity stage, both ammonium nitrogen and nitrate nitrogen show a decreasing trend, which reflects that the absorption and utilization of nitrogen by corn after the maturity stage is close to completion. Figure 2 , it can be seen from the data in that the ammonium nitrogen content in Example 3 is significantly higher than that in Comparative Examples 1-6. This shows that adding the fertilizer synergist treatment of Example 3 of the present invention can increase the ammonium nitrogen content in the soil at the jointing stage of corn and maintain the ammonium nitrogen content in the soil at a certain level in the later stage. Figure 3 , it can be seen that whether at the jointing stage or the maturity stage, the nitrate nitrogen content in Example 3 is significantly lower than that in other comparative examples. This shows that adding the fertilizer synergist treatment reduces the nitrate nitrogen content and reduces the risk of nitrate nitrogen leaching into the deep soil.

[0065] After drying the dry matter at maturity, it is ground and pulverized with a pulverizer. Weigh 0.2 g of the ground plant sample and decompose it by digestion with H2SO4-H2O2. After diluting the digestion solution, use an AA3 type continuous flow analyzer to measure the total nitrogen content of the plant, and calculate the relevant indicators: Partial factor productivity of nitrogen fertilizer (PFPN, kg / kg) = yield / nitrogen application rate; Agronomic efficiency of nitrogen fertilizer (NAE, kg / kg) = (yield of nitrogen application treatment - yield of non-nitrogen application treatment) / nitrogen application rate; Nitrogen use efficiency (NUE, %) = (nitrogen uptake in nitrogen application treatment - nitrogen uptake in non-nitrogen application treatment) / nitrogen application rate × 100. As shown in Table 1.

[0066] Table 1 Effects of fertilizer synergists in different treatment groups on nitrogen use efficiency of corn , it can be seen from Table 1 above that after using the fertilizer synergist of Example 3 of the present invention, the nitrogen use efficiency can be significantly improved, and the effects are better than those of other comparative examples. For Comparative Examples 1-6 with the raw material composition of the present invention changed, the corresponding effects become worse. This shows that the raw material composition and ratio of the present invention complement each other and are indispensable.

[0067] Harvest at maturity. Randomly select 30 ears from each plot to investigate the yield trait indicators, and examine the ear length, ear diameter, bald tip length, ear row number, grains per row, 1000-grain weight, ear grain weight, etc. of each ear. The statistical results are shown in Table 2.

[0068] Table 2 Corn yield and its component factors in different treatments It should be noted that the above embodiments are only some of the embodiments of the preferred implementation of the present invention, rather than all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A fertilizer synergist, characterized in that: The invention is composed of 0.1-0.3 parts of urease inhibitor, 0.3-0.5 parts of nitrification inhibitor, 5-10 parts of active agent, 30-40 parts of modified sepiolite powder and 5-8 parts of fatty alcohol polyoxyethylene ether; the active agent is composed of sludge extract and rice bran extract in a mass ratio of 2:

1.

2. The fertilizer synergist according to claim 1, characterized in that The sludge extract is prepared by the following method: Step 1, taking the residual sludge, drying it until the moisture content is less than 10%, and then crushing it into sludge particles with a particle size of 1 mm; Step 2, taking the sludge particles and a sulfuric acid solution with a mass concentration of 3% in a ratio of 1g:5ml, heating to 80-90°C, stirring and reacting for 3-4h, separating the solid and the liquid, washing the solid to neutrality to obtain filter residue I and acid hydrolyzate; Step 3, taking the filter residue I and mixing it with a sodium hydroxide solution with a mass concentration of 5% in a ratio of 1g:5ml, heating it to 90-100°C, stirring and reacting for 3-4h, and after the reaction, separating the solid and the liquid, washing the solid to neutrality to obtain the filter residue II and the alkaline hydrolysis solution; Step 4, take the filter residue II and add deionized water in a ratio of 1g:10ml, stir evenly, then add 1.5wt% of the composite enzyme solution, heat to 55-60°C and perform enzymolysis for 3-4h, then kill the enzyme, separate the solid and liquid, and obtain the filter residue III and the enzymolysis solution; Step 5, the obtained acid hydrolyzate, alkaline hydrolyzate and enzymatic hydrolyzate are mixed in a volume ratio of 1:1:2 to obtain a mixed solution, 10% of the total weight of activated carbon is added to the mixed solution, and the filtrate is filtered after stirring at room temperature for 1 hour, and the filtrate is further concentrated to one tenth of the original volume, and spray-dried into powder to obtain the sludge extract.

3. The fertilizer synergist according to claim 2, characterized in that The excess sludge comes from a sewage treatment plant that uses a biological method to treat sewage.

4. The fertilizer synergist according to claim 2, characterized in that The complex enzyme solution in step 5 contains 30-40 g / L of cellulase, 5-10 g / L of laccase, and 15-20 g / L of α-amylase.

5. The fertilizer synergist according to claim 4, characterized in that The enzymatic activity of the cellulase is 100,000 u / g, the enzymatic activity of the laccase is 100,000 u / g, and the enzymatic activity of the alpha-amylase is 30,000 u / g.

6. The fertilizer synergist according to claim 1, characterized in that The rice bran extract is prepared by the following method: (1) Defatted rice bran was dissolved in deionized water at a solid-liquid ratio of 1:10, and the mixture was stirred at room temperature for 1 hour. The pH of the mixture was adjusted to 9-10 with NaOH, and the mixture was heated to 50°C. After magnetic stirring for 2 hours, the supernatant was separated by centrifugation. 1 mol / L HCl solution was added to the supernatant to adjust its pH to 4.0, and the mixture was allowed to stand for 40-45 minutes. The solid was separated by centrifugation, and the solid product was washed with deionized water for 3-4 times, and then dried to obtain solid A; (2) Dissolve 1 g of solid A in 100 ml of deionized water, mix well, add neutral protease and perform enzymolysis at room temperature for 3-4 hours, then adjust the pH of the enzymatic solution to 6.0-6.5, add complex enzyme and perform enzymolysis at 50-55°C for 2-3 hours to inactivate the enzyme, adjust the enzymatic solution to neutral, centrifuge, take the supernatant and spray dry it into powder to obtain rice bran extract.

7. The fertilizer synergist according to claim 6, characterized in that The composite enzyme is composed of papain and bromelain in a mass ratio of 2:1; the amount of the neutral protease is 1% of the mass of the solid A, and the amount of the composite enzyme is 1.5% of the mass of the solid A; the enzyme activities of the neutral protease, papain and bromelain are all 100,000 u / g.

8. The fertilizer synergist according to claim 1, characterized in that: The modified sepiolite is prepared by the following method: (a) adding sepiolite powder to a 2 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:15, heating to 80°C, reacting for 10 h under magnetic stirring, filtering, repeatedly washing the solid until the surface is neutral, and drying to obtain acid-modified sepiolite powder; (b) The acid-modified sepiolite powder was mixed with 1 mol / L ferrous chloride solution at a solid-liquid ratio of 1:10, and the mixture was reacted under magnetic stirring at room temperature for 1 hour. The mixture was allowed to stand for 24 hours and then filtered. The solid precipitate was dried in an oven and then ground into powder to obtain the modified sepiolite powder.

9. The fertilizer synergist according to claim 1, characterized in that: The urease inhibitor is N-butylthiophosphoric triamide or N-propylthiophosphoric triamide; the nitrification inhibitor is dicyandiamide.

10. A method for preparing the fertilizer synergist according to any one of claims 1 to 9, characterized in that: It includes the following steps: S1: preparing sludge extract and rice bran extract respectively, and then forming active agents according to the mass ratio; S2: preparing modified sepiolite powder; S3: Dissolve fatty alcohol polyoxyethylene ether in 10 times the mass of water, then add modified sepiolite powder and active agent components, stir and mix at high speed for 30 minutes, then add urease inhibitor and nitrification inhibitor, stir and mix evenly, and then dry to obtain the fertilizer enhancer.

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