Environment-friendly nitrogen fertilizer synergist and preparation method thereof

Abstract

The invention discloses an environment-friendly nitrogen fertilizer synergist and a preparation method thereof, and belongs to the technical field of fertilizer synergists. The fertilizer is prepared from the following raw materials in parts by weight: 20-30 parts of humic acid, 10-15 parts of burdock leaf extract, 15-20 parts of charcoal, 1-3 parts of nano zinc oxide, 5-10 parts of lignosulfonate and 50-60 parts of water. The burdock leaf extract and the biochar are combined for use, so that the slow release performance of the nitrogen fertilizer can be further improved, the layered porous structure of the biochar can adsorb nitrogen in the nitrogen fertilizer, and multiple bioactive components in the burdock leaf extract can regulate the activity of soil microorganisms; meanwhile, a complex can be formed with nitrogen in the fertilizer, so that the hydrolysis of the nitrogen fertilizer is delayed, the volatilization of ammonia is reduced, and the utilization rate of the fertilizer is further improved. The nitrogen fertilizer synergist prepared in the invention has the advantages of easily available raw materials, environmental protection and no pollution, can effectively reduce the usage amount of chemical fertilizers, promotes the absorption and utilization of nitrogen fertilizers by plants, and significantly improves the yield and quality of crops.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizer synergists, and particularly relates to an environmentally friendly nitrogen fertilizer synergist and a preparation method thereof. Background Art

[0002] Fertilizer, as food for crops, can provide sufficient nutrients for the growth of crops. It is a key factor in ensuring stable and increased grain production. It plays a vital role in grain production, allowing agricultural production to keep pace with the rapid growth of the population (Burney et al., 2010). However, due to the unscientific and unreasonable application of fertilizers, the utilization rate of fertilizers is low, which will also cause a series of environmental problems, such as excessive nitrate content in groundwater, eutrophication of water bodies, and increased greenhouse gas emissions, which have a negative impact on the ecological environment and hinder the sustainable development of agriculture; it also affects the quality of crops and further threatens human health. Therefore, research on improving fertilizer utilization is of great significance.

[0003] Fertilizer synergists refer to a class of substances that are produced through biological, physical, and chemical processes and added to fertilizers to stimulate plant nutrient absorption, increase nutrient effectiveness, or improve nutrient utilization. Fertilizer is one of the important factors affecting plant yield. At present, my country is the country with the largest fertilizer usage in the world, and the use of chemical fertilizers accounts for about one-third of the total global fertilizer usage. Although my country uses the largest amount of chemical fertilizers, the fertilizer utilization rate is low. To solve this problem, a large number of researchers have added different fertilizer synergists to fertilizers to reduce fertilizer usage, improve fertilizer utilization, and increase plant yields.

[0004] Nitrogen fertilizer is an indispensable fertilizer in agricultural production, but its utilization rate is usually low. A large amount of nitrogen is lost through volatilization, leaching, etc., which not only causes resource waste, but also leads to environmental pollution (such as eutrophication of water bodies, greenhouse gas emissions, etc.). In the prior art, nitrogen fertilizer synergists are mostly made of chemical synthetic materials, which have problems such as high cost and great environmental risks. Therefore, it is of great significance to develop an environmentally friendly, efficient and low-cost nitrogen fertilizer synergist. Summary of the invention

[0005] The purpose of the present invention is to provide an environmentally friendly nitrogen fertilizer synergist, which uses substances produced by specific biological, physical and chemical processes as raw materials, and multiple raw materials are mixed and synergistically added to nitrogen fertilizers to stimulate plant nutrient absorption and improve nitrogen fertilizer utilization. At the same time, it can also increase the slow release of fertilizers, thereby improving nitrogen fertilizer utilization.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is: An environmentally friendly nitrogen fertilizer synergist is prepared from the following raw materials in parts by weight: 20-30 parts of humic acid, 10-15 parts of burdock leaf extract, 15-20 parts of biochar, 1-3 parts of nano zinc oxide, 5-10 parts of lignin sulfonate and 50-60 parts of water.

[0007] Preferably, the biochar is prepared by the following method: (1) The garlic stalks were washed with deionized water and dried, and then immersed in a saturated urea solution. After soaking at room temperature for 36 hours, the solution was taken out and dried to obtain pretreated garlic stalks; (2) placing the pretreated garlic straw in a muffle furnace, calcining at high temperature for 3 h under a nitrogen atmosphere, and cooling naturally to obtain a primary carbonization product; (3) Mix the primary carbonization product with the activation solution in a ratio of 1 g:10 ml, stir at room temperature for 30 min, evaporate and remove the solvent, put the evaporated mixture into a tubular furnace under nitrogen protection, calcine at high temperature for 2 h, cool and take out to obtain a secondary carbonization product; (4) The secondary carbonization product was mixed with 1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1 g:10 ml, stirred at room temperature for 8 h, washed with deionized water until neutral, and vacuum dried to obtain biochar.

[0008] Preferably, in step (2), the calcination temperature in the muffle furnace is 800°C, and the heating rate is 5°C / min; and in step (3), the calcination temperature in the tubular furnace is 800°C, and the heating rate is 10°C / min.

[0009] Preferably, the activation solution is a 0.2-0.3 g / mL KOH ethanol solution.

[0010] Preferably, the burdock leaf extract is prepared by the following method: (1) The burdock leaves were cleaned and cut into small pieces of 3-5 cm, then dried in an oven at 120°C for 30 min, then the temperature was adjusted to 55-60°C, dried to constant weight, ground into powder, passed through an 80-mesh sieve, and then further subjected to ultrafine grinding. After treatment, the powder was added to 70% anhydrous ethanol and heated under reflux for extraction for 1.5 hours, and the ethanol was removed by rotary evaporation to obtain a crude extract; (2) adding deionized water to the crude extract at a solid-liquid ratio of 1 g:40 ml to obtain a mixed solution, adding peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate to the mixed solution, adjusting the pH to 7.0, and then inoculating Lactobacillus buchneri seed solution and Corynebacterium glutamicum seed solution respectively, and fermenting and culturing at 28-30° C. for 2 days to obtain a mixed fermentation liquid; (3) The pH of the mixed fermentation liquid was adjusted to 5.0-5.5, 1.5 wt% of the complex enzyme solution was added thereto, and the mixture was enzymatically hydrolyzed at 40-45°C for 4 h. The pH was then adjusted to 6.5-7.0, 1 wt% of lysozyme was added, and the enzymatic hydrolysis was continued at 38-40°C for 2 h. Then, 1.5 wt% of mannanase was added and the mixture was enzymatically hydrolyzed at 45°C for 2 h. The enzyme was inactivated at high temperature to obtain an enzymatic solution, and the solution was separated by high-speed centrifugation. The supernatant was collected and concentrated and dried to obtain the burdock leaf extract.

[0011] Preferably, in step (2), the added amounts of peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate are 10-15 g / L, 5-8 g / L, 5-8 g / L, 1-1.5 g / L, 0.05-0.1 g / L, and 0.01-0.03 g / L, respectively.

[0012] Preferably, in step (2), the inoculation amount of Lactobacillus buchneri seed solution is 2-3% of the volume of the mixed solution, and the inoculation amount of Corynebacterium glutamicum seed solution is 1-2% of the volume of the mixed solution.

[0013] Preferably, the OD values ​​of the Lactobacillus buchneri seed solution and the Corynebacterium glutamicum seed solution are both 1.0.

[0014] Preferably, the complex enzyme solution in step (3) contains 20-30 g / L of cellulase and 15-20 g / L of neutral protease; the cellulase has an activity of 100,000 U / g, the neutral protease has an activity of 50,000 U / g, the lysozyme has an activity of 2000 U / mg, and the mannanase has an activity of 30,000 U / g.

[0015] The present invention also provides a method for preparing the above-mentioned environmentally friendly nitrogen fertilizer synergist, which comprises the following steps: S1: mixing humic acid with water to obtain a humic acid suspension; S2: Preparation of biochar: S3: preparing burdock leaf extract; S4: Mix the humic acid suspension, biochar, burdock leaf extract, nano zinc oxide and lignin sulfonate in proportion, stir evenly and then dry to obtain an environmentally friendly nitrogen fertilizer enhancer.

[0016] The environmentally friendly nitrogen fertilizer synergist of the invention is mixed with nitrogen fertilizer for use, and the dosage of the synergist is 3-5% of the fertilizer mass.

[0017] The beneficial effects of the present invention are: (1) The biochar prepared by the present invention is made from discarded garlic straw by a specific method and has a significant hierarchical porous structure (such as Figure 1As shown in a), this structure significantly increases the specific surface area of ​​biochar, thereby improving its adsorption capacity and reaction activity, and can effectively adsorb nitrogen in nitrogen fertilizers (such as ammonia nitrogen, nitrate nitrogen, etc.), thereby reducing the volatilization and loss of nitrogen fertilizers in the soil. This adsorption effect can prolong the effective time of nitrogen fertilizers in the soil, slowly release it, and improve the utilization efficiency of nitrogen fertilizers; nitrogen-doped bio-based porous carbon can adjust the surface charge distribution and chemical properties of biochar, making it more conducive to the attachment and growth of soil microorganisms, and soil microorganisms play a key role in the nitrogen conversion process, such as converting ammonia nitrogen into nitrate nitrogen, thereby improving the absorption of nitrogen by plants; at the same time, the biochar prepared by the present invention can also reduce the mobility of nitrogen in the soil by adsorbing and fixing nitrogen in the soil, thereby inhibiting denitrification and improving the utilization rate of nitrogen fertilizers.

[0018] (2) The burdock leaf extract prepared by the present invention is obtained by further fermenting the crude burdock leaf extract and then subjecting it to step-by-step enzymatic hydrolysis. The complex organic substances in the burdock leaf can be decomposed by microbial fermentation to produce more easily absorbed bioactive components, such as polysaccharides, flavonoids, amino acids and organic acids, and the microbial metabolites can also enhance the stress resistance of plants and reduce the negative impact of adversity on plant growth. The fermentation product is then subjected to multi-step enzymatic hydrolysis treatment with complex enzymes, lysozyme and mannanase to further destroy the complex organic structure in the fermentation product, release more small molecule bioactive components, improve the plant's nitrogen absorption efficiency, and promote the healthy growth of plants. The combined use of the burdock leaf extract of the present invention and bio-based porous carbon can further improve the slow-release performance of nitrogen fertilizer. The layered porous structure of biochar can adsorb nitrogen in nitrogen fertilizer, and the various bioactive components in the burdock leaf extract can regulate soil microbial activity, promote nitrogen absorption and utilization, and can also form complexes with nitrogen in fertilizers, delaying the hydrolysis of nitrogen fertilizers, reducing ammonia volatilization, and further improving fertilizer utilization.

[0019] (3) Through the synergistic effect of multiple mechanisms, the volatilization, leaching and fixation of nitrogen are reduced, and the utilization efficiency of nitrogen fertilizer is improved; the humic acid, biochar and lignin sulfonate in the present invention can improve the aeration and water retention of the soil and increase the aggregate structure of the soil; the biologically active ingredients in the burdock leaf extract can regulate the growth of plants, improve the absorption efficiency of nitrogen by plants, and promote the healthy growth of plants; by reducing the volatilization and loss of nitrogen, the pollution to the environment is reduced.

[0020] (4) The nitrogen fertilizer enhancer prepared by the present invention has readily available raw materials, is environmentally friendly and pollution-free, can effectively reduce the use of chemical fertilizers, promote the absorption and utilization of nitrogen fertilizers by plants, and significantly improve the yield and quality of crops. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1The SEM images of the microscopic morphology of the biochar prepared in Example 3 and Comparative Example 1 of the present invention, wherein a is Example 3 and b is Comparative Example 1; Figure 2 The ammonium nitrogen content in the soil of wheat in different treatment groups at different growth stages of the present invention; Figure 3 It is the nitrate nitrogen content in the soil of wheat in different treatment groups at different growth stages of the present invention. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below in conjunction with specific embodiments, but is not limited thereto.

[0023] Example 1 An environmentally friendly nitrogen fertilizer synergist is prepared from the following raw materials in parts by weight: 20 kg of humic acid, 10 kg of burdock leaf extract, 15 kg of biochar, 1 kg of nano zinc oxide, 5 kg of lignin sulfonate, and 50 kg of water.

[0024] The biochar is prepared by the following method: (1) The garlic stalks were washed with deionized water and dried, and then immersed in a saturated urea solution. After soaking at room temperature for 36 hours, the solution was taken out and dried to obtain pretreated garlic stalks; (2) The pretreated garlic straw was placed in a muffle furnace, heated to 800 °C at a rate of 5 °C / min under a nitrogen atmosphere, and calcined at high temperature for 3 h, followed by natural cooling to obtain a primary carbonization product; (3) The primary carbonization product was mixed with 0.2 g / mL KOH ethanol solution in a ratio of 1 g:10 ml, stirred at room temperature for 30 min, and then the solvent was evaporated to remove. The evaporated mixture was placed in a tubular furnace under nitrogen protection, and the temperature was increased to 800 °C at a rate of 10 °C / min, and calcined at high temperature for 2 h. After cooling, it was taken out to obtain a secondary carbonization product; (4) The secondary carbonization product was mixed with 1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1 g:10 ml, stirred at room temperature for 8 h, washed with deionized water until neutral, and vacuum dried to obtain biochar.

[0025] The burdock leaf extract is prepared by the following method: (1) The burdock leaves were cleaned and cut into small pieces of 3-5 cm, then dried in an oven at 120°C for 30 min, then the temperature was adjusted to 55-60°C, dried to constant weight, ground into powder, passed through an 80-mesh sieve, and then further subjected to ultrafine grinding. After treatment, the powder was added to 70% anhydrous ethanol and heated under reflux for extraction for 1.5 hours, and the ethanol was removed by rotary evaporation to obtain a crude extract; (2) adding deionized water to the crude extract at a solid-liquid ratio of 1 g:40 ml to obtain a mixed solution, adding peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate to the mixed solution, adjusting the pH to 7.0, and then inoculating Lactobacillus buchneri seed solution and Corynebacterium glutamicum seed solution respectively, and fermenting and culturing at 28-30° C. for 2 days to obtain a mixed fermentation liquid; (3) The pH of the mixed fermentation liquid was adjusted to 5.0, and 1.5 wt% of the complex enzyme solution was added thereto. After enzymatic hydrolysis at 40°C for 4 h, the pH was adjusted to 6.5, and 1 wt% of lysozyme was added thereto. After enzymatic hydrolysis at 38°C for 2 h, 1.5 wt% of mannanase was added thereto and enzymatic hydrolysis was continued at 45°C for 2 h. The enzyme was inactivated at high temperature to obtain an enzymatic hydrolyzate, which was separated by high-speed centrifugation. The supernatant was collected and concentrated and dried to obtain the burdock leaf extract.

[0026] In step (2), the added amounts of peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate are 10 g / L, 5 g / L, 5 g / L, 1 g / L, 0.05 g / L, and 0.01 g / L, respectively.

[0027] In step (2), the inoculation amount of Lactobacillus buchneri seed solution is 2% of the volume of the mixed solution, and the inoculation amount of Corynebacterium glutamicum seed solution is 1% of the volume of the mixed solution.

[0028] The OD values ​​of the Lactobacillus buchneri seed solution and the Corynebacterium glutamicum seed solution are both 1.0.

[0029] In step (3), the complex enzyme solution contains 20 g / L of cellulase and 15 g / L of neutral protease; the enzyme activity of the cellulase is 100,000 U / g, the enzyme activity of the neutral protease is 50,000 U / g, the enzyme activity of the lysozyme is 2000 U / mg, and the enzyme activity of the mannanase is 30,000 U / g.

[0030] The preparation method of the above-mentioned environmentally friendly nitrogen fertilizer synergist comprises the following steps: S1: mixing humic acid with water to obtain a humic acid suspension; S2: Preparation of biochar: S3: preparing burdock leaf extract; S4: Mix the humic acid suspension, biochar, burdock leaf extract, nano zinc oxide and lignin sulfonate in proportion, stir evenly and then dry to obtain an environmentally friendly nitrogen fertilizer enhancer.

[0031] Example 2 An environmentally friendly nitrogen fertilizer synergist is prepared from the following raw materials in parts by weight: 30 kg of humic acid, 15 kg of burdock leaf extract, 20 kg of biochar, 3 kg of nano zinc oxide, 10 kg of lignin sulfonate, and 60 kg of water.

[0032] The biochar is prepared by the following method: (1) The garlic stalks were washed with deionized water and dried, and then immersed in a saturated urea solution. After soaking at room temperature for 36 hours, the solution was taken out and dried to obtain pretreated garlic stalks; (2) The pretreated garlic straw was placed in a muffle furnace, heated to 800 °C at a rate of 5 °C / min under a nitrogen atmosphere, and calcined at high temperature for 3 h, followed by natural cooling to obtain a primary carbonization product; (3) The primary carbonization product was mixed with 0.3 g / mL KOH ethanol solution in a ratio of 1 g:10 ml, stirred at room temperature for 30 min, and then evaporated to remove the solvent. The evaporated mixture was placed in a tubular furnace under nitrogen protection, and the temperature was increased to 800 °C at a rate of 10 °C / min, and calcined at high temperature for 2 h. After cooling, it was taken out to obtain a secondary carbonization product; (4) The secondary carbonization product was mixed with 1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1 g:10 ml, stirred at room temperature for 8 h, washed with deionized water until neutral, and vacuum dried to obtain biochar.

[0033] The burdock leaf extract is prepared by the following method: (1) The burdock leaves were cleaned and cut into small pieces of 3-5 cm, then dried in an oven at 120°C for 30 min, then the temperature was adjusted to 55-60°C, dried to constant weight, ground into powder, passed through an 80-mesh sieve, and then further subjected to ultrafine grinding. After treatment, the powder was added to 70% anhydrous ethanol and heated under reflux for extraction for 1.5 hours, and the ethanol was removed by rotary evaporation to obtain a crude extract; (2) adding deionized water to the crude extract at a solid-liquid ratio of 1 g:40 ml to obtain a mixed solution, adding peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate to the mixed solution, adjusting the pH to 7.0, and then inoculating Lactobacillus buchneri seed solution and Corynebacterium glutamicum seed solution respectively, and fermenting and culturing at 28-30° C. for 2 days to obtain a mixed fermentation liquid; (3) The pH of the mixed fermentation broth was adjusted to 5.5, and 1.5 wt% of the complex enzyme solution was added thereto. After enzymatic hydrolysis at 45°C for 4 h, the pH was adjusted to 7.0, and 1 wt% of lysozyme was added thereto. After enzymatic hydrolysis at 40°C for 2 h, 1.5 wt% of mannanase was added thereto and enzymatic hydrolysis was continued at 45°C for 2 h. The enzyme was inactivated at high temperature to obtain an enzymatic hydrolyzate, which was separated by high-speed centrifugation. The supernatant was collected and concentrated and dried to obtain the burdock leaf extract.

[0034] In step (2), the added amounts of peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate are 15 g / L, 8 g / L, 8 g / L, 1.5 g / L, 0.1 g / L, and 0.03 g / L, respectively.

[0035] In step (2), the inoculation amount of Lactobacillus buchneri seed solution is 3% of the volume of the mixed solution, and the inoculation amount of Corynebacterium glutamicum seed solution is 2% of the volume of the mixed solution.

[0036] The OD values ​​of the Lactobacillus buchneri seed solution and the Corynebacterium glutamicum seed solution are both 1.0.

[0037] In step (3), the complex enzyme solution contains 30 g / L of cellulase and 20 g / L of neutral protease; the enzyme activity of the cellulase is 100,000 U / g, the enzyme activity of the neutral protease is 50,000 U / g, the enzyme activity of the lysozyme is 2000 U / mg, and the enzyme activity of the mannanase is 30,000 U / g.

[0038] The preparation method of the above-mentioned environmentally friendly nitrogen fertilizer synergist comprises the following steps: S1: mixing humic acid with water to obtain a humic acid suspension; S2: Preparation of biochar: S3: preparing burdock leaf extract; S4: Mix the humic acid suspension, biochar, burdock leaf extract, nano zinc oxide and lignin sulfonate in proportion, stir evenly and then dry to obtain an environmentally friendly nitrogen fertilizer enhancer.

[0039] Example 3 An environmentally friendly nitrogen fertilizer synergist is prepared from the following raw materials in parts by weight: 25 kg of humic acid, 12 kg of burdock leaf extract, 18 kg of biochar, 2 kg of nano zinc oxide, 8 kg of lignin sulfonate, and 55 kg of water.

[0040] The biochar is prepared by the following method: (1) The garlic stalks were washed with deionized water and dried, and then immersed in a saturated urea solution. After soaking at room temperature for 36 hours, the solution was taken out and dried to obtain pretreated garlic stalks; (2) The pretreated garlic straw was placed in a muffle furnace, heated to 800 °C at a rate of 5 °C / min under a nitrogen atmosphere, and calcined at high temperature for 3 h, followed by natural cooling to obtain a primary carbonization product; (3) The primary carbonization product was mixed with 0.2-0.3 g / mL KOH ethanol solution in a ratio of 1 g: 10 ml, stirred at room temperature for 30 min, and then evaporated to remove the solvent. The evaporated mixture was placed in a tubular furnace under nitrogen protection, and the temperature was increased to 800 ° C at a rate of 10 ° C / min, and calcined at high temperature for 2 h. After cooling, it was taken out to obtain a secondary carbonization product; (4) The secondary carbonization product was mixed with 1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1 g:10 ml, stirred at room temperature for 8 h, washed with deionized water until neutral, and vacuum dried to obtain biochar.

[0041] The burdock leaf extract is prepared by the following method: (1) The burdock leaves were cleaned and cut into small pieces of 3-5 cm, then dried in an oven at 120°C for 30 min, then the temperature was adjusted to 55-60°C, dried to constant weight, ground into powder, passed through an 80-mesh sieve, and then further subjected to ultrafine grinding. After treatment, the powder was added to 70% anhydrous ethanol and heated under reflux for extraction for 1.5 hours, and the ethanol was removed by rotary evaporation to obtain a crude extract; (2) adding deionized water to the crude extract at a solid-liquid ratio of 1 g:40 ml to obtain a mixed solution, adding peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate to the mixed solution, adjusting the pH to 7.0, and then inoculating Lactobacillus buchneri seed solution and Corynebacterium glutamicum seed solution respectively, and fermenting and culturing at 28-30° C. for 2 days to obtain a mixed fermentation liquid; (3) The pH of the mixed fermentation liquid was adjusted to 5.5, and 1.5 wt% of the complex enzyme solution was added thereto. After enzymatic hydrolysis at 45°C for 4 h, the pH was adjusted to 6.5, and 1 wt% of lysozyme was added thereto. After enzymatic hydrolysis at 40°C for 2 h, 1.5 wt% of mannanase was added thereto and enzymatic hydrolysis was continued at 45°C for 2 h. The enzyme was inactivated at high temperature to obtain an enzymatic hydrolyzate, and the supernatant was collected and concentrated and dried to obtain the burdock leaf extract.

[0042] In step (2), the added amounts of peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate are 12 g / L, 6 g / L, 6 g / L, 1.2 g / L, 0.08 g / L, and 0.02 g / L, respectively.

[0043] In step (2), the inoculation amount of Lactobacillus buchneri seed solution is 2.5% of the volume of the mixed solution, and the inoculation amount of Corynebacterium glutamicum seed solution is 1.5% of the volume of the mixed solution.

[0044] The OD values ​​of the Lactobacillus buchneri seed solution and the Corynebacterium glutamicum seed solution are both 1.0.

[0045] In step (3), the complex enzyme solution contains 25 g / L of cellulase and 18 g / L of neutral protease; the enzyme activity of the cellulase is 100,000 U / g, the enzyme activity of the neutral protease is 50,000 U / g, the enzyme activity of the lysozyme is 2000 U / mg, and the enzyme activity of the mannanase is 30,000 U / g.

[0046] The preparation method of the above-mentioned environmentally friendly nitrogen fertilizer synergist comprises the following steps: S1: mixing humic acid with water to obtain a humic acid suspension; S2: Preparation of biochar: S3: preparing burdock leaf extract; S4: Mix the humic acid suspension, biochar, burdock leaf extract, nano zinc oxide and lignin sulfonate in proportion, stir evenly and then dry to obtain an environmentally friendly nitrogen fertilizer enhancer.

[0047] Comparative Example 1 An environmentally friendly nitrogen fertilizer synergist is prepared from the following raw materials in parts by weight: 25 kg of humic acid, 12 kg of burdock leaf extract, 18 kg of biochar, 2 kg of nano zinc oxide, 8 kg of lignin sulfonate, and 55 kg of water.

[0048] The biochar is prepared by the following method: (1) The garlic stalks were washed with deionized water and dried, and then immersed in a saturated urea solution. After soaking at room temperature for 36 hours, the solution was taken out and dried to obtain pretreated garlic stalks; (2) The pretreated garlic straw was placed in a muffle furnace, heated to 800 °C at a rate of 5 °C / min under a nitrogen atmosphere, and calcined at high temperature for 3 h, followed by natural cooling to obtain biochar; The burdock leaf extract is prepared by the following method: (1) The burdock leaves were cleaned and cut into small pieces of 3-5 cm, then dried in an oven at 120°C for 30 min, then the temperature was adjusted to 55-60°C, dried to constant weight, ground into powder, passed through an 80-mesh sieve, and then further subjected to ultrafine grinding. After treatment, the powder was added to 70% anhydrous ethanol and heated under reflux for extraction for 1.5 hours, and the ethanol was removed by rotary evaporation to obtain a crude extract; (2) adding deionized water to the crude extract at a solid-liquid ratio of 1 g:40 ml to obtain a mixed solution, adding peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate to the mixed solution, adjusting the pH to 7.0, and then inoculating Lactobacillus buchneri seed solution and Corynebacterium glutamicum seed solution respectively, and fermenting and culturing at 28-30° C. for 2 days to obtain a mixed fermentation liquid; (3) The pH of the mixed fermentation liquid was adjusted to 5.5, and 1.5 wt% of the complex enzyme solution was added thereto. After enzymatic hydrolysis at 45°C for 4 h, the pH was adjusted to 6.5, and 1 wt% of lysozyme was added thereto. After enzymatic hydrolysis at 40°C for 2 h, 1.5 wt% of mannanase was added thereto and enzymatic hydrolysis was continued at 45°C for 2 h. The enzyme was inactivated at high temperature to obtain an enzymatic hydrolyzate, and the supernatant was collected and concentrated and dried to obtain the burdock leaf extract.

[0049] In step (2), the added amounts of peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate are 12 g / L, 6 g / L, 6 g / L, 1.2 g / L, 0.08 g / L, and 0.02 g / L, respectively.

[0050] In step (2), the inoculation amount of Lactobacillus buchneri seed solution is 2.5% of the volume of the mixed solution, and the inoculation amount of Corynebacterium glutamicum seed solution is 1.5% of the volume of the mixed solution.

[0051] The OD values ​​of the Lactobacillus buchneri seed solution and the Corynebacterium glutamicum seed solution are both 1.0.

[0052] In step (3), the complex enzyme solution contains 25 g / L of cellulase and 18 g / L of neutral protease; the enzyme activity of the cellulase is 100,000 U / g, the enzyme activity of the neutral protease is 50,000 U / g, the enzyme activity of the lysozyme is 2000 U / mg, and the enzyme activity of the mannanase is 30,000 U / g.

[0053] The preparation method of the above-mentioned environmentally friendly nitrogen fertilizer synergist comprises the following steps: S1: mixing humic acid with water to obtain a humic acid suspension; S2: Preparation of biochar: S3: preparing burdock leaf extract; S4: Mix the humic acid suspension, biochar, burdock leaf extract, nano zinc oxide and lignin sulfonate in proportion, stir evenly and then dry to obtain an environmentally friendly nitrogen fertilizer enhancer.

[0054] This comparative example is basically the same as Example 3, except that the biochar preparation method is different.

[0055] Comparative Example 2 An environmentally friendly nitrogen fertilizer synergist is prepared from the following raw materials in parts by weight: 25 kg of humic acid, 12 kg of burdock leaf extract, 2 kg of nano zinc oxide, 8 kg of lignin sulfonate, and 55 kg of water.

[0056] The burdock leaf extract is prepared by the following method: (1) The burdock leaves were cleaned and cut into small pieces of 3-5 cm, then dried in an oven at 120°C for 30 min, then the temperature was adjusted to 55-60°C, dried to constant weight, ground into powder, passed through an 80-mesh sieve, and then further subjected to ultrafine grinding. After treatment, the powder was added to 70% anhydrous ethanol and heated under reflux for extraction for 1.5 hours, and the ethanol was removed by rotary evaporation to obtain a crude extract; (2) adding deionized water to the crude extract at a solid-liquid ratio of 1 g:40 ml to obtain a mixed solution, adding peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate to the mixed solution, adjusting the pH to 7.0, and then inoculating Lactobacillus buchneri seed solution and Corynebacterium glutamicum seed solution respectively, and fermenting and culturing at 28-30° C. for 2 days to obtain a mixed fermentation liquid; (3) The pH of the mixed fermentation liquid was adjusted to 5.5, and 1.5 wt% of the complex enzyme solution was added thereto. After enzymatic hydrolysis at 45°C for 4 h, the pH was adjusted to 6.5, and 1 wt% of lysozyme was added thereto. After enzymatic hydrolysis at 40°C for 2 h, 1.5 wt% of mannanase was added thereto and enzymatic hydrolysis was continued at 45°C for 2 h. The enzyme was inactivated at high temperature to obtain an enzymatic hydrolyzate, and the supernatant was collected and concentrated and dried to obtain the burdock leaf extract.

[0057] In step (2), the added amounts of peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate are 12 g / L, 6 g / L, 6 g / L, 1.2 g / L, 0.08 g / L, and 0.02 g / L, respectively.

[0058] In step (2), the inoculation amount of Lactobacillus buchneri seed solution is 2.5% of the volume of the mixed solution, and the inoculation amount of Corynebacterium glutamicum seed solution is 1.5% of the volume of the mixed solution.

[0059] The OD values ​​of the Lactobacillus buchneri seed solution and the Corynebacterium glutamicum seed solution are both 1.0.

[0060] In step (3), the complex enzyme solution contains 25 g / L of cellulase and 18 g / L of neutral protease; the enzyme activity of the cellulase is 100,000 U / g, the enzyme activity of the neutral protease is 50,000 U / g, the enzyme activity of the lysozyme is 2000 U / mg, and the enzyme activity of the mannanase is 30,000 U / g.

[0061] The preparation method of the above-mentioned environmentally friendly nitrogen fertilizer synergist comprises the following steps: S1: mixing humic acid with water to obtain a humic acid suspension; S2: preparing burdock leaf extract; S3: Mix the humic acid suspension, burdock leaf extract, nano zinc oxide and lignin sulfonate in proportion, stir evenly and then dry to obtain an environmentally friendly nitrogen fertilizer enhancer.

[0062] The above comparative example is basically the same as Example 3, except that it does not contain the steps of biochar and its preparation method.

[0063] Comparative Example 3 An environmentally friendly nitrogen fertilizer synergist is prepared from the following raw materials in parts by weight: 25 kg of humic acid, 18 kg of biochar, 2 kg of nano zinc oxide, 8 kg of lignin sulfonate, and 55 kg of water.

[0064] The biochar is prepared by the following method: (1) The garlic stalks were washed with deionized water and dried, and then immersed in a saturated urea solution. After soaking at room temperature for 36 hours, the solution was taken out and dried to obtain pretreated garlic stalks; (2) The pretreated garlic straw was placed in a muffle furnace, heated to 800 °C at a rate of 5 °C / min under a nitrogen atmosphere, and calcined at high temperature for 3 h, followed by natural cooling to obtain a primary carbonization product; (3) The primary carbonization product was mixed with 0.2-0.3 g / mL KOH ethanol solution in a ratio of 1 g: 10 ml, stirred at room temperature for 30 min, and then evaporated to remove the solvent. The evaporated mixture was placed in a tubular furnace under nitrogen protection, and the temperature was increased to 800 ° C at a rate of 10 ° C / min, and calcined at high temperature for 2 h. After cooling, it was taken out to obtain a secondary carbonization product; (4) The secondary carbonization product was mixed with 1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1 g:10 ml, stirred at room temperature for 8 h, washed with deionized water until neutral, and vacuum dried to obtain biochar.

[0065] The preparation method of the above-mentioned environmentally friendly nitrogen fertilizer synergist comprises the following steps: S1: mixing humic acid with water to obtain a humic acid suspension; S2: Preparation of biochar: S3: Mix the humic acid suspension, biochar, nano zinc oxide and lignin sulfonate in proportion, stir evenly and then dry to obtain an environmentally friendly nitrogen fertilizer enhancer.

[0066] The above comparative example is basically the same as Example 3, except that it does not contain burdock leaf extract.

[0067] Application test examples The test site is located in the cultivated land of Gulugou Village, Economic Development Zone, Junan County, Linyi City, Shandong Province. The soil of the test site is loam. The basic physical and chemical properties of the soil before planting are: pH 7.89, soil organic matter content 21.36 g / kg, total nitrogen content 1.23g / kg, nitrate nitrogen content 21.25 mg / kg, ammonium nitrogen content 9.69 mg / kg, available phosphorus content 17.55 mg / kg, and available potassium content 155.21 mg / kg. The cultivation mode is wheat-corn rotation, and the sowing rate is 15kg / mu.

[0068] The experiment set up 7 treatments, namely, the treatment groups of Examples 1-3, the treatment groups of Comparative Examples 1-3 and the blank control group. The area of ​​each treatment group was 100m 2, 3 replicates were performed for each treatment, and the average value was taken for the test results. The tested crop varieties were: wheat, Linmai No. 14. All treatment groups turned the base fertilizer into the soil once before planting. The specific amount of base fertilizer was: urea (containing N 46%) 15kg / mu, superphosphate (containing P2O512%) 40kg / mu, potassium sulfate (containing K2O 52%) 12kg / mu, all of which were commercially available. Except for the blank control group, each treatment group was mixed with 5% of the mass of urea in Examples 1-3 and Comparative Examples 1-3 of the environmentally friendly nitrogen fertilizer synergist, and other field management measures were the same as local routine management.

[0069] At the heading stage of wheat, each treatment group selected areas with consistent growth to measure the leaf area of ​​the plants using the length-width coefficient method (leaf area = leaf length × leaf width × 0.83, leaf length is the distance from the base of the leaf to the tip of the leaf, and leaf width is the distance from the widest part of the leaf), calculate the leaf area, and calculate the leaf area index. Leaf area index = total leaf area m 2 / Land area m 2 In the same period, 30 wheat plants with the same growth were randomly selected from each treatment group, and the aboveground dry matter accumulation was calculated after drying. The specific results are shown in Table 1.

[0070] Table 1 Effects of different treatment groups on wheat growth It can be seen from the contents of Table 1 above that after using the environmentally friendly nitrogen fertilizer synergist obtained in Examples 1-3 of the present invention, the leaf area index and dry matter accumulation of wheat are higher than those of the comparative example and the blank control group. This is because after using the synergist, the synergistic effect of various raw materials prolongs the effective time of urea in the soil, allowing it to be slowly released, thereby improving the utilization efficiency of nitrogen fertilizer and promoting the growth and development of wheat.

[0071] Sampling was carried out on sunny days during the wintering and filling periods of wheat. 20g of soil from the 0~20cm tillage layer was collected from each plot using the 5-point sampling method. After mixing the soil samples, impurities were removed, and the soil samples were stored at 4°C as the test soil samples. The ammonium nitrogen and nitrate nitrogen contents in the soil of different samples were determined respectively. The ammonium nitrogen was determined by the indophenol blue colorimetric method, and the nitrate nitrogen was determined by the ultraviolet spectrophotometric correction factor method. The specific test results are shown in Figure 2-3 shown.

[0072] From the above Figure 2-3It can be seen that, whether in the wintering period or the filling period of wheat, the ammonium nitrogen content in the soil after using the environmentally friendly nitrogen fertilizer synergist prepared by Examples 1-3 of the present invention is significantly higher than that of the blank control group, while the nitrate nitrogen content is significantly lower than that of the blank control group. This is mainly because the burdock leaf extract and the bio-based porous carbon in the present invention can effectively slow down the conversion of ammonium nitrogen to nitrate nitrogen in the soil, synchronize the release of urea in the soil with the nitrogen demand of wheat, reduce nitrogen leaching losses, improve the utilization rate of nitrogen fertilizer, and reduce environmental pollution. After changing the raw material composition of the present invention, the effect of inhibiting the conversion of ammonium nitrogen to nitrate nitrogen after the synergist of Comparative Examples 1-3 is deteriorated.

[0073] Wheat was harvested at maturity, and the wheat yield and yield composition were counted. The specific results are shown in Table 2.

[0074] Table 2 Wheat yield and yield components in different treatment groups From the above Table 2, it can be seen that after the environmentally friendly nitrogen fertilizer synergist prepared by Examples 1-3 of the present invention is used, the wheat yield increases by an average of 14.57% compared with the control, while the yield increases of Comparative Examples 1-3 compared with the control are all less than those of Examples 1-3. It can be seen that the lack of any one of the raw materials of the present invention cannot achieve the same technical effect as the present invention, and the raw materials of the present invention complement each other and are indispensable.

[0075] It should be noted that the above embodiments are only partial embodiments of the preferred methods of implementing the present invention, rather than all embodiments. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

Claims

1. An environmentally friendly nitrogen fertilizer synergist, characterized in that: The invention is prepared from the following raw materials in parts by weight: 20-30 parts of humic acid, 10-15 parts of burdock leaf extract, 15-20 parts of biochar, 1-3 parts of nano zinc oxide, 5-10 parts of lignin sulfonate and 50-60 parts of water.

2. The environmentally friendly nitrogen fertilizer synergist according to claim 1, characterized in that: The biochar is prepared by the following method: (1) The garlic stalks were washed with deionized water and dried, and then immersed in a saturated urea solution at room temperature for 36 hours, and then taken out and dried to obtain pretreated garlic stalks; (2) placing the pretreated garlic straw in a muffle furnace, calcining at high temperature for 3 h under a nitrogen atmosphere, and cooling naturally to obtain a primary carbonization product; (3) Mix the primary carbonization product with the activation solution in a ratio of 1 g:10 ml, stir at room temperature for 30 min, evaporate and remove the solvent, put the evaporated mixture into a tubular furnace under nitrogen protection, calcine at high temperature for 2 h, cool and take out to obtain a secondary carbonization product; (4) The secondary carbonization product was mixed with 1 mol / L hydrochloric acid solution at a solid-liquid ratio of 1 g:10 ml, stirred at room temperature for 8 h, washed with deionized water until neutral, and vacuum dried to obtain biochar.

3. The environmentally friendly nitrogen fertilizer synergist according to claim 2, characterized in that: In the step (2), the calcination temperature in the muffle furnace is 800°C, and the heating rate is 5°C / min; in the step (3), the calcination temperature in the tubular furnace is 800°C, and the heating rate is 10°C / min.

4. The environmentally friendly nitrogen fertilizer synergist according to claim 2, characterized in that: The activation solution is a 0.2-0.3 g / mL KOH ethanol solution.

5. The environmentally friendly nitrogen fertilizer synergist according to claim 1, characterized in that: The burdock leaf extract is prepared by the following method: (1) The burdock leaves were cleaned and cut into small pieces of 3-5 cm, then dried in an oven at 120°C for 30 min, then the temperature was adjusted to 55-60°C, dried to constant weight, ground into powder, passed through an 80-mesh sieve, and then further subjected to ultrafine grinding. After treatment, the powder was added to 70% anhydrous ethanol and heated under reflux for extraction for 1.5 hours, and the ethanol was removed by rotary evaporation to obtain a crude extract; (2) adding deionized water to the crude extract at a solid-liquid ratio of 1 g:40 ml to obtain a mixed solution, adding peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate to the mixed solution, adjusting the pH to 7.0, and then inoculating Lactobacillus buchneri seed solution and Corynebacterium glutamicum seed solution respectively, and fermenting and culturing at 28-30° C. for 2 days to obtain a mixed fermentation liquid; (3) The pH of the mixed fermentation liquid was adjusted to 5.0-5.5, 1.5 wt% of the complex enzyme solution was added thereto, and the mixture was enzymatically hydrolyzed at 40-45°C for 4 h. The pH was then adjusted to 6.5-7.0, 1 wt% of lysozyme was added, and the enzymatic hydrolysis was continued at 38-40°C for 2 h. Then, 1.5 wt% of mannanase was added and the mixture was enzymatically hydrolyzed at 45°C for 2 h. The enzyme was inactivated at high temperature to obtain an enzymatic solution, and the solution was separated by high-speed centrifugation. The supernatant was collected and concentrated and dried to obtain the burdock leaf extract.

6. The environmentally friendly nitrogen fertilizer synergist according to claim 5, characterized in that: In step (2), the added amounts of peptone, beef extract, yeast extract, trisodium citrate, magnesium sulfate, and ferrous sulfate are 10-15 g / L, 5-8 g / L, 5-8 g / L, 1-1.5 g / L, 0.05-0.1 g / L, and 0.01-0.03 g / L, respectively.

7. The environmentally friendly nitrogen fertilizer synergist according to claim 5, characterized in that: In step (2), the inoculation amount of Lactobacillus buchneri seed solution is 2-3% of the volume of the mixed solution, and the inoculation amount of Corynebacterium glutamicum seed solution is 1-2% of the volume of the mixed solution.

8. The environmentally friendly nitrogen fertilizer synergist according to claim 5, characterized in that: The OD values ​​of the Lactobacillus buchneri seed solution and the Corynebacterium glutamicum seed solution are both 1.

0.

9. The environmentally friendly nitrogen fertilizer synergist according to claim 5, characterized in that: In step (3), the complex enzyme solution contains 20-30 g / L of cellulase and 15-20 g / L of neutral protease; the enzyme activity of the cellulase is 100,000 U / g, the enzyme activity of the neutral protease is 50,000 U / g, the enzyme activity of the lysozyme is 2000 U / mg, and the enzyme activity of the mannanase is 30,000 U / g.

10. A method for preparing the environmentally friendly nitrogen fertilizer synergist according to any one of claims 1 to 9, characterized in that: It includes the following steps: S1: mixing humic acid with water to obtain a humic acid suspension; S2: Preparation of biochar: S3: preparing burdock leaf extract; S4: Mix the humic acid suspension, biochar, burdock leaf extract, nano zinc oxide and lignin sulfonate in proportion, stir evenly and then dry to obtain an environmentally friendly nitrogen fertilizer enhancer.

Images