A hydrothermal carbon-distiller's grains organic fertilizer with a function of blocking and controlling nitrogen loss in saline-alkali soil and a preparation method thereof

Abstract

The present application belongs to the technical field of soil improvement, and relates to a water-thermal carbon-distiller's grains organic fertilizer with a function of blocking and controlling nitrogen loss of saline-alkali soil and a preparation method thereof. Permeate, seaweed extract, potassium dihydrogen phosphate and water are mixed to obtain a coating liquid. Water-thermal carbon powder, fermented distiller's grains and a binder are mixed to obtain a coating layer. Modified gypsum powder, humic acid, earthworm manure and diatomite are mixed and granulated. The coating liquid is sprayed during the granulation to obtain a master granule. The master granule is coated with the coating layer to obtain the water-thermal carbon-distiller's grains organic fertilizer granule. Through resource utilization of waste, double-coating controlled-release technology and synergistic effect of multifunctional components, the present application systematically solves the defects of existing saline-alkali soil conditioners in terms of nitrogen loss, insufficient organic matter, high cost and short effective period.

Description

Technical Field

[0001] This invention belongs to the technical field of soil improvement, and relates to a hydrothermal carbon-vinegar residue organic fertilizer with nitrogen loss control function in saline-alkali land and its preparation method. Background Technology

[0002] Saline-alkali land, characterized by high pH, ​​high salinity, poor soil structure, and reduced water and fertilizer retention capacity, severely restricts agricultural development and ecological environment improvement. Saline-alkali land management can not only improve land productivity and farmers' income, promoting regional economic development, but also increase arable land area to meet growing food demand. Furthermore, saline-alkali land management helps improve the ecological environment and prevent soil degradation. Therefore, saline-alkali land management not only has a positive impact on agricultural production and economic development, but also holds significant importance for environmental protection and sustainable development.

[0003] Saline-alkali land remediation is characterized by complexity, long-term nature, and high cost, and its impact on the ecological environment must also be considered, involving advanced technical requirements. Currently, there are four methods for saline-alkali land remediation: engineering measures, agronomic measures, chemical measures, and biological measures. Among these, chemical measures, especially the application of soil conditioners, have the advantages of being highly targeted, fast-acting, and easy to use. However, existing saline-alkali land soil conditioners have the following drawbacks:

[0004] 1) Chemical amendments (such as gypsum, sulfur, and sulfuric acid) improve soil salinization by replacing sodium ions or lowering pH. However, in high pH environments, ammonium nitrogen is easily volatilized, and nitrate nitrogen is easily leached. Chemical amendments lack nitrogen fixation mechanisms, resulting in low fertilizer utilization and an inability to replenish soil organic matter. Long-term use can lead to soil compaction and decreased microbial activity. 2) Organic amendments (such as compost and green manure) improve soil structure by increasing organic matter. However, organic materials cannot effectively control nitrogen release rates, requiring frequent application, increasing management costs, and posing a risk of nitrogen loss. 3) Mineral conditioners (such as zeolite and bentonite) fix salts through adsorption. However, the high cost of mineral mining and processing makes large-scale promotion difficult. Furthermore, they only adsorb salts and cannot simultaneously improve soil nutrients and the microbial environment.

[0005] Therefore, providing a fertilizer modifier with nitrogen loss control function has become an urgent problem to be solved. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a hydrothermal charcoal-vinegar residue organic fertilizer with nitrogen loss control function in saline-alkali land and its preparation method, specifically including the following steps:

[0007] Step 1: Mix plant straw and garden waste, crush into 2-5cm pieces, dry at 60-70℃ until the moisture content is ≤10%, then mix with water at a solid-liquid mass ratio of 1:8, and perform a hydrothermal reaction at 1.5-2.0 MPa and 190-210℃ for 2-3 hours. After cooling to room temperature, filter and remove the filtrate. Mix the filter residue with acid at a solid-liquid mass ratio of 1:4 and soak for 10-14 hours. After soaking, filter again and remove the filtrate. Activate the filter residue at 300-400℃ for 1-1.5 hours. After activation, crush to 150-200 mesh to obtain hydrothermal char powder.

[0008] Preferably, the mass ratio of plant straw to garden waste is 3:1.

[0009] Preferably, the plant straw is one or more of rice straw, corn straw, wheat straw, sorghum straw, cotton straw, soybean straw, and peanut straw, and the garden waste includes one or more of dead branches and leaves, bark, sawdust, and weeds.

[0010] Step 2: Crush the desulfurized gypsum to 100-120 mesh, then mix it with acid solution at a solid-liquid mass ratio of 1:3, microwave it at 600-650W for 10-15 minutes, filter it, remove the filtrate, and calcine the filter residue at 170-180℃ for 1-1.5 hours to obtain modified gypsum powder.

[0011] Preferably, the acid solution is one of the following: a phosphoric acid solution with a mass fraction of 5-6%, a lactic acid solution with a mass fraction of 7-8%, an acetic acid solution with a mass fraction of 15-20%, and a citric acid solution with a mass fraction of 8-10%.

[0012] Step 3: Mix vinegar residue with calcium carbonate to pH 5-5.5, then add carbon source, compound enzyme and compound bacteria, ferment at 35-45℃ and oxygen content ≤0.5% for 6-7 days, then ferment at 45-50℃ for 3-4 days, turning the pile once every 12 hours. After fermentation, collect the leachate, inactivate the leachate at 95-98℃ and collect it for later use. Dry the fermented material at 70-80℃ to a moisture content of 9-12% to obtain fermented vinegar residue.

[0013] Preferably, the mass ratio of the vinegar residue, carbon source, compound enzyme, and compound bacteria is 100:2:1:1.

[0014] Preferably, the carbon source is one or more of sucrose, glucose, lactose, maltose, fructose, and molasses.

[0015] Preferably, the complex enzyme comprises cellulase, pectinase and amylase in a mass ratio of 3:1:2.

[0016] Preferably, the compound bacteria include lactic acid bacteria and yeast in a mass ratio of 3:1.

[0017] Step four: Mix leachate, seaweed extract, potassium dihydrogen phosphate, and water to obtain a coating solution; mix hydrothermal charcoal powder, fermented vinegar residue, and binder to obtain a coating layer; mix modified gypsum powder, humic acid, earthworm castings, and diatomaceous earth for granulation; spray the coating solution into the mixture during granulation to obtain a coating thickness of 80-100 μm to obtain masterbatch; coat the masterbatch with the coating layer in a coating machine to obtain a coating thickness of 300-400 μm to obtain hydrothermal charcoal-vinegar residue organic fertilizer granules with a particle diameter of 1.6-2 mm.

[0018] Preferably, the mass ratio of the leachate, seaweed extract, potassium dihydrogen phosphate, and water is 10:5:3:100.

[0019] Preferably, the mass ratio of the hydrothermal charcoal powder, fermented vinegar residue, and binder is 40:20:3. Most preferably, the binder is a polyvinyl alcohol solution with a mass fraction of 5-6%.

[0020] Preferably, the mass ratio of the modified gypsum powder, humic acid, earthworm castings and diatomaceous earth is 4:2:3:1.

[0021] The present invention has the following advantages:

[0022] (1) The fertilizer conditioner prepared by the present invention adopts a double coating structure. The coating liquid forms a hydrophilic film to reduce nitrogen volatilization. The coating layer reduces nitrogen loss through pore adsorption and slow release. The hydrothermal carbon has a high specific surface area and functional groups after acid activation and high temperature carbonization. It can adsorb and slowly release ammonium nitrogen. The coating layer and coating liquid work together to achieve physical barrier and chemical slow release, avoiding the defects of traditional conditioners that lack nitrogen fixation mechanism and have excessive nitrogen volatilization and leaching rate in saline-alkali land.

[0023] (2) The fertilizer improver prepared by the present invention has multiple organic components. Fermented vinegar residue, earthworm castings and diatomaceous earth provide stable organic matter, promote microbial colonization, have high hydrothermal carbon chemical stability, can remain in the soil for a long time, and continuously improve the pore structure. After two fermentations, the organic matter content of fermented vinegar residue is significantly increased, which solves the problem that scientific conditioners cannot replenish organic matter and the nitrogen loss of traditional organic fertilizers.

[0024] (3) This invention uses plant straw, garden waste and vinegar residue as raw materials to reduce production costs. It uses natural acid liquid to modify gypsum to avoid strong acid pollution. Compared with commercial activated carbon and hydrothermal carbon, the cost is lower. It avoids the problems of high cost of mineral conditioning agents and pollution risk of chemical modifiers.

[0025] (4) The present invention has a multi-component synergistic effect. The modified gypsum powder provides calcium ions to replace sodium ions, humic acid chelate salts, and diatomaceous earth to improve air permeability. It simultaneously reduces salt, adjusts pH, and increases fertility. The coating layer design delays the decomposition of core particles, avoiding the problem of multiple applications and complex management of single-function conditioners. Detailed Implementation

[0026] The technical solutions in the embodiments of the invention are described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] Step 1: Mix rice straw and garden dead branches and leaves at a mass ratio of 3:1, crush them into 4-5cm pieces, dry them at 65℃ until the moisture content is ≤10%, then mix them with water at a solid-liquid mass ratio of 1:8, and perform a hydrothermal reaction at 2.0 MPa and 195℃ for 2.5 hours. After cooling to room temperature, filter and remove the filtrate. Mix the filter residue with a 5% phosphoric acid solution at a solid-liquid mass ratio of 1:4 and soak for 12 hours. After soaking, filter again and remove the filtrate. Activate the filter residue at 350℃ for 1.5 hours. After activation, crush it to 200 mesh to obtain hydrothermal char powder.

[0029] Step 2: Crush the desulfurized gypsum to 120 mesh, then mix it with a 10% citric acid solution at a solid-liquid mass ratio of 1:3, microwave it at 650W for 13 minutes, filter it, remove the filtrate, and calcine the filter residue at 180℃ for 1.5 hours to obtain modified gypsum powder.

[0030] Step 3: Mix vinegar residue with calcium carbonate until pH = 5-5.5, then add sucrose, compound enzymes, and compound bacteria. Ferment at 40℃ with an oxygen content ≤0.5% for 7 days, then at 50℃ for 3 days, turning the pile every 12 hours. After fermentation, collect the leachate, inactivate it at 98℃, and collect it for later use. Dry the fermented material at 75℃ until the moisture content is 10%, obtaining fermented vinegar residue. The mass ratio of vinegar residue, sucrose, compound enzymes, and compound bacteria is 100:2:1:1. The compound enzymes include cellulase, pectinase, and amylase in a mass ratio of 3:1:2. The compound bacteria include lactic acid bacteria and yeast in a mass ratio of 3:1.

[0031] Step four: Mix leachate, seaweed extract, potassium dihydrogen phosphate, and water in a mass ratio of 10:5:3:100 to obtain a coating solution. Mix hydrothermal charcoal powder, fermented vinegar residue, and 5% polyvinyl alcohol solution in a mass ratio of 40:20:3 to obtain a coating layer. Mix modified gypsum powder, humic acid, earthworm castings, and diatomaceous earth in a mass ratio of 4:2:3:1 and granulate. Spray the coating solution into the mixture during granulation to obtain a coating thickness of 80-100 μm, thus obtaining masterbatch. Coat the masterbatch with the coating layer in a coating machine to obtain a coating thickness of 300-400 μm, thus obtaining hydrothermal charcoal-vinegar residue organic fertilizer granules with a particle diameter of 1.6-2 mm.

[0032] The seaweed extract, lactic acid bacteria, and yeast were all purchased from Xi'an Musen Bioengineering Co., Ltd.

[0033] Experimental Example 1

[0034] 1. Experimental Groups:

[0035] The corn planting methods for the blank group, control group 1-2 and experimental group were all based on "High-Quality and High-Efficiency Corn Cultivation Technology" edited by Yu Qinglai. The basal fertilizer application rate, fertilization time, topdressing amount, topdressing time and other field management methods for control group 1-2 and experimental group were also based on "High-Quality and High-Efficiency Corn Cultivation Technology" and were kept consistent.

[0036] Blank group: No fertilizers or conditioners were applied.

[0037] Control group 1: No amendment was applied; conventional 15-15-15 compound fertilizer was applied as base fertilizer.

[0038] Control group 2: Gypsum and humic acid (mass ratio 1:1) were used as amendments, and 15-15-15 compound fertilizer was used as base fertilizer. The amendment was applied at a rate of 200 kg / mu and mixed with the base fertilizer.

[0039] Experimental group: The hydrothermal carbon-vinegar residue organic fertilizer prepared in Example 1 was used as a conditioner, and 15-15-15 compound fertilizer was used as a base fertilizer. The conditioner was applied at a rate of 200 kg / mu and mixed with the base fertilizer.

[0040] 2. Measurement of basic soil parameters

[0041] Sampling time: before fertilization (before sowing) and after corn harvest.

[0042] Measurement method:

[0043] pH value: Potentiometric method (soil-to-water ratio 1:2.5).

[0044] Electrical conductivity (EC): The conductivity meter is used to measure the extract.

[0045] Organic matter: potassium dichromate oxidation method.

[0046] Available nitrogen: alkaline hydrolysis diffusion method.

[0047] Yield: The dry weight of corn kernels is determined after harvest.

[0048] Quality: Determination of crude protein content in grains (Kjeldahl method).

[0049] 3. Nitrogen leaching simulation experiment

[0050] The soil column leaching method was used. Each assembly was filled with 5 kg of saline-alkali soil, and after fertilization, water was continuously applied (simulating 300 mm of rainfall). The leachate was collected, and nitrate nitrogen (NO3) was measured. --N) and ammonium nitrogen (NH4) + -N content (ultraviolet spectrophotometry).

[0051] 4. Ammonia Volatilization Determination

[0052] Determination method: Static chamber method combined with acid absorption method.

[0053] Device: A 30cm diameter PVC static box was placed in the center of each plot. An absorption bottle containing 20mL of 2% boric acid solution was placed inside the box. The contact area between the box and the soil was sealed with silicone.

[0054] Sampling frequency: Days 1, 3, 7, 14, and 21 after fertilization, with each sampling lasting 24 hours.

[0055] Measurement procedure:

[0056] 1. After sampling, remove the absorption bottle and titrate the absorption solution with 0.01 mol / L sulfuric acid to calculate the ammonia nitrogen content.

[0057] 2. Formula for calculating ammonia volatilization:

[0058] Ammonia volatilization (kg / mu) = (sulfuric acid consumption in titration × 0.01 × 14) / 1000 × 667 / sampling area (m²) 2 )

[0059] Table 1 Comparison of Soil Improvement Effects

[0060]

[0061]

[0062] Table 2 Comparison of nitrogen loss (kg / mu)

[0063]

[0064] Table 3 Comparison of Maize Yield and Quality

[0065] Blank group 420 - 8.2 Control group 1 580 38.1 9.0 Control group 2 640 52.4 9.5 experimental group 780 85.7 10.8

[0066] The fertilizer of this invention significantly reduced soil pH to 7.8, EC value to 1.06 dS / m, increased organic matter to 1.213%, and available nitrogen content to 102.6 mg / kg, significantly better than other groups. The total nitrogen loss rate of the fertilizer of this invention was only 30.8%, significantly lower than the control group by 1-2. The corn yield increased by 85.7% compared with the blank group, and the crude protein content increased to 10.8%, indicating that the fertilizer of this invention has both high yield and high quality characteristics. Through double coating controlled release technology and the synergistic effect of multi-source organic components, this invention systematically solves the problems of nitrogen loss and insufficient organic matter in saline-alkali land, significantly improving corn yield and quality.

[0067] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a hydrothermal charcoal-vinegar residue organic fertilizer with nitrogen loss control function in saline-alkali land, characterized in that, A coating solution is prepared by mixing leachate, seaweed extract, potassium dihydrogen phosphate and water. A coating layer is prepared by mixing hydrothermal carbon powder, fermented vinegar residue and binder. Modified gypsum powder, humic acid, earthworm castings and diatomaceous earth are mixed and granulated. The coating solution is sprayed into the granulation process to obtain masterbatch. The masterbatch is coated with the coating layer to obtain hydrothermal carbon-vinegar residue organic fertilizer granules. The leachate is the fermentation leachate collected after the vinegar residue fermentation is completed; The coating liquid has a coating thickness of 4-6.25% of the fertilizer particle diameter, and the coating layer has a coating thickness of 15-25% of the fertilizer particle diameter. The mass ratio of the permeate, seaweed extract, potassium dihydrogen phosphate and water is 10:5:3:100; The mass ratio of the hydrothermal charcoal powder, fermented vinegar residue, and binder is 40:20:3; The mass ratio of the modified gypsum powder, humic acid, earthworm castings and diatomaceous earth is 4:2:3:1; The modified gypsum powder is prepared by crushing desulfurized gypsum, mixing it with acid at a solid-liquid mass ratio of 1:3, microwaving, filtering, removing the filtrate, and calcining the filter residue to obtain modified gypsum powder.

2. The method for preparing a hydrothermal charcoal-vinegar residue organic fertilizer with nitrogen loss control function in saline-alkali land according to claim 1, characterized in that, The preparation method of the hydrothermal charcoal powder is as follows: plant straw and garden waste are mixed and crushed, dried to a moisture content of ≤10%, then mixed with water, and subjected to hydrothermal reaction at 1.5-2.0 MPa and 190-210℃ for 2-3 hours. After cooling to room temperature, the mixture is filtered to remove the filtrate. The filter residue is mixed with acid solution and soaked. After soaking, the mixture is filtered again to remove the filtrate. The filter residue is activated at 300-400℃ for 1-1.5 hours. After activation, the mixture is crushed to obtain hydrothermal charcoal powder.

3. A method for preparing a hydrothermal charcoal-vinegar residue organic fertilizer with nitrogen loss control function in saline-alkali land according to claim 1 or 2, characterized in that, The acid solution is one of the following: a phosphoric acid solution with a mass fraction of 5-6%, a lactic acid solution with a mass fraction of 7-8%, an acetic acid solution with a mass fraction of 15-20%, and a citric acid solution with a mass fraction of 8-10%.

4. The method for preparing a hydrothermal charcoal-vinegar residue organic fertilizer with nitrogen loss control function in saline-alkali land according to claim 1, characterized in that, The method for preparing fermented vinegar residue is as follows: vinegar residue is mixed with calcium carbonate to pH=5-5.5, then carbon source, compound enzyme and compound bacteria are added, followed by anaerobic fermentation and then aerobic fermentation. After fermentation is completed, the leachate is collected, inactivated and collected for later use. The fermented product is dried to a moisture content of 9-12% to obtain fermented vinegar residue.

5. The method for preparing a hydrothermal charcoal-vinegar residue organic fertilizer with nitrogen loss control function in saline-alkali land according to claim 4, characterized in that, The mass ratio of vinegar residue, carbon source, compound enzyme and compound bacteria is 100:2:1:

1.

6. The hydrothermal carbon-vinegar residue organic fertilizer prepared by the method according to any one of claims 1-5.

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