Preparation and technical method of composite saline soil modifier

Abstract

The invention relates to preparation and technical methods of a composite saline soil modifier. The modifier is prepared from 30-40 parts of charcoal, 8-10 parts of oxalic acid, 15-20 parts of desulfurized gypsum, 3-6 parts of wood vinegar, 1-2 parts of microbial agent fermentation liquor and 30-40 parts of other auxiliary components. Wherein the microbial agent fermentation liquor is prepared by fermenting bacillus subtilis, the biochar is prepared by pyrolyzing rice husk at 600 DEG C for 2 hours, and the desulfurized gypsum is prepared by wet desulfurization; the preparation method of the modifier comprises the following steps: uniformly mixing the raw materials in proportion, drying until the water content is lower than 10%, crushing and packaging. During application, the fertilizer is uniformly applied to salinized soil according to the dosage of 100 kg / mu, the ploughing depth is 20-30 cm, and the soil is kept moist. Experimental results show that the modifier can significantly reduce the pH value of soil, increase the number of water-stable aggregates, increase the water retention capacity of soil, promote the growth of soil microorganisms and enhance the salt resistance of crops, and has a significant improvement effect on mild to moderate salinized soil.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement, and specifically to a preparation method and technical method of a composite saline soil improver. Background Art

[0002] Saline soil is a common low-yield soil, and its high salt content and poor physical and chemical properties severely limit crop growth. Traditional improvement methods such as leaching and chemical improvers have problems such as high cost and short-lasting effects. Therefore, it is of great significance to develop an efficient, environmentally friendly and long-lasting saline soil improvement method.

[0003] At present, the research on composite improvers has become a hot spot in the field of saline soil improvement. By combining the advantages of various improvement materials, composite improvers achieve the synergistic effect of physical, chemical and biological improvements, thus overcoming the deficiencies of single improvement methods. For example, the combined use of biochar and microbial inoculum can not only improve the physical and chemical properties of the soil, but also promote the nutrient cycle in the soil and the growth of plants through the metabolic activities of microorganisms. In addition, the addition of organic acids such as oxalic acid can further reduce the pH value of the soil and relieve the stress of salinity and alkalinity on plants.

[0004] Although traditional saline soil improvement methods have alleviated the salinization problem to a certain extent, their limitations have prompted researchers to explore more efficient, environmentally friendly and sustainable improvement technologies. As an emerging improvement means, composite improvers show broad application prospects due to their combination of the advantages of various improvement materials. Based on the above problems, a composite saline soil improver using the combined action of biochar, oxalic acid, desulfurized gypsum, wood vinegar and microbial inoculum fermentation broth is proposed.

[0005] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a preparation method and technical method of a composite saline soil improver.

[0007] To solve the above problems, the technical solution of the present invention is a preparation method and technical method of a composite saline soil improver: including the following raw materials in parts by weight: 30-40 parts of biochar, 8-10 parts of oxalic acid, 15-20 parts of desulfurized gypsum, 3-6 parts of wood vinegar, 1-2 parts of microbial inoculum fermentation broth, and 30-40 parts of auxiliary agent.

[0008] Furthermore, the auxiliary agent is a moisturizer and a stabilizer.

[0009] Further, the preparation method of the microbial inoculum fermentation broth comprises the following steps: inoculating Bacillus subtilis strains into a liquid medium, fermenting at 30°C and 150 rpm for 48 hours; after fermentation, collecting the thalli by centrifugation, resuspending with sterile water and adding 5% glycerol as a protective agent, and finally obtaining a bacterial liquid with a concentration of 10 CFU / mL, a spore formation rate higher than 90%, and an OD600 value of the microbial inoculum fermentation broth being 0.18 - 0.22.

[0010] Further, the preparation method of the biochar comprises the following steps: washing and drying rice husks until the water content is lower than 15%, then crushing them into particles with a size of 1 - 3 cm, loading the raw materials into a pyrolysis furnace, heating to 600°C at a rate of 15°C / min under a nitrogen atmosphere, holding for 2 hours and then naturally cooling, crushing the generated biochar into 0.5 - 2 mm, washing with deionized water and drying; finally, the obtained biochar has a specific surface area of 350 m² / g, a pH value of 8.5, and an ash content of 12%.

[0011] Further, the preparation of the desulfurized gypsum comprises the following steps: obtaining a gypsum slurry through a wet desulfurization process, dehydrating the gypsum slurry with a vacuum belt filter to a water content below 10%, then drying in a rotary dryer at 120°C to a water content below 1%, crushing the dried gypsum with a hammer mill to 0.1 - 2 mm, and separating the qualified particles through a screening device; finally, the obtained desulfurized gypsum has a purity of 95%, a water content of 0.8%, and a particle size range of 0.1 - 2 mm.

[0012] Further, the oxalic acid reagent is a dihydrate oxalic acid reagent.

[0013] Further, the preparation method of a composite saline - soil conditioner comprises the following steps: Step 1: Weigh the raw materials according to the weight parts of 30 - 40 parts of biochar, 8 - 10 parts of oxalic acid, 15 - 20 parts of desulfurized gypsum, 3 - 6 parts of wood vinegar liquid, 1 - 2 parts of microbial inoculum fermentation broth, and 30 - 40 parts of auxiliary agent; Step 2: Mix the biochar, desulfurized gypsum, oxalic acid, and wood vinegar liquid evenly; Step 3: Add the microbial inoculum fermentation broth and stir evenly; Step 4: Dry the mixture until the water content is lower than 10%, crush and then package.

[0014] Further, the application method of a composite saline - soil conditioner comprises the following steps: Step 1: Apply the composite saline - soil conditioner to saline soil at a dosage of 100 kg / mu evenly; Step 2: The tillage depth is 20 - 30 cm, and keep the soil moist; Step 3. Regularly monitor the soil pH value, the quantity of water-stable aggregates, and the plant growth status.

[0015] Furthermore, for the application method of the composite saline soil conditioner, the soil is light to medium saline soil.

[0016] The advantages of the present invention compared with the existing technologies are as follows: 1. The composite saline soil conditioner of the present invention is composed of biochar, oxalic acid, desulfurized gypsum, wood vinegar liquid, and microbial inoculum fermentation broth. Each raw material interacts, promotes each other, and complements each other. The preparation process flow is short, the operation is simple, there are no special requirements for equipment, the reaction is mild, and it is easy to realize industrialization; this composite saline soil conditioner is composed of biochar, oxalic acid, desulfurized gypsum, wood vinegar liquid, and microbial inoculum fermentation broth. Each raw material interacts, promotes each other, and complements each other to obtain a composite saline soil conditioner; this composite saline soil conditioner can reduce the exchangeable sodium in the soil, convert the components with higher stability of soil organic phosphorus and inorganic phosphorus into components with higher activity, improve the soil texture, reduce the soil pH value, loosen the soil structure, also improve the water retention capacity of the soil, reduce the volatilization of water in the soil, promote the growth of indigenous microorganisms in the soil, increase the nutrient components in the soil, promote the growth of crops, also provide the necessary carbon source and nitrogen source for the growth of microorganisms, enhance the nitrogen fixation ability of crops, and have a significant promoting effect on the growth of crops in saline soil. Specific embodiments

[0017] In order to make the content of the present invention easier to be clearly understood, the technical solutions in the embodiments of the present invention are described clearly and completely.

[0018] A preparation and technical method for a saline soil conditioner includes the following steps: (1) Preparation of biochar Wash the rice husks and dry them to a water content of less than 15%, and then crush them into particles with a size of 1 - 3 cm; load the raw materials into a pyrolysis furnace, heat up to 600°C at a rate of 15°C / min under a nitrogen atmosphere, keep warm for 2 hours and then cool naturally; crush the generated biochar to 0.5 - 2 mm, wash it with deionized water and dry it. The specific surface area of the finally prepared biochar is 350 m² / g, and the ash content is 12%. Sort and remove impurities from the prepared biochar, crush and grind it to less than 1 mm, soak it in 15 ml / kg of wood vinegar liquid for 24 hours, shake, filter, rinse, and air-dry it at room temperature for standby.

[0019] (2) Preparation of desulfurized gypsum Gypsum slurry is prepared through a wet desulfurization process; the gypsum slurry is dehydrated by a vacuum belt filter to a moisture content of less than 10%, and then dried in a rotary dryer at 120°C to a moisture content of less than 1%; the dried gypsum is crushed by a hammer mill to 0.1 - 2 mm, and the qualified particles are separated by a screening device for standby.

[0020] (3) Preparation of Bacterial Liquid The Bacillus subtilis strain is inoculated into a liquid medium and fermented at 30°C and 150 rpm for 48 hours; after fermentation, the cells are collected by centrifugation, resuspended in sterile water and 5% glycerol is added as a protective agent; the final concentration of the prepared bacterial liquid is 10 CFU / mL, and the spore formation rate is higher than 90%. This bacterial liquid is reserved for use.

[0021] (4) Preparation of Modifier A composite saline - soil modifier is prepared from the following raw materials by weight: 30 - 40 parts of biochar, 15 - 20 parts of desulfurized gypsum, 8 - 10 parts of oxalic acid, 3 - 6 parts of wood vinegar liquid, 1 - 2 parts of microbial inoculant fermentation liquid, 30 - 40 parts of moisture - retaining agent and water - stabilizing agent. This saline - soil modifier can directly act on saline soil. Oxalic acid and wood vinegar liquid are used to reduce the soil pH value, biochar is used to adsorb salts and improve the soil structure, desulfurized gypsum is used to replace sodium ions in the soil, and the microbial inoculant fermentation liquid further enhances the soil carbon sequestration ability by increasing the number of soil microorganisms, achieving the effect of improving saline soil.

[0022] (5) Application of Modifier The above - mentioned modifier is evenly applied to saline soil at a dosage of 100 kg / mu, and the plowing depth is 20 - 30 cm. Keep the soil moist and regularly monitor the soil pH value, the number of water - stable aggregates and the plant growth status.

[0023] Example 1: A composite saline - soil modifier with a complete formula, and the formula composition includes the following components by weight ratio: Biochar: 30% (weight ratio) Desulfurized Gypsum: 20% (weight ratio) Oxalic Acid: 10% (weight ratio) Wood Acetic Acid: 5% (weight ratio) Bacillus subtilis: 1% (weight ratio) Other Auxiliary Components (Moisture - retaining Agent, Stabilizer): 34% (weight ratio) Preparation Method (1) Weigh each component according to the above ratio.

[0024] (2) Mix biochar, desulfurized gypsum, oxalic acid and wood acetic acid evenly.

[0025] (3) Add the Bacillus subtilis bacterial liquid and stir evenly.

[0026] (4) Dry the mixture until the water content is less than 10%, and then crush and package it.

[0027] Application method Apply the above-mentioned modifier evenly to the saline soil at a rate of 100 kg / mu, with a tillage depth of 20 - 30 cm. Keep the soil moist, and regularly monitor the soil pH value, the number of water-stable aggregates, and the plant growth status.

[0028] Example 2: A formulation lacking oxalic acid, and the formulation composition includes the following components by weight ratio Biochar: 30% (by weight ratio) Desulfurized gypsum: 20% (by weight ratio) Wood vinegar: 5% (by weight ratio) Bacillus subtilis: 1% (by weight ratio) Other auxiliary components (humectants, stabilizers): 44% (by weight ratio) Preparation method Same as Example 1, but without adding oxalic acid.

[0029] Application method Same as Example 1.

[0030] Example 3: A formulation lacking Bacillus subtilis, and the formulation composition includes the following components by weight ratio: Biochar: 30% (by weight ratio) Desulfurized gypsum: 20% (by weight ratio) Oxalic acid: 10% (by weight ratio) Wood vinegar: 5% (by weight ratio) Other auxiliary components (humectants, stabilizers): 35% (by weight ratio) Preparation method Same as Example 1, but without adding Bacillus subtilis.

[0031] Application method Same as Example 1.

[0032] Control Example 1 A traditional improvement method using only biochar and desulfurized gypsum, and the formulation composition includes the following components by weight ratio: Biochar: 30% (by weight ratio) Desulfurized gypsum: 70% (by weight ratio) Preparation method Mix biochar and desulfurized gypsum evenly, dry until the water content is less than 10%, and then crush and package.

[0033] Application method Same as Example 1.

[0034] Comparative Example 2: Unimproved saline soil Method: Select an unimproved saline soil as the control group without adding any amendment.

[0035] The improvement of saline soil by the composite saline soil amendment is shown in the following table:

[0036] In summary, the results show that the present invention has a significant effect on the improvement of saline soil. The composite saline soil amendment of the present invention significantly reduces the water-soluble salt content of saline soil, increases the number of water-stable aggregates in the soil, balances the soil pH value, improves the structure of soil microflora, enhances the soil biological activity, induces the stress tolerance of crops to soil salinization, and promotes the root development and yield formation of crops.

[0037] The present invention and its embodiments have been described above, and such description is not restrictive. Generally speaking, if those of ordinary skill in the art are inspired by it and design similar structural forms and embodiments without creative efforts without departing from the gist of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A composite soil stabilizer for saline soil, characterized in that, It includes the following raw materials in parts by weight: 30 - 40 parts of biochar, 8 - 10 parts of oxalic acid, 15 - 20 parts of desulfurized gypsum, 3 - 6 parts of wood vinegar liquid, 1 - 2 parts of microbial inoculum fermentation broth, and 30 - 40 parts of auxiliary agent.

2. The composite saline soil improver according to claim 1, characterized in that: The auxiliary agent is a humectant and a stabilizer.

3. A composite saline soil improver according to claim 1, characterized in that, The preparation method of the microbial inoculum fermentation broth includes the following steps: inoculating Bacillus subtilis strain into a liquid medium, fermenting at 30°C and 150 rpm for 48 hours; after fermentation, collecting the thalli by centrifugation, resuspending with sterile water and adding 5% glycerol as a protective agent, and finally obtaining a bacterial liquid with a concentration of 10 CFU / mL, a spore formation rate higher than 90%, and the OD600 value of the microbial inoculum fermentation broth being 0.18 - 0.

22.

4. A composite soil stabilizer for saline soil according to claim 1, characterized in that: The preparation method of the biochar includes the following steps: washing and drying rice husks until the water content is less than 15%, then crushing them into particles with a size of 1 - 3 cm, loading the raw materials into a pyrolysis furnace, heating to 600°C at a rate of 15°C / min under a nitrogen atmosphere, keeping warm for 2 hours and then naturally cooling, crushing the generated biochar into 0.5 - 2 mm, washing with deionized water and drying; finally, the specific surface area of the obtained biochar is 350 m² / g, the pH value is 8.5, and the ash content is 12%.

5. The composite saline soil improver according to claim 1, characterized in that: The preparation of the desulfurized gypsum includes the following steps: obtaining a gypsum slurry through a wet desulfurization process, dehydrating the gypsum slurry with a vacuum belt filter to a water content of less than 10%, then drying in a rotary dryer at 120°C to a water content of less than 1%, crushing the dried gypsum with a hammer mill to 0.1 - 2 mm, and separating the qualified particles through a screening device. Finally, the obtained desulfurized gypsum has a purity of 95%, a water content of 0.8%, and a particle size range of 0.1 - 2 mm.

6. The composite saline soil improver according to claim 1, characterized in that: The oxalic acid reagent is a dihydrate oxalic acid reagent.

7. The preparation method of a composite saline soil improver according to claims 1-6, characterized in that, It includes the following steps: Step 1: Weigh the raw materials according to the parts by weight of 30 - 40 parts of biochar, 8 - 10 parts of oxalic acid, 15 - 20 parts of desulfurized gypsum, 3 - 6 parts of wood vinegar liquid, 1 - 2 parts of microbial inoculum fermentation broth, and 30 - 40 parts of auxiliary agent. Step 2: Mix the biochar, desulfurized gypsum, oxalic acid, and wood vinegar liquid evenly. Step 3: Add the microbial inoculum fermentation broth and stir evenly. Step 4: Dry the mixture until the water content is less than 10%, crush it and then package it.

8. The application method of a composite saline soil improver according to claims 1-7, characterized in that, It includes the following steps: Step 1: Apply the compound saline - soil conditioner evenly to the saline soil at a rate of 100 kg / mu. Step 2: The tillage depth is 20 - 30 cm, and keep the soil moist. Step 3: Regularly monitor the soil pH value, the number of water - stable aggregates, and the plant growth status.

9. The application method of a composite saline soil improver according to claim 8, characterized in that, The soil is slightly to moderately saline soil.

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