Soil conditioner for salt-control fertile soil of coastal fish-retreating reclamation saline-alkali land and preparation method of soil conditioner

Abstract

The invention relates to the technical field of improvement of coastal saline-alkali land, in particular to a soil conditioner for salt-control fertile soil of coastal fishery reclamation saline-alkali land and a preparation method of the soil conditioner. The invention relates to a soil conditioner for salt-control fertile soil of coastal fishery receding reclamation saline-alkali land. The soil conditioner comprises the following raw material components in parts by mass: 40-60 parts of urea, 25-45 parts of calcium superphosphate, 30-45 parts of potassium sulfate, 20-25 parts of modified oyster shell powder, 10-15 parts of humic acid, 3-5 parts of a compound microbial agent, 10-20 parts of desulfurized gypsum and 25-35 parts of a biochar composite material, the biochar composite material is prepared from the following raw material components in parts by mass: 1 to 2 parts of sodium alginate, 1 to 2 parts of chitosan, 3 to 8 parts of biochar, 1 to 5 parts of calcium chloride, 10 to 20 parts of tuff stone powder, 0.25 to 2 parts of acidified attapulgite, 0.01 to 0.08 part of graphene oxide, 1 to 5 parts of ferric nitrate, 0.6 to 3 parts of copper nitrate and 0.1 to 0.5 part of silane coupling agent. By adopting the soil conditioner prepared by the invention, the pH value of soil, the volume weight of the soil and the total amount of water-soluble salts can be remarkably reduced, meanwhile, the organic matters of the soil are increased, and the porosity of the soil is increased.

Description

Technical Field

[0001] This application relates to the technical field of coastal saline-alkali land improvement, and in particular to a soil conditioner for controlling salt and creating fertile soil in coastal saline-alkali land reclaimed from fishing areas, and its preparation method. Background Technology

[0002] In recent years, with increased emphasis on farmland protection and ecological restoration, many aquaculture ponds in coastal areas have been required to be converted back to farmland due to policy mandates. However, these areas face several unique challenges due to long-term aquaculture activities: First, high soil salinity, exacerbated by the introduction of seawater during aquaculture, leading to high chloride saturation. - Na + 1. Salt accumulation: After the fishing industry is discontinued, residual salt levels can reach 0.5%-2.0%, far exceeding the tolerance threshold of crops such as rice. 2. Significant interaction between tides and groundwater: Groundwater levels in coastal areas are generally below 1 meter, and salt continues to rise through capillary action, making traditional leaching methods ineffective in eradicating the "salt return" phenomenon. 3. Deterioration of soil structure: Long-term flooding leads to particle dispersion and rapid decomposition of organic matter. After the fishing industry is discontinued, the soil hardens, develops cracks, and has extremely poor permeability and aeration. 4. Severe sodium toxicity: The percentage of exchangeable sodium often exceeds 15%, causing soil alkalization and inhibiting root development. 5. Depletion of organic matter: Dredging and frequent disinfection of aquaculture ponds result in low organic matter content, far below the standards for arable land. 6. Imbalance in microbial communities: Long-term use of antibiotics and disinfectants leads to a decline in microbial diversity and weak nutrient cycling capacity. 7. High risk of pollutant residues: Pond bottom mud may accumulate heavy metals such as copper and zinc, as well as antibiotics, directly threatening agricultural product safety during reclamation.

[0003] Current technologies for improving coastal saline-alkali land, such as gypsum application and freshwater leaching, have some effect, but they are difficult to adapt to the complex obstacles of high salinity, high water level, low fertility, and strong pollution in reclaimed land after fishing, resulting in problems such as high cost, slow effect, or secondary pollution.

[0004] Therefore, how to effectively reduce soil pH, soil bulk density, and total water-soluble salts, while increasing soil organic matter and soil porosity, has become an urgent problem to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application provides a soil conditioner for controlling salt content in saline-alkali land reclaimed from coastal fishing areas and its preparation method.

[0006] Firstly, this application provides a soil conditioner for controlling salinity and creating fertile soil in coastal saline-alkali land reclaimed from fishing areas, employing the following technical solution: A soil conditioner for controlling salt and creating fertile soil in saline-alkali land reclaimed from coastal fishing areas comprises the following raw material components in parts by weight: 40-60 parts urea, 25-45 parts superphosphate, 30-45 parts potassium sulfate, 20-25 parts modified oyster shell powder, 10-15 parts humic acid, 3-5 parts compound microbial agent, 10-20 parts desulfurized gypsum, and 25-35 parts biochar composite material. The biochar composite material comprises the following raw material components in parts by weight: 1-2 parts sodium alginate, 1-2 parts chitosan, 3-8 parts biochar, 1-5 parts calcium chloride, 10-20 parts tuff powder, 0.25-2 parts acidified attapulgite, 0.01-0.08 parts graphene oxide, 1-5 parts ferric nitrate, 0.6-3 parts copper nitrate, and 0.1-0.5 parts silane coupling agent.

[0007] By adopting the above technical solution, this application improves the raw materials by adding modified oyster shell powder. The added modified oyster shell powder can accelerate the reaction rate of neutralizing soil alkalinity; the porous structure of the modified oyster shell powder can adsorb sodium ions in the soil and reduce alkalinity through ion exchange; at the same time, the added modified oyster shell powder can increase soil porosity, alleviate compaction, and promote aeration and water infiltration; the added desulfurized gypsum can reduce soil alkalinity.

[0008] In this application, by improving the raw materials and adding biochar composite materials, the synergistic effect between the components of the biochar composite materials can systematically improve the physical structure of the soil, retain water and allow it to breathe, while balancing nutrients, buffering pH, activating the biological activity of the soil, and regulating the salinity in the soil.

[0009] Preferably, the modified oyster shell powder comprises the following raw material components in parts by weight: 5-15 parts of attapulgite clay and 1-3 parts of oyster shell powder.

[0010] By adopting the above technical solution, this application uses attapulgite clay to modify oyster shell powder, resulting in modified oyster shell powder that can control salinity and reduce alkali in saline-alkali land. The Ca released by the oyster shell powder... 2+ With soil Na + An exchange occurs, and Na is adsorbed and fixed between the attapulgite soil layers. + It works synergistically to reduce soil salinity and alkalinity, buffer pH, increase soil porosity, alleviate soil compaction, and the added oyster shell powder provides nutrients to the soil and accelerates nutrient cycling.

[0011] Preferably, the acidified attapulgite comprises the following raw material components in parts by weight: 5-10 parts of attapulgite and 90-110 parts of hydrochloric acid.

[0012] Preferably, the preparation method of the biochar composite material includes the following steps: Sodium alginate and chitosan were mixed, biochar was added and mixed again, and then calcium chloride was added and mixed to obtain the first mixture. After mixing acidified attapulgite and graphene oxide, ferric nitrate and copper nitrate are added and mixed to obtain a second mixture. The first mixture, the second mixture, and the silane coupling agent are mixed together, and then tuff rock powder is added and mixed to obtain a biochar composite material.

[0013] By adopting the above technical solution, this application uses sodium alginate, chitosan, biochar, acidified attapulgite, and graphene oxide as raw materials to prepare a biochar composite material. The prepared biochar composite material can control salt content and improve soil fertility in coastal saline-alkali lands. The biochar composite material can enhance the removal of sodium from the soil. + Cl - Physical adsorption and ion exchange of equal salt content significantly reduce soil alkalinity and increase soil porosity. At the same time, the prepared biochar composite material forms a protective film on the surface of the soil conditioner, which encapsulates the effective components in the soil conditioner. The porous structure of the film can slowly release nutrients, effectively extending the service life of the soil conditioner.

[0014] Preferably, the biochar composite material further includes 10-16 parts by weight of attapulgite composite material.

[0015] Preferably, the attapulgite composite material comprises the following raw material components in parts by weight: 0.5-1.5 parts ferric sulfate, 1.5-2.5 parts attapulgite, and 8-12 parts reed straw.

[0016] Preferably, the preparation method of the attapulgite composite material includes the following steps: mixing ferric sulfate, a third part of attapulgite, and reed straw, and then pyrolyzing the mixture at high temperature to obtain the attapulgite composite material.

[0017] Preferably, the pyrolysis temperature is 450-550℃ and the pyrolysis time is 1.5-2.5 hours.

[0018] By adopting the above technical solution, this application prepares an attapulgite composite material using ferric sulfate, attapulgite, and reed straw as raw materials. This composite material can control soil salinity and reduce alkalinity. Biochar adsorbs sodium ions through its pores, while attapulgite fixes sodium ions through interlayer exchange. Through the synergistic effect of the two, it can effectively reduce electrical conductivity and alkalinity, and regulate soil pH. The attapulgite composite material can improve soil structure, alleviate compaction, and promote water infiltration and aeration. It can also activate nutrients, with biochar in the composite material slowly releasing nitrogen and phosphorus, thus improving soil fertility. Furthermore, the prepared attapulgite composite material has long-term stability, effectively extending its service life in the soil.

[0019] Preferably, the compound microbial agent comprises the following raw material components in parts by weight: 10-20 parts of Bacillus subtilis, 10-20 parts of Bacillus megaterium, and 5-15 parts of Azotobacter chrysophyll.

[0020] Secondly, this application provides a method for preparing a soil conditioner for controlling salinity in saline-alkali land reclaimed from coastal fishing areas, using the following technical solution: A method for preparing a soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing areas, comprising the following steps: Weigh out each ingredient according to the formula; A soil conditioner is obtained by mixing urea, superphosphate, potassium sulfate, modified oyster shell, humic acid, compound microbial agent, desulfurized gypsum, and biochar composite material, and then drying the mixture.

[0021] In summary, this application includes at least one of the following beneficial technical effects: This application discloses a soil conditioner for controlling salt and creating fertile soil in saline-alkali land reclaimed from coastal fishing areas, and its preparation method. The soil conditioner prepared by this application can significantly reduce the soil pH, reduce soil bulk density, reduce total water-soluble salts, increase soil organic matter, increase soil porosity, and significantly improve the soil's physical and chemical properties. Detailed Implementation

[0022] The technical solutions of this application are further illustrated by specific embodiments below. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0023] All raw materials involved in this application are commercially available products, including oyster shells, which are from Fujian Mata Ecological Technology Co., Ltd. Attapulgite clay, purchased from Mingguang City Guoxing Attapulgite Co., Ltd.; Sodium alginate was purchased from Jiangsu Ruiduo Bioengineering Co., Ltd. Chitosan was purchased from Jiangsu Caiwei Biotechnology Co., Ltd. Tuffaceous rock powder with a particle size D(50) of 24.4 μm was purchased from Yongjing, Gansu. Graphene oxide, industrial grade graphene oxide, in the form of a dark brown powder, with a purity of 95%, a thickness of ~1nm, a carbon content of <50%, an oxygen content of >42%, a sulfur content of <4%, a sheet diameter of 10-50μm, and 1-2 layers, purchased from Suzhou CarbonFeng Graphene Technology Co., Ltd. Humic acid, purchased from Zhenxing Humic Acid Factory in Yaodu District, Linfen City, CAS No.: 1415-93-6, Item No.: HA-01; The compound microorganisms consist of Bacillus subtilis (active content ≥200×10⁸ CFU / g), Bacillus megaterium (active content ≥100×10⁸ CFU / g), and Azotobacter chrysotrichum (active content ≥30×10⁸ CFU / g). All of the above components were purchased from Yangzhou Herrenknecht Biotechnology Co., Ltd., and the bacterial powders were directly mixed in proportion before use.

[0024] Desulfurized gypsum was purchased from Tianjin Dongli Power Plant.

[0025] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0026] Preparation Example 1: Preparation of attapulgite composite materials: Mix 1g of ferric sulfate, 2g of attapulgite, 10g of reed straw, and 500mL of deionized water. Dry the mixture at 80℃ and sieve it. Heat the sieved mixture to 500℃ at a rate of 10℃ / min and pyrolyze it for 2 hours. Cool it to room temperature to obtain the attapulgite composite material.

[0027] Preparation Example 2: Preparation of attapulgite composite materials: Mix 0.5g of ferric sulfate, 1.5g of attapulgite, 8g of reed straw, and 500mL of deionized water. Dry the mixture at 80℃ and sieve it. Heat the sieved mixture to 450℃ at a rate of 10℃ / min and pyrolyze it for 1.5 hours. Cool it to room temperature to obtain the attapulgite composite material.

[0028] Preparation Example 3: Preparation of attapulgite composite materials: Mix 1.5g of ferric sulfate, 2.5g of attapulgite, 12g of reed stalks, and 500mL of deionized water. Dry the mixture at 80℃ and sieve it. Heat the sieved mixture to 550℃ at a rate of 10℃ / min and pyrolyze it for 2.5 hours. Cool it to room temperature to obtain the attapulgite composite material.

[0029] Preparation Example 4: The preparation method of biochar composite material includes the following steps: Step 1: Preparation of Biochar Bamboo is dried, ground, and passed through a 200-mesh sieve. After calcining at 600℃ for 2 hours, the biochar is washed three times with deionized water and dried at 60℃ to obtain biochar. Step 2: Preparation of acidified attapulgite: Mix 8g of attapulgite and 100g of hydrochloric acid for 2 hours, let stand to separate the layers, wash with distilled water until neutral, and dry at 80℃ to obtain acidified attapulgite.

[0030] Step 3: Preparation of biochar composite material: Dissolve 1.5g of sodium alginate in water to prepare a 2% sodium alginate solution. 1.5g of chitosan was dissolved in acetic acid (1% by volume) to prepare a chitosan solution with a mass concentration of 0.5%. Sodium alginate solution, chitosan solution and 500mL of water were mixed, 5g of biochar was added and mixed, and then 3g of calcium chloride was added and mixed to obtain the first mixture. Mix 3g of ferric nitrate with water to obtain a 5% ferric nitrate solution. 1.8g of copper nitrate was mixed with water to obtain a 5% copper nitrate solution. 1.5g of acidified attapulgite, 0.05g of graphene oxide, and 500mL of water were mixed, and then ferric nitrate solution and copper nitrate solution were added and mixed to obtain a second mixture. The first mixture, the second mixture, and 0.3g of silane coupling agent KH550 were mixed together, and then 15g of tuff rock powder, 14g of attapulgite composite material, and 1000mL of water were added and mixed. After filtration, the biochar composite material was obtained.

[0031] The attapulgite composite material was prepared according to Preparation Example 1.

[0032] Preparation Example 5: The preparation method of biochar composite material includes the following steps: Step 1: Preparation of Biochar Bamboo is dried, ground, and passed through a 200-mesh sieve. After calcining at 600℃ for 2 hours, the biochar is washed three times with deionized water and dried at 60℃ to obtain biochar. Step 2: Preparation of acidified attapulgite Mix 5g of attapulgite and 90g of hydrochloric acid for 2 hours, let stand to separate the layers, wash with distilled water until neutral, and dry at 80℃ to obtain acidified attapulgite.

[0033] Step 3: Preparation of biochar composite material: Dissolve 1g of sodium alginate in water to prepare a 2% sodium alginate solution. 1 g of chitosan was dissolved in acetic acid (1% by volume) to prepare a chitosan solution with a mass concentration of 0.5%. Sodium alginate solution, chitosan solution, and 500 mL of water were mixed. 3 g of biochar was added and mixed again. Then 1 g of calcium chloride was added and mixed to obtain the first mixture. Mix 1g of ferric nitrate with water to obtain a 1% ferric nitrate solution; 0.6g of copper nitrate was mixed with water to obtain a 1% copper nitrate solution. 0.25g of acidified attapulgite, 0.01g of graphene oxide, and 500mL of water were mixed, and then ferric nitrate solution and copper nitrate solution were added and mixed to obtain a second mixture. The first mixture, the second mixture, and 0.1g of silane coupling agent KH550 were mixed together, and then 10g of tuff rock powder, 10g of attapulgite composite material, and 1000mL of water were added and mixed. After filtration, the biochar composite material was obtained.

[0034] The attapulgite composite material was prepared in Preparation Example 2.

[0035] Preparation Example 6: The preparation method of biochar composite material includes the following steps: Step 1: Preparation of Biochar Bamboo is dried, ground, and passed through a 200-mesh sieve. After calcining at 600℃ for 2 hours, the biochar is washed three times with deionized water and dried at 60℃ to obtain biochar. Step 2: Preparation of acidified attapulgite Mix 10g of attapulgite and 110g of hydrochloric acid for 2 hours, let stand to separate the layers, wash with distilled water until neutral, and dry at 80℃ to obtain acidified attapulgite.

[0036] Step 3: Preparation of biochar composite material: Dissolve 2g of sodium alginate in water to prepare a 2% sodium alginate solution. 2g of chitosan was dissolved in acetic acid (1% by volume) to prepare a chitosan solution with a mass concentration of 0.5%. Sodium alginate solution, chitosan solution, and 500 mL of water were mixed. 8 g of biochar was added and mixed again. Then, 5 g of calcium chloride was added and mixed to obtain the first mixture. Mix 5g of ferric nitrate with water to obtain a 5% ferric nitrate solution. Mix 3g of copper nitrate with water to obtain a 5% copper nitrate solution. 2g of acidified attapulgite, 0.08g of graphene oxide, and 500mL of water were mixed, and then ferric nitrate solution and copper nitrate solution were added and mixed to obtain a second mixture. The first mixture, the second mixture, and 0.5g of silane coupling agent KH550 were mixed together, and then 20g of tuff rock powder, 16g of attapulgite composite material, and 1000mL of water were added and mixed. After filtration, the biochar composite material was obtained.

[0037] The attapulgite composite material was prepared in Preparation Example 3.

[0038] Preparation Example 7: The difference from Example 4 is that the amount of attapulgite composite material added is 10g.

[0039] Preparation Example 8: The difference from Example 4 is that the amount of attapulgite composite material added is 16g.

[0040] Example 1: A method for preparing a soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing areas includes the following steps: Step 1: Preparation of modified oyster shell powder 10g of attapulgite clay and 2g of oyster shell powder were ground in a grinder to obtain a mixed powder. The mixed powder was then calcined at 600℃ for 2 hours to obtain modified oyster shell powder.

[0041] Step 2: Preparation of Compound Microbial Agent 15g of Bacillus subtilis, 15g of Bacillus megaterium, and 10g of Azotobacter chrysotrichum were mixed to obtain a compound microbial agent.

[0042] Step 3: Preparation of Soil Conditioner Mix 50g of urea, 35g of superphosphate, 37g of potassium sulfate, 23g of modified oyster shell powder, 13g of humic acid, 4g of compound microbial agent, 15g of desulfurized gypsum, 30g of biochar composite material, and 1000mL of water at a speed of 400r / min for 3 hours, and then dry to obtain a soil conditioner.

[0043] The biochar composite material was obtained from Preparation Example 4.

[0044] Example 2: A method for preparing a soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing areas includes the following steps: Step 1: Preparation of modified oyster shell powder 5g of attapulgite clay and 1g of oyster shell powder were ground in a grinder to obtain a mixed powder. The mixed powder was then calcined at 600℃ for 2 hours to obtain modified oyster shell powder.

[0045] Step 2: Preparation of Compound Microbial Agent 10g of Bacillus subtilis, 10g of Bacillus megaterium, and 5g of Azotobacter chrysotrichum were mixed to obtain a compound microbial inoculant.

[0046] Step 3: Preparation of Soil Conditioner Mix 40g of urea, 25g of superphosphate, 30g of potassium sulfate, 20g of modified oyster shell powder, 10g of humic acid, 3g of compound microbial agent, 10g of desulfurized gypsum, 25g of biochar composite material, and 1000mL of water at a speed of 400r / min for 3 hours, and then dry to obtain a soil conditioner.

[0047] The biochar composite material was obtained from Preparation Example 5.

[0048] Example 3: A method for preparing a soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing areas includes the following steps: Step 1: Preparation of modified oyster shell powder 15g of attapulgite clay and 3g of oyster shell powder were ground in a grinder to obtain a mixed powder. The mixed powder was then calcined at 600℃ for 2 hours to obtain modified oyster shell powder.

[0049] Step 2: Preparation of Compound Microbial Agent 20g of Bacillus subtilis, 20g of Bacillus megaterium, and 15g of Azotobacter chrysotrichum were mixed to obtain a compound microbial agent.

[0050] Step 3: Preparation of Soil Conditioner Mix 60g of urea, 45g of superphosphate, 45g of potassium sulfate, 25g of modified oyster shell powder, 15g of humic acid, 5g of compound microbial agent, 20g of desulfurized gypsum, 35g of biochar composite material, and 1000mL of water at a speed of 400r / min for 3 hours, and then dry to obtain a soil conditioner.

[0051] The biochar composite material was obtained from Preparation Example 6.

[0052] Example 4: The difference from Example 1 is that the biochar composite material was obtained from Preparation Example 7.

[0053] Example 5: The difference from Example 1 is that the biochar composite material was obtained from Preparation Example 8.

[0054] Example 6: The difference from Example 1 is that the amount of biochar composite material added is 25g. Example 7: The difference from Example 1 is that the amount of biochar composite material added is 35g.

[0055] Comparative Example 1: The difference from Example 1 is that no biochar composite material is added.

[0056] Comparative Example 2: The difference from Example 1 is that the amount of biochar composite material added is 24g.

[0057] Comparative Example 3: The difference from Example 1 is that the amount of biochar composite material added is 36g.

[0058] Comparative Example 4: The difference from Example 1 is that no attapulgite composite material is added when preparing the biochar composite material.

[0059] Comparative Example 5: The difference from Example 1 is that the amount of attapulgite composite material added in the preparation of biochar composite material is 9g.

[0060] Comparative Example 6: The difference from Example 1 is that the amount of attapulgite composite material added in the preparation of biochar composite material is 17g.

[0061] Performance testing: 1. Soil chemical property testing: The performance of the soil conditioners prepared in Examples 1-7 and Comparative Examples 1-6 was tested in the coastal saline-alkali area of ​​Binzhou City, Shandong Province. Two weeks before corn planting, the topsoil of the planting area was deep-tilled using a deep-tilling machine. The depth of the deep-tilling treatment of the topsoil was 25 cm, and it was repeated 4 times. The soil conditioner was applied at a rate of 1.5 kg / mu. After application, the soil was reclaimed once to a depth of 30 cm. The physical and chemical properties of the soil were tested before corn planting and at corn harvest. Twenty samples were taken from each experimental field, and the average values ​​of each physical and chemical property were calculated.

[0062] The specific testing methods are as follows: pH value: measured using a pH meter (water:soil = 5:1); Organic matter: potassium dichromate method was used; Soil bulk density: Soil bulk density was determined using the ring sampler method; Total water-soluble salts: The conductivity of the solution after extraction was measured using a conductivity meter, and the total salt content of the soil was calculated.

[0063] Table 1 Soil physicochemical properties As shown in Table 1, the soil conditioners prepared in Examples 1-7 of this application can significantly reduce soil pH, reduce soil bulk density, reduce total water-soluble salts, increase soil organic matter, and increase soil porosity, thus significantly improving soil physicochemical properties. Compared with the original soil, the application of the soil conditioners from Examples 1-7 of this invention resulted in a decrease in soil pH and a significant reduction in total water-soluble salts, indicating that the soil conditioners of this invention can improve soil salinity and alkalinity and reduce total water-soluble salts.

[0064] Based on the test results of Example 1 and Comparative Example 1, it can be seen that after applying the soil conditioner prepared in Example 1, the soil pH, soil bulk density, total water-soluble salts, soil organic matter, and soil porosity were effectively improved. This indicates that the added biochar composite material can significantly reduce soil pH, reduce soil bulk density, reduce total water-soluble salts, increase soil organic matter, increase soil porosity, and significantly improve the physical and chemical properties of the soil.

[0065] Based on the test results of Examples 1, 6, 7, Comparative Example 2, and Comparative Example 3, it can be seen that the amount of biochar composite material added affects the physical and chemical properties of the soil, and the physical and chemical properties of the soil are optimal when the amount of biochar composite material added is 25-35 parts by mass.

[0066] Based on the test results of Example 1 and Comparative Example 4, it can be seen that after applying the soil conditioner prepared in Example 1, the soil pH, soil bulk density, total water-soluble salt content, soil organic matter, and soil porosity were effectively improved. This indicates that the added attapulgite composite material can significantly reduce soil pH, reduce soil bulk density, reduce total water-soluble salt content, increase soil organic matter, increase soil porosity, and significantly improve the physical and chemical properties of the soil.

[0067] Based on the test results of Examples 1, 4, 5, Comparative Example 5, and Comparative Example 6, it can be seen that the amount of attapulgite composite material added affects the physical and chemical properties of the soil, and the physical and chemical properties of the soil are optimal when the amount of attapulgite composite material added is 10-16 parts by mass.

[0068] 2. The impact of soil conditioners on corn The experiment consisted of 12 treatment groups, each covering 2 mu (approximately 0.16 acres). Soil conditioners prepared according to Examples 1-7 and Comparative Examples 1-6 of this application, along with conventional fertilizers, were applied to the experimental fields of each group. Two experimental fields served as a control group, with one field receiving no treatment and the other receiving conventional fertilization. Two weeks before corn sowing, deep tillage machinery was used to loosen the topsoil of the planting area to a depth of 25 cm, repeated four times. After applying the soil conditioner and conventional fertilizer, the field was reclaimed once to a depth of 30 cm. The conventional fertilizer dosage was 100 kg per mu, and the soil conditioner dosage was 1.5 kg per mu. The corn variety was Golden Grain MY73, and the planting density was 4000 plants per mu. After corn maturity, five sampling points were selected from each treatment group, and 20 ears were continuously sampled from each point to calculate the yield.

[0069] In conventional compound fertilizers, the ratio of nitrogen, phosphorus, and potassium is 33:10:4.

[0070] Table 2. Corn Yield deal with <![CDATA[Yield (kg / hm 2 )]]> blank 8541.3 conventional fertilizers 9143.2 Example 1 + Conventional Fertilizer 12035.1 Example 2 + Conventional Fertilizer 11553.7 Example 3 + Conventional Fertilizer 11449.6 Example 4 + Conventional Fertilizer 11842.7 Example 5 + Conventional Fertilizer 11941.4 Example 6 + Conventional Fertilizer 11643.4 Example 7 + Conventional Fertilizer 11749.6 Comparative Example 1 + Conventional Fertilizer 10245.6 Comparative Example 2 + Conventional Fertilizer 10442.8 Comparative ratio 3 + conventional fertilizer 10541.7 Comparative Example 4 + Conventional Fertilizer 10656.7 Comparison ratio 5 + conventional fertilizer 10752.2 Comparative ratio 6 + conventional fertilizer 10851.8 As shown in Table 2, compared with the treatment of adding only conventional fertilizer, the treatment of adding the soil conditioner prepared in Examples 1-7 and conventional fertilizer can significantly increase the yield of maize planted in coastal saline-alkali soil.

Claims

1. A soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing areas, characterized in that: The raw material components include the following parts by weight: 40-60 parts urea, 25-45 parts superphosphate, 30-45 parts potassium sulfate, 20-25 parts modified oyster shell powder, 10-15 parts humic acid, 3-5 parts compound microbial agent, 10-20 parts desulfurized gypsum, and 25-35 parts biochar composite material. The biochar composite material comprises the following raw material components in parts by weight: 1-2 parts sodium alginate, 1-2 parts chitosan, 3-8 parts biochar, 1-5 parts calcium chloride, 10-20 parts tuff powder, 0.25-2 parts acidified attapulgite, 0.01-0.08 parts graphene oxide, 1-5 parts ferric nitrate, 0.6-3 parts copper nitrate, and 0.1-0.5 parts silane coupling agent.

2. The soil conditioner for controlling salinity and creating fertile soil in coastal saline-alkali land reclaimed from fishing areas according to claim 1, characterized in that: The modified oyster shell powder comprises the following raw material components in parts by weight: 5-15 parts of attapulgite clay and 1-3 parts of oyster shell powder.

3. The soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing grounds according to claim 1, characterized in that: The acidified attapulgite comprises the following raw material components in parts by weight: 5-10 parts of attapulgite and 90-110 parts of hydrochloric acid.

4. The soil conditioner for controlling salinity and creating fertile soil in coastal saline-alkali land reclaimed from fishing areas according to claim 1, characterized in that: The preparation method of the biochar composite material includes the following steps: Sodium alginate and chitosan were mixed, biochar was added and mixed, and then calcium chloride was added and mixed to obtain the first mixture. Acidified attapulgite and graphene oxide are mixed, and then ferric nitrate and copper nitrate are added and mixed to obtain a second mixture. The first mixture, the second mixture, and the silane coupling agent are mixed together, and then tuff rock powder is added and mixed to obtain a biochar composite material.

5. The soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing grounds according to claim 1, characterized in that: The biochar composite material also includes 10-16 parts by weight of attapulgite composite material.

6. The soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing grounds according to claim 5, characterized in that: The attapulgite composite material comprises the following raw material components in parts by weight: 0.5-1.5 parts ferric sulfate, 1.5-2.5 parts attapulgite, and 8-12 parts reed straw.

7. The soil conditioner for controlling salinity and creating fertile soil in coastal saline-alkali land reclaimed from fishing areas according to claim 6, characterized in that: The preparation method of the attapulgite composite material is as follows: ferric sulfate, a third part of attapulgite, and reed straw are mixed and pyrolyzed at high temperature to obtain the attapulgite composite material.

8. The soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing grounds according to claim 1, characterized in that: The pyrolysis temperature is 450-550℃; the pyrolysis time is 1.5-2.5 hours.

9. The soil conditioner for controlling salinity and creating fertile soil in saline-alkali land reclaimed from coastal fishing grounds according to claim 1, characterized in that: The compound microbial agent comprises the following raw material components in parts by weight: 10-20 parts of Bacillus subtilis, 10-20 parts of Bacillus megaterium, and 5-15 parts of Azotobacter chrysotrichum.

10. A method for preparing a soil conditioner for controlling salinity in saline-alkali land reclaimed from coastal fishing areas as described in any one of claims 1-9, characterized in that: The preparation method steps are as follows: Weigh out each ingredient according to the formula; A soil conditioner is obtained by mixing urea, superphosphate, potassium sulfate, modified oyster shell, humic acid, compound microbial agent, desulfurized gypsum, and biochar composite material, and then drying the mixture.

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