A method of soil improvement

Abstract

The application discloses a soil improvement method and relates to the technical field of soil improvement.The method comprises the following steps: spraying a soil water-retaining agent on the surface of soil to be improved, and performing ridge tillage to mix the ridges; introducing biogas liquid into the ridged soil to irrigate the soil, and obtaining irrigated soil after standing; digging a plurality of pre-embedded pits on the irrigated soil, and embedding a gas-permeable net pipe in the pits; injecting a moss mixture into the gas-permeable net pipe, backfilling the pits with soil, and obtaining loose soil; taking out the gas-permeable net pipe after water conservation of the loose soil, and obtaining conserved soil; applying modified biochar fertilizer on the surface of the conserved soil, mixing the fertilizer after ploughing, planting legume crops, ploughing the crops into the soil after harvesting, and planting different crops in rotation, so that the soil is improved.The method can effectively improve the porosity and permeability of hardened soil, improve the water and fertilizer retention capacity of the soil, effectively alleviate soil hardening, and restore soil fertility.

Description

Technical Field

[0001] This application relates to the field of soil improvement technology, and in particular to a soil improvement method. Background Technology

[0002] Soil compaction is a significant manifestation of soil degradation. It occurs when the topsoil layer, lacking organic matter, has a poor structure, or is damaged by external factors such as irrigation and rainfall, leading to soil dispersion and hardening due to cohesion after drying. This reduces the soil's water and fertilizer retention capacity and permeability, thus affecting crop growth and development, resulting in decreased yields and economic benefits. Soil compaction is the result of numerous factors, with a large portion of arable land compaction being human-caused. Long-term application of nitrogen, phosphorus, and potassium fertilizers, insufficient organic fertilizers, excessive use of plastics, and unscientific farming practices, crop rotation systems, and fertilization methods all contribute to the destruction of the topsoil structure, leading to soil compaction and ultimately, a decline in soil arability. Currently, irrigation or deep plowing are commonly used to address soil compaction. However, due to the poor permeability of compacted soil, irrigation cannot penetrate the entire soil surface, resulting in insufficient internal water supply. Deep plowing, while effective, has a relatively short-term effect and is not significantly effective in improving compacted soil. Based on this, this application proposes a soil improvement method. Summary of the Invention

[0003] The main objective of this application is to provide a soil improvement method that addresses the technical problem that existing methods have limited effectiveness in improving compacted soil.

[0004] To achieve the above objectives, this application proposes a soil improvement method, comprising the following steps:

[0005] Spray a soil water-retaining agent on the surface of the soil to be improved, and then perform mulching and ridging.

[0006] Then, biogas slurry is introduced into the ridged soil for irrigation. After standing, irrigated soil is obtained.

[0007] Multiple pre-buried pits are dug in the irrigated soil, and breathable mesh pipes are buried in the multiple pre-buried pits;

[0008] Moss mixture is injected into the breathable mesh pipe, and then soil is backfilled into the multiple pre-buried pits to obtain loose soil;

[0009] After watering and maintaining the loose soil, the breathable mesh pipe is removed to obtain the maintained soil.

[0010] Modified biochar fertilizer is applied to the surface of the soil to be maintained. After tilling and mixing, legumes are planted and then rotary tilled into the soil after harvesting. The soil is then improved by rotating different crops.

[0011] Optionally, the soil water-retaining agent comprises, by weight, 30-50 parts of porous chitosan gel, 25-40 parts of graphene oxide, 12-25 parts of polyhydroxy alcohol ester, 25-40 parts of zeolite powder, 10-20 parts of diatomaceous earth, 3-6 parts of Bacillus subtilis and 3-6 parts of Bacillus licheniformis.

[0012] Optionally, the preparation steps of the porous chitosan gel include:

[0013] A γ-polyglutamic acid solution was mixed with Tween-20 at room temperature and a porogen was added to obtain a mixture.

[0014] Acetic acid was added to the chitosan solution, and then added dropwise to the mixture. After the reaction, the mixture was centrifuged and hydrochloric acid solution was added to allow the gas to escape. Then, concentrated ammonia was added and the pH was adjusted to 7. After washing with deionized water and ethanol in sequence, porous chitosan was obtained.

[0015] Acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and vinylpyrrolidone monomers were dissolved in water, and the pH was adjusted to 7-8. The mixture was stirred at a stirring rate of 80-120 rpm, and then the porous chitosan was added. After mixing, the mixture was heated to 55-65°C, and an inert gas was introduced to achieve an anaerobic environment. A phenolic crosslinking agent was then added, and the mixture was reacted for 2-3 hours. After cooling to room temperature and drying, a porous chitosan gel was obtained.

[0016] Optionally, the steps of spraying a soil water-retaining agent onto the surface of the soil to be improved, and performing ridge tillage and mixing include:

[0017] Mix the soil water-retaining agent with water at a mass ratio of 1:(100-115) and spray the mixture onto the surface of the soil to be improved. The spraying rate is 0.3-0.5 kg / m². 2 After standing for 2-5 hours, perform ridge cultivation, mix and ridge, and control the cultivation depth to 20-30cm.

[0018] Optionally, the step of introducing biogas slurry into the ridged soil for irrigation, and then allowing it to stand to obtain irrigated soil, includes:

[0019] Spread 50-60m into the ridged soil 3 Irrigation is carried out by introducing biogas slurry at a rate of 1 / mu, and after standing for 4-6 hours, irrigated soil is obtained.

[0020] Optionally, the step of excavating multiple pre-buried pits in the irrigated soil and burying breathable mesh pipes in the multiple pre-buried pits includes:

[0021] 2-3 per m 3 Multiple pre-buried pits are dug in the irrigated soil at a density of 35-50cm. Multiple breathable mesh pipes are then vertically buried in the walls of the multiple pre-buried pits, with one end of each breathable mesh pipe buried in the pre-buried pit and the other end exposed to the air.

[0022] Optionally, the step of injecting the moss mixture into the breathable mesh includes:

[0023] Inject the moss mixture into the breathable mesh until the breathable mesh is filled; the moss mixture is a mixture of moss, water and humus in a mass ratio of 1:(1.5-2):(1.5-2).

[0024] Optionally, the step of removing the breathable mesh pipe after watering the loose soil to obtain the cured soil includes:

[0025] Spray the loosened soil with clean water every 2-3 days for maintenance, with a spray volume of 5-8m³. 3 / acre, and after 28-35 days, the breathable mesh pipe is removed to obtain the cultivated soil.

[0026] Optionally, the preparation steps of the modified biochar fertilizer include:

[0027] Soybean straw biochar was added to a citric acid solution and stirred at 20-25℃ for 1-3 hours. The temperature was then raised to 55-65℃ and kept at that temperature for 22-24 hours. The temperature was then raised to 115-125℃ and kept at that temperature for 80-100 minutes. After cooling to room temperature, the biochar was washed and dried at 55-65℃ to obtain modified biochar.

[0028] Animal manure and crushed corn cobs are mixed at a mass ratio of 1:(1.5-2), and the moisture content is controlled at 50-60% to obtain compost raw materials;

[0029] The modified biochar and calcium-based bentonite are added to the composting raw materials, and aerobic composting is carried out. During the process, the temperature is controlled at 55-65℃, and the compost pile is turned over every 3-7 days. After 50-60 days, the modified biochar fertilizer is obtained.

[0030] The modified biochar is added at 5-8% of the mass of the composting raw material, and the calcium-based bentonite is added at 2-5% of the mass of the composting raw material.

[0031] Optionally, in the step of planting leguminous crops and rotary tilling them into the soil after harvesting, the leguminous crops include one or more of mung beans, soybeans, alfalfa, and acacia, and the rotary tillage depth is 10-20 cm.

[0032] This application includes at least the following beneficial effects:

[0033] This application first applies a soil water-retaining agent to the soil to be improved, followed by pulverized tillage to break up compacted soil, improve soil pore structure and permeability, and promote the full absorption of the soil water-retaining agent, thereby improving soil moisture and oxygen content and alleviating soil compaction. Then, biogas slurry is introduced for irrigation to increase soil organic matter content and the content of soil microorganisms, thus improving soil fertility. Next, permeable mesh pipes are buried in pre-buried pits to create aeration space in the soil, facilitating the entry of water and air and promoting soil moisture retention. Simultaneously, a moss mixture is injected into the soil to improve deep soil compaction. Furthermore, after decomposition by soil microorganisms, the moss effectively improves soil fertility and provides a suitable environment for plant root growth. Nutrients are applied, followed by watering to maintain soil moisture and promote moss growth, thus restoring soil fertility. Modified biochar fertilizer is then applied, allowing its organic colloids to form organic-inorganic complex colloids and various microbial aggregates with soil mineral colloids, thereby improving the soil's water, fertilizer, air, and heat properties and enriching the soil. Leguminous crops are then planted, and after harvesting, they are rotary tilled into the soil to further fix nitrogen and enrich the soil. Subsequent crop rotation is then implemented. Because multiple types of fertilizers are added during crop rotation, the damage caused by a single fertilizer to the soil is reduced. Different crops can effectively absorb excess nutrients remaining in the soil, further alleviating soil compaction. After the improvement method described in this application, the porosity and permeability of compacted soil are effectively improved, enhancing the soil's water and fertilizer retention capacity, facilitating water and fertilizer penetration throughout the soil, thereby effectively alleviating soil compaction, restoring soil fertility, and promoting crop growth. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0035] Figure 1 This is a schematic flowchart of the soil improvement method described in the embodiments of this application.

[0036] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0038] To address the technical problems existing in the prior art, embodiments of this application provide a soil improvement method, such as... Figure 1 As shown, it includes the following steps:

[0039] Spray a soil water-retaining agent on the surface of the soil to be improved, and then perform mulching and ridging.

[0040] Then, biogas slurry is introduced into the ridged soil for irrigation. After standing, irrigated soil is obtained.

[0041] Multiple pre-buried pits are dug in the irrigated soil, and breathable mesh pipes are buried in the multiple pre-buried pits;

[0042] Moss mixture is injected into the breathable mesh pipe, and then soil is backfilled into the multiple pre-buried pits to obtain loose soil;

[0043] After watering and maintaining the loose soil, the breathable mesh pipe is removed to obtain the maintained soil.

[0044] Modified biochar fertilizer is applied to the surface of the soil to be maintained. After tilling and mixing, legumes are planted and then rotary tilled into the soil after harvesting. The soil is then improved by rotating different crops.

[0045] This application first applies a soil water-retaining agent to the soil to be improved, followed by pulverized tillage to break up compacted soil, improve soil pore structure and permeability, and promote the full absorption of the soil water-retaining agent, thereby improving soil moisture and oxygen content and alleviating soil compaction. Then, biogas slurry is introduced for irrigation to increase soil organic matter content and the content of soil microorganisms, thus improving soil fertility. Next, permeable mesh pipes are buried in pre-buried pits to create aeration space in the soil, facilitating the entry of water and air and promoting soil moisture retention. Simultaneously, a moss mixture is injected into the soil to improve deep soil compaction. Furthermore, after decomposition by soil microorganisms, the moss effectively improves soil fertility and provides a suitable environment for plant root growth. Nutrients are applied, followed by watering to maintain soil moisture and promote moss growth, thus restoring soil fertility. Modified biochar fertilizer is then applied, allowing its organic colloids to form organic-inorganic complex colloids and various microbial aggregates with soil mineral colloids, thereby improving the soil's water, fertilizer, air, and heat properties and enriching the soil. Leguminous crops are then planted, and after harvesting, they are rotary tilled into the soil to further fix nitrogen and enrich the soil. Subsequent crop rotation is then implemented. Because multiple types of fertilizers are added during crop rotation, the damage caused by a single fertilizer to the soil is reduced. Different crops can effectively absorb excess nutrients remaining in the soil, further alleviating soil compaction. After the improvement method described in this application, the porosity and permeability of compacted soil are effectively improved, enhancing the soil's water and fertilizer retention capacity, facilitating water and fertilizer penetration throughout the soil, thereby effectively alleviating soil compaction, restoring soil fertility, and promoting crop growth.

[0046] As one possible implementation of this application, the soil water-retaining agent comprises, by weight, 30-50 parts of porous chitosan gel, 25-40 parts of graphene oxide, 12-25 parts of polyhydroxy alcohol ester, 25-40 parts of zeolite powder, 10-20 parts of diatomaceous earth, 3-6 parts of Bacillus subtilis and 3-6 parts of Bacillus licheniformis.

[0047] In the specific implementation process, graphene oxide is obtained by oxidizing raw graphene according to the Hummers method. The specific operation steps are as follows:

[0048] After stirring and mixing graphene, concentrated sulfuric acid, potassium persulfate, and phosphorus pentoxide, the mixture was heated to 80°C in an oil bath and kept at that temperature for 5.0 h. After cooling to room temperature, the mixture was filtered and washed until the pH reached 7.0. It was then dried at room temperature for 48 h. The product was then added to concentrated sulfuric acid and potassium permanganate, stirred in an ice bath for 1.0 h, and reacted at 50°C for 40-60 h. The mixture was then placed in ice water, and hydrogen peroxide was added and stirred continuously. When a bright yellow color appeared, the mixture was allowed to stand for 48 h. The supernatant was discarded, and the lower precipitate was obtained. The lower precipitate was washed until the pH reached 7.0 and dried at room temperature for 48 h to obtain graphene oxide.

[0049] Polyhydroxy alcohol esters are esterification products obtained by esterification reaction of polyols and long-chain fatty acids. The polyol is one of trimethylolpropane, pentaerythritol, 1,2,5-pentanetriol, and trimethylolpentane, and the long-chain fatty acid is one of hexadecanoic acid and octadecanoic acid.

[0050] The soil water-retaining agent of this application is prepared by mixing porous chitosan gel, graphene oxide, polyhydroxy alcohol esters, zeolite powder, diatomaceous earth, Bacillus subtilis, and Bacillus licheniformis. The porous chitosan gel has excellent water storage and swelling properties, which can improve the soil's water retention capacity. The hydroxyl and carboxyl functional groups on the surface of graphene oxide adsorb cations in the soil while releasing hydrogen ions, thus improving the soil's pH and allowing for better release of humic decomposition products, thereby increasing soil fertility. Furthermore, the dozens of oxide layers on the surface of graphene oxide can form a region approximately 1 nm thick, increasing its specific surface area and further facilitating adsorption on soil particle surfaces, thus retaining moisture. The polyhydroxy alcohol ester contains polar ends of polyhydroxyl groups, which... Containing nonpolar saturated hydrocarbon chains with 16 or 18 carbon atoms, polyhydroxy alcohol esters, when mixed with soil, can form hydrogen bonds with inorganic minerals in the soil to adhere soil particles, further forming larger aggregates with greater porosity. This increases soil oxygen content, permeability, and aeration. Zeolite powder has a rich porous structure that can adsorb large amounts of water molecules, while diatomaceous earth has certain dispersibility and adhesiveness, increasing the number of aggregates in the soil and thus increasing porosity. Bacillus subtilis and Bacillus licheniformis can improve soil fertility, enhance soil biological activity, improve soil aeration, and promote crop root growth. Applying the soil water-retaining agent of this application can effectively reduce soil moisture loss, significantly improve soil water and fertilizer retention capacity, improve the porosity and permeability of compacted soil, and increase soil oxygen content, thereby effectively alleviating soil compaction.

[0051] As one possible implementation of this application, the preparation steps of the porous chitosan gel include:

[0052] γ-polyglutamic acid and Tween-20 were mixed at a ratio of 1g:10mL at room temperature and a porogen K2CO3 was added to obtain a mixture with a mass fraction of 6% K2CO3 in the mixture.

[0053] Acetic acid was added to the chitosan solution, and then added dropwise to the mixture. After the reaction, the mixture was centrifuged and hydrochloric acid solution was added to allow the gas to escape. Then, concentrated ammonia was added and the pH was adjusted to 7. After washing with deionized water and ethanol in sequence, porous chitosan was obtained.

[0054] Acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and vinylpyrrolidone monomers were dissolved in water, and the pH was adjusted to 7-8. The mixture was stirred at a stirring rate of 80-120 rpm, and then the porous chitosan was added. After mixing, the mixture was heated to 55-65°C, and an inert gas was introduced to achieve an anaerobic environment. A phenolic crosslinking agent was then added, and the mixture was reacted for 2-3 hours. After cooling to room temperature and drying, a porous chitosan gel was obtained.

[0055] This application employs a gas-generating porogen method, adding a gas-generating porogen to the reaction system. Upon contact with acid in the reaction system, the porogen produces CO2 gas, leading to the formation of a porous channel structure on the surface of chitosan. This significantly increases the specific surface area and porosity of the porous chitosan. Further reaction with acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, and vinylpyrrolidone yields a porous chitosan gel with a porous surface, giving it superior water absorption capacity. This further enhances the water storage and swelling properties of the porous chitosan gel, allowing it to fully absorb water upon contact with irrigation water, thus keeping the soil moist for extended periods without easily compacting.

[0056] Specifically, the phenolic crosslinking agent is at least one of catechol, hydroquinone, p-phenylenediamine, and o-phenylenediamine.

[0057] As one possible implementation method of this application, the steps of spraying a soil water-retaining agent on the surface of the soil to be improved, and performing ridge tillage and mixing include:

[0058] Mix the soil water-retaining agent with water at a mass ratio of 1:(100-115) and spray the mixture onto the surface of the soil to be improved. The spraying rate is 0.3-0.5 kg / m². 2 After standing for 2-5 hours, perform ridge cultivation, mix and ridge, and control the cultivation depth to 20-30cm.

[0059] Specifically, applying a soil water-retaining agent to the soil followed by mulching can break up compacted soil, improve soil pore structure, promote the full absorption of the soil water-retaining agent by the soil, further effectively improve soil moisture and oxygen content, promote soil microbial activity, and improve soil fertility.

[0060] As one possible implementation method of this application, the step of introducing biogas slurry into the ridged soil for irrigation, and obtaining irrigated soil after settling, includes:

[0061] Spread 50-60m into the ridged soil 3 Irrigation is carried out by introducing biogas slurry at a rate of 1 / mu, and after standing for 4-6 hours, irrigated soil is obtained.

[0062] Specifically, biogas slurry contains abundant nutrients such as nitrogen, phosphorus, and potassium, which have a significant promoting effect on crop growth. As a liquid organic fertilizer, biogas slurry can be used to irrigate compacted soil, which can effectively increase the content of soil organic matter and soil microbial flora, thereby improving soil fertility.

[0063] As one possible implementation of this application, the step of digging multiple pre-buried pits in the irrigated soil and burying breathable mesh pipes in the multiple pre-buried pits includes:

[0064] 2-3 per m 3 Multiple pre-buried pits are dug in the irrigated soil at a density of 35-50cm. Multiple breathable mesh pipes are then vertically buried in the walls of the multiple pre-buried pits, with one end of each breathable mesh pipe buried in the pre-buried pit and the other end exposed to the air.

[0065] Specifically, the breathable mesh tube is made of bamboo tubes with irregular small holes in the tube wall.

[0066] This application increases the aeration space in the soil by burying a breathable mesh pipe in the pre-buried pit, which is conducive to the entry of water and air. The breathable mesh pipe also promotes the entry of moss mixture into the soil, thereby effectively improving the problem of deep soil compaction. After the moss is decomposed by soil microorganisms, it can effectively improve soil fertility and provide nutrients for the growth of plant roots.

[0067] As one possible implementation of this application, the step of injecting the moss mixture into the breathable mesh tube includes:

[0068] Inject the moss mixture into the breathable mesh until the breathable mesh is filled; the moss mixture is a mixture of moss, water and humus in a mass ratio of 1:(1.5-2):(1.5-2).

[0069] Because of its loose and porous structure, humus soil undergoes only minor dissolution of organic matter and solids when it comes into full contact with water. It has the characteristics of water retention, moisture retention, and fertilizer retention. The moss mixture of this application is made by mixing moss, water, and humus soil. When injected into the soil, it can effectively improve the soil pore structure and enhance soil fertility.

[0070] As one possible implementation of this application, the step of removing the breathable mesh pipe after watering and maintaining the loose soil to obtain the maintained soil includes:

[0071] Spray the loosened soil with clean water every 2-3 days for maintenance, with a spray volume of 5-8m³. 3 / acre, and after 28-35 days, the breathable mesh pipe is removed to obtain the cultivated soil.

[0072] Specifically, spraying water during soil maintenance can maintain a certain level of soil moisture and promote the growth of moss, thereby restoring soil fertility.

[0073] As one possible implementation method of this application, the preparation steps of the modified biochar fertilizer include:

[0074] Soybean straw biochar was added to a citric acid solution and stirred at 20-25℃ for 1-3 hours. The temperature was then raised to 55-65℃ and kept at that temperature for 22-24 hours. The temperature was then raised to 115-125℃ and kept at that temperature for 80-100 minutes. After cooling to room temperature, the biochar was washed and dried at 55-65℃ to obtain modified biochar.

[0075] Animal manure and crushed corn cobs are mixed at a mass ratio of 1:(1.5-2), and the moisture content is controlled at 50-60% to obtain compost raw materials;

[0076] The modified biochar and calcium-based bentonite are added to the composting raw materials, and aerobic composting is carried out. During the process, the temperature is controlled at 55-65℃, and the compost pile is turned over every 3-7 days. After 50-60 days, the modified biochar fertilizer is obtained.

[0077] The modified biochar is added at 5-8% of the mass of the composting raw material, and the calcium-based bentonite is added at 2-5% of the mass of the composting raw material.

[0078] This application describes the application of modified biochar fertilizer to the soil before planting crops to improve soil fertility. The modified biochar fertilizer is made by aerobic composting animal manure and crushed corn cobs with acid-treated soybean straw biochar, while adding calcium-based bentonite to promote composting. The organic colloids formed after the decomposition of animal manure and crushed corn cobs can form organic-inorganic composite colloids and various microbial aggregates with soil mineral colloids. This allows the obtained modified biochar fertilizer to provide a large amount of organic matter and various microorganisms, thereby improving the physical and chemical properties of the soil, such as water, fertilizer, air, and heat. It has a good soil fertilization effect and is beneficial to crop growth.

[0079] As one possible implementation of this application, in the step of planting leguminous crops and rotary tilling them into the soil after harvesting, the leguminous crops include one or more of mung beans, soybeans, alfalfa, and acacia, and the rotary tillage depth is 10-20cm.

[0080] Because legumes contain rhizobia in their roots, which can fix nitrogen and improve soil fertility, planting legumes on improved compacted soil and then rotary tilling them into the soil after harvesting can effectively improve the soil's water and fertilizer retention capacity and nutrient supply. In addition, mung beans, soybeans, alfalfa, and acacia, as perennial low-growing plants, can also effectively change the soil bulk density and slow down water evaporation, which is beneficial for the subsequent planting of other crops.

[0081] The technical solutions described above in this application will be explained in detail below with reference to specific embodiments.

[0082] Example 1

[0083] A soil improvement method includes the following steps;

[0084] The soil water-retaining agent was mixed with water at a mass ratio of 1:108 and then sprayed onto the surface of the soil to be improved at a rate of 0.4 kg / m². 2 After standing for 3 hours, the soil is tilled by mixing and ridging, and the tillage depth is controlled at 25cm. The soil water retention agent consists of: 400g of porous chitosan gel, 320g of graphene oxide, 190g of polyhydroxy alcohol ester, 320g of zeolite powder, 150g of diatomaceous earth, 45g of Bacillus subtilis and 45g of Bacillus licheniformis.

[0085] Then press 55m into the ridged soil. 3 A biogas slurry was introduced for irrigation at a rate of / mu (unit of land area), and after standing for 5 hours, irrigated soil was obtained.

[0086] 2 per m 3 Multiple pre-buried pits were dug in the irrigated soil at a density of 42cm. Multiple breathable mesh pipes were vertically buried in the walls of the multiple pre-buried pits, with one end of the breathable mesh pipes protruding from the ground and in contact with the air.

[0087] A moss mixture is injected into the breathable mesh pipe until it is full. The moss mixture is a mixture of moss, water and humus in a mass ratio of 1:1.75:1.75. Then, the soil is backfilled into the multiple pre-buried pits to obtain loose soil.

[0088] Spray the loosened soil with clean water every two days for maintenance, with a spray volume of 6.5m. 3 / acre, and after 31 days, the breathable mesh pipe is removed to obtain the curing soil;

[0089] Soybean straw biochar was added to a citric acid solution and stirred at 22°C for 2 hours. The temperature was then raised to 60°C and held for 23 hours. The temperature was then raised to 120°C and held for 90 minutes. After cooling to room temperature, the biochar was washed and dried at 60°C to obtain modified biochar.

[0090] Animal manure and crushed corn cobs were mixed at a mass ratio of 1:1.75, and the moisture content was controlled at 55% to obtain compost raw materials.

[0091] The modified biochar and calcium-based bentonite were added to the composting raw materials, and aerobic composting was carried out. During the process, the temperature was controlled at 60°C, and the compost pile was turned over every 5 days. After 55 days, the modified biochar fertilizer was obtained.

[0092] The modified biochar is added at 6.5% of the mass of the composting raw material, and the calcium-based bentonite is added at 3% of the mass of the composting raw material.

[0093] Modified biochar fertilizer is applied to the surface of the soil for maintenance. After tilling and mixing, mung beans, soybeans, alfalfa and acacia are planted. After harvesting, the crops are rotary tilled into the soil to a depth of 15cm. Then, different crops are rotated for planting to complete the soil improvement.

[0094] Example 2

[0095] A soil improvement method includes the following steps;

[0096] Mix the soil water-retaining agent with water at a mass ratio of 1:100 and spray it onto the surface of the soil to be improved. The spraying rate is 0.3 kg / m². 2 After standing for 2 hours, the soil is tilled by mixing and ridging, and the tillage depth is controlled at 20cm. The soil water retention agent consists of: 300g porous chitosan gel, 250g graphene oxide, 120g polyhydroxy alcohol ester, 250g zeolite powder, 100g diatomaceous earth, 30g Bacillus subtilis and 30g Bacillus licheniformis.

[0097] Then press 50m into the ridged soil. 3 A biogas slurry was introduced for irrigation at a rate of / mu (unit of land area), and after standing for 4 hours, irrigated soil was obtained.

[0098] 2 per m 3 The density is such that multiple pre-buried pits are dug in the irrigated soil, the depth of the pre-buried pits is 35cm, and multiple breathable mesh pipes are vertically buried in the walls of the multiple pre-buried pits, with one end of the breathable mesh pipes exposed above the ground and in contact with the air.

[0099] A moss mixture is injected into the breathable mesh pipe until it is full. The moss mixture is a mixture of moss, water and humus in a mass ratio of 1:1.5:1.5. The soil is then backfilled into the multiple pre-buried pits to obtain loose soil.

[0100] Spray the loosened soil with clean water every two days for maintenance, with a spray volume of 5m³. 3 / acre, and after 28 days, the breathable mesh pipe is removed to obtain the curing soil;

[0101] Soybean straw biochar was added to a citric acid solution and stirred at 20°C for 1 hour. The temperature was then raised to 55°C and kept at that temperature for 24 hours. The temperature was then raised to 115°C and kept at that temperature for 100 minutes. After cooling to room temperature, the biochar was washed and dried at 55°C to obtain modified biochar.

[0102] Animal manure and crushed corn cobs are mixed at a mass ratio of 1:1.5, and the moisture content is controlled at 50% to obtain compost raw materials;

[0103] The modified biochar and calcium-based bentonite were added to the composting raw materials, and aerobic composting was carried out. During the process, the temperature was controlled at 55°C, and the compost pile was turned over every 3 days. After 50 days, the modified biochar fertilizer was obtained.

[0104] The modified biochar is added at 5% of the mass of the composting raw material, and the calcium-based bentonite is added at 2% of the mass of the composting raw material.

[0105] Modified biochar fertilizer is applied to the surface of the soil for maintenance. After tilling and mixing, mung beans, soybeans, alfalfa and acacia are planted. After harvesting, the crops are rotary tilled into the soil to a depth of 10cm. Then, different crops are rotated for planting to complete the soil improvement.

[0106] Example 3

[0107] A soil improvement method includes the following steps;

[0108] Mix the soil water-retaining agent with water at a mass ratio of 1:115 and spray the mixture onto the surface of the soil to be improved at a rate of 0.5 kg / m². 2 After standing for 5 hours, the soil is tilled by mixing and ridging, and the tillage depth is controlled at 30cm. The soil water retention agent consists of: 500g porous chitosan gel, 400g graphene oxide, 250g polyhydroxy alcohol ester, 400g zeolite powder, 200g diatomaceous earth, 60g Bacillus subtilis and 60g Bacillus licheniformis.

[0109] Then press 60m into the ridged soil. 3 A biogas slurry was introduced for irrigation at a rate of / mu (unit of land area), and after standing for 6 hours, irrigated soil was obtained.

[0110] 3 per m 3 Multiple pre-buried pits were dug in the irrigated soil at a density of 50cm. Multiple breathable mesh pipes were vertically buried in the walls of the multiple pre-buried pits, with one end of the breathable mesh pipe protruding from the ground and in contact with the air.

[0111] A moss mixture is injected into the breathable mesh pipe until the breathable mesh pipe is filled. The moss mixture is a mixture of moss, water and humus in a mass ratio of 1:2:2. Then, the soil is backfilled into the multiple pre-buried pits to obtain loose soil.

[0112] Spray the loosened soil with clean water every 3 days for maintenance, with a spray volume of 8m³. 3 / acre, and after 35 days, the breathable mesh pipe is removed to obtain the curing soil;

[0113] Soybean straw biochar was added to a citric acid solution and stirred at 25°C for 1 hour. The temperature was then raised to 65°C and held for 22 hours. The temperature was then raised to 125°C and held for 80 minutes. After cooling to room temperature, the biochar was washed and dried at 65°C to obtain modified biochar.

[0114] Animal manure and crushed corn cobs are mixed at a mass ratio of 1:2, and the moisture content is controlled at 60% to obtain compost raw materials;

[0115] The modified biochar and calcium-based bentonite are added to the composting raw materials, and aerobic composting is carried out. During the process, the temperature is controlled at 65°C, and the compost pile is turned over every 7 days. After 60 days, the modified biochar fertilizer is obtained.

[0116] The modified biochar is added at 8% of the mass of the composting raw material, and the calcium-based bentonite is added at 5% of the mass of the composting raw material.

[0117] Modified biochar fertilizer is applied to the surface of the soil for maintenance. After tilling and mixing, mung beans, soybeans, alfalfa and acacia are planted. After harvesting, the crops are rotary tilled into the soil to a depth of 20cm. Then, different crops are rotated for planting to complete the soil improvement.

[0118] Comparative Example 1

[0119] Compared with Example 1, the soil water-retaining agent of this application is replaced with polyacrylamide, and the remaining steps are the same.

[0120] Comparative Example 2

[0121] Compared to Example 2, no moss mixture was injected into the breathable mesh tube, but all other steps were the same.

[0122] Comparative Example 3

[0123] Compared with Example 3, in the preparation of modified biochar fertilizer, the modified biochar was replaced with soybean straw biochar, and the remaining steps were the same.

[0124] Test case

[0125] Compacted soil was selected for the test, and a plot-based comparative experiment was conducted with a plot area of ​​24m². 2 The experimental design used a randomized block design (6m × 4m) with six treatments. The soil for each treatment was improved using the methods described in the examples and comparative examples. After improvement, the same variety of strawberry was planted in each plot. Three complete harvests were conducted randomly in each plot at the early, middle, and late stages of the strawberry harvest. The total yield of each plot was calculated based on the three harvests. Five strawberry plants were randomly selected each time to measure the weight of a single fruit, and the average weight of each fruit was calculated. The results are shown in Table 1 below.

[0126] Table 1

[0127]

[0128]

[0129] As shown in Table 1, after the improvement method of this application was used to improve compacted soil, the total strawberry yield can reach 3890.67 kg·hm². -2 The average single fruit weight reached over 27g. In Comparative Example 1, the soil water-retaining agent was replaced with conventional polyacrylamide, which had a certain impact on the yield and fruit weight of strawberries. This indicates that the soil water-retaining agent of this application is more beneficial to improving the soil's water and fertilizer retention capacity than conventional polyacrylamide, thus benefiting crop growth. In Comparative Example 2, no moss mixture was injected into the soil. Moss can effectively alleviate soil compaction and provide soil fertility, so Comparative Example 2 had a certain impact on the growth of strawberries. In Comparative Example 3, the soybean straw biochar was not modified. However, this application acid-treats the soybean straw biochar, which can increase the proportion of water-soluble organic matter in the soybean straw biochar, promote the supply of nutrients during composting, and enable the modified biochar fertilizer to provide a large amount of organic matter and various microorganisms to achieve the effect of soil enrichment. Therefore, the yield and fruit weight of strawberries in Comparative Example 3 decreased.

[0130] The above description is merely an optional embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A soil improvement method, characterized in that, Includes the following steps: Spray a soil water-retaining agent on the surface of the soil to be improved, and then perform mulching and ridging. Then, biogas slurry is introduced into the ridged soil for irrigation. After standing, irrigated soil is obtained. 2-3 per m 3 Multiple pre-buried pits are dug in the irrigated soil at a density of 35-50cm. Multiple breathable mesh pipes are then vertically buried in the walls of the multiple pre-buried pits, with one end of each breathable mesh pipe buried in the pre-buried pit and the other end exposed to the air. Inject the moss mixture into the breathable mesh until the breathable mesh is full; The moss mixture is a mixture of moss, water and humus in a mass ratio of 1:(1.5-2):(1.5-2); the soil is then backfilled into the multiple pre-buried pits to obtain loose soil. After watering and maintaining the loose soil, the breathable mesh pipe is removed to obtain the maintained soil. Modified biochar fertilizer is applied to the surface of the soil to be maintained. After tilling and mixing, legumes are planted and then rotary tilled into the soil after harvesting. The soil is then improved by rotating different crops.

2. The soil improvement method according to claim 1, characterized in that, The soil water-retaining agent comprises, by weight, 30-50 parts porous chitosan gel, 25-40 parts graphene oxide, 12-25 parts polyhydroxy alcohol ester, 25-40 parts zeolite powder, 10-20 parts diatomaceous earth, 3-6 parts Bacillus subtilis and 3-6 parts Bacillus licheniformis.

3. The soil improvement method according to claim 2, characterized in that, The preparation steps of the porous chitosan gel include: A γ-polyglutamic acid solution was mixed with Tween-20 at room temperature and a porogen was added to obtain a mixture. Acetic acid was added to the chitosan solution, and then added dropwise to the mixture. After the reaction, the mixture was centrifuged and hydrochloric acid solution was added to allow the gas to escape. Then, concentrated ammonia was added and the pH was adjusted to 7. After washing with deionized water and ethanol in sequence, porous chitosan was obtained. Acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, and vinylpyrrolidone monomers were dissolved in water, and the pH was adjusted to 7-8. The mixture was stirred at a stirring rate of 80-120 rpm, and then the porous chitosan was added. After mixing, the mixture was heated to 55-65°C, and an inert gas was introduced to achieve an anaerobic environment. A phenolic crosslinking agent was then added, and the mixture was reacted for 2-3 hours. After cooling to room temperature and drying, a porous chitosan gel was obtained.

4. The soil improvement method according to claim 3, characterized in that, The steps of spraying a soil water-retaining agent onto the surface of the soil to be improved, and then performing ridge tillage and mixing include: Mix the soil water-retaining agent with water at a mass ratio of 1:(100-115) and spray the mixture onto the surface of the soil to be improved. The spraying rate is 0.3-0.5 kg / m². 2 After standing for 2-5 hours, perform ridge cultivation, mix and ridge, and control the cultivation depth to 20-30cm.

5. The soil improvement method according to claim 1, characterized in that, The step of introducing biogas slurry into the ridged soil for irrigation, and then allowing it to stand to obtain irrigated soil, includes: Spread 50-60m into the ridged soil 3 Irrigation is carried out by introducing biogas slurry at a rate of 1 / mu, and after standing for 4-6 hours, irrigated soil is obtained.

6. The soil improvement method according to claim 1, characterized in that, The step of removing the breathable mesh pipe after watering and maintaining the loose soil to obtain the maintained soil includes: Spray the loosened soil with clean water every 2-3 days for maintenance, with a spray volume of 5-8m³. 3 / acre, and after 28-35 days, the breathable mesh pipe is removed to obtain the cultivated soil.

7. The soil improvement method according to claim 1, characterized in that, The preparation steps of the modified biochar fertilizer include: Soybean straw biochar was added to a citric acid solution and stirred at 20-25℃ for 1-3 hours. The temperature was then raised to 55-65℃ and kept at that temperature for 22-24 hours. The temperature was then raised to 115-125℃ and kept at that temperature for 80-100 minutes. After cooling to room temperature, the biochar was washed and dried at 55-65℃ to obtain modified biochar. Animal manure and crushed corn cobs are mixed at a mass ratio of 1:(1.5-2), and the moisture content is controlled at 50-60% to obtain compost raw materials; The modified biochar and calcium-based bentonite are added to the composting raw materials, and aerobic composting is carried out. During the process, the temperature is controlled at 55-65℃, and the compost pile is turned over every 3-7 days. After 50-60 days, the modified biochar fertilizer is obtained. The modified biochar is added at 5-8% of the mass of the composting raw material, and the calcium-based bentonite is added at 2-5% of the mass of the composting raw material.

8. The soil improvement method according to claim 1, characterized in that, In the step of planting leguminous crops and rotary tilling them into the soil after harvesting, the leguminous crops include one or more of mung beans, soybeans, alfalfa, and acacia, and the rotary tillage depth is 10-20cm.

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