Saline-alkali soil treatment and improvement method

Abstract

The invention relates to the technical field of saline-alkali soil improvement, in particular to a saline-alkali soil treatment and improvement method which comprises the following steps: S1, early-stage investigation and planning; s2, physical improvement; s3, chemical improvement; s4, biological improvement; s5, irrigation improvement; s6, later monitoring and maintenance; according to the saline-alkali soil treatment and improvement method, a traditional single improvement mode is broken through, physical, chemical, biological and engineering technologies are fused, a systematic improvement scheme is formed, and physical improvement effectively improves the soil structure and accelerates salt discharge through land leveling, deep ploughing, upturned soil sunning and concealed pipe laying for drainage; a soil conditioner and an acidic material are precisely applied for chemical improvement, and the soil acidity and alkalinity and ion composition are adjusted; in biological improvement, salt is absorbed by virtue of salt-tolerant plants and microbial agents, and soil microbial communities are improved; a fresh water resource or salt water desalination technology is reasonably utilized for irrigation improvement, and salt leaching and water resource recycling are achieved; through the synergistic effect of multiple means, the salt content of soil can be more efficiently reduced, and the soil structure is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of saline-alkali land improvement, and particularly to a method for treating and improving saline-alkali land. Background Art

[0002] Among the global land resources, saline-alkali land is widely distributed, seriously threatening the ecological environment and the sustainable development of agriculture, and also restricting the growth of agricultural economy and food security.

[0003] For a long time, the treatment of saline-alkali land has mainly adopted traditional methods. For example, in physical improvement, flooding for salt washing can reduce the surface soil salinity in the short term, but it is easy to cause the rise of the groundwater level, leading to soil waterlogging and secondary salinization, and serious waste of water resources; in chemical improvement, by applying a large amount of chemical improvers, the soil pH value can be quickly adjusted, but it will damage the soil structure, cause soil compaction, and at the same time there is a risk of polluting the soil and groundwater; biological improvement relies on planting single salt-tolerant plants or using ordinary microbial agents, and the improvement effect is slow, and it is difficult to fundamentally improve the soil ecological environment. With the continuous improvement of the requirements for ecological protection and the sustainable development of agriculture, the limitations of traditional saline-alkali land treatment methods are becoming increasingly prominent and difficult to meet the needs of modern land improvement.

[0004] Therefore, aiming at the problem that the above traditional saline-alkali land treatment and improvement rely more on single means and have certain limitations in terms of long-term effect, ecological impact and resource utilization, a method for treating and improving saline-alkali land can be designed. Summary of the Invention

[0005] In order to overcome the problem that the traditional saline-alkali land treatment and improvement rely more on single means and have certain limitations in terms of long-term effect, ecological impact and resource utilization.

[0006] The technical solution of the present invention is as follows: A method for treating and improving saline-alkali land, and its steps are as follows:

[0007] S1: Preliminary investigation and planning

[0008] By the grid point method, sampling points are set at intervals of 100-200 meters in the target saline-alkali land for sampling, and laboratory testing equipment is used to measure the soil salt content, pH value, organic matter content, cation exchange capacity, and draw a soil salinization degree distribution map;

[0009] S2: Physical improvement

[0010] Level the land and carry out deep plowing operations with a deep plow. After deep plowing, expose the soil to the sun for 15 - 30 days. Then, lay plastic underground pipes in the plot at intervals of 8 - 15 meters. The diameter of the underground pipes is 8 - 12 cm, and the slope is 0.3% - 0.5%. Cover the upper part of the underground pipes with 30 - 50 cm thick water-permeable materials. One end of the underground pipes is connected to the drainage ditch, and the salt and excess water in the soil are discharged from the plot through gravity.

[0011] S3: Chemical improvement

[0012] S31: According to the soil test results, select a suitable soil conditioner, evenly spread the conditioner on the soil surface, and then turn it into the soil by a rotary tiller to a depth of 20 - 30 cm, so that the conditioner is fully mixed with the soil, reducing the soil pH value and the content of exchangeable sodium.

[0013] S32: For strongly alkaline soil, use acidic substances for neutralization.

[0014] S4: Biological improvement

[0015] S41: Select plant varieties with strong salt tolerance, including Sesbania cannabina, Suaeda salsa, and Elaeagnus angustifolia, and plant them by drilling, hill-drop sowing, or transplanting.

[0016] S42: Inoculate beneficial microbial agents into the soil to decompose organic substances in the soil, release nutrients, improve the soil microbial community structure, and enhance the soil's salt resistance.

[0017] S5: Irrigation improvement

[0018] S51: Use fresh water for irrigation, and through leaching, bring the salt in the soil to the deep layer of the soil or discharge it from the plot.

[0019] S52: In areas with scarce fresh water resources, use membrane separation and electrodialysis technologies to desalinate saline water.

[0020] S6: Post - monitoring and maintenance.

[0021] Preferably, in S1, soil samples are collected from three layers of 0 - 20 cm, 20 - 40 cm, and 40 - 60 cm at each sampling point; and the climate conditions, groundwater level, water source status, and surrounding ecological environment around the saline - alkali land are investigated. Then, according to the test and investigation results, combined with the local actual situation and innovative governance concepts, a personalized saline - alkali land governance and improvement plan is formulated, clarifying the governance objectives, technical routes, and implementation steps.

[0022] Preferably, the detailed steps of land leveling in S2 are to use a bulldozer and a land grader to level the saline-alkali land, so that the flatness error of the plot is controlled within ±5 cm. During the leveling process, a drainage slope of 0.3%-0.5% is maintained to facilitate subsequent drainage and salt washing; the depth of deep plowing operation reaches 30-50 cm to break the plow sole and loosen the soil structure; through exposure to the sun for high-temperature evaporation and freeze-thaw alternation, the soil structure is improved, and the leaching and volatilization of salts are accelerated; the water-permeable material is specifically gravel or straw, which can prevent soil particles from blocking the pipeline.

[0023] Preferably, the soil conditioner in S31 includes gypsum, ferrous sulfate and humic acid; the application rate of gypsum is 1500-3000 kg / ha, the application rate of ferrous sulfate is 300-600 kg / ha, and the application rate of humic acid is 600-1200 kg / ha.

[0024] Preferably, in S32, the acidic substances include sulfuric acid and phosphoric acid. First, the acidic substances are diluted into a solution with a certain concentration, and then evenly applied to the soil through an irrigation system. The soil pH value is monitored while applying. When the pH value reaches the target range, the application stops. For slightly saline-alkali soil, the dilution concentration of sulfuric acid is 0.5%-1%, phosphoric acid 1%-2%, and the target pH value is close to 7; for severely saline-alkali soil, the concentration of sulfuric acid is increased to 1.5%-2%, phosphoric acid 2.5%-3%, and the target pH value is controlled at 6.5-7.

[0025] Preferably, in S41, when Sesbania cannabina is sown in rows, the row spacing is 30-40 cm, and the seeding rate is 3-5 kg / ha; when Suaeda salsa is sown in holes, the hole spacing is 20-30 cm, and 5-10 seeds are sown in each hole; after planting, strengthen field management, water, fertilize and weed in time to promote plant growth, absorb salts in the soil through plant growth, reduce the soil salt content, and improve the soil structure and ecological environment at the same time.

[0026] Preferably, in S42, the beneficial microbial inoculant includes phosphate-solubilizing bacteria, potassium-solubilizing bacteria, nitrogen-fixing bacteria and salt-resistant bacteria, and the beneficial microbial inoculant is mixed with organic fertilizer and then applied to the soil.

[0027] Preferably, in S51, the irrigation water volume is 800-1200 m³ / ha, and irrigation is carried out by flood irrigation, sprinkler irrigation or drip irrigation. When flood irrigating, pay attention to controlling the water level to avoid excessive waterlogging time; for sprinkler irrigation and drip irrigation, ensure the irrigation uniformity. After irrigation, drain in time to prevent the rise of the groundwater level from causing salt return.

[0028] Preferably, in S52, the desalinated water is used for irrigation, which can not only meet the water demand of crops, but also avoid the salinization effect of saline water on the soil; at the same time, the concentrated brine generated during the desalination process is reasonably disposed of for salt drying or other industrial uses to realize the recycling of water resources.

[0029] Preferably, the detailed steps of S6 are as follows:

[0030] S61: Set fixed monitoring points in the improved saline-alkali land, collect soil samples for testing every month to monitor the changes in soil salt content, pH value, and organic matter content; at the same time, use soil sensors to monitor soil moisture, temperature, and conductivity in real-time, upload the data to the monitoring platform, and timely discover the changing trends of soil salt and fertility through data analysis;

[0031] S62: Regularly observe the growth status of the planted crops, record the plant height, leaf color, tiller number, and yield of the crops, and evaluate the impact of the improvement effect on crop growth; according to the growth of the crops, adjust the management measures, and the management measures include fertilization and irrigation to ensure the normal growth of the crops;

[0032] S63: According to the soil monitoring and crop growth monitoring results, timely adjust and optimize the improvement measures. If it is found that the soil salt content rebounds, fresh water flushing or soil conditioner application is carried out again; if the soil fertility is insufficient, organic fertilizers and chemical fertilizers are increased; at the same time, strengthen the maintenance of the irrigation system, drainage system, and monitoring equipment to ensure their normal operation and guarantee the long-term stability of the saline-alkali land improvement effect.

[0033] Advantages of the present invention:

[0034] The saline-alkali land treatment and improvement method of the present invention breaks through the traditional single improvement mode, integrates physical, chemical, biological, and engineering technologies to form a systematic improvement plan. Physical improvement effectively improves the soil structure and accelerates salt discharge through land leveling, deep plowing and sunning, and laying buried pipes for drainage; chemical improvement accurately applies soil conditioners and acidic substances to adjust the soil pH value and ion composition; biological improvement uses salt-tolerant plants and microbial agents to absorb salts and improve the soil microbial community; irrigation improvement rationally utilizes fresh water resources or desalination technologies to achieve salt flushing and water resource recycling; the synergistic effect of multiple means can more efficiently reduce the soil salt content, improve the soil structure, and enhance the saline-alkali land improvement effect. Compared with the traditional single method, it greatly shortens the improvement cycle and improves the improvement quality;

[0035] The introduction of Internet of Things, big data, and remote sensing technologies realizes the real-time dynamic monitoring of parameters such as soil salt content, moisture, and pH value. Through data platform analysis, the changing trends of the soil can be timely grasped, and the improvement measures can be accurately adjusted. For example, according to the changes in soil salt content and pH value, the application amount of chemical modifiers can be precisely controlled; according to the soil moisture and fertility conditions, the irrigation and fertilization plans can be optimized. This precise monitoring and control avoid the blindness and empiricism of traditional methods, improve the pertinence and effectiveness of improvement measures, and ensure the stability and sustainability of the improvement effect;

[0036] Adopt eco-friendly materials such as degradable polymer water retainers, microbial inoculants, and plant-derived modifiers to reduce the use of chemical agents and lower the pollution to soil, groundwater, and the surrounding ecological environment. Planting salt-tolerant plants and inoculating microbial inoculants helps to restore and improve the soil ecosystem, increase biodiversity, and form a benign ecological cycle. At the same time, the reasonable disposal of the concentrated brine produced by desalination realizes the recycling of water resources, reduces waste emissions, meets the requirements of ecological protection and sustainable development, and greatly reduces the ecological risk compared with traditional methods; in irrigation improvement, the utilization of saline water resources is realized, the water resource utilization efficiency is improved, and the water use pressure in areas with water shortage of fresh water is alleviated. This recycling concept runs through the whole process of improvement, which not only improves the resource utilization efficiency but also reduces the overall improvement cost, making the improvement of saline-alkali land more economically feasible and popularizable.

[0037] A perfect post-monitoring and maintenance system, through regular soil testing and crop growth monitoring, timely discovers problems such as soil salt rebound and insufficient fertility, and adjusts improvement measures accordingly to continuously optimize the improvement effect; the maintenance of irrigation systems, drainage systems, and monitoring equipment ensures the normal operation of each improvement link, makes the improvement effect of saline-alkali land stable in the long term, avoids the problem of degradation of improvement effect caused by the lack of long-term monitoring and maintenance in traditional methods, ensures that the saline-alkali land continuously maintains a good state, and realizes sustainable utilization. Specific implementation manners

[0038] The present invention will be further described below in conjunction with embodiments.

[0039] When using the process of the present technical solution, the steps are as follows:

[0040] S1: Preliminary investigation and planning

[0041] By the grid point method, sampling points are set at intervals of 100 - 200 meters in the target saline-alkali land for sampling. Soil samples of three layers, namely 0 - 20 cm, 20 - 40 cm, and 40 - 60 cm, are collected at each sampling point, and laboratory testing equipment is used to measure the soil salt content, pH value, organic matter content, and cation exchange capacity, and a soil salinization degree distribution map is drawn. At the same time, the climate conditions, groundwater level, water source conditions, and the surrounding ecological environment around the saline-alkali land are investigated. Then, according to the test and investigation results, combined with the local actual situation and innovative treatment concepts, a personalized saline-alkali land treatment and improvement plan is formulated, clarifying the treatment objectives, technical routes, and implementation steps;

[0042] S2: Physical improvement

[0043] Level the land. Use bulldozers and graders to level the saline-alkali land, keeping the flatness error of the plot within ±5 cm. During the leveling process, maintain a drainage slope of 0.3%-0.5% for subsequent drainage and salt washing. Conduct deep plowing operations with a deep plow to a depth of 30-50 cm to break the plow sole and loosen the soil structure. After deep plowing, expose the soil to sunlight for 15-30 days. Then, lay plastic sub-surface drainage pipes in the plot at intervals of 8-15 m. The diameter of the sub-surface drainage pipes is 8-12 cm, and the slope is 0.3%-0.5%. Cover the upper part of the sub-surface drainage pipes with 30-50 cm thick pervious materials. One end of the sub-surface drainage pipes is connected to the drainage ditch, and through the action of gravity, the salts and excess water in the soil are drained out of the plot. Through exposure to sunlight for high-temperature evaporation and freeze-thaw alternation, it promotes the improvement of the soil structure and accelerates the leaching and volatilization of salts. The pervious materials specifically use gravel or straw, which can prevent soil particles from blocking the pipes.

[0044] S3: Chemical improvement

[0045] S31: According to the soil test results, select a suitable soil conditioner, evenly spread the conditioner on the soil surface, and then plow it into the soil by a rotary tiller to a depth of 20-30 cm to fully mix the conditioner with the soil, reducing the soil pH value and exchangeable sodium content. The soil conditioner includes gypsum, ferrous sulfate, and humic acid. The application rate of gypsum is 1500-3000 kg / ha, the application rate of ferrous sulfate is 300-600 kg / ha, and the application rate of humic acid is 600-1200 kg / ha.

[0046] S32: For strongly alkaline soil, use acidic substances for neutralization. The acidic substances include sulfuric acid and phosphoric acid. First, dilute the acidic substances into solutions of a certain concentration, and then evenly apply them to the soil through the irrigation system while monitoring the soil pH value during application. Stop applying when the pH value reaches the target range. For slightly saline-alkali soil, the dilution concentration of sulfuric acid is 0.5%-1%, and that of phosphoric acid is 1%-2%, with the target pH value close to 7. For severely saline-alkali soil, the concentration of sulfuric acid is increased to 1.5%-2%, and that of phosphoric acid is 2.5%-3%, with the target pH value controlled at 6.5-7.

[0047] S4: Biological improvement

[0048] S41: Select plant varieties with strong salt tolerance, including Sesbania cannabina, Suaeda salsa, and Elaeagnus angustifolia, and plant them by drilling, hill-drop sowing, or transplanting. When drilling Sesbania cannabina, the row spacing is 30-40 cm, and the seeding rate is 3-5 kg / ha. When hill-drop sowing Suaeda salsa, the hill spacing is 20-30 cm, and 5-10 seeds are sown in each hill. After planting, strengthen field management, water, fertilize, and weed in a timely manner to promote plant growth. Through the growth of plants, absorb the salts in the soil, reduce the soil salt content, and at the same time improve the soil structure and ecological environment.

[0049] S42: Inoculate the soil with beneficial microbial agents to decompose the organic matter in the soil, release nutrients, improve the soil microbial community structure, and enhance the soil's salt resistance. The beneficial microbial agents include phosphate-solubilizing bacteria, potassium-solubilizing bacteria, nitrogen-fixing bacteria, and salt-resistant bacteria. Mix the beneficial microbial agents with organic fertilizers and then apply them to the soil;

[0050] S5: Irrigation improvement

[0051] S51: Use fresh water for irrigation. Through leaching, bring the salt in the soil to the deep layer of the soil or drain it out of the plot. The irrigation water volume is 800 - 1200 cubic meters per hectare. Use flood irrigation, sprinkler irrigation, or drip irrigation for irrigation. When using flood irrigation, pay attention to controlling the water level to avoid excessive waterlogging time; for sprinkler irrigation and drip irrigation, ensure the irrigation uniformity. After irrigation, drain the water in time to prevent the salt from returning due to the rise of the groundwater level;

[0052] S52: In areas with scarce fresh water resources, use membrane separation and electrodialysis technologies to desalinate saline water and use the desalinated water for irrigation, which can not only meet the water requirements of crops but also avoid the salinization effect of saline water on the soil; at the same time, reasonably dispose of the concentrated brine generated during the desalination process for salt drying or other industrial uses to achieve the recycling of water resources;

[0053] S6: Post - improvement monitoring and maintenance

[0054] S61: Set up fixed monitoring points in the improved saline - alkali land, collect soil samples for testing every month to monitor the changes in soil salt content, pH value, and organic matter content indicators; at the same time, use soil sensors to real - time monitor soil moisture, temperature, and conductivity, and upload the data to the monitoring platform. Through data analysis, timely discover the changing trends of soil salt and fertility;

[0055] S62: Regularly observe the growth status of the planted crops, record the plant height, leaf color, tiller number, and yield of the crops, and evaluate the impact of the improvement effect on crop growth; according to the growth of the crops, adjust management measures, and the management measures include fertilization and irrigation to ensure the normal growth of the crops;

[0056] S63: According to the results of soil monitoring and crop growth monitoring, timely adjust and optimize the improvement measures. If it is found that the soil salt rebounds, conduct fresh water flushing or apply soil conditioners again; if the soil fertility is insufficient, increase the application of organic fertilizers and chemical fertilizers; at the same time, strengthen the maintenance of the irrigation system, drainage system, and monitoring equipment to ensure their normal operation and guarantee the long - term stability of the saline - alkali land improvement effect.

[0057] Experimental example

[0058] Take the saline-alkali land treatment and improvement method in the embodiment as Experimental Example 1, and take the traditional saline-alkali land treatment and improvement method, that is, using a single improvement method, such as the traditional flooding method for salt washing, as Experimental Example 2;

[0059] Experimental plots: Select two adjacent plots with similar degrees of soil salinization, with a salt content of 6 - 8‰, a pH of 8.5 - 9.0, and an area of 1 hectare each. The average annual precipitation in the experimental area is 300 mm, the evaporation is 2000 mm, and the groundwater level is 1.2 - 1.5 m. It belongs to a typical arid and semi-arid saline-alkali area;

[0060] Experimental period: The treatment period is 3 years, including preliminary investigation, improvement implementation, and crop planting; continuous monitoring for 2 years after treatment to evaluate the long-term effects;

[0061] Monitoring indicators:

[0062] Soil indicators: Salt content (‰), pH value, organic matter content (g / kg), cation exchange capacity (cmol / kg);

[0063] Crop indicators: Crop survival rate (%), yield (kg / ha), coverage of salt-tolerant plants (%);

[0064] Resource input: Freshwater consumption (m 3 / ha), cost of amendment (yuan / ha), labor cost (man-days / ha);

[0065] Sort out and statistically analyze the above collected data, calculate statistical quantities such as the average value and standard deviation of each index of Experimental Example 1 and Experimental Example 2. Through comparative analysis, the comparative data during the experiment are as follows:

[0066]

[0067]

[0068]

Claims

1. A method for treating and improving saline-alkali land, characterized in that, The steps are as follows: S1: Preliminary investigation and planning By using the grid point method, sampling points are set at intervals of 100 - 200 meters in the target saline-alkali land for sampling. Laboratory testing equipment is used to measure the soil salt content, pH value, organic matter content, and cation exchange capacity, and a soil salinization degree distribution map is drawn; S2: Physical improvement Level the land and carry out deep plowing operations with a deep plow. After deep plowing, let the soil be exposed to the sun for 15 - 30 days. Then, plastic buried pipes are laid in the plot at intervals of 8 - 15 meters. The diameter of the buried pipes is 8 - 12 cm, and the slope is 0.3% - 0.5%. A 30 - 50 cm thick water-permeable material is covered above the buried pipes. One end of the buried pipe is connected to the drainage ditch, and the salt and excess water in the soil are discharged from the plot through gravity; S3: Chemical improvement S31: According to the soil test results, select a suitable soil conditioner, evenly spread the conditioner on the soil surface, and then turn it into the soil by a rotary tiller to a depth of 20 - 30 cm, so that the conditioner is fully mixed with the soil, reducing the soil pH value and exchangeable sodium content; S32: For strongly alkaline soil, use acidic substances for neutralization; S4: Biological improvement S41: Select plant varieties with strong salt tolerance, including Sesbania cannabina, Suaeda salsa, and Elaeagnus angustifolia, and plant them by drilling, hill-drop sowing, or transplanting; S42: Inoculate beneficial microbial inoculants into the soil to decompose organic substances in the soil, release nutrients, improve the soil microbial community structure, and enhance the soil's salt resistance ability; S5: Irrigation improvement S51: Use fresh water for irrigation, and through leaching, bring the salt in the soil to the deep layer of the soil or discharge it from the plot; S52: In areas with scarce fresh water resources, use membrane separation and electrodialysis technologies to desalinate brackish water; S6: Post - monitoring and maintenance.

2. The method for treating and improving saline-alkali land according to claim 1, wherein: In S1, soil samples are collected from three layers of 0 - 20 cm, 20 - 40 cm, and 40 - 60 cm at each sampling point; and the climate conditions, groundwater level, water source status, and surrounding ecological environment around the saline-alkali land are investigated. Then, according to the test and investigation results, combined with the local actual situation and innovative governance concepts, a personalized saline-alkali land treatment and improvement plan is formulated, clarifying the governance objectives, technical routes, and implementation steps.

3. The method for treating and improving saline-alkali land according to claim 1, wherein: The detailed steps of land leveling in S2 are to level the saline-alkali land with a bulldozer and a land grader, controlling the flatness error of the plot within ±5 cm. During the leveling process, maintain a drainage slope of 0.3% - 0.5% for subsequent drainage and salt washing; the depth of the deep plowing operation reaches 30 - 50 cm to break the plow sole and loosen the soil structure; through exposure to the sun for high-temperature evaporation and freeze-thaw alternation, promote the improvement of the soil structure and accelerate the leaching and volatilization of salts; the water-permeable material specifically uses gravel or straw, which can prevent soil particles from blocking the pipes.

4. A method for treating and improving saline-alkali land according to claim 1, characterized in that: The soil conditioners in S31 include gypsum, ferrous sulfate, and humic acid; the application rate of gypsum is 1500 - 3000 kg / ha, the application rate of ferrous sulfate is 300 - 600 kg / ha, and the application rate of humic acid is 600 - 1200 kg / ha.

5. A method for treating and improving saline-alkali land according to claim 1, characterized in that: In S32, the acidic substances include sulfuric acid and phosphoric acid. First, dilute the acidic substances into solutions with a certain concentration, and then uniformly apply them to the soil through an irrigation system while monitoring the soil pH value during the application. Stop the application when the pH value reaches the target range. For slightly saline-alkali soil, the dilution concentration of sulfuric acid is 0.5%-1%, and that of phosphoric acid is 1%-2%, with the target pH value close to 7. For severely saline-alkali soil, the concentration of sulfuric acid is increased to 1.5%-2%, and that of phosphoric acid is 2.5%-3%, with the target pH value controlled within 6.5-7.

6. The improvement method for saline-alkali land treatment according to claim 1, characterized in that: In S41, when sowing Sesbania cannabina in rows, the row spacing is 30-40 cm, and the seeding rate is 3-5 kg / ha; when sowing Suaeda salsa in holes, the hole spacing is 20-30 cm, and 5-10 seeds are sown in each hole. After planting, strengthen field management, water, fertilize, and weed in a timely manner to promote plant growth, absorb the salt in the soil through the growth of plants, reduce the soil salt content, and improve the soil structure and ecological environment at the same time.

7. A method for treating and improving saline-alkali land according to claim 1, characterized in that: In S42, the beneficial microbial inoculants include phosphate-solubilizing bacteria, potassium-solubilizing bacteria, nitrogen-fixing bacteria, and salt-tolerant bacteria, and the beneficial microbial inoculants are mixed with organic fertilizers and then applied to the soil.

8. A method for treating and improving saline-alkali land according to claim 1, characterized in that: In S51, the irrigation water volume is 800-1200 m³ / ha, and irrigation is carried out by means of flood irrigation, sprinkler irrigation, or drip irrigation. When carrying out flood irrigation, pay attention to controlling the water level to avoid excessive waterlogging time; for sprinkler irrigation and drip irrigation, ensure the irrigation uniformity. After irrigation, drain the water in a timely manner to prevent the salt from returning due to the rise of the groundwater level.

9. A method for treating and improving saline-alkali land according to claim 1, characterized in that: In S52, using the desalinated water for irrigation can not only meet the water demand of crops but also avoid the salinization effect of saline water on the soil; at the same time, reasonably dispose of the concentrated brine generated during the desalination process for salt drying or other industrial uses to realize the recycling of water resources.

10. A method for treating and improving saline-alkali land according to claim 1, characterized in that: The detailed steps of S6 are as follows: S61: Set fixed monitoring points in the improved saline-alkali land, collect soil samples for testing every month, and monitor the changes in soil salt content, pH value, and organic matter content indicators; at the same time, use soil sensors to monitor soil moisture, temperature, and conductivity in real time, upload the data to the monitoring platform, and timely discover the change trends of soil salt and fertility through data analysis; S62: Regularly observe the growth status of the planted crops, record the plant height, leaf color, tiller number, and yield of the crops, and evaluate the impact of the improvement effect on crop growth; according to the growth of the crops, adjust the management measures, and the management measures include fertilization and irrigation to ensure the normal growth of the crops; S63: According to the soil monitoring and crop growth monitoring results, timely adjust and optimize the improvement measures. If it is found that the soil salt rebounds, carry out fresh water flushing or apply soil conditioners again; if the soil fertility is insufficient, apply more organic fertilizers and chemical fertilizers; at the same time, strengthen the maintenance of the irrigation system, drainage system, and monitoring equipment to ensure their normal operation and guarantee the long-term stability of the saline-alkali land improvement effect.

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