Comprehensive treatment method for saline-alkali soil

Abstract

The invention discloses a comprehensive treatment method for saline-alkali soil, and belongs to the technical field of saline-alkali soil treatment, the method comprises the following steps: (1) covering the surface of saline-alkali soil under a photovoltaic panel with sand; (2) preparing saline-alkaline tolerant plant seeds into pelletized seeds, and then sowing the pelletized seeds in the sand-covered soil; (3) thoroughly watering after sowing, subsequently managing and protecting according to a conventional method, blocking capillary action by covering sand, reducing the salinity and alkalinity of the earth surface, pelleting the seeds, sowing the pelletized seeds in sandy soil, and ensuring that the seeds can better germinate and grow in the sandy soil to absorb and reduce the salinity of the soil and improve the properties of the soil, so that the soil quality is improved. The photovoltaic panel is matched for shielding to reduce direct solar radiation and surface wind speed, evaporation of surface moisture and accumulation of salt are reduced, comprehensive treatment is carried out on the saline-alkali soil under the combined action, and the treatment efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of saline-alkali land treatment, and in particular to a comprehensive saline-alkali land treatment method. Background Art

[0002] Saline-alkali land is a general term for various saline and alkaline soils as well as soils with different degrees of salinization and alkalization. According to data released by UNESCO and FAO, the total area of ​​saline-alkali land in the world exceeds 900 million hectares, of which my country's saline-alkali land accounts for about one-tenth of the world's total saline-alkali land. According to expert estimates, there are nearly 1.5 billion mu of saline-alkali land in my country, mainly distributed in the northwest, northeast, north China and coastal areas, of which about 550 million mu are usable. Improving and utilizing saline-alkali land can increase the area of ​​arable land and ease the contradiction between people and land, but in the 21st century when my country's agriculture is developing sustainably, the improvement and utilization of saline-alkali land is still a problem.

[0003] Photovoltaic agriculture is a new low-carbon and energy-saving industrial model that combines solar power generation components with agricultural facilities and agricultural breeding to achieve rooftop power generation and under-shed breeding. It is of great significance to improve land utilization, enhance economic benefits, and stabilize agricultural production. The shading of photovoltaic components reduces direct sunlight and surface wind speed, reduces the evaporation of surface water and the accumulation of salt. Planting salt-tolerant plants under photovoltaic panels to absorb salt in the soil and improve soil properties can effectively improve the efficiency of saline-alkali land management, thereby better promoting the development and utilization of saline-alkali land. However, due to the high salt concentration, compact soil, easy compaction, poor permeability, and the germination and growth of plants, the survival rate of plants planted under the panels is low, which reduces the efficiency of saline-alkali land management.

[0004] Therefore, there is a need to find a method for saline-alkali land soil treatment to improve the survival rate of plants planted under photovoltaic panels, thereby improving the efficiency of saline-alkali land treatment and better promoting the development and utilization of saline-alkali land. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a comprehensive management method for saline-alkali land, which can be comprehensively managed by covering the saline-alkali land with sand, planting salt-alkali tolerant plants and other measures, supplemented by the role of photovoltaic facilities, to improve the management efficiency of saline-alkali land, and thus better promote the development and utilization of saline-alkali land.

[0006] The present invention solves the above technical problems by the following technical means:

[0007] A comprehensive treatment method for saline-alkali land, the method is as follows:

[0008] (1) Cover the saline-alkali soil surface under the photovoltaic panels with sand;

[0009] (2) preparing salt-alkali tolerant plant seeds into pelletized seeds, and then sowing them in the soil covered with sand;

[0010] (3) After sowing, water the plants thoroughly and then perform maintenance in the usual way.

[0011] Under the shade of photovoltaic panels, direct sunlight and surface wind speed can be reduced, and the evaporation of surface water and the accumulation of salt can be reduced. Then, covering the surface of the saline-alkali land with sand can effectively block the capillary action and inhibit the accumulation of salt to the soil surface. Planting salt-alkali tolerant plants in the soil covered with sand can effectively reduce the salt-alkali stress of plants in the early stage of sowing and improve the survival rate of plants. Plants can effectively absorb salt in the soil and root secretions, which can better improve the soil properties, thereby achieving effective management of saline-alkali soil.

[0012] Furthermore, the thickness of the sand covering in step (1) is 12 to 20 cm.

[0013] Furthermore, the content of sand particles with a particle size of 0.02 to 2 mm in the covered sand in step (1) is ≥85%.

[0014] Furthermore, the salt-alkali tolerant plant includes any one of Artemisia halogenis, Caragana microsporum, Achnatherum splendens, Medicago sativa, Adansonia sutchuenensis, Elymus dahliae, and Kochia scoparia.

[0015] Further, the pelletized seeds preparation method is as follows:

[0016] A: Add chitosan to isopropanol and stir to disperse, let stand for 1 to 2 hours, adjust the pH to 7 to 8, then add arachidonic acid and heat to 45 to 55°C to react for 3 to 6 hours. After the reaction is completed, let stand overnight to obtain a chitosan mixed solution; add methyl anthranilate to a 75% ethanol solution and dissolve it, then add it to the chitosan mixed solution, heat to 55-65°C and stir to react for 1 to 2 hours. After the reaction is completed, cool to room temperature, filter to remove the filtrate, and dry to obtain modified chitosan;

[0017] B: Add the modified chitosan to a 2wt% acetic acid solution, stir to dissolve, then add a 2wt% glutaraldehyde solution, heat to 50-60°C and react at a constant temperature for 60-90 minutes. After the reaction is completed, cool to room temperature and place for 12-24 hours. Then, add ethyl acetate and mix evenly to obtain a chitosan gel;

[0018] C: Dissolve urea, superphosphate and potassium sulfate, add diatomaceous earth and mix evenly, adjust the pH to 5-6 to obtain a coating material; select salt-alkali tolerant plant seeds with full particles, remove impurities and add them to the coating material and mix evenly, then add chitosan gel and mix evenly, put them into a granulator to make particles with a particle size of 0.1-1 cm, and obtain pelletized seeds after drying.

[0019] Planting plants after covering the surface of saline-alkali land with sand can effectively reduce the contact of plant seeds with saline-alkali substances after sowing, reduce saline-alkali stress, and thus improve the survival rate of plant planting. However, sand has high permeability and poor water and fertilizer retention, and the specific heat capacity of sand is small, so the temperature difference between the sand layer and the day and night is large, which can easily inhibit the germination and growth of plant seeds. Therefore, the present invention uses chitosan gel and diatomaceous earth as main raw materials to coat seeds and prepare pelletized seeds. Chitosan gel and diatomaceous earth have good water absorption and water retention, and can absorb and store water for seed germination; at the same time, because diatomaceous earth has low thermal conductivity, it can reduce the internal temperature difference of pelletized seeds. The amplitude of the change, thereby solving the problem of the large temperature difference between the day and night in the sand inhibiting seed germination.

[0020] In order to ensure better water absorption and water retention and relative stability of the internal temperature of pelletized seeds, it is necessary to increase the dosage of chitosan gel and shelling material. However, the increased dosage leads to a thick coating, which is easy to hinder the normal respiration of the seeds inside and the emergence of plants. Therefore, the present invention treats chitosan before preparing the chitosan gel, so that the chitosan gel can be quickly disintegrated after the pelletized seeds are sown, making the shell layer structure loose, thereby ensuring the normal entry and exit of the seeds' respiratory gas and eliminating the barrier of the shell layer to germination and growth.

[0021] Specifically, chitosan is first put into isopropanol for dispersion and expansion, arachidonic acid and methyl o-aminobenzoate are added in sequence for reaction to prepare modified chitosan, and then the modified chitosan is made into gel and ethyl acetate is added to obtain chitosan gel; in the process, arachidonic acid is combined with the chitosan molecular chain to change the structural properties of the chitosan molecular chain, and after pelletized seeds are sown, the products of the rapid decomposition of ethyl acetate in the chitosan gel attack the modified chitosan to cause the molecular chain to break, and methyl o-aminobenzoate is combined with the chitosan molecular chain to change the electron cloud density of the chemical bonds in the molecular chain to increase the reaction activity of the modified chitosan with the decomposition products of ethyl acetate, so that the gel formed by the modified chitosan is attacked by the decomposition products of ethyl acetate to cause the molecular chain to break quickly, and the gel network structure gradually becomes loose, so that the respiratory metabolic gas of the seeds can enter and exit smoothly, and the germination buds can easily break through the coating layer, thereby ensuring the planting survival rate and the good growth of the plant seedlings.

[0022] Furthermore, in step A, the mass ratio of chitosan, isopropanol, arachidonic acid and methyl anthranilate is (0.1-0.2):(10-20):(0.01-0.02):(0.008-0.015).

[0023] Furthermore, in step B, the mass ratio of modified chitosan, 2wt% acetic acid solution, 2wt% glutaraldehyde solution, and ethyl acetate is (0.1-0.2):(2-4):(0.8-1):(0.05-0.1).

[0024] Furthermore, in step C, the mass ratio of urea, superphosphate, potassium sulfate and diatomaceous earth is (0.04-0.08): (0.1-0.15): (0.04-0.08): (5-7).

[0025] Furthermore, in step C, the mass ratio of the shelling material, the seeds, and the chitosan gel is (6-8): (0.05-0.1): (3-5).

[0026] Furthermore, the drying operation in step C is specifically drying at 30-40° C., and the moisture content of the pelletized seeds after drying is 10-15%.

[0027] Beneficial effects:

[0028] 1. The present invention covers the surface of saline-alkali soil under photovoltaic panels with sand and then plants salt-alkali tolerant plants, thereby ensuring the good growth of salt-alkali tolerant plants, thereby achieving better management of saline-alkali land and promoting the development and utilization of saline-alkali land.

[0029] 2. The present invention pelletizes the seeds and then sows them. The outer coating material of the pelletized seeds absorbs water and retains fertilizer while suppressing the drastic change of the internal temperature of the seeds, thereby ensuring better conditions for seed germination and improving the seed germination rate. In addition, the outer coating material can be gradually decomposed in a relatively short period of time, thereby ensuring normal respiration and metabolism of the seeds, and will not inhibit the germination and growth of the seeds, thereby improving the survival rate of plant planting, so that well-grown salt-alkali tolerant plants can better improve the saline-alkali soil and improve the efficiency of saline-alkali land management. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 : This is a picture of the soil under the photovoltaic panel after being covered with sand;

[0031] Figure 2 : is a picture of the growth status of alfalfa in Example 4 of the present invention

[0032] Figure 3 : It is a picture of the growth status of Astragalus membranaceus in Example 5 of the present invention. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings:

[0034] Example 1: Preparation of pelletized seeds

[0035] A: Add 0.15 kg of chitosan to 15 kg of isopropanol and stir to disperse, let stand for 1.5 hours, adjust the pH to 7.5, then add 0.015 kg of arachidonic acid and heat to 50°C for 4 hours, let stand overnight to obtain a chitosan mixture; add 0.012 kg of methyl anthranilate to 0.12 kg of 75% by volume ethanol solution to dissolve, then add to the chitosan mixture, heat to 60°C, stir to react for 1.5 hours, cool to room temperature after the reaction is completed, filter to remove the filtrate, and dry at 45°C to obtain modified chitosan;

[0036] B: 0.15 kg of modified chitosan was added to 3 kg of 2 wt% acetic acid solution, stirred and dissolved, and then 0.9 kg of 2 wt% glutaraldehyde solution was added, and the temperature was raised to 55°C and kept constant for 70 min. After the reaction was completed, it was cooled to room temperature and placed for 16 h. 0.07 kg of ethyl acetate was added and mixed evenly to obtain a chitosan gel;

[0037] C: 0.06 kg urea, 0.12 kg superphosphate and 0.06 kg potassium sulfate were added to 6 kg water, dissolved, and then 6 kg diatomaceous earth was added and mixed evenly, and the pH was adjusted to 5.5 to obtain a coating material; after screening the Astragalus membranaceus seeds with full particles to remove impurities, 0.06 kg of seeds were taken, added to 7 kg of the coating material and mixed evenly, 4 kg of chitosan gel was added, mixed evenly, and then put into a granulator to make particles with a particle size of 0.4 cm, and dried at 35° C. to a water content of 12% to obtain pelletized seeds.

[0038] Example 2: Preparation of pelletized seeds

[0039] A: Add 0.1 kg of chitosan to 10 kg of isopropanol and stir to disperse, let stand for 1 hour, adjust the pH to 7, then add 0.01 kg of arachidonic acid and heat to 45°C for 6 hours. After the reaction is completed, let stand overnight to obtain a chitosan mixed solution; add 0.008 kg of methyl anthranilate to 0.08 kg of 75% by volume ethanol solution to dissolve, then add to the chitosan mixed solution, heat to 55°C, stir to react for 2 hours, cool to room temperature after the reaction is completed, filter to remove the filtrate, and dry at 45°C to obtain modified chitosan;

[0040] B: 0.1 kg of modified chitosan was added to 2 kg of 2 wt% acetic acid solution, stirred and dissolved, and then 0.8 kg of 2 wt% glutaraldehyde solution was added, and the temperature was raised to 50°C and kept constant for 90 min. After the reaction was completed, it was cooled to room temperature and placed for 12 h. 0.05 kg of ethyl acetate was added and mixed evenly to obtain a chitosan gel;

[0041] C: 0.04 kg urea, 0.1 kg superphosphate and 0.04 kg potassium sulfate are added to 5 kg water, dissolved, and then 5 kg diatomaceous earth is added and mixed evenly, and the pH is adjusted to 5 to obtain a coating material; after screening the Astragalus membranaceus seeds with full particles to remove impurities, 0.05 kg of seeds are taken, added to 6 kg of the coating material and mixed evenly, 3 kg of chitosan gel is added, mixed evenly, and then put into a granulator to make particles with a particle size of 0.4 cm, and dried at 30° C. to a water content of 15% to obtain pelletized seeds.

[0042] Example 3: Pelleted Seed Preparation III

[0043] A: Add 0.2 kg of chitosan to 20 kg of isopropanol and stir to disperse, let stand for 2 hours, adjust the pH to 8, then add 0.02 kg of arachidonic acid and heat to 55°C for 3 hours. After the reaction is completed, let stand overnight to obtain a chitosan mixed solution; add 0.015 kg of methyl anthranilate to 0.15 kg of 75% by volume ethanol solution to dissolve, then add to the chitosan mixed solution, heat to 65°C, stir to react for 1 hour, cool to room temperature after the reaction is completed, filter to remove the filtrate, and dry at 45°C to obtain modified chitosan;

[0044] B: 0.2 kg of modified chitosan was added to 4 kg of 2 wt% acetic acid solution, stirred and dissolved, and then 1 kg of 2 wt% glutaraldehyde solution was added, and the temperature was raised to 60°C and kept at this temperature for 90 min. After the reaction was completed, the mixture was cooled to room temperature and placed for 24 h. 0.1 kg of ethyl acetate was added and mixed evenly to obtain a chitosan gel;

[0045] C: 0.08 kg urea, 0.15 kg superphosphate and 0.08 kg potassium sulfate were added to 7 kg water, dissolved, and then 7 kg diatomaceous earth was added and mixed evenly, and the pH was adjusted to 6 to obtain a coating material; after screening the Astragalus membranaceus seeds with full particles to remove impurities, 0.1 kg of seeds were taken, added to 8 kg of the coating material and mixed evenly, 5 kg of chitosan gel was added, mixed evenly, and then put into a granulator to make particles with a particle size of 0.4 cm, and dried at 40° C. to a water content of 10% to obtain pelletized seeds.

[0046] Comparative Example 1: Pelleted Seed Preparation

[0047] In contrast to Example 1, the only difference is that in the preparation of pelletized seeds in Comparative Example 1, no arachidonic acid is added in step A for reaction, as follows:

[0048] A: Add 0.15 kg of chitosan to 15 kg of isopropanol and stir to disperse, let stand for 1.5 hours and then adjust the pH to 7.5 to obtain a chitosan mixed solution; add 0.012 kg of methyl anthranilate to 0.12 kg of 75% by volume ethanol solution to dissolve and then add to the chitosan mixed solution, heat to 60°C and stir to react for 1.5 hours, cool to room temperature after the reaction is completed, filter to remove the filtrate and then dry at 45°C to obtain modified chitosan;

[0049] BC: Same as Example 1.

[0050] Comparative Example 2: Pelleted Seed Preparation

[0051] In contrast to Example 1, the only difference is that in the preparation of pelletized seeds in Comparative Example 2, methyl anthranilate is not added in step A for reaction, as follows:

[0052] A: Add 0.15 kg chitosan to 15 kg isopropanol and stir to disperse. After standing for 1.5 hours, adjust the pH to 7.5, then add 0.015 kg arachidonic acid and heat to 50°C for 4 hours. After the reaction is completed, stand overnight to obtain a chitosan mixture. After filtering out the filtrate, dry at 45°C to obtain modified chitosan.

[0053] B~C: Same as Example 1.

[0054] Comparative Example 3: Pelleted Seed Preparation

[0055] In contrast to Example 1, the only difference is that in Comparative Example 3, ethyl acetate is not added in step B during the preparation of pelletized seeds, as follows:

[0056] A: Same as Example 1;

[0057] B: 0.15 kg of modified chitosan was added to 3 kg of 2 wt% acetic acid solution, stirred and dissolved, and then 0.9 kg of 2 wt% glutaraldehyde solution was added, and the temperature was raised to 55°C and kept at this temperature for 70 min. After the reaction was completed, the mixture was cooled to room temperature and placed for 16 h to obtain a chitosan gel;

[0058] C: Same as Example 1.

[0059] Comparative Example 4: Pelleted Seed Preparation

[0060] In contrast to Example 1, the only difference is that in Comparative Example 4, the pelletized seeds are prepared without step A, and chitosan is not modified, as follows:

[0061] B: 0.15 kg of chitosan was added to 3 kg of 2 wt% acetic acid solution, stirred and dissolved, and then 0.9 kg of 2 wt% glutaraldehyde solution was added, and the temperature was raised to 55°C and kept constant for 70 min. After the reaction was completed, the mixture was cooled to room temperature and placed for 16 h. 0.07 kg of ethyl acetate was added and mixed evenly to obtain a chitosan gel;

[0062] C: Same as Example 1.

[0063] Comparative Example 5: Pelleted Seed Preparation

[0064] In contrast to Example 1, the only difference is that in Comparative Example 5, the pH is adjusted to 4 in step C during the preparation of pelletized seeds.

[0065] Comparative Example 6: Pelleted Seed Preparation

[0066] In contrast to Example 1, the only difference is that in Comparative Example 6, the pH is adjusted to 7 in step C during the preparation of pelletized seeds.

[0067] Example 4: Salt-alkali land management

[0068] This embodiment comprehensively treats the saline-alkali soil under the photovoltaic panels in the Shaanxi Coal Fengwan Photovoltaic Project plant area in Dingbian County, Yulin City, Shaanxi Province. The specific method is as follows:

[0069] (1) Select sand with a particle size of 0.02-2 mm and a sand content of about 90%, and spread it on the surface of the saline-alkali soil under the photovoltaic panel, with a sand covering thickness of about 15 cm;

[0070] (2) preparing alfalfa pelletized seeds according to the method of Example 1, and sowing them in the sand-covered soil by drilling;

[0071] (3) Water the seeds after sowing to allow them to fully absorb water, and then perform maintenance in the usual way.

[0072] Example 5: Salt-alkali land management

[0073] This embodiment comprehensively treats the saline-alkali soil under the photovoltaic panels in the Shaanxi Coal Fengwan Photovoltaic Project plant area in Dingbian County, Yulin City, Shaanxi Province. The specific method is as follows:

[0074] (1) Select sand with a particle size of 0.02-2 mm and a sand content of about 90%, and spread it on the surface of the saline-alkali soil under the photovoltaic panel, with a sand covering thickness of about 15 cm;

[0075] (2) preparing pelletized seeds of Astragalus membranaceus according to the method of Example 3, and sowing them in the soil covered with sand by broadcasting;

[0076] (3) Water the seeds after sowing to allow them to fully absorb water, and then perform maintenance in the usual way.

[0077] Experiment 1: Pelleted seed germination experiment

[0078] (1) Experimental preparation: 800 alfalfa seeds with full grains and no pests and diseases were selected and evenly divided into 8 groups, each with 100 seeds. The 8 groups corresponded to Example 1, Comparative Examples 1-6, and a blank control group, respectively. The seeds of Example 1 and Comparative Examples 1-6 were prepared into pelletized seeds according to the methods of Example 1 and Comparative Examples 1-6, respectively. The seeds of the blank control group were directly sown without pelletization.

[0079] (2) Experimental method: An experimental area was set aside under the photovoltaic panels of the Shaanxi Coal Fengwan Photovoltaic Project Plant in Dingbian County, Yulin City, Shaanxi Province for the experiment. The soil surface of the experimental area was covered with sand with a particle size of 0.02-2 mm and a sand content of about 90% with a thickness of about 15 cm. The experimental area was then evenly divided into 8 small areas, corresponding to Example 1, Comparative Examples 1-6 and a blank control. Then, the pelletized seeds of each group in (1) and the seeds of the blank control group were sown in the corresponding areas according to the same sowing method. After sowing, water was poured thoroughly. Then, the emergence rate of each group was observed 25 days and 35 days after sowing. The data obtained are shown in Table 1:

[0080] Table 1

[0081]

[0082] According to the data in Table 1:

[0083] (1) The alfalfa pelleted seeds in Example 1 germinate quickly and have a high germination rate, with a germination rate of 90% at 25 days and a germination rate of 93% at 35 days. The alfalfa seeds in Example 1 basically germinate in 25 days, indicating that the seeds can be pelleted according to the method of the present invention and then sown on saline-alkali land covered with sand, which can better ensure the germination rate of the seeds and the growth of the seedlings, and can improve the efficiency of the treatment of saline-alkali land by salt-alkali tolerant plants.

[0084] (2) In the seed pelleting process of Comparative Example 1, arachidonic acid was not added to treat chitosan. After sowing, the stable coating of chitosan gel inhibited the normal growth of germination. The emergence rates on the 25th and 30th days were significantly lower than those in Example 1. In Comparative Example 2, methyl anthranilate was not added during the pelleting of seeds. The reaction activity of chitosan was low, so the decomposition and chain breaking rate was slow, which inhibited the germination and germination growth of seeds. The emergence rate was lower than that in Example 1. In Comparative Example 3, ethyl acetate was not added during the preparation of pelletized seeds. In Comparative Example 4, chitosan was not modified during the preparation of pelletized seeds. The chitosan gel in Comparative Example 3 was mainly decomposed and broken by microorganisms. The chitosan in Comparative Example 4 had higher stability. The outer coating layer of Comparative Examples 3 and 4 coated the seeds for a long time, which hindered the respiratory metabolism of the seeds and the growth of germination. The emergence rate was significantly reduced.

[0085] (3) In comparative example 5, the pH of the coating material was adjusted to 4 during the preparation of pelleted seeds. The pH of the coating layer was too low, which inhibited seed germination. In comparative example 6, the pH of the coating material was adjusted to 7. The change in pH affected the decomposition of ethyl acetate, resulting in a slow disintegration of the chitosan gel structure, which caused the coating layer to inhibit seed germination and growth.

[0086] Experiment 2: Salt-alkali land management experiment

[0087] The experiment was conducted in the Shaanxi Coal Fengwan Photovoltaic Project Plant in Dingbian County, Yulin City, Shaanxi Province. A separate plot of land was selected as the experimental site, and the experimental site was evenly divided into 8 small areas, including experimental group 1, control groups 1 to 6, and blank control group:

[0088] Experimental Group 1 used the pelletized seeds prepared in Example 1 and the treatment method of Example 5;

[0089] Control groups 1 to 6 respectively used the pelletized seeds of Comparative Examples 1 to 6 and the treatment method of Example 5;

[0090] The blank control group did not pelletize the seeds (the amount of seeds in the pelletized seeds of Example 1 and Comparative Examples 1-6 was 0.06 kg, so the blank control group directly took 0.06 kg of seeds), and the rest were sown using the treatment method of Example 5.

[0091] 2. Before the experiment, the soil salt content and pH of the experimental area were measured. After 3 months of sowing, each group of Astragalus membranaceus was harvested and the weight of fresh grass of each group was recorded. Astragalus membranaceus had good regeneration, so it was harvested twice a year. Then, the soil salt content and pH were measured again after 2 years. The data were shown in Table 2:

[0092] Table 2

[0093]

[0094]

[0095] According to the data analysis in Table 2:

[0096] (1) The treatment effect of saline-alkali land in experimental group 1 was good. After 2 years of planting Astragalus membranaceus, the soil salt content and pH value decreased significantly. In addition, the weight of fresh grass in experimental group 1 at the first harvest was higher than that in control groups 1 to 6 and the blank control group. This indicates that the method of the present invention is used to pelletize seeds, and then combined with sowing after covering with sand under the photovoltaic panels, the combined effect of comprehensive treatment of saline-alkali land can effectively improve the treatment efficiency of saline-alkali land.

[0097] (2) In the control groups 1 to 6, due to the lack of raw materials or changes in conditions during the preparation of pelletized seeds, the seeds experienced symptoms including respiratory metabolism obstruction and growth inhibition after sowing, which inhibited the germination and growth of the seeds and resulted in low biomass of the Astragalus membranaceus obtained, thereby reducing the absorption of salt by the Astragalus membranaceus pile and the improvement of the soil, and reducing the efficiency of saline-alkali land management.

[0098] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. A method for comprehensive management of saline-alkali land, characterized in that: The method is as follows: (1) Cover the saline-alkali soil surface under the photovoltaic panels with sand; (2) Pelleting the salt-alkali tolerant plant seeds and sowing them in the soil covered with sand; (3) After sowing, water the plants thoroughly and then perform maintenance in the usual way.

2. A comprehensive treatment method for saline-alkali land according to claim 1, characterized in that: The thickness of the sand covering in step (1) is 12 to 20 cm.

3. A comprehensive treatment method for saline-alkali land according to claim 2, characterized in that: The content of sand particles with a particle size of 0.02 to 2 mm in the covered sand in step (1) is ≥ 85%.

4. A comprehensive treatment method for saline-alkali land according to claim 3, characterized in that: The salt-alkali tolerant plants include any one of Artemisia halodendron, Caragana microphylla, Achnatherum splendens, Medicago sativa, Adansonia sutchuenensis, Elymus dahliae, and Kochia scoparia.

5. A comprehensive treatment method for saline-alkali land according to claim 4, characterized in that: The pelletized seed preparation method is as follows: A: Add chitosan to isopropanol and stir to disperse, let stand for 1 to 2 hours, adjust the pH to 7 to 8, then add arachidonic acid and heat to 45 to 55°C to react for 3 to 6 hours. After the reaction is completed, let stand overnight to obtain a chitosan mixed solution; add methyl anthranilate to a 75% ethanol solution and dissolve it, then add it to the chitosan mixed solution, heat to 55-65°C and stir to react for 1 to 2 hours. After the reaction is completed, cool to room temperature, filter to remove the filtrate, and dry to obtain modified chitosan; B: Add the modified chitosan to a 2wt% acetic acid solution, stir to dissolve, then add a 2wt% glutaraldehyde solution, heat to 50-60°C and react at a constant temperature for 60-90 minutes. After the reaction is completed, cool to room temperature and place for 12-24 hours. Then, add ethyl acetate and mix evenly to obtain a chitosan gel; C: Dissolve urea, superphosphate and potassium sulfate, add diatomaceous earth and mix evenly, adjust the pH to 5-6 to obtain a coating material; select salt-alkali tolerant plant seeds with full particles, remove impurities and add them to the coating material and mix evenly, then add chitosan gel and mix evenly, put them into a granulator to make particles with a particle size of 0.1-1 cm, and obtain pelletized seeds after drying.

6. A comprehensive treatment method for saline-alkali land according to claim 5, characterized in that: In the step A, the mass ratio of chitosan, isopropanol, arachidonic acid and methyl anthranilate is (0.1-0.2):(10-20):(0.01-0.02):(0.008-0.015).

7. A comprehensive treatment method for saline-alkali land according to claim 6, characterized in that: In the step B, the mass ratio of the modified chitosan, 2wt% acetic acid solution, 2wt% glutaraldehyde solution and ethyl acetate is (0.1-0.2):(2-4):(0.8-1):(0.05-0.1).

8. A comprehensive treatment method for saline-alkali land according to claim 7, characterized in that: In the step C, the mass ratio of urea, superphosphate, potassium sulfate and diatomaceous earth is (0.04-0.08): (0.1-0.15): (0.04-0.08): (5-7).

9. A comprehensive treatment method for saline-alkali land according to claim 8, characterized in that: In the step C, the mass ratio of the shelling material, the seeds, and the chitosan gel is (6-8): (0.05-0.1): (3-5).

10. A comprehensive treatment method for saline-alkali land according to claim 9, characterized in that: The drying operation in step C is specifically drying at 30-40° C., and the moisture content of the pelletized seeds after drying is 10-15%.

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