A compound soil modifier suitable for horqin sandy land, preparation method and application

Abstract

The application discloses a kind of compound soil improver suitable for Keerqin sandy land, preparation method and application, by mass fraction, raw material includes water-retention slow-release component 10 parts, microbial immobilization capsule 10~15 parts and soil nutrient component 20~25 parts;The water-retention slow-release component includes the mass ratio of 1∶(30~50)∶(0.5~1) polymeric amino acid-humic acid compound, modified diatomite and biochar;The microbial immobilization capsule uses drought-resistant bacteria, plant rhizosphere growth-promoting bacteria and modified diatomite as core layer, uses sodium alginate as shell layer;The soil nutrient component is prepared by grassland plant straw and cow dung fermentation;The application uses "deficit irrigation+soil organic improvement" synergistic to soil water and fertilizer supply, proves its comprehensive promotion effect to oat and alfalfa yield, quality, water use efficiency and soil carbon sink, to optimize water and fertilizer management, comprehensively promote grassland water-saving, carbon-increasing and high yield level, promote the sustainable development of Keerqin sandy land agriculture.

Description

Technical Field

[0001] This invention belongs to the field of soil improvement technology, specifically relating to a composite soil conditioner suitable for the Horqin Sandy Land, its preparation method, and its application. Background Technology

[0002] In recent years, with the rapid adjustment of the agricultural and pastoral structure, oats ( Avena sativa ) and alfalfa ( Medicago sativa The planting area of ​​high-quality forage crops such as cow manure is constantly expanding. However, traditional water and fertilizer management models are difficult to meet the needs of precise water supply and efficient nutrient utilization in the Horqin Sandy Land. The sandy soil in this region has large particles and high porosity, resulting in rapid water infiltration, serious nutrient loss, and an unbalanced water and fertilizer supply in the root zone, which significantly affects the nutrient absorption and growth of crops. Traditional surface irrigation methods not only have high water evaporation and low utilization efficiency, but may also induce soil salinization and exacerbate soil degradation. Cow manure, as a low-cost soil conditioner rich in organic nutrients, can significantly improve soil structure, enhance soil water and fertilizer retention capacity, and promote soil microbial activity, thereby optimizing the rhizosphere environment. However, traditional cow manure treatment methods, such as direct piling or simple landfill, may lead to nitrogen and phosphorus loss, soil compaction, and increased greenhouse gas emissions. Improvement measures, such as the composting treatment of cow manure and its combined application with other components, can effectively improve the stability and nutrient release efficiency of cow manure. Although there are relevant studies, existing soil conditioners with added cow manure have not been ideal for the yield, quality, and soil improvement effects of forage in the Horqin region. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention discloses a composite soil conditioner suitable for the Horqin Sandy Land, its preparation method, and its application. This invention employs a synergistic approach of "deficit irrigation + organic soil improvement" to enhance soil water and fertilizer supply, demonstrating its comprehensive effect on improving the yield, quality, water use efficiency, and soil carbon sequestration of oats and alfalfa. This optimizes water and fertilizer management, comprehensively improves grassland water conservation, carbon sequestration, and high yield levels, and promotes the sustainable development of agriculture in the Horqin Sandy Land.

[0004] This invention provides a composite soil conditioner suitable for the Horqin Sandy Land, comprising, by weight, 10 parts of a water-retaining slow-release component, 10-15 parts of microbial immobilization capsules, and 20-25 parts of soil nutrient components; the water-retaining slow-release component comprises a polymeric amino acid-humic acid complex, modified diatomaceous earth, and biochar in a weight ratio of 1:(30-50):(0.5-1); the microbial immobilization capsules have drought-resistant bacteria, plant rhizosphere growth-promoting bacteria, and modified diatomaceous earth as the core layer and sodium alginate as the shell layer; the soil nutrient components are prepared by fermentation of grassland plant straw and cow dung.

[0005] As a further improvement of the present invention, the preparation method of the water-retaining slow-release component is as follows: the polymerized amino acid-humic acid complex, modified diatomaceous earth and biochar are uniformly mixed according to the mass ratio, a binder is sprayed, and granulation is performed.

[0006] As a further improvement of the present invention, the modified diatomaceous earth is obtained by modifying diatomaceous earth with inorganic acid.

[0007] Optionally, the inorganic acid includes dilute hydrochloric acid, dilute sulfuric acid, or dilute nitric acid.

[0008] As a further improvement of the present invention, the preparation method of the microbial fixed capsule is as follows: drought-resistant bacteria, plant rhizosphere growth-promoting bacteria and modified diatomaceous earth are mixed in a mass ratio of (3~5):(3~5):100 and added to grassland plant water extract to prepare a core layer suspension; the core layer suspension is added dropwise to sodium alginate solution, and calcium chloride solution is added dropwise to fully cross-link the mixture, and then freeze-dried to prepare microcapsules.

[0009] Preferably, the volume ratio of the core layer suspension to the sodium alginate solution is 1:8; the concentration of the sodium alginate solution is 3 wt%; and the concentration of the calcium chloride solution is 0.5 M.

[0010] Optionally, the drought-resistant bacteria are selected from Bacillus subtilis; the plant rhizosphere growth-promoting bacteria are selected from nitrogen-fixing bacteria.

[0011] Optionally, the preparation method of the grassland plant water extract is to directly add the roots, stems, leaves or whole plant of the grassland plant to water and heat to boiling for 1-2 hours, and then separate the filtrate to obtain the extract.

[0012] As a further improvement of the present invention, the preparation method of the polymeric amino acid-humic acid complex is as follows: humic acid is dissolved in water to prepare a solution with a concentration of 5-10 wt%, and polymeric amino acid is prepared into a solution with a concentration of 10-15 wt%. Under stirring conditions, the polymeric amino acid solution is added dropwise to an equal volume of humic acid solution, and the reaction is stirred for 3-4 hours. The polymeric amino acid-humic acid complex is obtained by spray drying.

[0013] As a further improvement of the present invention, the plants in the grassland plant straw and the grassland plant water extract are independently selected from at least one of Artemisia annua, Artemisia argyi, Artemisia frigida, Aster tataricus or Taraxacum mongolicum.

[0014] Artemisia annua, Artemisia argyi, and Artemisia frigida are plants of the Artemisia genus, rich in volatile oils, flavonoids, polysaccharides, and organic acids. Low-concentration extracts can stimulate seed germination, root development, and plant growth. They also inhibit various soil-borne pathogenic fungi (such as Fusarium and Rhizoctonia solani) and bacteria, reducing seedling diseases; they repel or kill certain pests (aphids, spider mites, etc.); and they enhance crop tolerance to abiotic stresses such as drought and salinity. Aster tataricus and Taraxacum mongolicum contain abundant triterpenoids, sesquiterpene lactones, flavonoids, inulin, and chlorogenic acid, which can stimulate seed germination, seedling growth, and leaf photosynthesis. They also inhibit various plant pathogens, and inulin and other substances can be utilized by soil microorganisms, improving the microecology. The plants used in this invention are native to the Horqin region. Their long-term adaptation to the soil environment has fostered a harmonious relationship between them, and the components accumulated within the plants are beneficial for improving the local soil. At the same time, the use of local agricultural waste promotes crop-livestock recycling, achieving resource recycling and reducing the preparation cost of the soil conditioner.

[0015] The second aspect of the present invention is to provide a method for preparing a composite soil conditioner suitable for the Horqin Sandy Land, which is obtained by mixing water-retaining slow-release components, microbial immobilized capsules and soil nutrient components in a certain mass ratio.

[0016] The third aspect of this invention is to provide a composite soil conditioner suitable for the Horqin Sandy Land for the application of improving grassland soil in the Horqin region.

[0017] The fourth aspect of this invention is to provide a method for improving grassland soil in the Horqin region, which involves using a composite soil conditioner suitable for Horqin sandy land coupled with deficit irrigation for soil improvement.

[0018] Furthermore, the deficit irrigation is 60-65% of field capacity.

[0019] Compared with the prior art, the present invention has the following technical effects: This invention's soil conditioner organically combines water-retaining slow-release components, microbial immobilized capsules, and soil nutrient components. During soil improvement, it easily forms soil aggregates with complex internal nutrient cycling, thus continuously improving the soil in the Horqin region. When combined with deficit irrigation, this conditioner significantly improves water and fertilizer use efficiency, reduces nutrient loss and greenhouse gas emissions, and improves sandy soil structure through precise irrigation and organic soil improvement. Furthermore, it boosts forage production and quality, leading to increased income and contributing to regional economic development. This invention provides a scientific basis and technical specifications for precise water conservation, efficient organic fertilizer utilization, and soil carbon sequestration in arid and semi-arid regions, promoting the green, efficient, and sustainable transformation of agriculture in the Horqin sandy land. It also provides a replicable integrated model for similar ecologically fragile areas, demonstrating significant scientific and socio-economic benefits. Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0023] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0024] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0025] This invention discloses a composite soil conditioner suitable for the Horqin Sandy Land. By mass, the raw materials include 10 parts of a water-retaining slow-release component, 10-15 parts of microbial immobilized capsules, and 20-25 parts of soil nutrients. The water-retaining slow-release component comprises a polymeric amino acid-humic acid complex, modified diatomaceous earth, and biochar in a mass ratio of 1:(30-50):(0.5-1). The microbial immobilized capsules use drought-resistant bacteria, plant rhizosphere growth-promoting bacteria, and modified diatomaceous earth as the core layer and sodium alginate as the shell layer. The soil nutrients are prepared by fermenting grassland plant straw and cow dung.

[0026] In some embodiments of the present invention, the preparation method of the water-retaining and slow-release component is as follows: the polymerized amino acid-humic acid complex, modified diatomaceous earth and biochar are uniformly mixed according to the mass ratio, a binder is sprayed, and granulation is performed.

[0027] In some embodiments of the present invention, the modified diatomaceous earth is obtained by modifying diatomaceous earth with inorganic acid.

[0028] In optional embodiments, the inorganic acid includes dilute hydrochloric acid, dilute sulfuric acid, or dilute nitric acid; preferably, the concentration of the inorganic acid is 1~2M.

[0029] In some embodiments of the present invention, the method for preparing the microbial fixed capsules is as follows: drought-resistant bacteria, plant rhizosphere growth-promoting bacteria and modified diatomaceous earth are mixed in a mass ratio of (3~5):(3~5):100 and added to grassland plant water extract to prepare a core layer suspension; the core layer suspension is added dropwise to sodium alginate solution, and calcium chloride solution is added dropwise to fully cross-link the mixture, and then freeze-dried to prepare microcapsules.

[0030] Preferably, the volume ratio of the core layer suspension to the sodium alginate solution is 1:8; the concentration of the sodium alginate solution is 3 wt%; and the concentration of the calcium chloride solution is 0.5 M.

[0031] Optionally, the drought-resistant bacteria are selected from Bacillus subtilis; the plant rhizosphere growth-promoting bacteria are selected from nitrogen-fixing bacteria.

[0032] Optionally, the preparation method of the grassland plant water extract is to directly add the roots, stems, leaves or whole plant of the grassland plant to water and heat to boiling for 1-2 hours, and then separate the filtrate to obtain the extract.

[0033] In some embodiments of the present invention, the preparation method of the polymeric amino acid-humic acid complex is as follows: humic acid is dissolved in water to prepare a solution with a concentration of 5-10 wt%, and polymeric amino acids are prepared into a solution with a concentration of 10-15 wt%. Under stirring conditions, the polymeric amino acid solution is added dropwise to an equal volume of humic acid solution, and the reaction is stirred for 3-4 hours. The polymeric amino acid-humic acid complex is obtained by spray drying.

[0034] In some embodiments of the present invention, the plants in the grassland plant straw and grassland plant aqueous extract are independently selected from at least one of Artemisia annua, Artemisia argyi, Artemisia frigida, Aster tataricus or Taraxacum mongolicum.

[0035] Artemisia annua, Artemisia argyi, and Artemisia frigida are plants of the Artemisia genus, rich in volatile oils, flavonoids, polysaccharides, and organic acids. Low-concentration extracts can stimulate seed germination, root development, and plant growth. They also inhibit various soil-borne pathogenic fungi (such as Fusarium and Rhizoctonia solani) and bacteria, reducing seedling diseases; they repel or kill certain pests (aphids, spider mites, etc.); and they enhance crop tolerance to abiotic stresses such as drought and salinity. Aster tataricus and Taraxacum mongolicum contain abundant triterpenoids, sesquiterpene lactones, flavonoids, inulin, and chlorogenic acid, which can stimulate seed germination, seedling growth, and leaf photosynthesis. They also inhibit various plant pathogens, and inulin and other substances can be utilized by soil microorganisms, improving the microecology.

[0036] This invention also provides a method for preparing a composite soil conditioner suitable for the Horqin Sandy Land, which involves mixing water-retaining slow-release components, microbial immobilized capsules, and soil nutrient components in a specific mass ratio.

[0037] This invention also provides an application of a composite soil conditioner suitable for the Horqin Sandy Land in improving grassland soil in the Horqin region.

[0038] This invention also provides a method for improving grassland soil in the Horqin region, which involves using a composite soil conditioner suitable for Horqin sandy land coupled with deficit irrigation for soil improvement.

[0039] In a preferred embodiment, the deficit irrigation is 60-65% of field capacity.

[0040] The preparation method of the grassland plant aqueous extract used in the following examples and comparative examples is as follows: collect Artemisia annua, Artemisia argyi, Artemisia frigida, Aster tataricus and Taraxacum mongolicum (in any proportion), crush them, add 20 times the amount of water and decoct for 1.5 hours, filter, and cool the filtrate to obtain the grassland plant aqueous extract.

[0041] Biochar was obtained by drying the filter residue remaining during the preparation of grassland plant aqueous extract and then pyrolyzing it at 600℃ for 2 hours.

[0042] Preparation method of modified diatomaceous earth: diatomaceous earth is impregnated in 1M dilute hydrochloric acid for 2 hours, separated and dried, and then pulverized and passed through a 50-mesh sieve.

[0043] The raw materials used in the embodiments and comparative examples of this invention were all obtained through conventional commercial channels; Bacillus subtilis was purchased from Shandong Xinzhuoyuan Biotechnology Co., Ltd., with a viable bacterial content of 20 billion / g; nitrogen-fixing bacteria were purchased from Hubei Nongkegu Ecological Technology Co., Ltd., with a viable bacterial content of 2 billion / g.

[0044] Grassland plant straw can be made from the roots, stems, or whole plants of Artemisia annua, Artemisia argyi, Artemisia frigida, Aster tataricus, and Taraxacum mongolicum, and there is no strict limit to the mixing ratio.

[0045] It should be noted that any technical means not described in detail in the following embodiments and comparative examples can be achieved using conventional technical means in the field.

[0046] Example 1 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1. Preparation of polymeric amino acid-humic acid complex: Humic acid was dissolved in water to prepare a 5 wt% solution, and polyaspartic acid was prepared to prepare an 11 wt% solution. Under stirring conditions, the polymeric amino acid solution was added dropwise to an equal volume of humic acid solution, and the reaction was stirred for 3 h. The polymeric amino acid-humic acid complex was obtained by spray drying. S2. Preparation of water-retaining slow-release components: Weigh out the polymeric amino acid-humic acid complex, modified diatomaceous earth and biochar according to the mass ratio of 2:50:1, mix them evenly, spray with binder (bentonite mixed with 3 times the amount of water to make slurry), and granulate. S3. Preparation of microbial immobilized capsules: Bacillus subtilis inoculant, nitrogen-fixing bacteria inoculant, and modified diatomaceous earth were mixed in a mass ratio of 3:3:100 and added to 10 times the mass of grassland plant aqueous extract to prepare a core layer suspension; the core layer suspension was added dropwise to sodium alginate solution (3wt%), and calcium chloride solution (0.5M) was added dropwise for cross-linking, and then freeze-dried to prepare microcapsules; wherein, the volume ratio of core layer suspension to sodium alginate solution was 1:8; S4. Preparation of soil nutrient components: Mix fresh cow manure and grassland plant straw (mass ratio 3:1), add 0.5% Bacillus subtilis inoculant, add water to adjust the humidity to 60%, cover with film for fermentation, turn the pile after the core temperature rises to 50℃, and ferment for 15 days until the odor disappears, then fermentation is complete; dry the fermented compost and crush it. S5. Preparation of soil conditioner: Mix 10 parts of water-retaining slow-release component, 10 parts of microbial immobilized capsules and 25 parts of soil nutrient component to obtain soil conditioner.

[0047] Example 2 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1-S4 are the same as in Example 1; S5. Preparation of soil conditioner: Mix 10 parts of water-retaining slow-release component, 15 parts of microbial immobilized capsules and 22 parts of soil nutrient component to obtain soil conditioner.

[0048] Example 3 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1-S4 are the same as in Example 1; S5. Preparation of soil conditioner: Mix 10 parts of water-retaining slow-release component, 12 parts of microbial immobilized capsules and 20 parts of soil nutrient component to obtain soil conditioner.

[0049] Example 4 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1. Same as Example 1; S2. Preparation of water-retaining slow-release components: Weigh out the polymeric amino acid-humic acid complex, modified diatomaceous earth and biochar in a mass ratio of 1:30:1, mix them evenly, spray with binder (bentonite mixed with 3 times the amount of water to make slurry), and granulate. S3-S5 are the same as in Example 1.

[0050] Example 5 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1. Same as Example 1; S2. Preparation of water-retaining slow-release components: Weigh out the polymeric amino acid-humic acid complex, modified diatomaceous earth and biochar according to the mass ratio of 1:50:0.5, mix them evenly, spray with binder (bentonite mixed with 3 times the amount of water to make slurry), and granulate. S3-S5 are the same as in Example 1.

[0051] Example 6 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1-S2. Same as Example 1 S3. Preparation of microbial immobilized capsules: Bacillus subtilis inoculant, nitrogen-fixing bacteria inoculant, and modified diatomaceous earth were mixed in a mass ratio of 3:5:100 and added to 10 times their mass of grassland plant aqueous extract to prepare a core layer suspension; the core layer suspension was added dropwise to sodium alginate solution (3wt%), and calcium chloride solution (0.5M) was added dropwise for cross-linking, followed by freeze-drying to prepare microcapsules; wherein, the volume ratio of core layer suspension to sodium alginate solution was 1:8; S4-S5. Same as Example 1.

[0052] Example 7 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1-S2. Same as Example 1 S3. Preparation of microbial immobilized capsules: Bacillus subtilis inoculant, nitrogen-fixing bacteria inoculant, and modified diatomaceous earth were mixed at a mass ratio of 5:3:100 and added to 10 times their mass of grassland plant aqueous extract to prepare a core layer suspension; the core layer suspension was added dropwise to sodium alginate solution (3wt%), and calcium chloride solution (0.5M) was added dropwise for cross-linking, followed by freeze-drying to prepare microcapsules; wherein, the volume ratio of core layer suspension to sodium alginate solution was 1:8; S4-S5. Same as Example 1.

[0053] Comparative Example 1 Same as Example 1, except that the mass of the microbial immobilization capsules is replaced with soil nutrient components.

[0054] Comparative Example 2 Same as Example 1, except that the water-retaining slow-release component is replaced by soil nutrient components of equal mass.

[0055] Comparative Example 3 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1. Preparation of water-retaining slow-release components: Modified diatomaceous earth and biochar are mixed evenly at a mass ratio of 50:1, and a binder (bentonite mixed with 3 times the amount of water to make a slurry) is sprayed on and granulated. S2. Preparation of microbial immobilized capsules: Bacillus subtilis inoculant, nitrogen-fixing bacteria inoculant, and modified diatomaceous earth were mixed in a ratio of 3:3:100 and added to 10 times their weight of grassland plant aqueous extract to prepare a core layer suspension; the core layer suspension was added dropwise to sodium alginate solution (3wt%), and calcium chloride solution (0.5M) was added dropwise for cross-linking, followed by freeze-drying to prepare microcapsules; wherein, the volume ratio of core layer suspension to sodium alginate solution was 1:8; S3. Preparation of soil nutrient components: Mix fresh cow manure and grassland plant straw (mass ratio 3:1), add 0.5% Bacillus inoculant, add water to adjust the humidity to 60%, cover with film for fermentation, turn the pile after the core temperature rises to 50℃, fermentation is completed after the odor disappears after 15 days; dry the fermented compost and then crush it. S4. Preparation of soil conditioner: Mix 10 parts of water-retaining slow-release component, 10 parts of microbial immobilized capsules and 25 parts of soil nutrient component to obtain soil conditioner.

[0056] Comparative Example 4 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1. Preparation of polymeric amino acid-humic acid complex: Humic acid was dissolved in water to prepare a 5 wt% solution, and polyaspartic acid was prepared to prepare an 11 wt% solution. Under stirring conditions, the polymeric amino acid solution was added dropwise to an equal volume of humic acid solution, and the reaction was stirred for 3 h. The polymeric amino acid-humic acid complex was obtained by spray drying. S2. Preparation of water-retaining slow-release components: Weigh out the polymeric amino acid-humic acid complex, modified diatomaceous earth and biochar at a mass ratio of 1:50:1, mix them evenly, spray with binder (bentonite mixed with 3 times the amount of water to make slurry), and granulate. S3. Preparation of microbial immobilized capsules: Bacillus subtilis inoculant and modified diatomaceous earth were mixed at a mass ratio of 6:100 and added to 10 times the mass of grassland plant aqueous extract to prepare a core layer suspension; the core layer suspension was added dropwise to sodium alginate solution (3wt%), and calcium chloride solution (0.5M) was added dropwise for cross-linking, and then freeze-dried to prepare microcapsules; wherein, the volume ratio of core layer suspension to sodium alginate solution was 1:8; S4. Preparation of soil nutrient components: Mix fresh cow manure and grassland plant straw (mass ratio 3:1), add 0.5% Bacillus inoculant, add water to adjust the humidity to 60%, cover with film for fermentation, turn the pile after the core temperature rises to 50℃, fermentation is complete when the odor disappears after 15 days; dry the fermented compost and then crush it. S5. Preparation of soil conditioner: Mix 10 parts of water-retaining slow-release component, 10 parts of microbial immobilized capsules and 25 parts of soil nutrient component to obtain soil conditioner.

[0057] Comparative Example 5 A composite soil conditioner suitable for the Horqin Sandy Land is prepared as follows: S1. Preparation of polymeric amino acid-humic acid complex: Humic acid was dissolved in water to prepare a 5 wt% solution, and polyaspartic acid was prepared to prepare an 11 wt% solution. Under stirring conditions, the polymeric amino acid solution was added dropwise to an equal volume of humic acid solution, and the reaction was stirred for 3 h. The polymeric amino acid-humic acid complex was obtained by spray drying. S2. Preparation of water-retaining slow-release components: Weigh out the polymeric amino acid-humic acid complex, modified diatomaceous earth and biochar at a mass ratio of 1:50:1, mix them evenly, spray with binder (bentonite mixed with 3 times the amount of water to make slurry), and granulate. S3. Preparation of soil nutrient components: Mix fresh cow manure and grassland plant straw (mass ratio 3:1), add 0.5% Bacillus inoculant, add water to adjust the humidity to 60%, cover with film for fermentation, turn the pile after the core temperature rises to 50℃, fermentation is completed after the odor disappears after 15 days; dry the fermented compost and then crush it. S4. Preparation of soil conditioner: Mix 10 parts of water-retaining slow-release component, 0.3 parts of Bacillus subtilis inoculant, 0.3 parts of nitrogen-fixing bacteria inoculant, and 25 parts of soil nutrient components to obtain the soil conditioner.

[0058] Application examples The performance of the soil conditioners prepared in Examples 1-7 and Comparative Examples 1-5 was verified.

[0059] 1. Experimental Site: The experimental site is located in the Agricultural Science and Technology Park of Inner Mongolia University for Nationalities in the West Liaohe Plain. Latitude: 43°38′N, Longitude: 122°04′E, Altitude: 178m. The experimental area has a typical temperate continental monsoon climate, with an average annual temperature of 6.4℃, an extreme minimum temperature of -30.9℃, an accumulated temperature ≥10℃ of 3184℃, a frost-free period of 150 days, and an average annual precipitation of 400mm, with 89% of the annual precipitation occurring during the growing season (April to September). The soil at the experimental site is aeolian sandy soil, the main soil type in the area, with an organic matter content of 4.22g·kg⁻¹. -1 Available nitrogen 11.15 mg·kg -1 5.44 mg / kg of readily available phosphorus -1 94.65 mg·kg of readily available potassium -1 pH value 8.20.

[0060] 2. Experimental Methods: A split-plot experiment was established in the Horqin Sandy Land, setting up two irrigation levels (conventional and deficit irrigation) and 12 soil organic amendment combinations. The experiment compared the growth, yield, quality, and changes in soil physicochemical properties of oats and alfalfa, focusing on obtaining high-precision data on water use efficiency, soil carbon and nitrogen balance, and microbial activity. Deficit irrigation was implemented at 60-65% of the field capacity of conventional irrigation.

[0061] The method of applying the soil conditioner is as follows: apply it to the soil to be improved before planting pasture grass, at a rate of 50 kg / 667 m². 2 They were deeply tilled into the soil and planted with oats and alfalfa using conventional methods.

[0062] Each test area is 66.7m². 2 Each embodiment or comparative example has three replicates, and each experimental area ensures that the pasture planting density and water and fertilizer management methods are consistent.

[0063] Soil sampling: Soil samples were collected after the forage was harvested. Ten samples were collected from each experimental area at a depth of 30 cm from the soil surface.

[0064] 3. The experimental results are statistically summarized in Tables 1-4 (the statistical results are average values).

[0065] Table 1. Statistics of Oat Experimental Results (Adjusted for Deficit) Table 2. Statistical analysis of oat experimental area results (routine) Table 3. Statistics of alfalfa experimental areas (adjusted for deficit) Table 4. Statistics of Alfalfa Experimental Areas (Routine) As shown in Tables 1-4, the soil conditioners of Examples 1-7 of this invention have a significant effect on improving sandy soil in this region. Compared with Comparative Examples 1-5, both soil texture and forage yield are significantly improved. Moreover, the soil conditioner coupled with deficit irrigation has a similar soil improvement effect to conventional irrigation, indicating that the technical approach of soil conditioner coupled with deficit irrigation improves water and fertilizer use efficiency, reduces nutrient loss, and is suitable for sandy soil conditions in the Horqin region.

[0066] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A composite soil conditioner suitable for the Horqin Sandy Land, characterized in that, By weight, the raw materials include 10 parts of water-retaining slow-release component, 10-15 parts of microbial immobilized capsules, and 20-25 parts of soil nutrient component; The water-retaining and slow-release components include a polymeric amino acid-humic acid complex, modified diatomaceous earth, and biochar in a mass ratio of 1:(30~50):(0.5~1). The microbial fixation capsule uses drought-resistant bacteria, plant rhizosphere growth-promoting bacteria and modified diatomaceous earth as the core layer and sodium alginate as the shell layer. The soil nutrient components are prepared by fermenting grassland plant straw and cow manure.

2. The composite soil conditioner for the Horqin Sandy Land according to claim 1, characterized in that, The preparation method of the water-retaining and slow-release component is as follows: the polymerized amino acid-humic acid complex, modified diatomaceous earth and biochar are mixed evenly in proportion, a binder is sprayed on, and granulation is performed.

3. The composite soil conditioner for the Horqin Sandy Land according to claim 2, characterized in that, The modified diatomaceous earth is obtained by modifying diatomaceous earth with inorganic acids.

4. The composite soil conditioner for the Horqin Sandy Land according to claim 1, characterized in that, The method for preparing the microbial fixed capsules is as follows: drought-resistant bacteria, plant rhizosphere growth-promoting bacteria and modified diatomaceous earth are mixed in a mass ratio of (3~5):(3~5):100 and added to grassland plant water extract to prepare a core layer suspension; the core layer suspension is added dropwise to sodium alginate solution, and calcium chloride solution is added dropwise for cross-linking, and then freeze-dried to prepare microcapsules.

5. The composite soil conditioner for the Horqin Sandy Land according to claim 1, characterized in that, The preparation method of the polymeric amino acid-humic acid complex is as follows: humic acid is dissolved in water to prepare a solution with a concentration of 5-10 wt%, and polymeric amino acid is prepared into a solution with a concentration of 10-15 wt%. Under stirring conditions, the polymeric amino acid solution is added dropwise to an equal volume of humic acid solution, and the reaction is stirred for 3-4 hours. The polymeric amino acid-humic acid complex is obtained by spray drying.

6. The composite soil conditioner for the Horqin Sandy Land according to claim 4, characterized in that, The plants in the grassland plant straw and grassland plant water extract are independently selected from at least one of Artemisia annua, Artemisia argyi, Artemisia frigida, Aster tataricus or Taraxacum mongolicum.

7. A method for preparing a composite soil conditioner suitable for the Horqin Sandy Land as described in any one of claims 1 to 6, characterized in that, The water-retaining slow-release component, microbial immobilized capsules, and soil nutrient components are mixed according to the mass ratio to obtain the product.

8. The application of the composite soil conditioner for Horqin Sandy Land as described in any one of claims 1 to 6 in improving grassland soil in the Horqin region.

9. A method for improving grassland soil in the Horqin region, characterized in that, Soil improvement is carried out by using the composite soil conditioner for Horqin Sandy Land as described in any one of claims 1 to 6 coupled with deficit irrigation.

10. The method for improving grassland soil in the Horqin region according to claim 9, characterized in that, The deficit irrigation mentioned above is 60-65% of field capacity.

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