Fertilizer for sandy soil improvement and preparation thereof

Abstract

The invention discloses a fertilizer for sandy soil improvement and preparation thereof, and belongs to the technical field of soil improvement. The fertilizer for sandy soil improvement is prepared from the following components in parts by weight: 0.17 to 0.19 part by mass of bentonite, 0.055 to 0.065 part by mass of charcoal, 0.34 to 0.38 part by mass of a microbial agent, 0.34 to 0.38 part by mass of mushroom dregs, 0.05 to 0.07 part by mass of humic acid, 1.03 to 1.05 part by mass of urea and 0.45 to 0.47 part by mass of monopotassium phosphate. Wherein the microbial agent at least comprises bacillus mucilaginosus; the prepared fertilizer for improving the sandy soil can effectively improve the physicochemical properties of the sandy soil and improve the water and fertilizer retention capacity of the soil.

Description

Technical Field

[0001] The invention relates to a fertilizer for improving sandy soil and a preparation method thereof. Background Art

[0002] Sandy soils, due to their coarse particles, high porosity, and low organic matter content, generally suffer from problems such as poor water and fertilizer retention, nutrient loss, and insufficient microbial activity. Although traditional soil improvement methods can alleviate these shortcomings to a certain extent, they still have many limitations:

[0003] Current technologies primarily rely on single organic fertilizers (such as composted straw and livestock manure) or mineral materials (such as wood ash and pond mud) for soil improvement. For example, returning straw to the fields or increasing the amount of manure applied can effectively increase soil organic matter content. However, these materials have problems with nutrient release rates being difficult to control and lack stability, and are prone to nutrient loss in highly permeable sandy soils.

[0004] Some studies have attempted to use waste materials such as sewage sludge and food waste to create soil conditioners in an effort to reduce production costs. However, these raw materials may carry heavy metals or pathogenic microorganisms, posing a risk of secondary contamination with long-term use. Furthermore, to reduce their potential toxicity, they often require complex fermentation processes, which in turn increases the cost of practical application.

[0005] In recent years, synthetic materials such as polyacrylamide and polylactic acid-urea-formaldehyde resin have been proposed for improving the water retention of sandy soils. While these materials can enhance soil water retention through physical adsorption, their non-degradability can easily lead to soil compaction. Furthermore, these materials often rely on imported raw materials (such as GeoRevive), resulting in high costs and limiting their widespread application.

[0006] Most existing microbial agents (such as Bacillus subtilis and nitrogen-fixing bacteria) focus on a specific function (such as phosphorus solubilization or nitrogen fixation), lack the ability to systematically regulate the formation of soil aggregate structure, and do not fully combine organic and inorganic composite carriers to maintain the stability and activity of the bacterial community.

[0007] Therefore, there is an urgent need to develop a fertilizer for efficient and sustainable improvement of sandy soil. Summary of the Invention

[0008] The purpose of the present invention is to provide a fertilizer for improving sandy soil and its preparation method, so as to solve the technical problems mentioned in the above background technology.

[0009] The technical solution for achieving the purpose of the present invention is:

[0010] In a first aspect, the present invention provides a fertilizer for improving sandy soil, which comprises, by weight, 0.17 to 0.19 parts by mass of bentonite, 0.055 to 0.065 parts by mass of biochar, 0.34 to 0.38 parts by mass of microbial agents, 0.34 to 0.38 parts by mass of fungal residues, 0.05 to 0.07 parts by mass of humic acid, 1.03 to 1.05 parts by mass of urea, and 0.45 to 0.47 parts by mass of potassium dihydrogen phosphate.

[0011] Furthermore, the bentonite is calcium-based bentonite.

[0012] Furthermore, the pH of the calcium-based bentonite is 7.11-7.20, containing 58.72-64.85% silicon dioxide, 17.03-18.9% aluminum oxide, 6.81-8.29% iron oxide, 5.07-5.33% calcium oxide, 1.7-2.76% magnesium oxide, an expansion capacity of 5.8-6.5 mL / g, and a colloid value of 38-45 mL / g.

[0013] Furthermore, the microbial agent at least includes Bacillus subtilis.

[0014] Furthermore, the pH value of the fungus residue is 6.5-6.7, and it contains 38-39% organic matter, 31.5-32.5% total carbon, 1.2-1.4% total nitrogen, 22.1-22.3% lignin, 12.6-13% cellulose, and 8-9% hemicellulose.

[0015] Furthermore, the pH value of the humic acid is 5.8-6, and contains 30-35% organic matter.

[0016] Furthermore, the biochar has a pH of 9.45-9.47, an organic carbon content of 2.1-2.12 g / kg, an effective phosphorus content of 28.81-2.85 mg / kg, a total nitrogen content of 0.4-0.44 g / kg, a total phosphorus content of 0.1-0.14 g / kg, and a total potassium content of 0.8-0.82 g / kg.

[0017] In a second aspect, the present invention provides a method for preparing the sandy soil improving fertilizer as described in the first aspect, comprising the following preparation steps:

[0018] (1) Weigh and prepare the ingredients according to the mass fraction of each component;

[0019] (2) drying the bentonite weighed in step (1), rolling it through a 0.5 mm sieve, sterilizing it at 120° C. for 15 to 25 minutes, then adding the weighed microbial agent and stirring and mixing it evenly, then adding the weighed fungus residue, continuing to stir and mix it evenly, and then heat-insulating and composting it at 29.5 to 30.5° C. for 14 to 28 days to obtain a first mixed fertilizer;

[0020] (3) The fertilizer mixed for the first time in step (2) is evenly mixed with the biochar, humic acid, urea, and potassium dihydrogen phosphate weighed in step (1) to obtain a fertilizer for improving sandy soil.

[0021] In a third aspect, the present invention provides a use of the sandy soil improving fertilizer as described in the first aspect, wherein the amount of the sandy soil improving fertilizer is 15-20% of the mass of the sandy soil.

[0022] By adopting the above technical solution, the present invention has the following beneficial effects:

[0023] (1) The sandy soil improving fertilizer of the present invention comprises, by weight, 0.17 to 0.19 parts by weight of bentonite, 0.055 to 0.065 parts by weight of biochar, 0.34 to 0.38 parts by weight of microbial agent, 0.34 to 0.38 parts by weight of fungal residue, 0.05 to 0.07 parts by weight of humic acid, 1.03 to 1.05 parts by weight of urea, and 0.45 to 0.47 parts by weight of potassium dihydrogen phosphate. The obtained sandy soil improving fertilizer can effectively improve the physical and chemical properties of sandy soil and achieve the effect of water and fertilizer conservation.

[0024] (2) The addition of microbial agents to the fertilizer for improving sandy soil of the present invention can promote the circulation and activation of soil nutrients. By participating in biochemical processes such as organic matter decomposition and humus formation, it converts insoluble nutrients into forms that can be absorbed and utilized by plants. At the same time, it has the ability to fix nitrogen and decompose mineral components, thereby improving the soil nutrient structure, increasing the level of fast-acting nutrient supply, and prolonging the duration of fertilizer effect. Secondly, in terms of improving soil biological properties, microbial agents help to increase the number and diversity of beneficial microorganisms such as bacteria and actinomycetes in the soil, and promote the increase of plant root secretions, providing a good colonization environment for microorganisms in the agent and enhancing their survival ability. In addition, it can also improve the physical structure of the soil, effectively alleviate the problem of soil compaction, enhance the ability to resist soil erosion, regulate the pH value of the soil, and improve the water-stable aggregate structure and aggregate stability. In sandy environments, it can also promote microbial reproduction through sand fixation, form biological crusts, reduce water evaporation, and improve the local microecological environment. At the same time, microbial agents can significantly promote plant growth and increase yield, and increase crop yield by enhancing the absorption and utilization of key nutrients such as alkaline nitrogen and fast-acting potassium by plants.

[0025] (3) The sandy soil improvement fertilizer of the present invention improves the soil by adding biochar, which has a high specific surface area and rich mineral nutrients such as P, K, Ca, and Mg. After the biochar is applied, it can directly increase the organic matter content of the soil and replenish the soil phosphorus pool through the phosphorus and soluble mineral elements such as Ca and Mg it contains. At the same time, it improves the biological effectiveness of soil phosphorus by changing the physical and chemical properties of the soil, such as adjusting pH, increasing cation exchange capacity, and regulating the biochemical process of phosphorus form conversion, such as promoting microbial activity and inhibiting phosphorus fixation. In addition, the porous structure of biochar can also optimize soil moisture and aeration, promote crop root development and the release of rhizosphere secretions (such as organic acids), thereby activating the insoluble phosphorus in the soil and improving the crop's phosphorus absorption efficiency.

[0026] (4) The fertilizer used in the present invention for improving sandy soil is added with bentonite, which has many positive effects on sandy soil: bentonite can increase the soil moisture content of the 0-100 cm soil layer, reduce water evaporation, and play a role in moisture conservation and water storage and drought resistance and seedling protection; at the same time, it can also reduce soil bulk density, increase porosity, and promote the formation of large soil aggregates; it can also improve the bonding properties of fine sand particles; bentonite can significantly increase the soil cation exchange capacity and the total amount of base ions, thereby enhancing the soil's fertilizer retention and supply capacity and fertility buffering capacity; and it can increase the content of nutrients such as fast-acting nitrogen, phosphorus, and potassium, fix nitrogen, phosphorus, and potassium nutrients through adsorption, and effectively reduce nitrogen loss.

[0027] (5) The sandy soil improvement fertilizer of the present invention promotes the formation of aggregates in sandy soil by adding humic acid and utilizing its colloidal properties, thereby improving soil porosity and water retention capacity, and effectively alleviating the problems of loose sandy soil and fertilizer and water leakage. Functional groups such as carboxyl and phenolic hydroxyl groups in humic acid molecules can adsorb soil particles and build a stable soil structure; its high water absorption and ion exchange capacity can also reduce water evaporation, adsorb nutrients such as nitrogen, phosphorus, and potassium, and prolong the fertilizer effect time; in addition, humic acid releases fixed trace elements (such as iron and zinc) in the soil through chelation, promoting the absorption of these nutrients by plants; at the same time, it can also inhibit the fixation reaction of phosphate fertilizer in the soil, thereby increasing the utilization rate of phosphorus by more than 30%; humic acid also provides a carbon source for soil microorganisms, accelerates the decomposition process of organic matter such as straw, and enhances the activity of soil enzymes such as sucrase and phosphatase, thereby enhancing the self-repair ability and biological activity of sandy soil.

[0028] (6) The addition of fungus residue to the fertilizer for improving sandy soil of the present invention has many positive effects on sandy soil: a huge amount of fungus residue is discarded in my country every year, and there is a wide range of raw material sources; the raw materials used for cultivating edible fungi usually contain a large amount of macromolecular nutrients that are difficult to be directly utilized by plants. After the mycelium decomposes, the remaining fungus residue contains organic matter and carbon and nitrogen nutrients that can be directly absorbed by plants. At the same time, the remaining living mycelium is also a kind of efficient nutrient source, which can continuously provide energy for plant growth; in addition, fungus residue has unique physical properties, which can enhance the fertilization capacity and acid and alkali resistance of the deep soil layer, increase the organic matter and total nitrogen content in the soil, increase the proportion of aggregate structure with a particle size greater than 0.25 mm, and reduce the soil bulk density; fungus residue can also improve the physical and chemical properties and enzyme activity of the soil, help vegetation recovery, and improve crop yield and quality; the fungus residue itself has a low bulk density, loose texture, and good permeability, and also shows significant effects in improving the soil's water and fertilizer retention capacity.

[0029] (7) When preparing the fertilizer for improving sandy soil of the present invention, bentonite, microbial agent and bacterial residue are premixed and piled for 14 to 28 days. The carbonic anhydrase produced by Bacillus subtilis can fix carbon dioxide in the atmosphere, so that the interaction between microorganisms and soil is maintained in a weak alkaline environment. This weak alkaline condition promotes the conversion of montmorillonite minerals in bentonite to illite, reduces the content of montmorillonite in bentonite, and effectively controls the swelling and shrinkage potential of bentonite, effectively improves the physical properties of sandy soil, and makes its structure more stable; bacterial residue can provide nutrients for microbial agent, ensure the activity and sustained action ability of microorganisms, and the synergistic effect of the three further improves the physical and chemical properties of sandy soil to achieve the effect of water and fertilizer conservation. DETAILED DESCRIPTION

[0030] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0031] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0032] The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0033] The bentonite used is calcium-based bentonite; the pH of the calcium-based bentonite is 7.11, and it contains 58.72% of silicon dioxide, 18.95% of aluminum oxide, 6.81% of iron oxide, 5.07% of calcium oxide, and 2.76% of magnesium oxide, with an expansion capacity of 5.8 mL / g and a colloidal value of 38 mL / g.

[0034] The microbial agent was ordered from Shandong Paul Timhan Biotechnology Co., Ltd. and consists of Bacillus subtilis, Bacillus megaterium, and Bacillus mucilaginosus, with a live bacterial content of 2×10 10 CFU·g -1 .

[0035] The pH value of the fungus residue is 6.6, and it contains 38.5% organic matter, 32% total carbon, 1.3% total nitrogen, 22.2% lignin, 12.8% cellulose, and 8.5% hemicellulose.

[0036] The pH value of humic acid is 5.8 and it contains 30% organic matter.

[0037] The pH of biochar is 9.46, the organic carbon content is 2.11g / kg, the available phosphorus content is 28.83mg / kg, the total nitrogen content is 0.42g / kg, the total phosphorus content is 0.12g / kg, and the total potassium content is 0.81g / kg.

[0038] (Example 1)

[0039] A method for preparing a fertilizer for improving sandy soil comprises the following steps:

[0040] (1) Weigh and prepare the following ingredients according to the mass parts of each component: 0.17 mass parts of bentonite, 0.055 mass parts of biochar, 0.34 mass parts of microbial agent, 0.34 mass parts of bacterial residue, 0.05 mass parts of humic acid, 1.03 mass parts of urea, and 0.45 mass parts of potassium dihydrogen phosphate;

[0041] (2) drying the bentonite weighed in step (1), rolling it through a 0.5 mm sieve, sterilizing it at 120° C. for 15 min, then adding the weighed microbial agent and stirring and mixing it evenly, then adding the weighed fungus residue, continuing to stir and mix it evenly, and then heat-insulating and composting it at 29.5° C. for 14 days to obtain a first mixed fertilizer;

[0042] (3) The fertilizer mixed for the first time in step (2) is evenly mixed with the biochar, humic acid, urea, and potassium dihydrogen phosphate weighed in step (1) to obtain a fertilizer for improving sandy soil.

[0043] (Example 2)

[0044] A method for preparing a fertilizer for improving sandy soil comprises the following steps:

[0045] (1) Weigh and prepare the following ingredients according to the mass parts of each component: 0.18 mass parts of bentonite, 0.06 mass parts of biochar, 0.36 mass parts of microbial agent, 0.36 mass parts of bacterial residue, 0.06 mass parts of humic acid, 1.04 mass parts of urea, and 0.46 mass parts of potassium dihydrogen phosphate;

[0046] (2) drying the bentonite weighed in step (1), rolling it through a 0.5 mm sieve, sterilizing it at 120° C. for 20 min, then adding the weighed microbial agent and stirring and mixing it evenly, then adding the weighed fungus residue, continuing to stir and mix it evenly, and then heat-insulating and composting it at 30° C. for 21 days to obtain a first mixed fertilizer;

[0047] (3) The fertilizer mixed for the first time in step (2) is evenly mixed with the biochar, humic acid, urea, and potassium dihydrogen phosphate weighed in step (1) to obtain a fertilizer for improving sandy soil.

[0048] (Example 3)

[0049] A method for preparing a fertilizer for improving sandy soil comprises the following steps:

[0050] (1) Weigh and prepare the following ingredients according to the mass parts of each component: 0.19 mass parts of bentonite, 0.065 mass parts of biochar, 0.38 mass parts of microbial agent, 0.38 mass parts of bacterial residue, 0.07 mass parts of humic acid, 1.05 mass parts of urea, and 0.47 mass parts of potassium dihydrogen phosphate;

[0051] (2) drying the bentonite weighed in step (1), rolling it through a 0.5 mm sieve, sterilizing it at 120° C. for 25 min, then adding the weighed microbial agent and stirring and mixing it evenly, then adding the weighed fungus residue, continuing to stir and mix it evenly, and then heat-insulating and composting it at 30.5° C. for 28 days to obtain a first mixed fertilizer;

[0052] (3) The fertilizer mixed for the first time in step (2) is evenly mixed with the biochar, humic acid, urea, and potassium dihydrogen phosphate weighed in step (1) to obtain a fertilizer for improving sandy soil.

[0053] (Comparative Example 1)

[0054] A method for preparing a fertilizer for improving sandy soil comprises the following steps:

[0055] (1) Weigh and prepare the following ingredients according to the mass parts of each component: 0.18 mass parts of bentonite, 0.36 mass parts of microbial agent, 0.36 mass parts of bacterial residue, 0.06 mass parts of humic acid, 1.04 mass parts of urea, and 0.46 mass parts of potassium dihydrogen phosphate;

[0056] (2) drying the bentonite weighed in step (1), rolling it through a 0.5 mm sieve, sterilizing it at 120° C. for 20 min, then adding the weighed microbial agent and stirring and mixing it evenly, then adding the weighed fungus residue, continuing to stir and mix it evenly, and then heat-insulating and composting it at 30° C. for 21 days to obtain a first mixed fertilizer;

[0057] (3) Evenly mixing the fertilizer mixed for the first time in step (2) with the humic acid, urea, and potassium dihydrogen phosphate weighed in step (1) to obtain a fertilizer for improving sandy soil.

[0058] (Comparative Example 2)

[0059] A method for preparing a fertilizer for improving sandy soil comprises the following steps:

[0060] (1) Weigh the following ingredients according to their mass fractions: 0.18 mass parts of bentonite, 0.06 mass parts of biochar, 0.36 mass parts of fungus residue, 0.06 mass parts of humic acid, 1.04 mass parts of urea, and 0.46 mass parts of potassium dihydrogen phosphate;

[0061] (2) drying the bentonite weighed in step (1), rolling it through a 0.5 mm sieve, sterilizing it at 120° C. for 20 min, adding the weighed fungus residue, continuing to stir and mix evenly, and then heat-insulating and composting it at 30° C. for 21 days to obtain a first mixed fertilizer;

[0062] (3) The fertilizer mixed for the first time in step (2) is evenly mixed with the biochar, humic acid, urea, and potassium dihydrogen phosphate weighed in step (1) to obtain a fertilizer for improving sandy soil.

[0063] (Comparative Example 3)

[0064] A method for preparing a fertilizer for improving sandy soil comprises the following steps:

[0065] (1) Weigh and prepare the following ingredients according to their mass fractions: 0.18 mass parts of bentonite, 0.36 mass parts of fungus residue, 0.06 mass parts of humic acid, 1.04 mass parts of urea, and 0.46 mass parts of potassium dihydrogen phosphate;

[0066] (2) drying the bentonite weighed in step (1), rolling it through a 0.5 mm sieve, sterilizing it at 120° C. for 20 min, adding the weighed fungus residue, continuing to stir and mix evenly, and then heat-insulating and composting it at 30° C. for 21 days to obtain a first mixed fertilizer;

[0067] (3) Evenly mixing the fertilizer mixed for the first time in step (2) with the humic acid, urea, and potassium dihydrogen phosphate weighed in step (1) to obtain a fertilizer for improving sandy soil.

[0068] (Comparative Example 4)

[0069] A method for preparing a fertilizer for improving sandy soil comprises the following steps:

[0070] (1) Weigh and prepare the following ingredients according to the mass parts of each component: 0.18 mass parts of bentonite, 0.06 mass parts of biochar, 0.36 mass parts of microbial agent, 0.36 mass parts of bacterial residue, 0.06 mass parts of humic acid, 1.04 mass parts of urea, and 0.46 mass parts of potassium dihydrogen phosphate;

[0071] (2) The components weighed in step (1) are mixed evenly to obtain a fertilizer for improving sandy soil.

[0072] (Effect Example)

[0073] On March 12, 2024, eight adjacent test plots were selected from sandy soil farmland in Zhanggutai Town, Zhangwu County, Fuxin City, Liaoning Province as the improvement object. The crop was wheat, and three plots were respectively applied with the sandy soil improvement fertilizers of Example 1, Example 2 and Example 3; four plots were respectively applied with the sandy soil improvement fertilizers of Comparative Examples 1 to 4; the eighth plot was not fertilized and was treated as a blank case; the application rate of the sandy soil improvement fertilizer was 500 kg / mu, and it was applied as a base when planting wheat; the content of water-stable macroaggregates at a depth of 0 to 25 cm was measured before and after fertilization, and the wheat yield was measured at harvest.

[0074] Table 1 below shows the performance data of the soils of Examples 1 to 3, Comparative Examples 1 to 4, and a blank example, as well as the performance data of wheat yield:

[0075] Table 1

[0076]

[0077] From Table 1 above, it can be seen that the physical and chemical properties of the soil to which the sandy soil improving fertilizers of Examples 1 to 3 were applied were better, and the wheat yield was higher.

[0078] The difference between Comparative Example 1 and Example 2 is that no biochar is added in Comparative Example 1, the difference between Comparative Example 2 and Example 2 is that no microbial agent is added in Comparative Example 1, the difference between Comparative Example 3 and Example 2 is that no biochar and microbial agent are added in Comparative Example 1, and the difference between Comparative Example 4 and Example 2 is that all the components are directly mixed in Comparative Example 4 without stacking; compared with Example 2, it is obvious that Example 2 uses 0.18 parts by mass of bentonite, 0.06 parts by mass of biochar, 0.36 parts by mass of microbial agent, 0.36 parts by mass of fungus residue, 0.06 parts by mass of humic acid, 1.04 parts by mass of urea, and 0.46 parts by mass of potassium dihydrogen phosphate, and the bentonite, microbial agent, and fungus residue are pre-piled. The physical and chemical properties of the soil applied with the fertilizer for sandy soil improvement are good and the crop yield is high.

[0079] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fertilizer for improving sandy soil, characterized in that: In parts by weight, the components include 0.17 to 0.19 parts by mass of bentonite, 0.055 to 0.065 parts by mass of biochar, 0.34 to 0.38 parts by mass of microbial agent, 0.34 to 0.38 parts by mass of fungus residue, 0.05 to 0.07 parts by mass of humic acid, 1.03 to 1.05 parts by mass of urea, and 0.45 to 0.47 parts by mass of potassium dihydrogen phosphate.

2. The fertilizer for improving sandy soil according to claim 1, characterized in that: The bentonite is calcium-based bentonite.

3. The fertilizer for improving sandy soil according to claim 2, characterized in that: The calcium-based bentonite has a pH of 7.11-7.20, contains 58.72-64.85% of silicon dioxide, 17.03-18.9% of aluminum oxide, 6.81-8.29% of iron oxide, 5.07-5.33% of calcium oxide, 1.7-2.76% of magnesium oxide, an expansion capacity of 5.8-6.5 mL / g, and a colloid value of 38-45 mL / g.

4. The fertilizer for improving sandy soil according to claim 1, characterized in that: The microbial agent at least includes Bacillus subtilis.

5. The fertilizer for improving sandy soil according to claim 1, characterized in that: The pH value of the fungus residue is 6.5-6.7, and it contains 38-39% of organic matter, 31.5-32.5% of total carbon, 1.2-1.4% of total nitrogen, 22.1-22.3% of lignin, 12.6-13% of cellulose, and 8-9% of hemicellulose.

6. The fertilizer for improving sandy soil according to claim 1, characterized in that: The pH value of the humic acid is 5.8-6, and the organic matter content is 30-35%.

7. The fertilizer for improving sandy soil according to claim 1, characterized in that: The biochar has a pH of 9.45-9.47, an organic carbon content of 2.1-2.12 g / kg, an effective phosphorus content of 28.81-2.85 mg / kg, a total nitrogen content of 0.4-0.44 g / kg, a total phosphorus content of 0.1-0.14 g / kg, and a total potassium content of 0.8-0.82 g / kg.

8. A method for preparing the sandy soil improving fertilizer according to any one of claims 1 to 7, characterized in that: The method comprises the following preparation steps: (1) Weigh and prepare the ingredients according to the mass fraction of each component; (2) drying the bentonite weighed in step (1), rolling it through a 0.5 mm sieve, sterilizing it at 120° C. for 15 to 25 minutes, then adding the weighed microbial agent and stirring and mixing it evenly, then adding the weighed fungus residue, continuing to stir and mix it evenly, and then heat-treating it at 29.5 to 30.5° C. for 14 to 28 days to obtain a first mixed fertilizer; (3) The fertilizer mixed for the first time in step (2) is evenly mixed with the biochar, humic acid, urea, and potassium dihydrogen phosphate weighed in step (1) to obtain a fertilizer for improving sandy soil.

9. Use of the fertilizer for improving sandy soil according to any one of claims 1 to 7, characterized in that: The amount of the fertilizer for improving sandy soil is 15-20% of the mass of the sandy soil.

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