Sandy soil soybean efficient modifier and soybean efficient cultivation method

Abstract

The invention discloses an efficient sandy soil soybean improver and an efficient soybean cultivation method, and belongs to the technical field of soil improvement and crop cultivation. According to the method, the rhizobium sinense and the bradyrhizobium angersonii are selected as root viable bacterium additives and are applied together with the modifying agent, so that the soybean root flora environment is improved. According to the invention, through a synergistic improvement technology of soil structure improvement, microbial activity enhancement and accurate and efficient operation of water and fertilizer, promotion of soil aggregate and straw returning by biochar and attapulgite, promotion of soil microbial activity by application of organic fertilizer, improvement of fertilizer efficiency by application of slow and controlled release fertilizer, and reduction of nitrogen and phosphorus non-point source pollution loss are realized. In addition, cultivation synergy measures are enhanced, a foliar topdressing link is supplemented, and a set of soybean efficient cultivation technical system adapting to sandy soil is constructed. According to the method, soil structure optimization, organic matter increase and soybean yield increase are achieved, and an efficient and sustainable improvement scheme is provided for sandy soil.

Description

Technical Field

[0001] This invention relates to the field of soil improvement and crop cultivation technology, specifically to a highly efficient soybean amendment for sandy soil and a highly efficient soybean cultivation method. Background Technology

[0002] Soybeans Glycine max (L.) Merr. is an annual herbaceous plant belonging to the genus *Glycine* in the legume family (Fabaceae). Native to my country, it is cultivated throughout the country, particularly in the Northeast and the Huang-Huai-Hai Plain, and is also widely cultivated worldwide. Soybeans are one of my country's important food crops, historically known as "shu," and have a cultivation history of over 5,000 years. Soybean seeds contain 35%–40% protein, making them a rich source of plant protein. Soybeans are most commonly used to make various soy products, extract soybean oil, brew soy sauce, and extract protein.

[0003] Sandy soil, also known as sandy loam, refers to soil with high sand content, coarse particles, and severe organic matter loss. Due to its high sand content and low clay content, sandy soil has a loose structure, requiring improved fertilizer utilization and increased organic matter content to achieve higher economic benefits. Existing sandy soil improvement and soybean cultivation technologies generally suffer from the following problems: insufficient synergy, simply adding materials without leveraging the synergistic effects of physical structure optimization, nutrient retention, and organic matter replenishment; and a lack of focus on improving the root environment, resulting in a weak response to soybean nitrogen fixation characteristics. Therefore, how to improve the soybean root microbial environment while simultaneously increasing soil porosity and organic matter content to achieve increased soybean yield is an important research direction. Summary of the Invention

[0004] In view of the above-mentioned prior art, the purpose of this invention is to provide a highly efficient soybean amendment for sandy soil and a highly efficient soybean cultivation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a highly efficient soybean soil conditioner for sandy soil, comprising the following raw materials in parts by weight: 1-5 parts controlled-release urea, 2-16 parts diammonium phosphate, 2-8 parts potassium sulfate, 150-250 parts organic fertilizer, 400-600 parts straw biochar, 300-500 parts citric acid-modified attapulgite, 400-600 parts crushed crop straw, 2-20 parts humic acid; 0.5-5 parts root-derived live bacteria additive; and 10-15 parts borax-zinc sulfate foliar fertilizer. The root-derived live bacteria additive includes at least one of Rhizobium sinense or Rhizobium esculentum.

[0006] Furthermore, the *Rhizobium sinense* used ( Sinorhizobium arboris ), with accession number CCTCC HB20081581; *Staphylococcus esculenta* ( Bradyrhizobium elkanii), with accession number CICC 23903.

[0007] Furthermore, in the aforementioned root probiotic additive, the ratio of live bacteria counts of Rhizobium sinense and Rhizobium esculentum is (0.5-5):(0.5-5).

[0008] Furthermore, the number of live bacteria in the root probiotic additive shall not be less than 1×10⁻⁶. 9 cfu / g.

[0009] Furthermore, the controlled-release urea used has a controlled-release period of 50-70 days, the organic matter content of the organic fertilizer is ≥45%, and the straw biochar is crop straw biochar pyrolyzed at 400-600℃; the borax-zinc sulfate foliar fertilizer is a compound aqueous solution containing 0.1-0.5wt% borax and 0.1-0.5wt% zinc sulfate; the citric acid-modified attapulgite clay used is prepared by the following method: Mix attapulgite with a 2-10% citric acid solution at a solid-liquid ratio of (0.5-5) kg: 5 L, stir in a constant temperature water bath at 50-70℃ for 1-3 hours, filter, wash the solid with deionized water until the pH of the filtrate reaches 6.5-7.5, and then dry the solid at 70-90℃ to obtain citric acid modified attapulgite.

[0010] In a second aspect, the present invention provides the application of the aforementioned high-efficiency soybean amendment for sandy soil in any one of the following (1)-(3): (1) Increase soil porosity; (2) Increase soil organic matter content; (3) Increase soybean yield.

[0011] A third aspect of the present invention provides a method for efficient soybean cultivation, including a method for stratified fertilization and seed-fertilizer isolation of soybeans, as detailed below: For stratified fertilization, the fertilization method and the amount of fertilizer per acre are as follows: The depth of the lower layer of fertilized soil is 16-30cm. The following ingredients are added to the sandy soil soybean high-efficiency conditioner: corn straw biochar, root live bacteria additive, diammonium phosphate, potassium sulfate, and citric acid modified attapulgite. The dosage is 400-600kg of straw biochar, 0.25-2.5kg of root live bacteria additive, 2-16kg of diammonium phosphate, 2-8kg of potassium sulfate, and 150-250kg of citric acid modified attapulgite. The surface fertilization soil depth is 10-15cm. The controlled-release urea, root probiotic additive, organic fertilizer, crop straw, citric acid modified attapulgite soil, and humic acid in the sandy soil soybean high-efficiency conditioner are applied. The dosage is 1-5kg of controlled-release urea, 0.25-2.5kg of root probiotic additive, 150-250kg of organic fertilizer, 400-600kg of crop straw, 150-250kg of citric acid modified attapulgite soil, and 2-20kg of humic acid. For seed-fertilizer separation, the seed-fertilizer co-sowing technique is used, where seeds are sown on top of the surface fertilizer layer, with a spacing of 5-7 cm between the seeds and the fertilizer layer.

[0012] This invention employs a synergistic approach of biochar and modified attapulgite: the porous structure of biochar adsorbs nutrients, while the layered colloidal structure of modified attapulgite locks in moisture. The combination of the two reduces the nutrient leaching rate of sandy soil, prolongs the water retention time, rapidly promotes the formation of soil aggregates, improves aggregate stability, and enhances the stability, aeration, and permeability of the soil structure.

[0013] This invention employs a synergistic approach of organic fertilizer, straw, and rhizobia: straw decomposition provides a carbon source, organic fertilizer supplements nitrogen and phosphorus, and together they stimulate the reproduction of rhizobia, improve soil microbial activity, increase the nitrogen fixation capacity of soybeans, and reduce the amount of chemical fertilizer nitrogen used; it also increases soil organic matter content, enhances soil biological vitality, promotes the release of readily available nutrients, improves soil enzyme activity, and promotes the reproduction of soil microorganisms.

[0014] This invention employs a layered fertilization method adapted to sandy soils: a deep layer of phosphorus and potassium fertilizer plus biochar is applied to match the deep root development characteristics of soybeans (main root depth 30-40cm), while a surface layer of fast-acting nitrogen fertilizer plus various improved fertilizers is applied. Among these, slow-release fertilizers can precisely regulate nutrient release, significantly improving fertilizer utilization efficiency and reducing nutrient loss. This combination not only meets the needs of seedlings but also achieves precise and efficient water and fertilizer management through the continuous improvement of soil structure by biochar and attapulgite soil, and the enhancement of microbial activity by organic fertilizers. This effectively enhances the chlorophyll content and lodging resistance of plants, significantly increasing crop yield and avoiding the problem of "dry upper layer and leaky lower layer" in sandy soils.

[0015] This invention utilizes biochar to promote the formation of micro-aggregates, optimize physical structure, and enhance nutrient retention. Citric acid-modified attapulgite effectively improves aggregate stability, enhances water and fertilizer retention capacity, regulates nutrient slow release, promotes microbial activity, enhances soil buffering capacity, and improves soil fertility. Organic fertilizer and straw decomposition increase humus, promote micro-aggregate formation, and reduce soil bulk density. Biochar and attapulgite synergistically improve porosity, increase water holding capacity of sandy soil, reduce nutrient leaching, supplement key nutrients for soybeans, and enhance nitrogen fixation capacity. Attapulgite is rich in Mg and Ca, promoting chlorophyll synthesis; biochar carries trace elements such as Zn and B, increasing nodulation rate. Organic fertilizer provides a carbon source, stimulates rhizobium reproduction, enhances soybean nitrogenase activity, strengthens stress resistance, and improves quality. The combination of citric acid-modified attapulgite soil and corn straw biochar poses no safety risks and has significantly better water and fertilizer retention capacity than commonly used improvement materials in existing technologies. The formula is targeted: it is designed according to the sand content of sandy soil and supplements essential trace elements such as Zn, B, and Mg for soybeans. Its adaptability is far higher than the general or cross-crop formulas of existing technologies.

[0016] Furthermore, during the initial flowering stage, weeding and foliar spraying should be carried out in conjunction with cultivation.

[0017] This invention adopts a combination of "layered deep application + foliar topdressing" to effectively solve the problem of nutrient leaching in sandy soils. It is different from the single fertilization mode of existing technologies and has superior effects: soybean yield is increased compared with existing technologies, and it has significant economic and ecological value.

[0018] Furthermore, a foliar spray containing a compound aqueous solution of 0.1-0.5 wt% borax and 0.1-0.5 wt% zinc sulfate can be applied.

[0019] Furthermore, the dosage of the compound aqueous solution is 10-15 kg per acre.

[0020] The beneficial effects of this invention are: This invention selects *Rhizobium sinense* and *Rhizobium esculentum* as root-derived probiotic additives, which are applied simultaneously with other fertilizers to improve the root microbial environment of soybeans. This invention utilizes a synergistic improvement technology of "soil structure improvement - microbial activity enhancement - precise and efficient water and fertilizer management" to achieve the following: biochar and attapulgite promote soil aggregates; organic fertilizer promotes soil microbial activity; and slow-release fertilizer improves fertilizer efficiency, reducing nitrogen and phosphorus non-point source pollution losses. This invention uses crop straw to prepare biochar (without heavy metal risk), balancing economic efficiency and safety. The base fertilizer uses a targeted formula to effectively enhance water and fertilizer retention capacity, while adding humic acid synergists to enhance the slow-release effect of nutrients. In terms of fertilization methods, an innovative combination of "layered deep application + seed-fertilizer isolation" technology is adopted, significantly reducing nutrient leaching. Furthermore, by strengthening cultivation synergy measures and combining the nutrient requirements of soybeans during their growth stages, foliar fertilization is supplemented, constructing a high-efficiency soybean cultivation technology system adapted to sandy soils. This invention improves soil aggregate stability, increases organic matter, increases nitrogen-fixing bacteria abundance, and increases soybean yield, providing an efficient and sustainable improvement solution for sandy soils. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0022] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0023] The experimental materials used in the embodiments of this invention, unless otherwise specified, are all conventional experimental materials in the art and can be purchased through commercial channels. The *Rhizobium sinense* used in this invention (…) Sinorhizobium arboris ), with accession number CCTCC HB 20081581; *Syntrophus esculenta* ( Bradyrhizobium elkanii Sinorhizobium arboris Bradyrhizobium elkanii Sinorhizobium arboris Bradyrhizobium elkanii Sinorhizobium arbor The product has the accession number CICC23903. The organic fertilizer, humic acid, and controlled-release urea were purchased from Shandong Agricultural University Fertilizer Co., Ltd. The organic fertilizer has an organic matter content ≥45%, and the controlled-release urea has a controlled-release period of 60 days. The straw biochar is 500℃ pyrolyzed corn straw biochar. The foliar fertilizer used is a compound aqueous solution containing 0.2wt% borax and 0.3wt% zinc sulfate, i.e., borax-zinc sulfate foliar fertilizer.

[0024] Example 1: Preparation of raw materials for a high-efficiency soybean conditioner for sandy soil 1. Preparation of Citric Acid Modified Attapulgite Attapulgite was mixed with a 5% citric acid solution at a solid-liquid ratio of 1 kg: 5 L, stirred in a constant temperature water bath at 60 °C for 2 h, filtered, and then the solid was washed with deionized water until the pH of the filtrate reached 7 ± 0.5. The solid was then dried at 80 °C, pulverized and passed through a 100-mesh sieve to obtain citric acid modified attapulgite, which was used for subsequent experiments.

[0025] 2. Preparation of root probiotic additives Rhizobium sinense and Rhizobium esculentum were selected and mixed at a 1:1 ratio to create a root microbial additive. The resulting mixture contained 6 × 10⁻⁶ live bacteria. 9 cfu / g.

[0026] Example 2: High-efficiency soybean conditioner for sandy soil and high-efficiency soybean cultivation method The high-efficiency soybean soil conditioner for sandy soil used in this invention comprises the following materials and dosages: 3 kg controlled-release urea, 8 kg diammonium phosphate, 4 kg potassium sulfate, 200 kg commercial organic fertilizer, 500 kg corn straw biochar, 400 kg citric acid modified attapulgite, 500 kg corn straw crushed to 5 cm, 12 kg humic acid; 1 kg root probiotic additive, 13 kg foliar fertilizer.

[0027] Layered fertilization is adopted, and the fertilization method and amount per acre are as follows: Lower layer (16-30cm depth): 500kg corn stalk biochar, 0.5kg root microbial additive prepared in Example 1, 8kg diammonium phosphate, 4kg potassium sulfate, and 200kg citric acid-modified attapulgite. The porous structure of the biochar is utilized to adsorb phosphorus and potassium nutrients, reducing leaching from deeper layers.

[0028] Top layer (10-15cm depth): 3kg controlled-release urea, 0.5kg root probiotic additive prepared in Example 1, 200kg commercial organic fertilizer, 500kg corn stalks, 200kg citric acid-modified attapulgite soil, and 12kg humic acid. This promotes the formation of soil aggregates in the top layer, providing readily available nutrients for soybean seedlings.

[0029] The seed-fertilizer separation method is adopted, using a seed-fertilizer co-seeding machine to sow seeds on top of the surface fertilizer layer, with a distance of 6cm between the seeds and the fertilizer layer. The distance between the seeds and the fertilizer layer should be ≥5cm to avoid burning the seedlings.

[0030] During the initial flowering stage, in conjunction with weeding and cultivation, use drones to spray a compound aqueous solution containing 0.2wt% borax and 0.3wt% zinc sulfate on the leaves at a rate of 13kg per acre to promote rhizobium activity and pod formation.

[0031] Example 3: High-efficiency soybean conditioner for sandy soil and high-efficiency soybean cultivation method The high-efficiency soybean soil conditioner for sandy soil used in this invention comprises the following materials and dosage: 3 kg controlled-release urea, 8 kg diammonium phosphate, 4 kg potassium sulfate, 200 kg commercial organic fertilizer, 500 kg corn straw biochar, 400 kg citric acid modified attapulgite, 500 kg corn straw crushed to 5 cm, 12 kg humic acid, 1 kg root probiotic additive, and 13 kg foliar fertilizer.

[0032] Layered fertilization is adopted, and the fertilization method and amount per acre are as follows: Lower layer (16-30cm depth): 500kg corn stalk biochar, 0.4kg root microbial additive prepared in Example 1, 8kg diammonium phosphate, 4kg potassium sulfate, and 200kg citric acid-modified attapulgite. The porous structure of the biochar is utilized to adsorb phosphorus and potassium nutrients, reducing leaching from deeper layers.

[0033] Top layer (10-15cm depth): 3kg controlled-release urea, 0.6kg root microbial additive prepared in Example 1, 200kg commercial organic fertilizer, 500kg corn stalks, 200kg citric acid-modified attapulgite soil, and 12kg humic acid. This promotes the formation of soil aggregates in the top layer, providing readily available nutrients for soybean seedlings.

[0034] The seed-fertilizer separation method is adopted, using a seed-fertilizer co-seeding machine to sow seeds on top of the surface fertilizer layer, with a distance of 6cm between the seeds and the fertilizer layer. The distance between the seeds and the fertilizer layer should be ≥5cm to avoid burning the seedlings.

[0035] During the initial flowering stage, in conjunction with weeding and cultivation, use drones to spray a compound aqueous solution containing 0.2wt% borax and 0.3wt% zinc sulfate on the leaves at a rate of 13kg per acre to promote rhizobium activity and pod formation.

[0036] Example 4: High-efficiency soybean conditioner for sandy soil and high-efficiency soybean cultivation method The high-efficiency soybean soil conditioner for sandy soil used in this invention comprises the following materials and dosage: 3 kg controlled-release urea, 8 kg diammonium phosphate, 4 kg potassium sulfate, 200 kg commercial organic fertilizer, 500 kg corn straw biochar, 400 kg citric acid modified attapulgite, 500 kg corn straw crushed to 5 cm, 12 kg humic acid, 1 kg root probiotic additive, and 13 kg foliar fertilizer.

[0037] Layered fertilization is adopted, and the fertilization method and amount per acre are as follows: Lower layer (16-30cm depth): 500kg corn stalk biochar, 0.6kg root microbial additive prepared in Example 1, 8kg diammonium phosphate, 4kg potassium sulfate, and 200kg citric acid-modified attapulgite. The porous structure of the biochar is utilized to adsorb phosphorus and potassium nutrients, reducing leaching from deeper layers.

[0038] Top layer (10-15cm depth): 3kg controlled-release urea, 0.4kg root probiotic additive prepared in Example 1, 200kg commercial organic fertilizer, 500kg corn stalks, 200kg citric acid-modified attapulgite soil, and 12kg humic acid. This promotes the formation of surface soil aggregates, providing readily available nutrients for soybean seedlings.

[0039] The seed-fertilizer separation method is adopted, using a seed-fertilizer co-seeding machine to sow seeds on top of the surface fertilizer layer, with a distance of 6cm between the seeds and the fertilizer layer. The distance between the seeds and the fertilizer layer should be ≥5cm to avoid burning the seedlings.

[0040] During the initial flowering stage, combine weeding with foliar spraying of a compound aqueous solution containing 0.2wt% borax and 0.3wt% zinc sulfate at a rate of 13kg per acre to promote rhizobium activity and pod formation.

[0041] Comparative Example 1 The difference between Comparative Example 1 and Example 2 is that the root bacteria additive used contains only Rhizobium sinense, with a viable count of 6 × 10⁻⁶. 9 cfu / g.

[0042] A highly effective soybean amendment for sandy soil, with the following content: 3 kg controlled-release urea, 8 kg diammonium phosphate, 4 kg potassium sulfate, 200 kg commercial organic fertilizer, 500 kg corn straw biochar, 400 kg citric acid modified attapulgite, 500 kg corn straw crushed to 5 cm, 12 kg humic acid, 1 kg root probiotic additive, and 13 kg foliar fertilizer.

[0043] Layered fertilization is adopted, and the fertilization method and amount per acre are as follows: Lower layer (16-30cm depth): 500kg corn stalk biochar, 0.5kg root microbial additive, 8kg diammonium phosphate, 4kg potassium sulfate, and 200kg citric acid-modified attapulgite. The porous structure of the biochar adsorbs phosphorus and potassium nutrients, reducing leaching from deeper layers.

[0044] Top layer (10-15cm depth): 3kg controlled-release urea, 0.5kg root bacteria additive, 200kg commercial organic fertilizer, 500kg corn stalks, 200kg citric acid-modified attapulgite soil, and 12kg humic acid. This promotes the formation of soil aggregates in the top layer, providing readily available nutrients for soybean seedlings.

[0045] The seed-fertilizer separation method is adopted, using a seed-fertilizer co-seeding machine to sow seeds on top of the surface fertilizer layer, with a distance of 6cm between the seeds and the fertilizer layer. The distance between the seeds and the fertilizer layer should be ≥5cm to avoid burning the seedlings.

[0046] During the initial flowering stage, combine weeding with foliar spraying of a compound aqueous solution containing 0.2wt% borax and 0.3wt% zinc sulfate at a rate of 13kg per acre to promote rhizobium activity and pod formation.

[0047] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that the root microbial additive used contains only *Rhizobium esculentum*, with a viable count of 6 × 10⁻⁶. 9 cfu / g.

[0048] A highly effective soybean amendment for sandy soil, with the following content: 3 kg controlled-release urea, 8 kg diammonium phosphate, 4 kg potassium sulfate, 200 kg commercial organic fertilizer, 500 kg corn straw biochar, 400 kg citric acid modified attapulgite, 500 kg corn straw crushed to 5 cm, 12 kg humic acid, 1 kg root probiotic additive, and 13 kg foliar fertilizer.

[0049] Layered fertilization is adopted, and the fertilization method and amount per acre are as follows: Lower layer (16-30cm depth): 500kg corn stalk biochar, 0.5kg root microbial additive, 8kg diammonium phosphate, 4kg potassium sulfate, and 200kg citric acid-modified attapulgite. The porous structure of the biochar adsorbs phosphorus and potassium nutrients, reducing leaching from deeper layers.

[0050] Top layer (10-15cm depth): 3kg controlled-release urea, 0.5kg root bacteria additive, 200kg commercial organic fertilizer, 500kg corn stalks, 200kg citric acid-modified attapulgite soil, and 12kg humic acid. This promotes the formation of soil aggregates in the top layer, providing readily available nutrients for soybean seedlings.

[0051] The seed-fertilizer separation method is adopted, using a seed-fertilizer co-seeding machine to sow seeds on top of the surface fertilizer layer, with a distance of 6cm between the seeds and the fertilizer layer. The distance between the seeds and the fertilizer layer should be ≥5cm to avoid burning the seedlings.

[0052] During the initial flowering stage, combine weeding with foliar spraying of a compound aqueous solution containing 0.2wt% borax and 0.3wt% zinc sulfate at a rate of 13kg per acre to promote rhizobium activity and pod formation.

[0053] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that no root-derived live bacteria additive was added.

[0054] A highly effective soybean amendment for sandy soil, with the following content: 3 kg of controlled-release urea, 8 kg of diammonium phosphate, 4 kg of potassium sulfate, 200 kg of commercial organic fertilizer, 500 kg of corn straw biochar, 400 kg of citric acid-modified attapulgite, 500 kg of corn straw crushed to 5 cm, 12 kg of humic acid, and 13 kg of foliar fertilizer.

[0055] Layered fertilization is adopted, and the fertilization method and amount per acre are as follows: Lower layer (16-30cm depth): 500kg corn stalk biochar, 8kg diammonium phosphate, 4kg potassium sulfate, and 200kg citric acid-modified attapulgite. The porous structure of the biochar adsorbs phosphorus and potassium nutrients, reducing leaching from deeper layers.

[0056] Top layer (10-15cm depth): 3kg controlled-release urea, 200kg commercial organic fertilizer, 500kg corn stalks, 200kg citric acid-modified attapulgite soil, and 12kg humic acid. This promotes the formation of soil aggregates in the top layer, providing readily available nutrients for soybean seedlings.

[0057] The seed-fertilizer separation method is adopted, using a seed-fertilizer co-seeding machine to sow seeds on top of the surface fertilizer layer, with a distance of 6cm between the seeds and the fertilizer layer. The distance between the seeds and the fertilizer layer should be ≥5cm to avoid burning the seedlings.

[0058] During the initial flowering stage, combine weeding with foliar spraying of a compound aqueous solution containing 0.2wt% borax and 0.3wt% zinc sulfate at a rate of 13kg per acre to promote rhizobium activity and pod formation.

[0059] Experimental Example 1 1. Fertilization and sowing The drought-resistant soybean variety He Dou 37 was selected. The experimental site was a sandy soil area in Caoxian County, which was randomly divided into four plots, each with an area of ​​3 mu (approximately 0.2 hectares). Fertilizer application methods and amounts were applied according to Example 2 and Comparative Examples 1-3, with each method applied to 3 mu of land as three parallel operations, simultaneously with sowing. Sowing was carried out in late May, with a seeding rate of 30,000 plants per mu (approximately 0.067 hectares), row spacing of 42±2 cm, and plant spacing of 9±1 cm. To avoid drought affecting germination in the sandy soil surface, the sowing depth was 3±1 cm.

[0060] 2. Field Management and Harvesting Soybeans have a growth period of 100-120 days. During the growth period, the soil moisture content should be maintained at 20±2%. Sandy soils need to be shallowly irrigated every 10-15 days, with a single irrigation volume of 30-40 m³ per mu. The optimal harvest time is in late September when the plant stems turn yellow, 20%-25% of the leaves fall off naturally, the pods turn brown, and the seeds harden. The experimental soybeans were then harvested.

[0061] Results Measurement After harvest, the content of water-stable aggregates, organic matter content, abundance of nitrogen-fixing bacteria in the soil (Chao1 index), and soybean yield were measured. The content of water-stable aggregates was determined using a wet sieving method, and the organic matter content was determined using a potassium dichromate oxidation-external heating method. The results are shown in Table 1. Table 1. Soil water-stable aggregate content, organic matter content, soil nitrogen-fixing bacteria abundance, and soybean yield. As shown in Table 1, Example 2 is superior to Comparative Examples 1-3 in terms of soil water-stable aggregate content, organic matter content, soil nitrogen-fixing bacteria abundance, and soybean yield. In terms of root live bacteria additives, the use of Rhizobium sinense and Rhizobium esculentum is superior to the use of either one alone.

[0062] This invention utilizes a quaternary synergistic system of "biochar-modified attapulgite soil-organic fertilizer-deep return of corn straw" to achieve integrated "structural improvement-slow nutrient release-enhanced nitrogen fixation-long-lasting and stable effects," realizing synergistic improvement of organic and inorganic elements and effectively enhancing the quality of sandy soil. This technology enhances soil fertility, reduces bulk density, and improves aeration and permeability. Simultaneously, the soil conditioner is rich in micronutrients such as calcium, magnesium, zinc, and boron, essential for soybean growth, which can promote rhizobium activity, enhance nitrogen fixation capacity in legumes, thereby increasing soybean protein content, strengthening stress resistance, and ultimately achieving increased yield and improved quality and income.

[0063] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A highly efficient soybean conditioner for sandy soil, characterized in that, The product comprises the following raw materials by weight: 1-5 parts controlled-release urea, 2-16 parts diammonium phosphate, 2-8 parts potassium sulfate, 150-250 parts organic fertilizer, 400-600 parts corn straw biochar, 300-500 parts citric acid-modified attapulgite, 400-600 parts crushed corn straw, 2-20 parts humic acid; 0.5-5 parts root-derived probiotic additive; and 10-15 parts borax-zinc sulfate foliar fertilizer. The root-derived live bacteria additive includes at least one of Rhizobium sinense or Rhizobium esculentum.

2. The high-efficiency soybean conditioner for sandy soil according to claim 1, characterized in that, The Chinese rhizobium used ( Sinorhizobium arboris ), with accession number CCTCC HB 20081581; *Syntrophus esculenta* ( Bradyrhizobium elkanii ), with accession number CICC 23903.

3. The high-efficiency soybean conditioner for sandy soil according to claim 1, characterized in that, In the aforementioned root probiotic additive, the ratio of live bacteria of Rhizobium sinense and Rhizobium esculentum is (0.5-5):(0.5-5).

4. The high-efficiency soybean conditioner for sandy soil according to claim 1, characterized in that, The number of live bacteria in the root probiotic additive shall not be less than 1×10 9 cfu / g.

5. The high-efficiency soybean conditioner for sandy soil according to claim 1, characterized in that, The controlled-release urea used has a controlled-release period of 50-70 days; the organic fertilizer has an organic matter content of ≥45%; the straw biochar is crop straw biochar pyrolyzed at 400-600℃; the borax-zinc sulfate foliar fertilizer is a composite aqueous solution containing 0.1-0.5wt% borax and 0.1-0.5wt% zinc sulfate; the citric acid-modified attapulgite clay used is prepared by the following method: Mix attapulgite with a 2-10% citric acid solution at a solid-liquid ratio of (0.5-5) kg: 5 L, stir in a constant temperature water bath at 50-70℃ for 1-3 hours, filter, wash the solid with deionized water until the pH of the filtrate reaches 6.5-7.5, and then dry the solid at 70-90℃ to obtain citric acid modified attapulgite.

6. The application of the high-efficiency soybean amendment for sandy soil according to any one of claims 1-5 in any one of the following (1)-(3): (1) Increase soil porosity; (2) Increase soil organic matter content; (3) Increase soybean yield.

7. A method for efficient soybean cultivation, characterized in that, This includes methods for stratified fertilization of soybeans and seed-fertilizer isolation, as detailed below: For stratified fertilization, the fertilization method and the amount of fertilizer per acre are as follows: The depth of the lower layer of fertilized soil is 16-30cm. The following are the components of the high-efficiency soybean soil conditioner for sandy soil described in claim 1: straw biochar, root live bacteria additive, diammonium phosphate, potassium sulfate, and citric acid modified attapulgite. The dosage is 400-600kg of straw biochar, 0.25-2.5kg of root live bacteria additive, 2-16kg of diammonium phosphate, 2-8kg of potassium sulfate, and 150-250kg of citric acid modified attapulgite. The surface fertilization soil depth is 10-15cm, and the controlled-release urea, root live bacteria additive, organic fertilizer, crop straw, citric acid modified attapulgite soil and humic acid in the sandy soil soybean high-efficiency conditioner described in claim 1 are applied. The dosage is 1-5kg of controlled-release urea, 0.25-2.5kg of root live bacteria additive, 150-250kg of organic fertilizer, 400-600kg of crop straw, 150-250kg of citric acid modified attapulgite soil and 2-20kg of humic acid. For seed-fertilizer separation, the seed-fertilizer co-sowing technique is used, where seeds are sown on top of the surface fertilizer layer, with a spacing of 5-7 cm between the seeds and the fertilizer layer.

8. The high-efficiency soybean cultivation method according to claim 7, characterized in that, During the initial flowering stage, combine weeding and cultivation with foliar spraying.

9. The high-efficiency soybean cultivation method according to claim 8, characterized in that, Foliar spray with a compound aqueous solution containing 0.1-0.5 wt% borax and 0.1-0.5 wt% zinc sulfate.

10. The high-efficiency soybean cultivation method according to claim 9, characterized in that, The dosage of the compound aqueous solution is 10-15 kg per mu.

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