Soil conditioner and application thereof

Abstract

The invention provides a soil conditioner and application thereof, and relates to the technical field of agriculture, the soil conditioner comprises the following components by weight: 30-150 parts of hydrotalcite modified hydrothermal carbon, 10-90 parts of an active nutrient composition, 10-60 parts of a growth promoting compound, and 10-30 parts of a plant source bacteriostatic agent. According to the conditioner, hydrotalcite modified hydrothermal carbon, an active nutrient composition, a growth promoting compound and a plant source bacteriostatic agent are compounded to prepare the multifunctional soil conditioner. The modifier can effectively relieve soil acidification, increase the soil nutrient content, passivate heavy metal cadmium, reduce the bioavailability of the heavy metal cadmium, promote crop growth and improve stress resistance in practical application, and has a good inhibition effect on soil-borne pathogenic bacteria, so that the disease incidence rate is reduced. According to the technical scheme, resource high-value utilization of agricultural waste is achieved, environmental restoration and agricultural yield increase are both considered, and the method has remarkable ecological and economic benefits.

Description

Technical Field

[0001] This invention relates to the field of agricultural technology, and in particular to a soil conditioner and its application. Background Technology

[0002] With the continuous advancement of global industrialization and urbanization, soil degradation and heavy metal pollution have become increasingly prominent issues, posing a key challenge to sustainable agricultural development and ecological security. Soil degradation manifests not only as acidification, fertility decline, destruction of soil aggregates, and reduction of organic matter, but also as a complex problem accompanied by salinization and soil erosion. Its direct consequence is a decline in crop yield and quality, thus posing a severe challenge to food security. Meanwhile, heavy metals such as cadmium, lead, and arsenic, due to their difficulty in natural degradation, easy migration and transformation, and accumulation in the food chain, pose long-term and hidden risks to ecosystems and human health. Therefore, there is an urgent need to develop efficient, safe, and sustainable soil remediation and treatment technologies to restore soil health.

[0003] Currently, the main technical approaches to remediate soil degradation and heavy metal pollution include physical remediation, chemical regulation, and bioremediation. Physical methods, such as soil replacement, topsoil application, deep tillage, and mulching, can improve soil physicochemical properties in the short term, but their application is limited due to high costs and difficulties in widespread adoption. Chemical regulation methods, such as the application of lime, gypsum, phosphates, modified silicates, and synthetic passivating agents, can alleviate acidification or fix heavy metal ions to some extent, but they pose potential risks of causing secondary environmental problems and soil microecological imbalance. Bioremediation methods include phytoremediation (such as hyperaccumulating plants absorbing heavy metals), inoculation with specific functional microorganisms (such as phosphorus-solubilizing, growth-promoting, or heavy metal-tolerant strains), and the application of organic materials (such as compost, humic acid, and straw charcoal). While these methods have eco-friendly and long-term improvement potential, their effectiveness is slow, and their remediation results are greatly limited by environmental conditions.

[0004] In recent years, comprehensive soil improvement technologies have gained increasing attention. By combining various modifying materials, organic resources, and functional components, soil pH can be improved simultaneously, nutrient availability enhanced, heavy metal activity neutralized, and soil microbial communities optimized, thereby achieving an overall improvement in soil quality. However, currently available soil conditioners tend to have limited functionality, primarily focusing on pH adjustment or fertility supplementation, and are insufficient in achieving comprehensive effects such as pollution control, growth promotion, and disease suppression. Furthermore, some conditioners may introduce salt accumulation, nutrient imbalance, or new environmental risks during long-term use, which are detrimental to crop growth and the stability of the soil ecosystem. Therefore, developing a green, resource-efficient, highly effective, and multifunctional soil conditioner has become an urgent technical challenge and a research hotspot. Summary of the Invention

[0005] To overcome the shortcomings of existing soil conditioners, such as limited functionality, poor stability, and potential environmental risks, this invention aims to provide a soil conditioner and its application, which possesses multiple functions. The soil conditioner provided by this invention integrates physicochemical improvement, pollution control, nutrient supply, and disease prevention, breaking through the limitations of existing conditioners that "target a single problem," and has strong practicality and promotional value.

[0006] In a first aspect, the present invention provides a soil conditioner comprising the following components in parts by weight: 30-150 parts of hydrotalcite-modified hydrothermal char, 10-90 parts of an active nutrient composition, 10-60 parts of a growth-promoting compound, and 10-30 parts of a plant-derived antibacterial agent. The active nutrient composition includes a heat-treated mixture, nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer prepared by heat treatment of straw, superphosphate, and diatomaceous earth powder in a weight ratio of (3:1:1) to (20:1:1); The growth-promoting compound includes chitosan, fulvic acid, and alginate, wherein the weight ratio of chitosan, fulvic acid, and alginate is 10:(0.5~5).

[0007] Preferably, the diatomaceous earth powder has a calcium (Ca) content of 45.3% to 61.4%, a silicon (Si) content of 22.1% to 35.2%, and a magnesium (Mg) content of 3.49% to 8.21% by mass.

[0008] More preferably, the diatomaceous earth powder, calculated by mass content, has a calcium (Ca) content of 45.3%~61.4%, a silicon (Si) content of 22.1%~35.2%, a carbon (C) content of 6.77%~12.4%, a magnesium (Mg) content of 3.49%~8.21%, and a sulfur (S) content of 2.14%~4.65%.

[0009] Preferably, the weight ratio of chitosan, humic acid and alginic acid is 10:(0.5~1):(0.5~1).

[0010] Preferably, the soil conditioner comprises the following components in parts by weight: 50-110 parts of the hydrotalcite-modified hydrothermal char, 30-70 parts of the active nutrient composition, 20-50 parts of the growth-promoting compound, and 10-20 parts of the plant-derived antibacterial agent.

[0011] Preferably, the soil conditioner comprises the following components in parts by weight: 70-90 parts of the hydrotalcite-modified hydrothermal char, 25-45 parts of the active nutrient composition, 25-35 parts of the growth-promoting compound, and 10-20 parts of the plant-derived antibacterial agent.

[0012] Preferably, the soil conditioner comprises the following components in parts by weight: 50-110 parts of the hydrotalcite-modified hydrothermal char, 10-50 parts of the active nutrient composition, 10-50 parts of the growth-promoting compound, and 10-30 parts of the plant-derived antibacterial agent. Preferably, the soil conditioner comprises the following components in parts by weight: 50-100 parts of the hydrotalcite-modified hydrothermal char, 20-40 parts of the active nutrient composition, 10-40 parts of the growth-promoting compound, and 10-20 parts of the plant-derived antibacterial agent. Preferably, the soil conditioner comprises the following components in parts by weight: 70-90 parts of the hydrotalcite-modified hydrothermal char, 25-35 parts of the active nutrient composition, 25-35 parts of the growth-promoting compound, and 10-20 parts of the plant-derived antibacterial agent.

[0013] Preferably, the hydrotalcite-modified hydrothermal carbon is prepared by the following method: The dried animal feces and the solution containing magnesium salts and iron salts were mixed at a solid-liquid ratio of 1:8 to 1:20 (g:mL), the pH was adjusted to 8 to 12, and then a hydrothermal reaction was carried out at a temperature of 140 to 280 °C for 1 to 30 h to obtain the hydrotalcite-modified hydrothermal carbon. The concentrations of magnesium salt and iron salt in the solution containing magnesium salt and iron salt are each independently 25~1000 mM, preferably 80~200 mM.

[0014] More preferably, the hydrotalcite-modified hydrothermal carbon is prepared by the following method: (1) The fresh animal feces were crushed and passed through a 40-100 mesh sieve, and then dried at 60-150℃ for 12-36 h to obtain solid material A; (2) Mix magnesium salt and iron salt with water to prepare liquid B (the concentration of magnesium salt and iron salt in liquid B is 25~1000 mM, preferably 80~200 mM). (3) According to the solid-liquid raw material ratio of 1:10~1:15 (g:mL), take solid material A and liquid material B into containers, seal them, and stir. Set the stirring speed to 300~1000 rpm. After they are completely mixed, the mixture C is obtained. (4) Keep stirring, then adjust the pH of mixture C to 8~10, and mix thoroughly to obtain mixture D; (5) Mixture D is subjected to hydrothermal reaction at a temperature of 140~280 ℃ for 1~30 h. After the hydrothermal reaction is completed, it is naturally cooled to room temperature to obtain mixture E. (6) The mixture E is subjected to solid-liquid centrifugation. The bottom slurry product is repeatedly washed with pure water or alcohol and then dried to obtain the hydrotalcite-modified hydrothermal carbon.

[0015] More preferably, the hydrotalcite-modified hydrothermal carbon is prepared by the following method: (1) The fresh pig manure to be tested was crushed and passed through a 40-100 mesh sieve, and then dried at 60-150 ℃ for 12-36 h to obtain solid material A; (2) Magnesium salt (preferably magnesium chloride hexahydrate) and iron salt (preferably ferric chloride hexahydrate) are mixed with water at a molar ratio of magnesium ions to iron ions of (6:1) to (1:1) to obtain liquid B (preferably mixed under stirring conditions). The concentrations of magnesium salt and iron salt in liquid B are each 25 to 1000 mM, preferably 80 to 200 mM. (3) According to the solid-liquid raw material ratio of 1:10~1:15 (g:mL), take solid material A and liquid material B into containers, seal them and stir. Set the stirring speed to 300~1000 rpm. After they are completely mixed, the mixture C is obtained. (4) Keep stirring, and then add potassium hydroxide solution with a concentration of 1~6 mol / L dropwise to mixture C until the pH value of the mixture is 8~10. After mixing thoroughly, mixture D is obtained. (5) Mixture D is subjected to hydrothermal reaction at a temperature of 140~280 ℃ for 1~4 h to obtain mixture E; (6) The mixture E is subjected to solid-liquid centrifugation. The bottom slurry product is repeatedly washed with pure water or alcohol and then dried to obtain the hydrotalcite-modified hydrothermal carbon.

[0016] Preferably, the hydrotalcite-modified hydrothermal carbon is a highly crystalline material.

[0017] As a preferred embodiment, the X-ray diffraction (XRD) pattern of hydrotalcite-modified hydrothermal carbon showed diffraction peaks of SiO2 and CaCO3 at 2θ=20.8°, 26.6° and 29.3°, and 39.3°. In addition, characteristic peaks belonging to magnesium-iron layered bimetallic hydroxides appeared at 2θ=10.5° and 42.4°.

[0018] Preferably, the hydrotalcite-modified hydrothermal carbon has a carbon (C) content of 33.2%~45.4%, a hydrogen (H) content of 5.23%~6.20%, an oxygen (O) content of 16.7%~32.7%, a nitrogen (N) content of 4.78%~5.79%, a phosphorus (P) content of 0.81%~3.02%, a pH value of 5.73~6.21, and an EC (electrical conductivity) value of 0.62~1.37 mS / cm.

[0019] Preferably, the hydrotalcite-modified hydrothermal carbon has an average pore size of 5.11–9.77 nm and a pore volume of 0.03–0.17 cm³. 3 / g, with a specific surface area of ​​14.7~54.6 m². 2 / g.

[0020] Preferably, the active nutrient composition is prepared by the following method: Straw, superphosphate, and diatomaceous earth powder are mixed in a weight ratio of (3:1:1) to (20:1:1) and then subjected to heat treatment. The specific conditions for heat treatment are: reaction at a temperature of 250 to 600 ℃ for 0.5 to 3 h to obtain heat-treated mixture. Then, the heat-treated mixture, nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer are mixed to obtain an active nutrient composition.

[0021] More preferably, the active nutrient composition is prepared by the following method: (1) The raw material straw is air-dried, crushed and screened. Then, according to the weight ratio of straw powder, superphosphate and diatomite powder (3:1:1) to (20:1:1), the straw powder, superphosphate and diatomite powder are weighed, and the mixture is thoroughly mixed for 10 to 20 minutes to obtain mixture A. (2) Heat treatment is performed on mixture A. The specific conditions for heat treatment are: heating to 250-600 ℃ at a rate of 8-12 ℃ / min, maintaining the temperature for 0.5-3 h, then starting the cooling program, and taking it out after cooling to room temperature to obtain mixture B; (3) Grind and mix material B and pass it through a 40-100 mesh sieve. Then mix it with nitrogen, phosphorus and potassium compound fertilizer at a mass ratio of (1:1) to (5:1). After mixing for 10-20 minutes, take it out to obtain an active nutrient composition.

[0022] More preferably, the active nutrient composition is prepared by the following method: (1) The raw material corn stalks are air-dried, crushed and screened, and then the straw powder, superphosphate and diatomite powder are weighed (in the weight ratio of straw powder, superphosphate and diatomite powder (8:1:1)~(12:1:1)), and mixed thoroughly for 10~20 min to obtain mixture A; (2) Heat treatment is performed on mixture A. The specific conditions for heat treatment are: heating to 250-600 ℃ at a rate of 8-12 ℃ / min, maintaining the temperature for 1-2 h, cooling to room temperature after the reaction is completed, and then taking it out to obtain mixture B. (3) Grind and mix material B and sieve it. Then mix it with nitrogen, phosphorus and potassium compound fertilizer at a mass ratio of (1:1) to (3:1) for 10 to 20 minutes to obtain an active nutrient composition.

[0023] More preferably, the straw powder, superphosphate, and diatomaceous earth powder are mixed in a weight ratio of 10:1:1.

[0024] More preferably, in step (2), the specific conditions for the heat treatment are: heating to 400-600 ℃ at a rate of 8-12 ℃ / min and maintaining the temperature for 1-2 h.

[0025] Preferably, the growth-promoting compound is prepared by the following method: Chitosan colloidal solution, fulvic acid and alginic acid were mixed, and the pH value was adjusted to 4-9. The mixture was then dried to obtain the growth-promoting compound. The concentration of the chitosan colloidal solution is 0.5% g / mL to 2.0% g / mL.

[0026] More preferably, the growth-promoting compound is prepared by the following method: Chitosan was dissolved in acetic acid solution and stirred thoroughly until completely dissolved to form a chitosan colloidal solution. Then, fulvic acid and alginic acid were added under continuous stirring. Finally, the pH of the mixture was adjusted to 4-9 and dried to obtain the growth-promoting compound. The concentration of the chitosan colloidal solution is 0.5% g / mL to 2.0% g / mL; The mass ratio of fulvic acid to alginic acid is 1:(1~3).

[0027] More preferably, the growth-promoting compound is prepared by the following method: Chitosan was dissolved in an aqueous acetic acid solution with a concentration of 0.10~0.60 mol / L (preferably 0.2~0.4 mol / L) and stirred thoroughly until completely dissolved to form a chitosan colloidal solution. Then, fulvic acid and alginic acid were added to the chitosan colloidal solution under continuous stirring. The pH was adjusted to 4~9 with 0.1~0.15 mol / L potassium hydroxide solution, and then dried at low temperature, controlled at 40~70 °C, for 2~10 hours, until the water content was less than 10 wt%, to obtain the growth-promoting compound. The concentration of the chitosan colloidal solution is 0.5% g / mL to 2.0% g / mL; The mass ratio of fulvic acid to alginic acid is 1:(1~3).

[0028] More preferably, the mass ratio of fulvic acid to alginic acid is 1:1.

[0029] More preferably, the concentration of the chitosan colloidal solution is 1.0% g / mL (w / v).

[0030] More preferably, the concentration of the acetic acid aqueous solution is 0.40 mol / L.

[0031] More preferably, after adding fulvic acid and alginic acid to the chitosan colloidal solution, the pH is adjusted to 6-8 with potassium hydroxide solution.

[0032] Preferably, the chitosan has a degree of deacetylation of 80% to 90%, a molecular weight of 50 to 105 kDa, and a nitrogen (N) mass content of 7% to 9%. Preferably, the plant-derived antibacterial agent comprises the following components in parts by weight: 1-3 parts chitosan, 0.5-2 parts tea seed cake, and 0.1-1 parts Sophora flavescens root.

[0033] Preferably, the plant-derived antibacterial agent comprises the following components in parts by weight: 1-3 parts chitosan, 0.5-2 parts tea seed cake, and 0.1-1 parts Sophora flavescens root.

[0034] Preferably, the plant-derived antibacterial agent is prepared by the following method: By weight, 1-3 parts chitosan, 0.5-2 parts tea seed cake, and 0.1-1 parts Sophora flavescens root are thoroughly mixed for 10-20 minutes and then removed to obtain a plant-derived antibacterial agent.

[0035] More preferably, the weight ratio of chitosan, tea seed cake, and sophora root is 2:1:0.5.

[0036] Preferably, the chitin contains 80wt%~90wt% N-acetyl-D-glucosamine polymer, 1wt%~5wt% protein, and 2wt%~10wt% calcium carbonate.

[0037] Preferably, the tea seed cake contains 10wt%~18wt% crude protein, 12wt%~18wt% crude fiber, 8wt%~15wt% saponins, 2wt%~6wt% crude fat, and 2wt%~5wt% soluble sugars; Preferably, the Sophora flavescens root contains 1wt%~3wt% matrine, 5wt%~10wt% crude protein, 2wt%~5wt% polysaccharide, and 70wt%~80wt% cellulose.

[0038] Preferably, the present invention provides a method for preparing the soil conditioner, comprising: mixing the hydrotalcite-modified hydrothermal char, the active nutrient composition, the growth-promoting compound and the plant-derived antibacterial agent in proportion and then grinding them to obtain the soil conditioner.

[0039] Preferably, the grinding is carried out by dry grinding using a planetary ball mill, with a grinding ball to material mass ratio of (20~120):1, a grinding time of 1~10 h, and a grinding speed of 200~400 rpm.

[0040] Preferably, the grinding ball is an agate grinding ball with a diameter of 4-8 mm.

[0041] A second aspect of the present invention provides the use of the soil conditioner described in the first aspect in at least one of the following aspects: (1) Improve degraded soil and increase the nutrient content in the soil; (2) Passivate heavy metals in the soil; (3) Promotes crop growth and alleviates heavy metal stress; (4) Enhance the prevention and control of soil-borne diseases.

[0042] Preferably, the degraded soil is acidic heavy metal contaminated soil. Preferably, the heavy metal is cadmium. More preferably, the crop is a melon or vegetable, and the soil-borne disease is cucumber wilt.

[0043] In practical applications, the soil conditioner of this invention can be applied in powder form, which not only facilitates storage and transportation but also makes application methods simpler and more diverse. Users can choose from various methods such as broadcasting, strip application, layering, or mixing with soil according to their actual needs, greatly improving the convenience and flexibility of use and making the conditioner more easily accepted and promoted by farmers and agricultural enterprises.

[0044] A third aspect of the present invention provides a method for soil improvement, comprising: preparing the soil conditioner described in the first aspect above into a soil conditioner suspension with a concentration of 1% to 8% g / mL (m / v) or applying it to the soil in the form of soil conditioner powder; Preferably, the concentration of the soil conditioner suspension is 4% g / mL to 5% g / mL.

[0045] Preferably, the soil conditioner is applied at a rate of 100-300 kg / mu.

[0046] The application rate of the soil conditioner described in this plan can be adjusted according to the severity of the soil problem. For mildly acidified or polluted soils, the recommended application rate is 100-200 kg / mu; for moderately to severely acidified, compacted, or heavy metal polluted soils, the recommended application rate is 200-300 kg / mu.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a soil conditioner that adheres to the environmental protection concept of "treating pollution with waste," making full use of agricultural waste resources. Through scientific formulation and modification processes, it combines hydrotalcite-modified hydrothermal char, an active nutrient composition, growth-promoting compounds, and plant-derived antibacterial agents to create a multifunctional soil conditioner. In practical applications, this conditioner can effectively alleviate soil acidification, increase soil nutrient content, passivate the heavy metal cadmium and reduce its bioavailability, promote crop growth, improve stress resistance, and has a good inhibitory effect on soil-borne pathogens, thereby reducing the incidence of diseases. This technical solution achieves high-value resource utilization of agricultural waste, taking into account both environmental remediation and increased agricultural production, and has significant ecological and economic benefits.

[0048] The soil conditioner provided by this invention, through optimized formulation design and composite modification process, can synergistically achieve soil degradation remediation and heavy metal pollution control. Its mechanism of action includes: regulating soil pH, improving aggregate structure and aeration; using functional materials to passivate and fix heavy metal ions, reducing their bioavailability and thus mitigating the toxic effects of heavy metals on crops; effectively enhancing soil nutrient supply capacity and crop growth potential by enriching active nutrients and growth-promoting factors; and simultaneously integrating disease-suppressing components to inhibit the occurrence and reproduction of harmful pathogens, thereby enhancing crop resistance and health.

[0049] This invention provides a multifunctional soil conditioner that uses agricultural and domestic waste as its main raw materials. Through scientific formulation and process optimization, it achieves a synergistic effect of multiple components. While promoting the resource utilization of waste, it effectively solves problems such as soil acidification and heavy metal pollution.

[0050] Compared to traditional single-function soil conditioners, the conditioner of this invention has multiple functions: it can not only regulate soil pH and improve soil physicochemical structure, but also passivate heavy metal ions and reduce their bioavailability. Simultaneously, this conditioner can enhance soil nutrient supply capacity, promote crop growth and development, and inhibit soil-borne diseases to a certain extent. Its comprehensive improvement effect has significant application value for restoring soil ecological function, improving farmland productivity, and ensuring ecological environment security.

[0051] Furthermore, the preparation process of this invention is simple, production costs are easy to control, and it possesses high technical feasibility and potential for large-scale application. After industrial-scale production is achieved, it can be widely applied to different types of soil improvement needs, promoting the dissemination and application of this technology.

[0052] In summary, the multifunctional soil conditioner provided by this invention offers a practical solution to the problems of soil degradation and heavy metal pollution. It not only provides technical support for soil quality improvement and environmental remediation, but also opens up new paths for green agriculture and sustainable development. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0054] Figure 1 The X-ray diffraction pattern of the hydrothermal carbon modified with hydrotalcite prepared in Example 1 of this invention is shown. The test target is a copper target, the scanning range is 5~90°, and the scanning speed is 5° / min.

[0055] Figure 2 The image is a scanning electron microscope (SEM) image (10 μm) of the hydrotalcite-modified hydrothermal carbon prepared in Example 1 of this invention.

[0056] Figure 3 The image shows a scanning electron microscope (5 μm) of the hydrotalcite-modified hydrothermal carbon prepared in Example 1 of this invention.

[0057] Figure 4 The image shows a scanning electron microscope (SEM) image (2 μm) of the hydrotalcite-modified hydrothermal carbon prepared in Example 1 of this invention.

[0058] Figure 5 This is a visual representation of the effect of the soil conditioner of Example 1 of the present invention on the growth of Chinese cabbage in acidic soil contaminated with heavy metal Cd. CK represents the treatment without soil conditioner; T1 represents the treatment with 5% soil conditioner by weight.

[0059] Figure 6 This is a graph showing the effect of the soil conditioner of Example 1 of the present invention on rice yield in a field experiment on acidic soil contaminated with heavy metal Cd. CK represents no soil conditioner applied; T1 represents the application of 300 kg / mu of soil conditioner.

[0060] Figure 7 The image shows the effect of the soil conditioner of Example 1 of this invention on the cadmium concentration in rice leaves during a field experiment on acidic soil contaminated with heavy metal Cd. The CK treatment was no soil conditioner applied, and the T1 treatment was 300 kg / mu of soil conditioner applied.

[0061] Figure 8 The image shows the effect of the soil conditioner of Example 1 of this invention on the cadmium concentration in rice stems during a field experiment on acidic soil contaminated with heavy metal Cd. The CK treatment was no soil conditioner applied, and the T1 treatment was 300 kg / mu of soil conditioner applied.

[0062] Figure 9The image shows the effect of the soil conditioner of Example 1 of the present invention on the cadmium concentration in rice grains in a field experiment on acidic soil contaminated with heavy metal Cd. The CK treatment was no soil conditioner applied, and the T1 treatment was 300 kg / mu of soil conditioner applied.

[0063] Figure 10 The graph shows the effect of the soil conditioner of Example 1 of the present invention on the disease grade of cucumber after being applied to farmland soil; CK represents the treatment without inoculation with Fusarium oxysporum inoculum and without application of soil conditioner; FOC represents the treatment with inoculation with Fusarium oxysporum inoculum (FOC) alone; C1 represents the treatment with 5% soil conditioner by weight applied on the basis of inoculation with FOC inoculum.

[0064] Figure 11 The graph shows the effect of the soil conditioner of Example 1 of the present invention on the incidence of cucumber disease after being applied to farmland soil; CK represents the treatment without inoculation with Fusarium oxysporum inoculum and without application of soil conditioner; FOC represents the treatment with inoculation with Fusarium oxysporum inoculum (FOC) alone; C1 represents the treatment with 5% soil conditioner by weight applied on the basis of inoculation with FOC inoculum.

[0065] Figure 12 This is a visual effect diagram of the soil conditioner of Example 1 of the present invention applied to farmland soil on cucumber plants; CK represents treatment without inoculation with Fusarium oxysporum inoculum and without application of soil conditioner; FOC represents treatment with inoculation with Fusarium oxysporum inoculum (FOC) alone; C1 represents treatment with inoculation with FOC inoculum and application of soil conditioner at 5% of soil weight. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.

[0067] Example 1 This embodiment provides a soil conditioner, which, by weight, comprises 80 parts of hydrotalcite-modified hydrothermal char, 40 parts of an active nutrient composition, 30 parts of a growth-promoting compound, and 10 parts of a plant-derived antibacterial agent.

[0068] The hydrothermal carbon modified with hydrotalcite was prepared by the following method: (1) Fresh pig manure was crushed by a crusher and passed through a 100-mesh sieve. Then 100 g was weighed and placed in an oven to dry at 60 ℃ for 24 h to obtain solid material A. (2) According to the molar ratio of magnesium to iron ions of 3:1, magnesium chloride hexahydrate (MgCl2·6H2O) and ferric chloride hexahydrate (FeCl3·6H2O) were weighed and placed in a 500 mL beaker. 100 mL of deionized water was added, and then the mixture was magnetically stirred for 10 min at 25 °C and 600 r / min to obtain liquid B (the concentration of magnesium chloride hexahydrate was 0.3 mol / L and the concentration of ferric chloride hexahydrate was 0.1 mol / L). (3) Weigh 20 g of solid material A and 200 mL of liquid material B into a 500 mL beaker, seal the mouth of the beaker with plastic wrap, and place it on a constant temperature magnetic stirrer. Set the stirring speed to 600 rpm. After the mixture is completely homogeneous, the mixture C is obtained. (4) Adjust and maintain the rotation speed at 1000 r / min, connect the benchtop digital pH meter, and add 1 mol / L potassium hydroxide solution (KOH solution) drop by drop until the pH of the mixture stabilizes at 8, thus obtaining mixture D; (5) The obtained mixture D was quickly transferred to the 250 mL polytetrafluoroethylene reactor liner, the reactor was tightened and placed in a 180 ℃ forced-air drying oven for 4 h to obtain mixture E; (6) After the reactor is cooled to room temperature, pour the above mixture E into a centrifuge tube and centrifuge at 25 °C and 6000 r / min. Discard the supernatant and repeatedly rinse the bottom product with deionized water until the filtrate is neutral. Place the solid product in a 60 °C forced-air drying oven to dry it thoroughly. Finally, grind and crush it and pass it through a 0.2 mm sieve to obtain hydrotalcite modified hydrothermal carbon.

[0069] The hydrothermal carbon modified with hydrotalcite prepared in this embodiment was characterized by X-ray diffraction patterns, and the results are as follows: Figure 1 As shown, it exhibits typical diffraction peaks characteristic of magnesium-iron layered bimetallic hydroxides, as well as characteristic peaks of natural organic compounds. Figures 2-4 This is a scanning electron microscope image of hydrothermal carbon modified with hydrotalcite, which shows a distinct layered structure and some organic matter covering the surface.

[0070] The active nutrient composition is prepared by the following method: (1) The collected corn stalks were air-dried, crushed, and sieved through a 0.3 mm sieve. 200 g of stalks, 20 g of superphosphate and 20 g of diatomaceous earth powder (containing 51.4% calcium, 25.1% silicon and 7.5% magnesium) were weighed and added to a micro mixer and mixed for 15 min. The mixture was then removed to obtain mixture A. (2) Transfer the mixture A to a crucible and place it in a muffle furnace. Heat the mixture to 600 °C at a rate of 10 °C / min and react at 600 °C for 2 h. After the reaction is complete, cool it to room temperature and remove it to obtain the mixture B. (3) Grind the mixture B and pass it through a 100-mesh sieve. Then weigh 100 g of the mixture B and 100 g of the commercial compound fertilizer (purchased from Guangdong Ruifeng Ecological Co., Ltd., with N, P and K nutrient mass percentage content of 15%, i.e. N:P2O5:K2O 15:15:15) and add them to a micro mixer and mix for 20 min to obtain an active nutrient composition.

[0071] The growth-promoting compound was prepared by the following method: Dissolve 25 g of chitosan in 250 mL of 0.4 mol / L dilute acetic acid (CH3COOH) solution. Stir the solution on a magnetic stirrer at 400 r / min until completely dissolved, forming a chitosan colloidal solution. Maintaining the stirring speed, add 2.5 g of fulvic acid and 2.5 g of alginic acid sequentially. Finally, connect a benchtop digital pH meter and add 0.1 mol / L potassium hydroxide solution (KOH) dropwise until the pH of the mixture stabilizes at 7, thus obtaining the growth-promoting compound.

[0072] The plant-derived antibacterial agent was prepared by the following method: Weigh 20 g of chitosan powder (Hebei Qiansheng Biotechnology Co., Ltd.), 10 g of tea seed cake powder (Hangzhou Zhongye Natural Plant Technology Co., Ltd.), and 5 g of Sophora flavescens root powder (Shandong Xinxiong Biotechnology Co., Ltd.), add them to a micro mixer, mix for 20 min, and then remove to obtain a plant-derived antibacterial agent.

[0073] The preparation method of the soil conditioner in this embodiment is as follows: (1) Weigh 80 parts of hydrotalcite-modified hydrothermal carbon, 40 parts of active nutrient composition, 30 parts of growth-promoting compound and 10 parts of plant-derived antibacterial agent, mix them evenly to obtain the pseudo-ball milling material; (2) The material was dry-milled using a planetary ball mill. The grinding balls were 5 mm in diameter agate grinding balls. The mass ratio of the agate grinding balls to the material was 20:1. The milling time was 10 h and the milling speed was 400 rpm. Soil conditioner (referred to as formula 1) was obtained.

[0074] Example 2 To investigate the effect of the proportions of each component on efficacy, four additional soil conditioners with different proportions (Formulas 2 to 5) were designed based on Example 1 (denoted as Formula 1). The preparation methods, raw material sources, and process conditions of all formulas were consistent with those of Example 1. The composition (parts by weight) of the different soil conditioner formulas is shown in Table 1.

[0075] Table 1. Composition (parts by weight) of different soil conditioner formulations

[0076] Acidified soil (initial pH 5.2) from a greenhouse in Shouguang, Shandong Province was collected, air-dried, and sieved. Exogenous cadmium nitrate solution (Cd(NO3)2·4H2O) was added to simulate pollution, bringing the soil cadmium content to 2 mg / kg, and the mixture was allowed to equilibrate for one week. The five soil conditioners mentioned above were mixed with the contaminated soil at 2% of the soil mass (i.e., 2 g of conditioner per 100 g of soil), with the treatment without conditioner serving as a blank control (CK). Each treatment was replicated three times and incubated at 25℃ for 30 days. After incubation, the pH of the soil filtrate was measured using a pH meter (soil-to-water ratio 2.5:1), and the available cadmium content was determined by flame atomic absorption spectrophotometry (GB / T 23739-2009).

[0077] The experimental results (Table 2) show that all formulations can increase soil pH and reduce available cadmium content. The improvement effect significantly increased with increasing amounts of hydrotalcite-modified hydrothermal char (formulations 1, 4, and 5), demonstrating its key role as a core passivating and acid-regulating component. Formulation 5 (150 parts hydrotalcite char) showed the best effect but had the highest unit cost. Formulation 2 (60 parts hydrotalcite char) was significantly less effective than formulation 1 due to insufficient core components. Formulation 3 (which increased nutrients and disease-suppressing components but did not increase hydrotalcite char) had limited improvement effects on acidification and passivation, indicating that excessive addition of other components cannot replace the function of the core material. Formulation 1, while ensuring excellent improvement effects (pH increased from 4.6 to 5.6, available cadmium reduced by 77.1%), also had the best material cost-effectiveness. Therefore, Example 1 (formulation 1) is the preferred embodiment of this invention.

[0078] Table 2. Effects of different soil conditioner formulations on acidified and cadmium-contaminated soils.

[0079] Example 3 This embodiment uses the soil conditioner prepared in Example 1 to conduct a soil culture experiment, aiming to preliminarily explore the comprehensive effects of the conditioner in alleviating soil acidification, passivating heavy metal activity, and improving nutrient availability.

[0080] Soil from a cadmium-contaminated farmland in Xiangtan City, Hunan Province, was selected as the test soil. Samples were taken from the 0-20 cm soil layer. After manually removing larger clods, stones, and plant debris, the soil was ground and sieved through a 4 mm sieve. The sieved soil was then spread flat on the ground to air dry. After air drying, a well-mixed soil sample was taken and its basic physicochemical properties were determined according to the relevant testing methods for soil agrochemical analysis (3rd edition) (ISBN 978-7-109-06644-1). The results of the basic physicochemical properties are shown in Table 3.

[0081] Table 3. Basic physicochemical properties of soil from a cadmium-contaminated farmland in Xiangtan City, Hunan Province

[0082] The experiment was conducted in a greenhouse on the West Campus of China Agricultural University. Plastic pots with a rim diameter of 14 cm, a base diameter of 10 cm, and a height of 16 cm were used. Filter paper was placed at the bottom of the pot's flowerpot. The sieved soil sample was mixed thoroughly with a soil conditioner at a concentration of 5% by weight of the soil, and then filled into the pots, with each pot containing 1 kg of soil. Two treatments were set up: CK (no soil conditioner) and T1 (5% by weight of soil conditioner). After 30 days of static incubation, the soil's physicochemical properties were measured.

[0083] After the experiment, the collected soil samples were air-dried, gently crushed, and sieved through a 0.15 mm sieve to ensure sample homogeneity. Then, 10 g of soil sample was weighed and placed in a 100 mL Erlenmeyer flask, and 25 mL of deionized water was added at a soil-to-water ratio of 1:2.5. The flask was sealed and allowed to stand for 10 min to allow the soil sample to fully swell. The flask was then placed in a constant-temperature orbital shaking incubator and shaken at 180 rpm for 30 min at 25℃. After removal, it was allowed to stand for 5 min to release air bubbles. The shaken suspension was then vacuum filtered through a 0.45 μm filter membrane, and the filtrate was collected as the test solution. Finally, the pH and conductivity of the filtrate were measured at 25℃ using a calibrated pH meter and conductivity meter, respectively. Specifically, a DDS-307A conductivity meter was used to measure conductivity, and a Leici PHS-3E pH meter was used to measure pH. The available Cd content in soil was determined using the national standard method GB / T 23739-2009; the soil organic matter content was determined using NY / T 85-1988; and the Cd content in plant samples was determined using DB61 / T 902.1-2013.

[0084] The experimental results (Table 4) show that the soil physicochemical properties under the CK treatment did not change significantly, while the soil pH and available nutrient content under the T1 treatment increased significantly, and the available cadmium content decreased significantly. This indicates that the addition of soil conditioner improved the soil physicochemical properties to some extent and promoted cadmium fixation.

[0085] Table 4. Effects of soil conditioner on soil physicochemical properties in soil-cultured experimental plants.

[0086] Example 4 This embodiment uses the soil conditioner prepared in Example 1 to conduct a pot experiment, aiming to systematically evaluate the comprehensive effects of the conditioner in alleviating soil acidification, passivating heavy metal activity, improving nutrient availability, and enhancing crop stress resistance and growth promotion.

[0087] The experimental soil was taken from the topsoil of cadmium-contaminated farmland in Xiangtan City, Hunan Province, and the Chinese cabbage variety "Jingcui 60" was used as the test crop. Through pot cultivation, the effects of soil conditioner on soil physicochemical properties, available heavy metal content, nutrient levels, and plant growth and stress resistance were investigated to verify its practical application potential for soil improvement and remediation.

[0088] The experiment consisted of two treatment groups: a control group (CK, no soil conditioner added) and a treatment group (soil conditioner added at 5% of soil weight). Before the experiment, the collected soil samples were air-dried, ground, and sieved through a 2 mm sieve to ensure sample homogeneity. Chinese cabbage seeds were soaked in a 2% NaClO solution for 10 min, rinsed thoroughly with tap water, placed on gauze, and germinated in a constant temperature incubator. Germinated seeds were then placed in seedling trays for seedling cultivation. When the seedlings reached two leaves and a central bud, they were transplanted into plastic pots, one seedling per pot, with 1 kg of soil per pot. Each treatment was repeated three times. Plant and soil samples were collected after 30 days of cultivation.

[0089] As shown in Table 5, compared with the control group (CK), the treatment with the soil conditioner of this invention significantly improved soil physicochemical properties and crop growth performance. Specifically, the soil pH increased by 1.58 units, and the EC value increased by 3.47 times, significantly alleviating acidification; the soil organic matter content increased by 45.06%, significantly improving soil nutrient supply capacity; and the available Cd content decreased by 49.67%, indicating that its fixation of Cd in the soil effectively reduced bioavailability. Regarding crop growth, the aboveground fresh weight of Chinese cabbage increased by 30.10%, significantly increasing plant biomass; simultaneously, the Cd content in the plant decreased by 29.92%, indicating that the risk of Cd migration to the crop was effectively suppressed.

[0090] Figure 5 The results further visually demonstrated the soil conditioner's promoting effect on Chinese cabbage growth, with the treated group showing significantly better plant growth than the control. In summary, the application of this soil conditioner can improve acidified soil, increase soil organic matter, and passivate and fix Cd, while effectively inhibiting crop absorption of Cd, promoting robust crop growth, and increasing yield, demonstrating significant application value.

[0091] Table 5. Effects of soil conditioners on soil physicochemical properties and crop growth.

[0092] In summary, the application of the soil conditioner provided by this invention can alleviate soil acidification, increase soil organic matter content, fix Cd in the soil and inhibit crop absorption of Cd, and also promote the growth of Chinese cabbage plants, increase biomass, and help increase crop yield.

[0093] Example 5 This embodiment aims to further explore and verify the comprehensive effects of the multifunctional soil conditioner prepared in Example 1 in mitigating soil acidification, passivating heavy metal activity, improving nutrient availability, and enhancing crop stress resistance and growth promotion after field application.

[0094] The field trial was conducted in a cadmium-contaminated farmland in Anding County, Hainan Province. The test crop was rice, variety Teyou 458. The physicochemical properties of the soil in the field are shown in Table 6.

[0095] Table 6 Physicochemical properties of cadmium-contaminated farmland in Anding County, Hainan Province

[0096] The experiment was set up with two treatments: CK (conventional fertilization) and T1 (conventional fertilization plus soil conditioner 300 kg / mu). Each treatment was replicated three times, with each replicate corresponding to one plot, and each plot was 30 m². 2 (6 m × 5 m) The plots were randomly arranged, with a 1 m wide irrigation ditch around each plot as a protective row. A 0.5 m isolation row was left between plots. Daily field management was kept completely consistent across plots. The soil conditioner was applied manually and evenly to the experimental plots 10 days before rice transplanting, and the land was plowed to ensure even distribution of the conditioner in the topsoil. The entire experimental period was flooded. Yield and cadmium content were measured at harvest in September.

[0097] The experimental results show (see) Figure 6 (Tables 7, 8, 9 and 7) Under treatment T1, rice yield increased by 4.9% compared to the control (CK), and the content of nutrients such as phosphorus, potassium, calcium, and magnesium in the aboveground parts of rice also increased compared to the CK. This indicates that the amendment can effectively improve the crop's ability to absorb and utilize nutrients and enhance its stress resistance. In addition, the cadmium concentration in rice stems, leaves, and grains decreased significantly.

[0098] Table 7. Effects of soil conditioner on nutrient content in rice.

[0099] Regarding soil physicochemical properties (Table 8), the amendment significantly increased soil pH, alleviated soil acidification, and effectively reduced the content of available cadmium in the soil.

[0100] Table 8. Effects of soil conditioners on soil physicochemical properties

[0101] Example 6 Cucumber wilt is characterized by rapid onset and high incidence, caused by soil-borne pathogens such as *Fusarium oxysporum*, a specialized vascular fungus affecting cucumbers. Fusarium oxysporum f. sp. Cucumerinum Disease caused by phytotoxicity (FOC) is seriously threatening cucumber production worldwide. This example aims to explore and verify the disease-suppressing function of the multifunctional soil conditioner prepared in Example 1 when applied to farmland soil. Soil from a farmland in Beijing was selected as the test soil. Samples were taken from the 0-20 cm soil layer. After manually removing larger clods, stones, and plant debris, the soil was ground through a 4 mm sieve. The sieved soil was then spread flat on the ground to dry. After air drying, a uniformly mixed soil sample was taken and its basic physicochemical properties were determined according to the relevant testing methods for soil agrochemical analysis (third edition) (ISBN 978-7-109-06644-1). The results of the basic physicochemical property determination are shown in Table 9.

[0102] Table 9. Results of determination of basic physical and chemical properties of soil

[0103] In this embodiment, the "Jinyan No. 4" cucumber variety was selected as the test crop. The cucumber seeds were purchased from Tianjin Hongfeng Vegetable Research Co., Ltd. The experiment was conducted in a greenhouse at the West Campus of China Agricultural University. Plastic pots with a rim diameter of 14 cm, a bottom diameter of 10 cm, and a height of 16 cm were used. A layer of filter paper was placed at the bottom of the plastic pots, and the sieved soil sample was mixed thoroughly before being placed in the pots. Two treatment groups were set up: C1 was inoculated with FOC bacterial solution alone; C2 was inoculated with FOC bacterial solution and then treated with 5% of the soil weight of soil conditioner. The control group (CK) was not inoculated with Fusarium oxysporum bacterial solution and did not receive any soil conditioner treatment.

[0104] Cucumber seeds were disinfected with a 2% sodium hypochlorite (NaClO) solution for 10 min, rinsed thoroughly with sterile water to remove residual disinfectant, and then placed in a 25 ℃ dark incubator for germination. After 24 h, the germinated seeds were sown in sterilized soil. Pot experiments were conducted when seedlings reached the "two-leaf, one-heart" stage. Before transplanting, except for the control (CK), each treatment soil was treated with 5% of the appropriate soil amendment and inoculated with 30% of the soil mass of *Fusarium oxysporum* inoculum. Seedlings were transplanted 3 days after inoculation, and plant height and disease index were recorded 10 days after transplanting.

[0105] The experimental results show (see) Figure 10(Figures 11 and 12) Cucumber plants in the CK treatment showed no signs of Fusarium wilt and had the tallest plant height; the treatment with Fusarium oxysporum inoculation alone resulted in the most severe disease; while in the treatment groups with soil amendments, the incidence of cucumber Fusarium wilt was suppressed to some extent. The statistical results of the effects of soil amendments on soil physicochemical properties and cucumber growth are shown in Table 10.

[0106] Table 10 Effects of soil conditioner on soil physicochemical properties and cucumber growth

[0107] In summary, the soil conditioner of this invention can effectively alleviate soil acidification, increase nutrient content, and passivate toxic heavy metals, thereby promoting crop growth and preventing soil-borne diseases, ultimately achieving the safe production goals of improving degraded soil, controlling heavy metal pollution, and improving crop growth.

[0108] It is worth emphasizing that this invention adheres to the green development concept of "treating pollution with waste and recycling" in its preparation process. It fully utilizes renewable resources such as animal manure, straw, shrimp shells, and agricultural by-product processing residues. Through scientific treatment and efficient transformation, these resources are prepared into functional components with high stability and activity. This technological approach not only realizes the resource utilization and high-value utilization of agricultural waste, reducing production costs and the risk of secondary pollution, but also promotes the circular development of agricultural ecosystems and the achievement of environmental protection goals. The innovative solution proposed in this invention aligns with the current strategic needs of green agricultural development and soil health management, providing new ideas and practical approaches for agricultural waste utilization and soil pollution prevention and control.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A soil conditioner, characterized in that, It includes the following components by weight: 30-150 parts of hydrotalcite-modified hydrothermal char, 10-90 parts of active nutrient composition, 10-60 parts of growth-promoting compound, and 10-30 parts of plant-derived antibacterial agent; The active nutrient composition includes a heat-treated mixture, nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer prepared by heat treatment of straw, superphosphate, and diatomaceous earth powder in a weight ratio of (3:1:1) to (20:1:1); The growth-promoting compound includes chitosan, fulvic acid, and alginic acid, wherein the weight ratio of chitosan, fulvic acid, and alginic acid is 10:(0.5~5):(0.5~5).

2. The soil conditioner according to claim 1, characterized in that, The soil conditioner comprises the following components in parts by weight: 50-110 parts of the hydrotalcite-modified hydrothermal char, 30-70 parts of the active nutrient composition, 20-50 parts of the growth-promoting compound, and 10-20 parts of the plant-derived antibacterial agent.

3. The soil conditioner according to claim 1 or 2, characterized in that, The hydrotalcite-modified hydrothermal char is prepared by the following method: The dried animal feces and the solution containing magnesium salts and iron salts were mixed at a solid-liquid ratio of 1:8 to 1:20 (g:mL), the pH was adjusted to 8 to 12, and then a hydrothermal reaction was carried out at a temperature of 140 to 280 °C for 1 to 30 h to obtain the hydrotalcite-modified hydrothermal carbon. The concentrations of magnesium salt and iron salt in the solution containing magnesium salt and iron salt are each independently 25~1000 mM, preferably 80~200 mM.

4. The soil conditioner according to any one of claims 1 or 3, characterized in that, The active nutrient composition is prepared by the following method: Straw, superphosphate, and diatomaceous earth powder are mixed and then subjected to heat treatment. The specific conditions for heat treatment are: reaction at a temperature of 250~600 ℃ for 0.5~3 h to obtain heat-treated mixture. Then, the heat-treated mixture, nitrogen fertilizer, phosphorus fertilizer, and potassium fertilizer are mixed to obtain an active nutrient composition.

5. The soil conditioner according to any one of claims 1 or 4, characterized in that, The growth-promoting compound was prepared by the following method: Chitosan colloidal solution, fulvic acid and alginic acid were mixed, and the pH value was adjusted to 4-9. The mixture was then dried to obtain the growth-promoting compound. The concentration of the chitosan colloidal solution is 0.5% g / mL to 2.0% g / mL.

6. The soil conditioner according to claim 1 or 5, characterized in that, The plant-derived antibacterial agent comprises the following components in parts by weight: 1-3 parts chitosan, 0.5-2 parts tea seed cake, and 0.1-1 parts Sophora flavescens root; The plant-derived antibacterial agent comprises the following components in parts by weight: 1-3 parts chitosan, 0.5-2 parts tea seed cake, and 0.1-1 parts Sophora flavescens root.

7. The use of the soil conditioner according to any one of claims 1 to 6 in at least one of the following aspects: (1) Improve degraded soil and increase the nutrient content in the soil; (2) Passivate heavy metals in the soil; (3) Promotes crop growth and alleviates heavy metal stress; (4) Enhance the prevention and control of soil-borne diseases.

8. The application according to claim 7, characterized in that, The degraded soil is acidic soil contaminated with heavy metals. Preferably, the heavy metal is cadmium. More preferably, the crop is a melon or vegetable, and the soil-borne disease is cucumber wilt.

9. A method for soil improvement, characterized in that, include: The soil conditioner according to any one of claims 1 to 6 is prepared into a soil conditioner suspension with a concentration of 1% g / mL to 8% g / mL or applied to the soil in the form of soil conditioner powder; Preferably, the concentration of the soil conditioner in the soil conditioner suspension is 4% g / mL to 5% g / mL.

10. The method for soil improvement according to claim 9, characterized in that, The application rate of the soil conditioner is 100-300 kg / mu.

Images