Composite soil conditioner, preparation method and method for combined remediation of paddy-rice rotation farmland

Abstract

The application discloses a kind of composite soil conditioner, preparation method and rice joint repair farmland method of rotation, the preparation method of the composite soil conditioner includes: step (1) preparation mineral solid waste source high-activity silicon powder;Step (2) preparation soil composite conditioner;Step (3) preparation traditional Chinese medicine source nutrient solution;Step (4) preparation foliar spraying nutrient solution.The application not only improves the soil from the root, guarantees the quality and safety of agricultural products, but also improves the yield and quality by enhancing the health of crops.Especially, with high-yield economic crops rotation, and reduce pesticide fertilizer input, significantly improve the net income per unit of land area, stimulate the endogenous motivation of farmers to adopt green technology.

Description

Technical Field

[0002] This invention relates to the field of fertilizers, and in particular to a compound soil conditioner, its preparation method, and a method for combined rice-crop rotation to restore arable land. Background Technology

[0003] Due to long-term high-intensity farming and excessive application of chemical fertilizers and pesticides, rice-growing areas in southern China generally suffer from a series of complex problems, including soil acidification and compaction, increased activity of heavy metals (such as cadmium), soil fertility decline, reduced crop resistance, and risks to agricultural product quality and safety (such as pesticide residues). Existing remediation technologies mostly employ single-function soil conditioners (such as lime for acidification and silica-calcium materials for improvement) or chemical passivators. While these may be effective for individual problems, they cannot simultaneously and systematically address the intertwined issues of soil degradation, heavy metal pollution, and soil-borne diseases. Furthermore, they pose a risk of secondary pollution and increase the cost of planting inputs. While green control methods such as biopesticides are environmentally friendly, they generally have limitations such as slow efficacy, short duration of action, and high cost.

[0004] Furthermore, traditional mineral activation preparation methods are energy-intensive (typically 1100℃ - 1350℃), with the cost of producing highly active silicon-based materials exceeding 1000 yuan / ton, resulting in high product prices and hindering large-scale promotion. Meanwhile, although rice cultivation can increase income to some extent by improving yield per unit area, the comparative benefits are low, leading to low farmer enthusiasm and restricting sustainable agricultural development. Summary of the Invention

[0005] To address the problems of existing composite soil conditioners, this invention proposes a composite soil conditioner, its preparation method, and a method for combined rice-crop rotation to restore arable land.

[0006] A method for preparing a composite soil conditioner, comprising: Step (1) Preparation of highly active silica powder from mineral solid waste source: The mineral solid waste raw material is crushed and ground to a first preset particle size, and heavy metals are targeted leaching and removal using a mixed acid composed of organic acid and inorganic acid in a preset mass ratio. Then, an activator is added to activate and calcine at a first preset temperature to obtain highly active silicon powder. Step (2) Preparation of soil compound conditioner: Using the highly active silica powder as the main material and calcium carbonate and biochar as auxiliary materials, the main material and auxiliary materials are mixed with corrosion inhibitors and organic matter to prepare a powdered composite soil conditioner; wherein, the total amount of the auxiliary materials does not exceed half the amount of the main material, and the amount of biochar as an auxiliary material does not exceed half the amount of calcium carbonate as an auxiliary material. Step (3) Preparation of nutrient solution from Chinese medicinal herbs: After crushing and grinding various Chinese medicinal plant materials, water is added and boiled at a second preset temperature. After filtration, preservative microorganisms are added to the filtrate for fermentation to obtain a Chinese medicinal nutrient solution. Step (4) Prepare foliar spray nutrient solution: The highly active silica powder is ground to a second preset particle size and neutralized to a first preset pH value with an organic acid. It is then mixed with the herbal nutrient solution and filtered. The resulting filtrate is the foliar spray nutrient solution.

[0007] Furthermore, the method also includes: A binder is added to the powdered composite soil conditioner, and then granulated and dried to obtain a granular composite soil conditioner.

[0008] Furthermore, the first preset particle size is less than or equal to 0.1 mm, the preset mass ratio is 1:1, the first preset temperature is below 800℃, the total activation and calcination time is less than 3 hours, the content of the obtained high-activity silica powder is greater than 40%, the amount of the corrosion inhibitor and the binder accounts for 2%-5% of the total amount, the amount of the organic matter accounts for 2%-5% of the total amount, the second preset temperature is 100℃, the cooking time is 1-2 hours, the fermentation time is 7-15 days, the second preset particle size is less than or equal to 0.3 mm, and the first preset pH value is 7-8.

[0009] Furthermore, in step (1), the heavy metals leached out by the heavy metal targeted removal treatment are recovered or safely disposed of through chemical precipitation, adsorption or electrochemical methods; the waste acid after the reaction is recovered and recycled. The activator is composed of sodium hydroxide, sodium carbonate and calcium carbonate, and the amount used does not exceed half of the main mineral solid waste material from which heavy metals are removed by grinding; the mass ratio of sodium carbonate to calcium carbonate is 1:1, and the total amount used does not exceed half of the amount of sodium hydroxide. The calcination process of the activator involves first assisted activation and calcination with borax for less than 2 hours at a first preset temperature and with the activator, followed by assisted calcination with potassium ferrite for less than 1 hour. Borax or potassium ferrite accounts for no more than 5% of the total amount used.

[0010] Furthermore, in steps (1) and (4), the organic acid is selected from citric acid, oxalic acid, wood vinegar, amino acid mother liquor or monosodium glutamate tail liquor; the inorganic acid is selected from sulfuric acid, nitric acid or hydrochloric acid.

[0011] Furthermore, in step (2), the main material in the mineral solid waste is selected from at least one of tailings, low-grade non-metallic clay minerals, and coal-based solid waste; the calcium carbonate auxiliary material is selected from at least one of limestone, dolomite, and oyster shells.

[0012] Furthermore, in step (3), the medicinal plant materials include star anise, Dryopteris crassirhizoma, rhubarb, Coptis chinensis, Phellodendron chinense, buckwheat leaves, camellia oleifera residue, Artemisia argyi, tobacco, garlic, chrysanthemum, Stemona japonica, Sichuan pepper, sandalwood and chinaberry, and the mass of each medicinal plant material does not exceed one-fifth of the total mass of the medicinal plant materials. The binder is sodium carboxymethyl cellulose, the slow-release agent is polyacrylamide, and the organic matter is the filter residue from the decoction of traditional Chinese medicine and the filter residue from foliar spraying of nutrient solution.

[0013] The present invention also proposes a multifunctional compound soil conditioner that integrates medicine and fertilizer, prepared by the above-described preparation method.

[0014] This invention also proposes a method for combined rice-crop rotation to restore arable land, applied to the aforementioned multifunctional compound soil conditioner integrating pesticide and fertilizer, comprising the following steps: Soil basic conditioning: Before the planting of rice and dryland cash crops, the granular compound soil conditioner is evenly spread on the soil surface at a rate of 100-200 kg / mu and then tilled to a depth of 15-20 cm to mix it thoroughly. Topdressing during the rice growing season: During the tillering and heading stages of rice, spray the foliar nutrient solution diluted 50-100 times, with a nutrient solution dosage of 5-10 kg / mu. Green control of diseases and pests: 7-10 days after rice transplanting, spray the leaves with a diluted Chinese herbal nutrient solution at a ratio of 15: 5-10 kg / mu. The number of foliar sprays will be determined based on the field monitoring of diseases and pests. For dryland cash crops: 7-10 days after planting, apply a diluted 15-fold solution of Chinese herbal medicine nutrient solution by micro-spraying or root irrigation at a rate of 5-10 kg / mu. The number of foliar sprays will be determined based on field pest and disease monitoring. During the tillering and heading stages, apply a foliar spray solution diluted 50-100 times at a rate of 5-10 kg / mu.

[0015] Compared with existing technologies, the composite soil conditioner, preparation method, and rice-crop rotation combined method for restoring cultivated land in this invention deeply integrate the highly active silicon and calcium nutrients and soil-improving properties from mineral sources with the biological pesticides and growth-stimulating functions from plant sources, achieving a three-in-one approach of "conditioner, fertilizer, and pesticide," and achieving synergistic treatment effects of "soil improvement, fertilization, antibacterial properties, stress resistance, and quality enhancement." Through the targeted removal of heavy metals by mixed acid and the low-temperature calcination process of composite activators, the activation temperature of highly active silicon powder is reduced from the traditional above 1100℃ to below 800℃, and the active silicon content is increased to over 40%, greatly reducing production costs and giving the product a significant market price advantage. The core raw materials are mineral solid waste and traditional Chinese medicine plants / dregs, realizing high-value-added resource utilization of waste. The active ingredients of traditional Chinese medicine are derived from nature and are biodegradable, avoiding the risks of chemical pesticide residues and environmental pollution. It not only improves the soil from the root and ensures the quality and safety of agricultural products, but also improves yield and quality by enhancing crop health. In particular, crop rotation with high-yield cash crops and reduction of pesticide and fertilizer inputs have significantly increased net income per unit area of ​​land and stimulated farmers' intrinsic motivation to adopt green technologies.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] Figure 1 This is a flowchart of a method for preparing a composite soil conditioner according to the first embodiment of the present invention; Figure 2 This is a graph showing the effect of different activators on the effective silicon content in the first embodiment of the present invention; Figure 3 This is a graph showing the effect of different doping ratios of attapulgite and sodium hydroxide on the effective silicon content in the first embodiment of the present invention. Figure 4 This is a graph showing the effect of different temperatures on the effective silicon content in the first embodiment of the present invention; Figure 5 This is a graph showing the effect of different times on the effective silicon content in the first embodiment of the present invention; Figure 6 This is a comparison diagram of unactivated and activated materials in the first embodiment of the present invention; Figure 7 This is a diagram showing the effective silicon content of different materials in the first embodiment of the present invention; Figure 8 The images show the XRD patterns of copper tailings and copper tailings-based highly active silica powder in the first embodiment of the present invention, where (a) is a wavenumber intensity diagram and (b) is a diffraction intensity diagram. Figure 9The images are SEM images of copper tailings and copper tailings-based highly active silica powder in the first embodiment of the present invention, wherein (a) and (b) are copper tailings, and (c) and (d) are copper tailings-based highly active silica powder. Figure 10 The graph shows the pH value, available cadmium content, total copper content, and available copper content of the soil at different test sites for copper tailings based on heavy metal removal and silicon activation in the second embodiment of the present invention. Figure 11 The graph shows the lodging rate, yield, total cadmium content and total lead content in the soil of copper tailings based on heavy metal removal and silicon activation at different test sites in the second embodiment of the present invention. The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0018] To make the objectives, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention are described in detail below with reference to the examples. Several embodiments of the present invention are given in the examples. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be more thorough and complete.

[0019] Example 1 Please see Figure 1 The diagram shows a method for preparing a composite soil conditioner according to the first embodiment of the present invention, specifically including steps S101 to S104: S101. Preparation of highly active silica powder from mineral solid waste sources: The mineral solid waste raw material is crushed and ground to a first preset particle size, and heavy metals are targeted leaching and removal using a mixed acid composed of organic acid and inorganic acid in a preset mass ratio. Then, an activator is added to activate and calcine at a first preset temperature to obtain highly active silicon powder. It should be noted that, in this embodiment, the first preset particle size is less than or equal to 0.1 mm, the preset mass ratio is 1:1, the first preset temperature is 600-900℃, the total activation and calcination time is 2-4 hours, and the content of the obtained high-activity silicon powder is greater than 40%. Furthermore, in step S101, the heavy metals leached out by the targeted removal treatment are recovered or safely disposed of through chemical precipitation, adsorption, or electrochemical methods; the waste acid after the reaction is recovered and recycled. The activator is composed of sodium hydroxide, sodium carbonate and calcium carbonate, and the amount used does not exceed half of the main mineral solid waste material from which heavy metals are removed by grinding; the mass ratio of sodium carbonate to calcium carbonate is 1:1, and the total amount used does not exceed half of the amount of sodium hydroxide.

[0020] Furthermore, in the calcination process of the activator, under the first preset temperature and activator, the calcination time is less than 2 hours with the assistance of borax activation, and then less than 1 hour with the assistance of potassium ferrite calcination, with borax or potassium ferrite accounting for no more than 5% of the total amount used.

[0021] S102. Preparation of compound soil conditioner: Using the highly active silica powder as the main material and calcium carbonate and biochar as auxiliary materials, the main material and auxiliary materials are mixed with corrosion inhibitors and organic matter to prepare a powdered composite soil conditioner; wherein, the total amount of the auxiliary materials does not exceed half the amount of the main material, and the amount of biochar as an auxiliary material does not exceed half the amount of calcium carbonate as an auxiliary material. It should be noted that in this embodiment, the amount of corrosion inhibitor used accounts for 2%-5% of the total amount, and the amount of organic matter used accounts for 2%-5% of the total amount.

[0022] Furthermore, in step S102, the main material in the mineral solid waste is selected from at least one of tailings, low-grade non-metallic clay minerals, and coal-based solid waste; the calcium carbonate auxiliary material is selected from at least one of limestone, dolomite, and oyster shells.

[0023] S103. Preparation of nutrient solution from traditional Chinese medicine sources: After crushing and grinding various Chinese medicinal plant materials, water is added and boiled at a second preset temperature. After filtration, preservative microorganisms are added to the filtrate for fermentation to obtain a Chinese medicinal nutrient solution. It should be noted that in this embodiment, the second preset temperature is 100℃, the cooking time is 1-2 hours, and the fermentation time is 7-15 days.

[0024] Furthermore, in step S103, the medicinal plant materials include star anise, Dryopteris crassirhizoma, rhubarb, Coptis chinensis, Phellodendron chinense, buckwheat leaves, camellia oleifera residue, mugwort leaves, tobacco, garlic, chrysanthemum, Stemona japonica, Sichuan pepper, sandalwood fruit, and chinaberry fruit, and the mass of each medicinal plant material does not exceed one-fifth of the total mass of the medicinal plant materials. The binder is sodium carboxymethyl cellulose, the slow-release agent is polyacrylamide, and the organic matter is the filter residue from the decoction of traditional Chinese medicine and the filter residue from foliar spraying of nutrient solution.

[0025] S104. Preparation of foliar spray nutrient solution: The highly active silica powder is ground to a second preset particle size and neutralized to a first preset pH value with an organic acid. It is then mixed with the herbal nutrient solution and filtered. The resulting filtrate is the foliar spray nutrient solution.

[0026] It should be noted that in this embodiment, the second preset particle size is less than or equal to 300 nm, and the first preset pH value is 7-8.

[0027] Furthermore, in steps S101 and S104, the organic acid is selected from citric acid, oxalic acid, wood vinegar, amino acid mother liquor, or monosodium glutamate tail liquor; the inorganic acid is selected from sulfuric acid, nitric acid, or hydrochloric acid.

[0028] In some alternative embodiments, the method further includes: A binder is added to the powdered composite soil conditioner, and then granulated and dried to obtain a granular composite soil conditioner.

[0029] It should be noted that in this embodiment, the amount of adhesive used accounts for 2%-5% of the total amount.

[0030] In this specific implementation, the mineral-sourced solid waste used is copper tailings with a particle size ≤0.15mm; the activator is sodium hydroxide, sodium carbonate, and calcium carbonate (mass ratio approximately 2:1:1); the traditional Chinese medicine materials are star anise, Dryopteris crassirhizoma, rhubarb, Coptis chinensis, Phellodendron chinense, buckwheat leaves, camellia oleifera residue, Artemisia argyi, tobacco, garlic, chrysanthemum, Stemona japonica, Sichuan pepper, sandalwood, and Melia toosendan (each material is mixed in equal mass to ensure that the mass of any single material does not exceed half of the total mass); the additives include excipients: limestone powder (calcium carbonate excipient), biochar powder, sodium carboxymethyl cellulose (binder), and polyacrylamide (slow-release agent).

[0031] Furthermore, the preparation steps are as follows: 1. Preparation of High-Activity Silicon Powder: 1 kg of copper tailings powder was ground to 600 nm. The powder was then treated with a mixture of citric acid and sulfuric acid (mass ratio 1:1) at 60°C with stirring for 2 hours. The mixture was filtered and washed to remove heavy metals. 0.4 kg of a composite activator (0.3 kg sodium hydroxide, 0.025 kg sodium carbonate, and 0.075 kg calcium carbonate) was added to the detoxified powder. After thorough mixing, the powder was calcined in a muffle furnace at 750°C for 3 hours. After cooling, the powder was pulverized and passed through a 100-mesh sieve to obtain high-activity silicon powder with an active silicon content of approximately 42%. For details on the preparation of copper tailings-based high-activity silicon powder and its effect on the activation of silicon-containing minerals, please refer to [link to relevant documentation]. Figures 2 to 7 For the material morphology and structural characterization of copper tailings-based highly reactive silicon, please refer to [link to relevant documentation]. Figures 8 to 9 .

[0032] 2. Preparation of Traditional Chinese Medicine Nutrient Solution: Take 1 kg of the mixed traditional Chinese medicine materials, crush them, add 10 times the weight (10 kg) of water, and reflux and boil at 100℃ for 1.5 hours. Filter, collect the filtrate, inoculate the filtrate with compound probiotics, and ferment in a sealed container at 35℃ for 10 days to obtain a dark brown traditional Chinese medicine nutrient solution with a special odor.

[0033] 3. Compound Granulation (Soil Granules): Take 5 kg of the highly active silica powder obtained in step 1 as the main material, add 1.5 kg of limestone powder, 0.75 kg of biochar powder, 0.2 kg of polyacrylamide (accounting for ~2.7% of the total amount), and 0.2 kg of traditional Chinese medicine residue powder (accounting for ~2.7% of the total amount), and mix evenly to obtain a powder. Then add 0.2 kg of sodium carboxymethyl cellulose to the powder, stir evenly, add water to adjust the humidity, granulate using a disc granulator (controlling the particle size to 2-4 mm), and then dry in a 60℃ oven until the moisture content is <10%, thus obtaining the granular composite soil conditioner.

[0034] 4. Preparation of foliar nutrient solution: Take 100 g of the highly active silica powder obtained in step 1 and grind it to a particle size ≤300 nm using a planetary ball mill. Slowly add wood vinegar solution while stirring until the pH of the slurry stabilizes at 7.5. Mix this neutral nano-silica slurry with the herbal nutrient solution obtained in step 2 at a mass ratio of 1:3, stir thoroughly, let stand, and filter. The resulting clear filtrate is the foliar spray nutrient solution.

[0035] Example 2 The second embodiment of the present invention provides a method for combined rice-crop rotation and restoration of arable land, applied to the above-mentioned multifunctional compound soil conditioner integrating pesticide and fertilizer, comprising the following steps: Soil basic conditioning: Before the planting of rice and dryland cash crops, the granular compound soil conditioner is evenly spread on the soil surface at a rate of 100-200 kg / mu and then tilled to a depth of 15-20 cm to mix it thoroughly. Topdressing during the rice growing season: During the tillering and heading stages of rice, spray the foliar nutrient solution diluted 50-100 times, with a nutrient solution dosage of 5-10 kg / mu. Green control of diseases and pests: 7-10 days after rice transplanting, spray the leaves with a diluted Chinese herbal nutrient solution at a ratio of 15: 5-10 kg / mu. The number of foliar sprays will be determined based on the field monitoring of diseases and pests. For dryland cash crops: 7-10 days after planting, apply a 15-fold diluted herbal nutrient solution via micro-spraying or root irrigation at a rate of 5-10 kg / mu. Subsequent foliar spraying frequency will be determined based on field pest and disease monitoring. During the tillering and heading stages, apply a 50-100 fold diluted foliar nutrient solution at a rate of 5-10 kg / mu. In practical implementation, the combined field restoration of rice and economic crop rotation is applied as follows: 1. Location and Background: Highly active silicon based on copper tailings was applied in the fields of Chaisang, Shanggao and Anfu, and the integrated fertilizer and pesticide product was demonstrated on a large scale in Yushui District of Xinyu. The soil was acidified red soil with an initial pH of 5.2 and an available Cd content of 0.35 mg / kg.

[0036] 2. Crop rotation pattern: Rice - Prunella vulgaris (Chinese medicinal herb with high economic value) 3. Application method: Soil base conditioning: 15 days before early rice transplanting, the granular composite soil conditioner prepared in Example 1 is evenly spread on the field surface at a rate of 150 kg / mu. Then, a rotary tiller is used to plow the soil to a depth of 15-20 cm to ensure that the conditioner is fully mixed with the topsoil.

[0037] Topdressing during the growing season: During the peak tillering period of rice, use the foliar nutrient solution prepared in Example 1, diluted 80 times, and spray evenly on the leaves at a rate of 75 L / mu.

[0038] Green pest and disease control: 12 days after rice transplanting, spray with a diluted 15-fold solution of medicinal herb nutrient solution at a rate of 80 L / mu. Subsequent spraying should be done again at the initial stage of pest and disease outbreaks, based on pest monitoring.

[0039] Integrated management: Throughout the process, we will use the locally promoted resistant rice varieties and implement formula fertilization based on soil testing results, while controlling the amount of nitrogen fertilizer used.

[0040] 4. Effect monitoring: Soil indicators: Soil samples were taken and tested after the remediation cycle (one season of rice + one season of Prunella vulgaris). Soil pH increased from 5.2 to 5.8; available Cd content decreased from 0.35 mg / kg to 0.28 mg / kg, a decrease of 20%.

[0041] Crop performance: The lodging rate of rice was reduced by more than 30% compared with the control field; the incidence of diseases such as rice blast and sheath blight, as well as pests, was reduced by about 35% in total.

[0042] Input and Output: Chemical pesticide application was reduced by more than 25%, and fertilizer application was reduced by more than 10%; rice yield increased by 8% compared to the control, and Cd content in the rice was undetectable. The yield and quality of Prunella vulgaris were superior to conventional planting, with overall benefits more than five times that of single-season rice. See details for further information. Figures 10 to 11 .

[0043] Example 3 This embodiment presents a comparative experiment on the formulation optimization of the first embodiment, as detailed below: 1. Experimental Design: To determine the optimal mixing ratio of highly active silica powder and traditional Chinese medicine nutrient solution in foliar spray, four different ratio treatments (highly active silica powder: traditional Chinese medicine nutrient solution = 1:1, 1:3, 1:5, 1:8) were set up for pot experiments, with water spraying serving as a blank control. The test crop was rice.

[0044] 2. Observation indicators: chlorophyll content (SPAD value) of rice leaves, plant height, and field repellency rate against rice planthoppers.

[0045] 3. Experimental Results: Comprehensive analysis of various indicators showed that a 1:3 ratio yielded the most significant effect. Under this treatment, rice leaves were dark green, SPAD values ​​were highest, plants were robust, and the repellency rate against rice planthoppers reached its peak. This result verifies that within the 1:1-1:5 ratio range selected in this embodiment, 1:3 is the optimal choice for foliar spraying, combining nutritional supplementation with pest and disease control.

[0046] Furthermore, two blank control groups (denoted as T1 and T2, where T1 was not sprayed with pesticides and T2 was sprayed with pesticides) and two treatment groups (denoted as T3 and T4, where both groups were fertilized at 100 kg / mu; T3 group used the silicon-based fertilizer in this embodiment and was sprayed with pesticides; T4 group used the silicon-based fertilizer in this embodiment, did not spray with pesticides, but was sprayed with 4 kg / mu of the Chinese herbal medicine nutrient solution in this embodiment before tillering and 4 kg / mu before flowering). For detailed results, please refer to Tables 1 and 2 below: Table 1

[0047] Table 2

[0048] In summary, the composite soil conditioner, preparation method, and rice-crop rotation combined method for restoring arable land described in the above embodiments of the present invention deeply integrate the highly active silicon and calcium nutrients and soil-improving properties from mineral sources with the biological pesticides and growth-stimulating functions from plant sources, achieving a three-in-one approach of "conditioner, fertilizer, and pesticide," and achieving synergistic treatment effects of "soil improvement, fertilization, antibacterial properties, stress resistance, and quality enhancement." Through the targeted removal of heavy metals by mixed acid and the low-temperature calcination process of composite activators, the activation temperature of highly active silicon powder is reduced from the traditional above 1100℃ to below 800℃, and the active silicon content is increased to over 40%, greatly reducing production costs and giving the product a significant market price advantage. The core raw materials are mineral solid waste and traditional Chinese medicine plants / dregs, realizing high-value-added resource utilization of waste. The active ingredients of traditional Chinese medicine are derived from nature and are biodegradable, avoiding the risks of chemical pesticide residues and environmental pollution. It not only improves the soil from the root and ensures the quality and safety of agricultural products, but also improves yield and quality by enhancing crop health. In particular, crop rotation with high-yield cash crops and reduction of pesticide and fertilizer inputs have significantly increased net income per unit area of ​​land and stimulated farmers' intrinsic motivation to adopt green technologies.

[0049] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for preparing a composite soil conditioner, characterized in that, include: Step (1) Preparation of highly active silica powder from mineral solid waste source: The mineral solid waste raw material is crushed and ground to a first preset particle size, and heavy metals are targeted leaching and removal using a mixed acid composed of organic acid and inorganic acid in a preset mass ratio. Then, an activator is added to activate and calcine at a first preset temperature to obtain highly active silicon powder. Step (2) Preparation of soil compound conditioner: Using the highly active silica powder as the main material and calcium carbonate and biochar as auxiliary materials, the main material and auxiliary materials are mixed with corrosion inhibitors and organic matter to prepare a powdered composite soil conditioner; wherein, the total amount of the auxiliary materials does not exceed half the amount of the main material, and the amount of biochar as an auxiliary material does not exceed half the amount of calcium carbonate as an auxiliary material. Step (3) Preparation of nutrient solution from Chinese medicinal herbs: After crushing and grinding various Chinese medicinal plant materials, water is added and boiled at a second preset temperature. After filtration, preservative microorganisms are added to the filtrate for fermentation to obtain a Chinese medicinal nutrient solution. Step (4) Prepare foliar spray nutrient solution: The highly active silica powder is ground to a second preset particle size and neutralized to a first preset pH value with an organic acid. It is then mixed with the herbal nutrient solution and filtered. The resulting filtrate is the foliar spray nutrient solution.

2. The method for preparing the composite soil conditioner according to claim 1, characterized in that, The method further includes: A binder is added to the powdered composite soil conditioner, and then granulated and dried to obtain a granular composite soil conditioner.

3. The method for preparing the composite soil conditioner according to any one of claims 1-2, characterized in that, The first preset particle size is less than or equal to 0.1 mm, the preset mass ratio is 1:1, the first preset temperature is 600-900℃, the total activation and calcination time is less than 3 hours, the content of the obtained high-activity silica powder is greater than 40%, the amount of the corrosion inhibitor and the binder accounts for 2%-5% of the total amount, the amount of the organic matter accounts for 2%-5% of the total amount, the second preset temperature is 100℃, the cooking time is 1-2 hours, the fermentation time is 7-15 days, the second preset particle size is less than or equal to 0.3 mm, and the first preset pH value is 7-8.

4. The method for preparing the composite soil conditioner according to claim 1, characterized in that, In step (1), the heavy metals leached out by the targeted removal treatment are recovered or safely disposed of through chemical precipitation, adsorption or electrochemical methods; the waste acid after the reaction is recovered and recycled. The activator is composed of sodium hydroxide, sodium carbonate and calcium carbonate, and the amount used does not exceed half of the main mineral solid waste material from which heavy metals are removed by grinding; the mass ratio of sodium carbonate to calcium carbonate is 1:1, and the total amount used does not exceed half of the amount of sodium hydroxide. The calcination process of the activator involves first assisted activation and calcination with borax for less than 2 hours at a first preset temperature and with the activator, followed by assisted calcination with potassium ferrite for less than 1 hour. Borax or potassium ferrite accounts for no more than 5% of the total amount used.

5. The method for preparing the composite soil conditioner according to claim 1, characterized in that, In steps (1) and (4), the organic acid is selected from citric acid, oxalic acid, wood vinegar, amino acid mother liquor or monosodium glutamate tail liquor; the inorganic acid is selected from sulfuric acid, nitric acid or hydrochloric acid.

6. The method for preparing the composite soil conditioner according to claim 1, characterized in that, In step (2), the main material of the mineral solid waste is selected from at least one of tailings, low-grade non-metallic clay minerals, and coal-based solid waste; the calcium carbonate auxiliary material is selected from at least one of limestone, dolomite, and oyster shells.

7. The method for preparing the composite soil conditioner according to claim 1, characterized in that, In step (3), the medicinal plant materials include star anise, Dryopteris crassirhizoma, rhubarb, Coptis chinensis, Phellodendron chinense, buckwheat leaves, camellia oleifera residue, mugwort leaves, tobacco, garlic, chrysanthemum, Stemona japonica, Sichuan pepper, sandalwood and chinaberry, and the mass of each medicinal plant material does not exceed one-fifth of the total mass of the medicinal plant materials. The binder is sodium carboxymethyl cellulose, the slow-release agent is polyacrylamide, and the organic matter is the filter residue from the decoction of traditional Chinese medicine and the filter residue from foliar spraying of nutrient solution.

8. A multifunctional compound soil conditioner integrating pesticide and fertilizer, prepared by the preparation method according to any one of claims 1-7.

9. A method for combined rice-crop rotation and restoration of arable land, characterized in that, The application of the integrated fertilizer and pesticide compound soil conditioner according to claim 8 includes the following steps: Soil basic conditioning: Before the planting of rice and dryland cash crops, the granular compound soil conditioner is evenly spread on the soil surface at a rate of 100-200 kg / mu and then tilled to a depth of 15-20 cm to mix it thoroughly. Topdressing during the rice growing season: During the tillering and heading stages of rice, spray the foliar nutrient solution diluted 50-100 times, with a nutrient solution dosage of 5-10 kg / mu. Green control of diseases and pests: 7-10 days after rice transplanting, spray the leaves with a diluted Chinese herbal nutrient solution at a ratio of 15: 5-10 kg / mu. The number of foliar sprays will be determined based on the field monitoring of diseases and pests. For dryland cash crops: 7-10 days after planting, apply a diluted 15-fold solution of Chinese herbal medicine nutrient solution by micro-spraying or root irrigation at a rate of 5-10 kg / mu. The number of foliar sprays will be determined based on field pest and disease monitoring. During the tillering and heading stages, apply a foliar spray solution diluted 50-100 times at a rate of 5-10 kg / mu.

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