Soil remediation material for cucumber continuous cropping obstacle, and preparation method and soil remediation method thereof

Abstract

The application discloses a soil remediation material suitable for cucumber continuous cropping obstacles and a preparation method and a soil remediation method, relates to the technical field of cucumber planting and soil remediation, and solves the problems of physicochemical deterioration, microbial imbalance and nutrient deficiency in continuous cropping soil by combining the physicochemical improvement characteristics of functional biochar, the nutrient supply capacity of organic material and the biological regulation function of microbial inoculum.

Description

Technical Field

[0001] This invention relates to the field of cucumber cultivation and soil remediation technology, and in particular to a soil remediation material suitable for cucumber continuous cropping obstacles, as well as its preparation method and soil remediation method. Background Technology

[0002] Continuous cropping obstacles (CCOs) refer to the phenomenon that, even with normal field management measures, crop yields decline, quality deteriorates, and pests and diseases frequently occur after cucumbers or their closely related crops are continuously planted on the same plot. This has become a key issue restricting the sustainable development of the cucumber industry.

[0003] The core causes of cucumber continuous cropping obstacles include three aspects: First, the deterioration of soil physical and chemical properties, manifested as soil acidification, salinization, nutrient imbalance, abnormal soil bulk density, and decreased fertilizer and water retention capacity. In particular, the problem of salt accumulation is more serious in hot and dry valley areas due to strong evaporation. Second, the soil microbial community is imbalanced, with the soil transforming from "bacterial" to "fungal". The relative abundance of soil-borne pathogens, with Fusarium as the core, is as high as 17.52%, the total abundance of plant parasitic nematodes exceeds 12%, and the number of beneficial microorganisms (such as Luteitalea, RSA9, etc.) decreases, reducing the soil's disease resistance. Third, the accumulation of plant autotoxic substances and the long-term retention of allelochemicals in the soil inhibit cucumber growth and development and aggravate disease occurrence.

[0004] Existing remediation technologies include soil improvement (high-temperature fumigation and disinfection), field management (straw return and no-till), rational planting (intercropping and relay cropping), and biological control (application of microbial agents), but they have significant limitations: straw return alone has limited inhibitory effects on pathogens (less than 50% reduction) and slow nutrient release; microbial agents alone have difficulty colonizing in the harsh environment of continuously cropped soils, resulting in unstable effects and a 30%-50% loss rate of viable bacteria; strong reducing sterilization treatment can inhibit pathogens, but it destroys beneficial soil microbial communities, leading to soil ecological function degradation and a decrease of more than 50% in the abundance of ammonia-oxidizing bacteria; and the application of biochar alone cannot simultaneously solve the problems of soil nutrient imbalance and microbial network reconstruction.

[0005] In typical cucumber-growing areas such as the Yuanmou Dry-Hot Valley in my country, the region boasts abundant light and heat resources and is a major off-season vegetable base, accounting for about half of the national off-season cucumber production. However, the unique dry and hot climate leads to high soil evaporation and easy salt accumulation, exacerbating continuous cropping obstacles. Existing technologies struggle to achieve synergistic improvements in soil physicochemical properties, microbial communities, and nutrient cycling. Therefore, developing a soil remediation material, its preparation method, and soil remediation techniques suitable for cucumber continuous cropping obstacles, along with a composite remediation technology that can simultaneously optimize soil structure, regulate microbial flora, and enhance nutrient supply capacity, is of significant practical importance for solving cucumber continuous cropping obstacles and ensuring the sustainable development of regional agriculture. Summary of the Invention

[0006] In view of this, the present invention addresses the deficiencies of existing technologies. Its main objective is to provide a soil remediation material, preparation method, and soil remediation method suitable for cucumber continuous cropping obstacles. By combining the physicochemical improvement properties of functional biochar, the nutrient supply capacity of organic materials, and the bioregulatory function of microbial agents, it simultaneously solves the three core problems of soil physicochemical deterioration, microbial imbalance, and nutrient deficiency caused by continuous cropping. The remediation effect is superior to that of applying a single material. Functional biochar provides a stable habitat for microorganisms, organic materials provide carbon and energy sources for microbial growth, and compound microbial agents directly supplement beneficial bacteria. The synergistic effect of these three factors solves the problems of difficult microbial colonization and poor community stability in existing technologies.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A soil remediation material suitable for cucumber continuous cropping obstacles includes functional biochar, organic materials and microbial agents. The application rate of functional biochar is 30-60 t / ha, the application rate of organic materials is 6-6.5 t / ha, and the application rate of microbial agents is 15-20 kg / ha. The mass ratio of functional biochar, organic materials and microbial agents is (30-60):(6-6.5):(0.015-0.02).

[0009] As a preferred embodiment: the organic material is selected from one or two of alfalfa straw and mushroom residue; the microbial agent is a compound agent of Bacillus subtilis and Trichoderma longifolia.

[0010] As a preferred option, the application scheme of the soil remediation material when applied to soil with mild continuous cropping obstacles is as follows: 30 t / ha of functional biochar, 6 t / ha of alfalfa straw and 15 kg / ha of compound microbial agent; the specific characteristics of soil with mild continuous cropping obstacles are: continuous cropping period of 3-5 years, soil pH of 6.5-7.0, relative abundance of Fusarium of 5%-10%, and EC value of <1.0 mS / cm.

[0011] As a preferred embodiment, the application scheme of the soil remediation material when applied to soils with moderate continuous cropping obstacles is as follows: 45 t / ha of functional biochar, 6.5 t / ha of inoculum residue, and 18 kg / ha of compound inoculant; the specific characteristics of soils with moderate continuous cropping obstacles are: continuous cropping period of 6-10 years, soil pH of 6.0-6.5, relative abundance of Fusarium of 10%-15%, and EC value of 1.0-1.5 mS / cm.

[0012] As a preferred embodiment, the application scheme of the soil remediation material when applied to soils with severe continuous cropping obstacles is as follows: 60 t / ha of functional biochar, 6 t / ha of alfalfa straw, 3.25 t / ha of inoculum residue, and 20 kg / ha of compound inoculant. The specific characteristics of soils with severe continuous cropping obstacles are: continuous cropping period of more than 10 years, soil pH of 5.5-6.0, relative abundance of Fusarium above 15%, and EC value > 1.5 mS / cm.

[0013] A method for preparing a soil remediation material suitable for cucumber continuous cropping obstacles includes the following steps:

[0014] S1. Preparation of Functional Biochar: Using corn stalks as raw material, anaerobic pyrolysis is carried out at 500-600℃ for 2-3 hours. After cooling, the biochar is pulverized and sieved. The resulting biochar has a specific surface area ≥150 m². 2 / g, with a pore size distribution of 2-50 nm, a pH value of 8.5-10.0, and an organic matter content of ≥75%, functional biochar was obtained;

[0015] S2. Preparation of organic materials: Select alfalfa straw or mushroom residue, crush it to 1-3 cm, wherein the organic matter content of alfalfa straw is ≥80% and the moisture content is ≤15%, and the organic matter content of mushroom residue is ≥75% and the moisture content is ≤20%;

[0016] S3. Selection of microbial agents: Use a compound agent of Bacillus subtilis and Trichoderma longifolia, with an effective viable count ≥2 billion CFU / g, a Bacillus subtilis to Trichoderma longifolia ratio of 1:1, a temperature range of 15-45℃, and a pH range of 5.5-8.5 to maintain activity.

[0017] As a preferred embodiment: In step S1, anaerobic pyrolysis is performed at 500-600℃ for 2-3 hours, followed by cooling and pulverization and sieving. Specifically, a continuous anaerobic pyrolysis furnace is used, with a heating rate controlled at 10℃ / min, raising the temperature to 500-600℃ while maintaining an anaerobic environment with an oxygen content of <5%, and pyrolysis is performed for 2-3 hours. After pyrolysis, the material is allowed to cool naturally to room temperature to avoid rapid cooling that could damage the pore structure. The material is then sieved using a standard 2mm stainless steel sieve, and the undersize material is collected for later use. Large particles on the sieve are returned to the pulverizer for secondary pulverization to ensure particle size uniformity ≥95%.

[0018] As a preferred option: when using alfalfa straw or mushroom residue in step S2, select fresh alfalfa straw, dry it until the moisture content is ≤15%, and crush it to 1-3cm; or select waste mushroom residue after edible mushroom cultivation, which is fermented at high temperature, kept at 60℃ for 7 days, and the fermentation degree is tested, with a germination index ≥85%, and crushed to 2-3cm.

[0019] A soil remediation method using the aforementioned soil remediation material suitable for cucumber continuous cropping obstacles includes the following steps:

[0020] First, pretreatment: 10-20 days before planting, spread functional biochar and organic materials evenly on the soil surface in a certain proportion, and use a rotary tiller to plow to a depth of 20-30 cm to fully mix the functional biochar and organic materials with the 0-30 cm topsoil layer, with a mixing uniformity of ≥90%;

[0021] Second, water regulation: After applying functional biochar and organic materials, water is applied to keep the soil moisture content at 60%-70% of field capacity. This is maintained for 5-7 days for pre-fermentation, during which the soil temperature is controlled at 25-35℃.

[0022] Third, application of microbial agents: 1-5 days before planting, dilute 15-20 kg / ha of microbial agents with water 500 times and apply them to the soil by drip irrigation or root irrigation. The application rate is 20-30 L / ha. Ensure that the microbial agents are evenly distributed in the root growth zone, that is, in the 0-20 cm soil layer.

[0023] Fourth, field management: After cucumber planting, apply microbial inoculant every 10-20 days. Dilute 15-20 kg / ha of microbial inoculant with water 1000 times. Apply 10-15 L / ha each time, and repeat 2-3 times.

[0024] As a preferred option: In the field management of step four, the soil moisture content should be maintained at 50%-60% of field capacity during the cucumber's growing season. Conventional fertilization management: NPK compound fertilizer should be applied according to the standard, and the time interval between the application of microbial agents should be avoided to less than 3 days.

[0025] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution:

[0026] (1) This invention combines the physicochemical improvement properties of functional biochar, the nutrient supply capacity of organic materials, and the bioregulatory function of microbial agents to simultaneously solve the three core problems of soil physicochemical deterioration due to continuous cropping, microbial imbalance, and nutrient deficiency. The remediation effect is better than that of applying a single material. Experimental data show that after treatment using Scheme 2, the soil pH increased from 6.2 to 7.3, CEC reached 15.8 cmol / kg, and the organic matter content increased by 32%; the relative abundance of Fusarium decreased by 68%, and the abundance of plant parasitic nematodes decreased by 91%; the aboveground dry matter of cucumber was 2.8 times that of the control, and the yield increased by 35%.

[0027] (2) Outstanding effect of microbial community optimization: functional biochar provides a stable habitat for microorganisms, organic materials provide carbon and energy sources for microbial growth, and compound microbial agents directly supplement beneficial bacteria. The synergistic effect of the three increases the modularization and clustering coefficient of soil microbial network by more than 40%, enhances network robustness, and significantly improves anti-interference ability compared to single remediation technology, solving the problems of difficult microbial colonization and poor community stability in existing technologies.

[0028] (3) Adapting to the needs of special climate zones: In response to the characteristics of hot and dry valley climate, the high specific surface area and pore structure of functional biochar can enhance the soil's water and fertilizer retention capacity, reduce water evaporation and salt accumulation, and the heat released during the fermentation process of organic materials can moderately improve the soil microenvironment. The combination of the stress resistance of compound microbial agents and the buffering effect of functional biochar improves the adaptability and stability of remediation technology in high temperature and drought environments.

[0029] (4) Ecological and environmentally friendly and sustainable: The remediation materials are all derived from agricultural waste (corn stalks, alfalfa stalks, and mushroom residue), realizing resource recycling and without the introduction of chemical pollutants; after remediation, the soil microbial community structure is optimized, the nutrient cycling efficiency is improved, and the basic soil fertility is continuously improved, providing a long-term sustainable soil environment for cucumber continuous cropping and avoiding the damage to the soil ecosystem caused by traditional chemical disinfection methods.

[0030] To more clearly illustrate the structural features and effects of the present invention, a detailed description is provided below in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0031] Figure 1 This is a pH comparison chart for each group in this invention;

[0032] Figure 2 This is a comparison chart of soil nutrient data for each group in this invention;

[0033] Figure 3 This is a comparison chart of soil enzyme activity data for each group in this invention;

[0034] Figure 4 This is a comparison chart of the abundance of key bacterial communities in each group according to the present invention. Detailed Implementation

[0035] The present invention is as follows Figure 1 As shown in Figure 4, a soil remediation material suitable for cucumber continuous cropping obstacles includes functional biochar, organic materials and microbial agents. The application rate of functional biochar is 30-60 t / ha, the application rate of organic materials is 6-6.5 t / ha, and the application rate of microbial agents is 15-20 kg / ha. The mass ratio of functional biochar, organic materials and microbial agents is (30-60):(6-6.5):(0.015-0.02).

[0036] The organic material is selected from one or two of alfalfa straw and mushroom residue; the microbial agent is a compound agent of Bacillus subtilis and Trichoderma longifolia.

[0037] Bacillus subtilis is deposited at the China General Microbiological Culture Collection Center, accession number CGMCC No. 14514, and was purchased from Tianjin Kunhe Biotechnology Co., Ltd.

[0038] The Trichoderma longifolia strain is deposited at the China Industrial Microbial Culture Collection Center, with accession number CICC13053. It was purchased from Shandong Hezhong Kangyuan Biotechnology Co., Ltd., with product number MES810.

[0039] The application scheme for this soil remediation material when applied to soils with mild continuous cropping obstacles is as follows: 30 t / ha of functional biochar, 6 t / ha of alfalfa straw, and 15 kg / ha of compound microbial agent; the specific characteristics of soils with mild continuous cropping obstacles are: continuous cropping period of 3-5 years, soil pH of 6.5-7.0, relative abundance of Fusarium of 5%-10%, and EC value of <1.0 mS / cm.

[0040] The application scheme for this soil remediation material when applied to soils with moderate continuous cropping obstacles is as follows: 45 t / ha of functional biochar, 6.5 t / ha of inoculum residue, and 18 kg / ha of compound inoculant. The specific characteristics of soils with moderate continuous cropping obstacles are: continuous cropping period of 6-10 years, soil pH of 6.0-6.5, relative abundance of Fusarium of 10%-15%, and EC value of 1.0-1.5 mS / cm.

[0041] The application scheme for this soil remediation material when applied to soils with severe continuous cropping obstacles is as follows: 60 t / ha of functional biochar, 6 t / ha of alfalfa straw, 3.25 t / ha of inoculum residue, and 20 kg / ha of compound inoculant. The specific characteristics of soils with severe continuous cropping obstacles are: continuous cropping period of more than 10 years, soil pH of 5.5-6.0, relative abundance of Fusarium above 15%, and EC value > 1.5 mS / cm.

[0042] A method for preparing a soil remediation material suitable for cucumber continuous cropping obstacles includes the following steps:

[0043] S1. Preparation of Functional Biochar: Using corn stalks as raw material, anaerobic pyrolysis is carried out at 500-600℃ for 2-3 hours. After cooling, the biochar is pulverized and sieved. The resulting biochar has a specific surface area ≥150 m². 2 / g, with a pore size distribution of 2-50 nm, a pH value of 8.5-10.0, and an organic matter content of ≥75%, functional biochar was obtained;

[0044] S2. Preparation of organic materials: Select alfalfa straw or mushroom residue, crush it to 1-3 cm, wherein the organic matter content of alfalfa straw is ≥80% and the moisture content is ≤15%, and the organic matter content of mushroom residue is ≥75% and the moisture content is ≤20%;

[0045] S3. Selection of microbial agents: Use a compound agent of Bacillus subtilis and Trichoderma longifolia, with an effective viable count ≥2 billion CFU / g, a Bacillus subtilis to Trichoderma longifolia ratio of 1:1, a temperature range of 15-45℃, and a pH range of 5.5-8.5 to maintain activity.

[0046] In step S1, anaerobic pyrolysis is performed at 500-600℃ for 2-3 hours. After cooling, the material is pulverized and sieved. Specifically, a continuous anaerobic pyrolysis furnace is used, with a heating rate controlled at 10℃ / min, raising the temperature to 500-600℃ while maintaining an anaerobic environment with an oxygen content of <5%. Pyrolysis is carried out for 2-3 hours. After pyrolysis, the material is allowed to cool naturally to room temperature to avoid rapid cooling that could damage the pore structure. The material is then sieved using a standard 2mm stainless steel sieve, and the undersize material is collected for later use. Large particles on the sieve are returned to the pulverizer for secondary pulverization to ensure particle size uniformity ≥95%.

[0047] When using alfalfa straw or mushroom residue in step S2, select fresh alfalfa straw and dry it until the moisture content is ≤15%, then crush it to 1-3cm; or select waste mushroom residue after edible mushroom cultivation, which is composted at high temperature, kept at 60℃ for 7 days, and tested for compostability, with a germination index ≥85%, then crushed to 2-3cm.

[0048] A soil remediation method using a soil remediation material suitable for cucumber continuous cropping obstacles includes the following steps:

[0049] First, pretreatment: 15 days before planting, spread functional biochar and organic materials evenly on the soil surface in a certain proportion, and use a rotary tiller to cultivate to a depth of 20-30 cm to fully mix the functional biochar and organic materials with the 0-30 cm topsoil layer, with a mixing uniformity of ≥90%.

[0050] Second, water regulation: After applying functional biochar and organic materials, water is applied to keep the soil moisture content at 60%-70% of field capacity. This is maintained for 5-7 days for pre-fermentation, during which the soil temperature is controlled at 25-35℃.

[0051] Third, application of microbial agents: 3 days before planting, dilute 15-20 kg / ha of microbial agents with clean water 500 times and apply them to the soil by drip irrigation or root irrigation. The application rate is 20-30 L / ha. Ensure that the microbial agents are evenly distributed in the root growth zone, that is, in the 0-20 cm soil layer.

[0052] Fourth, field management: After cucumber planting, apply microbial inoculant every 15 days. Dilute 15-20 kg / ha of microbial inoculant with water 1000 times. The application rate is 10-15 L / ha each time, and repeat 2-3 times.

[0053] In the fourth step of field management, the soil moisture content should be maintained at 50%-60% of field capacity during the cucumber's growing season. Routine fertilization management: NPK compound fertilizer should be applied according to the standard, and the time interval between application and application of microbial agents should be less than 3 days.

[0054] Key indicator detection methods:

[0055] Soil physicochemical indicators: pH value was measured using a pH meter (soil-to-water ratio 1:2.5), EC value was measured using a conductivity meter, DOC was measured using an ultraviolet spectrophotometer, CEC was measured using the ammonium acetate exchange method, and organic matter was measured using the potassium dichromate oxidation method.

[0056] Microbial indicators: Bacterial and fungal community structure was analyzed using high-throughput sequencing technology (16S rRNA / ITS gene sequencing), Fusarium abundance was determined by real-time quantitative PCR, and nematode abundance was determined by microscopic counting after separation by sucrose centrifugation.

[0057] Crop indicators: The dry weight of the aboveground parts was determined by blanching at 105℃ for 30 minutes and then drying at 75℃ to constant weight. The yield was calculated based on actual field harvest. The vitamin C content was determined by titration with 2,6-dichlorophenolindophenol.

[0058] Example 1: Application scheme of soil remediation materials in soil with mild continuous cropping obstacles

[0059] Applicable scenarios: continuous cropping for 3-5 years, soil pH 6.5-7.0, relative abundance of Fusarium 5%-10%, EC value <1.0 mS / cm;

[0060] Application scheme: 30 t / ha of functional biochar, 6 t / ha of alfalfa straw and 15 kg / ha of compound microbial agent;

[0061] Results: Soil pH stabilized at 7.2-7.5, Fusarium abundance decreased by 45%, and cucumber yield increased by 28%.

[0062] Example 2: Application scheme of soil remediation materials in soils with moderate continuous cropping obstacles

[0063] Applicable scenarios: continuous cropping for 6-10 years, soil pH 6.0-6.5, relative abundance of Fusarium 10%-15%, EC value 1.0-1.5 mS / cm;

[0064] Application scheme: 45 t / ha of functional biochar, 6.5 t / ha of microbial residue and 18 kg / ha of compound microbial agent;

[0065] Results: Soil pH stabilized at 7.1-7.4, CEC increased to 15.8 cmol / kg, Fusarium abundance decreased by 68%, harmful nematode abundance decreased by 91%, cucumber aboveground dry matter was 2.8 times that of the control, and yield increased by 35%.

[0066] Example 3: Application scheme of soil remediation materials in soils with severe continuous cropping obstacles

[0067] Applicable scenarios: continuous cropping for more than 10 years, soil pH 5.5-6.0, relative abundance of Fusarium above 15%, EC value > 1.5 mS / cm;

[0068] Application scheme: 60 t / ha of functional biochar, 6 t / ha of alfalfa straw, 3.25 t / ha of mushroom residue and 20 kg / ha of compound microbial agent;

[0069] Results: Soil pH stabilized at 7.0-7.3, EC value decreased by 38%, Fusarium abundance decreased by 75.9%, beneficial bacteria Luteitalea abundance increased by 138.8%, and cucumber yield increased by 29.4%.

[0070] Comparative Example: Through multiple parallel comparative experiments, the remediation effect of the composite remediation system of "functional biochar + organic materials + microbial agents" was verified, the suitability of different combinations of remediation materials and different application ratios in soils with mild, moderate and severe continuous cropping obstacles was clarified, and the remediation differences between single materials and composite materials were compared.

[0071] Test materials: Functional biochar, made from corn stalks, anaerobically pyrolyzed at 500-600℃ for 2-3 hours, pulverized and passed through a 2mm sieve, with a specific surface area ≥150m² / g, pH 8.5-10.0, and organic matter content ≥75%; Organic materials, alfalfa stalks (dried to moisture ≤15%, pulverized to 1-3cm, organic matter ≥80%), and edible fungi waste residue (composted at 60℃ for 7 days, germination index ≥85%, pulverized to 2-3cm, organic matter ≥75%); Microbial inoculants, a compound inoculant of Bacillus subtilis and Trichoderma longifolia, with an effective viable count ≥2 billion CFU / g, a count ratio of 1:1, a temperature tolerance of 15-45℃, and a suitable pH of 5.5-8.5.

[0072] Test soils: Soils with mild continuous cropping obstacles (2-3 years of continuous cropping, pH 6.5-7.0, relative abundance of Fusarium 5%-10%, EC value <1.0 mS / cm, organic matter content 1.2%-1.5%); Soils with moderate continuous cropping obstacles (4-5 years of continuous cropping, pH 6.0-6.5, relative abundance of Fusarium 10%-15%, EC value 1.0-1.5 mS / cm, organic matter content 0.8%-1.2%); Soils with severe continuous cropping obstacles (8-10 years or more of continuous cropping, pH 5.5-6.0, relative abundance of Fusarium ≥15%, EC value >1.5 mS / cm, organic matter content 0.5%-0.8%).

[0073] Test crop: Cucumber varieties selected from the local main varieties, with a seed germination rate of ≥90%.

[0074] Experimental instruments: pH meter (soil-to-water ratio 1:2.5), conductivity meter, ultraviolet spectrophotometer, high-throughput sequencing platform, real-time quantitative PCR instrument, sucrose centrifuge, microscope, constant temperature oven, rotary tiller, drip irrigation equipment, electronic balance, stainless steel sieves (2mm, 5mm), etc.

[0075] Experimental Design: A field plot experiment was conducted in a typical cucumber-growing area in the Yuanmou dry-hot valley of my country (simulating local climate conditions: average annual temperature 21℃, annual precipitation 613mm, and evaporation exceeding 3500mm). One plot each of mild, moderate, and severe continuous cropping obstacles were selected, and each plot was divided into several plots. Plot dimensions: 5m × 5m = 25m², with a plot spacing of 1m and a protective row (2m wide) around the perimeter to prevent cross-contamination. Replication: Each treatment was replicated three times using a randomized block design to avoid interference from environmental factors such as topography and sunlight.

[0076] Cultivation and Management: Apply the functional biochar and organic materials evenly to the soil surface according to the specified proportions. Till the soil to a depth of 20-30cm (25cm for light obstacles, 30cm for heavy obstacles) using a rotary tiller, repeating this process three times to ensure the material is mixed evenly with the 0-30cm soil layer (≥90%). Water after application to maintain soil moisture at 60%-70% of field capacity. Allow 5-7 days for pre-fermentation, controlling the soil temperature to 25-35℃ during fermentation. Till the soil every two days (to a depth of 15cm). Dilute the compound microbial agent 500 times with water according to the specified ratio and apply it to the soil via drip irrigation at a rate of 20-30 L / ha, ensuring even distribution of the agent in the 0-20cm root growth zone. Transplant cucumber seedlings after seed cultivation, spacing them 30cm x 40cm, with 100 seedlings per plot. During the growing season, maintain soil moisture content at 50%-60%. Apply NPK compound fertilizer according to standard phases (100 kg / ha at 20 days, 150 kg / ha at 40 days, and 120 kg / ha at 60 days after planting), with an interval of ≥3 days between fertilization and microbial agent application. Manually weed; chemical herbicides and highly toxic fungicides are prohibited. Apply compound microbial agent every 15 days after planting, diluted 1:1000, at a rate of 10-15 L / ha each time, for 2-3 consecutive applications.

[0077] Table 1: pH control table for each group

[0078] Processing type Returning to the field for 1 month Planting for 1 month Planting for 2 months Planting for 3 months CK (control, no repair) 6.2 6 5.8 5.7 Functional biochar + alfalfa 7.5 7.4 7.3 7.2 Functional biochar + mushroom residue 7.6 7.5 7.4 7.3 Functional biochar + alfalfa + microbial agent 7.4 7.3 7.3 7.2 Functional biochar + mushroom residue + microbial agent 7.5 7.4 7.4 7.3 Example 2 (Moderate Obstacle Repair) 7 7.1 7.2 7.3

[0079] Table 2: Comparison of Soil Nutrient Data for Each Group

[0080] Processing type Soluble organic carbon (DOC) (g / kg) Improvement compared to CK (%) Quick-acting potassium (AK) (mg / kg) Improvement compared to CK (%) Available phosphorus (AP) (mg / kg) Improvement compared to CK (%) CK (control, no repair) 8.2 - 125.6 - 28.3 - Functional biochar alone 11.5 40.2 158.3 26 33.5 18.4 Functional biochar + alfalfa 14.8 80.5 196.8 56.7 36.9 30.4 Functional biochar + mushroom residue 13.9 69.5 165.2 31.5 39.7 40.3 Functional biochar + alfalfa + microbial agent 16.3 98.8 212.4 69.1 42.5 50.2 Functional biochar + mushroom residue + microbial agent 15.7 91.5 188.7 49.9 45.8 61.8 Example 1 (Mild Impairment) 14.3 74.4 182.5 45.3 38.1 34.6 Example 2 (Moderate Disability) 15.7 91.5 188.7 49.9 45.8 61.8 Example 3 (Severe Disability) 16.5 101.2 205.3 63.5 43.2 52.6

[0081] Table 3: Comparison Table of Soil Enzyme Activity Data for Each Group

[0082] Processing type Urease (U / g·d) Improvement compared to CK (%) Phosphatase (U / g·d) Improvement compared to CK (%) Sucrase (U / g·d) Improvement compared to CK (%) CK (control, no repair) 1.85 - 0.92 - 5.32 - Functional biochar alone 2.58 39.5 1.27 38 7.45 39.9 Functional biochar + alfalfa 3.26 76.2 1.53 66.3 9.88 85.7 Functional biochar + mushroom residue 3.01 62.7 1.48 60.9 8.96 68.4 Functional biochar + alfalfa + microbial agent 4.12 122.7 1.87 103.3 12.54 135.7 Functional biochar + mushroom residue + microbial agent 3.86 108.6 1.75 90.2 11.68 119.5 Example 1 (Mild Impairment) 3.12 68.6 1.42 54.3 9.23 73.5 Example 2 (Moderate Disability) 3.86 108.6 1.75 90.2 11.68 119.5 Example 3 (Severe Disability) 4.35 135.1 1.96 113 13.21 148.3

[0083] Table 4: Comparison of the abundance of key bacterial communities in each group

[0084] Processing type Abundance (%) of beneficial bacteria Luteitalea Improvement compared to CK (%) Abundance (%) of beneficial bacteria RSA9 Improvement compared to CK (%) Total abundance of harmful nematodes (%) The decrease compared to CK (%) CK (control, no repair) 0.85 - 0.62 - 12.3 - Functional biochar alone 1.28 50.6 0.85 37.1 8.5 30.9 Functional biochar + alfalfa 1.52 78.8 1.03 66.1 3.3 73.2 Functional biochar + mushroom residue 1.36 60 0.91 46.8 8 35 Functional biochar + alfalfa + microbial agent 1.96 130.6 1.45 133.9 1.1 91.1 Functional biochar + mushroom residue + microbial agent 1.82 114.1 1.33 114.5 1.3 89.4 Example 1 (Mild Impairment) 1.45 70.6 1.01 62.9 4.1 66.7 Example 2 (Moderate Disability) 1.82 114.1 1.33 114.5 1.3 89.4 Example 3 (Severe Disability) 2.03 138.8 1.51 143.5 1.6 87

[0085] From Tables 1 to 4, we can see that:

[0086] This application achieves a simultaneous solution to three core problems in continuously cropped soils: physical and chemical deterioration, microbial imbalance, and nutrient deficiency through the synergistic effect of functional biochar, organic materials, and compound microbial agents. The remediation effect far exceeds that of applying a single material, and this advantage is fully demonstrated in multiple sets of charts and data.

[0087] First, the soil physicochemical properties were significantly improved, and acidification and salinization were effectively alleviated: Figure 1 (pH control diagram) shows that the soil pH value of the control treatment (CK) continued to decrease with the planting cycle, from 6.2 one month after returning to the field to 5.7 three months after planting, showing a clear acidification trend; while all treatment groups applying remediation materials were able to maintain or increase the soil pH value. Among them, the pH value of Example 2 (moderate obstacle remediation) steadily increased from 7.0 to 7.3, and the pH value of the functional biochar + inoculum residue + inoculant combination remained stable between 7.3 and 7.5, which is completely in line with the suitable pH range for cucumber growth (7.0-7.8). This indicates that the alkaline characteristics of functional biochar and the buffering effect of organic materials work synergistically to effectively block the soil acidification process caused by continuous cropping, especially suitable for salinization problems caused by strong evaporation in arid and hot valley areas; Data from Example 3 (severe obstacle remediation) showed that the soil EC value was reduced by 38% compared with CK, confirming the salt adsorption capacity of biochar with high specific surface area.

[0088] Second, the soil nutrient supply capacity was significantly improved, and the nutrient cycling efficiency was optimized: Figure 2 (soil nutrient data) clearly shows that the nutrient supply effect of the composite remediation system far exceeds that of single biochar treatment: the soluble organic carbon (DOC) in Example 3 increased by 101.2% compared to the control (CK), available potassium increased by 63.5%, and available phosphorus increased by 52.6%; even in Example 1, which was a mild obstacle remediation, DOC and available phosphorus increased by 74.4% and 34.6% respectively compared to the control (CK). Compared with single biochar treatment (DOC increased by 40.2% and available phosphorus increased by 18.4%), organic materials (alfalfa straw, fungal residue) act as a natural nutrient reservoir, working synergistically with the adsorption and fertilizer retention function of biochar. This not only directly replenished carbon sources, phosphorus, potassium, and other nutrients, but also promoted nutrient activation by improving soil structure, completely solving the technical limitation that single biochar could not simultaneously address nutrient imbalance.

[0089] Third, soil enzyme activity is a core indicator of soil fertility and microbial activity: Figure 3 (soil enzyme activity data) shows that the activities of urease, phosphatase, and sucrase were all doubled under the composite remediation system: the urease activity in Example 3 was 135.1% higher than the control (CK), the phosphatase activity was 113% higher, and the sucrase activity was 148.3% higher; the sucrase activity of the functional biochar + alfalfa + microbial agent combination was 135.7% higher than the control (CK). This result indicates that the stable habitat provided by biochar, the carbon source provided by organic materials, and the beneficial microbial community supplemented by the composite microbial agent work synergistically to significantly enhance the metabolic activity of microorganisms participating in nutrient cycling, providing a continuous and stable nutrient supply for cucumber growth.

[0090] Fourth, the microbial network reconstruction effect is outstanding, and the soil's stress resistance and stability are significantly enhanced: Figure 4 (abundance of key microbial communities) shows that in Example 3, the abundance of beneficial bacteria Luteitalea increased by 138.8% compared to the control (CK), and the abundance of RSA9 increased by 143.5%; in Example 2, the total abundance of harmful nematodes decreased by 89.4% compared to the control (CK), and the relative abundance of Fusarium decreased by 68%. Compared with the single biochar treatment (Luteitalea abundance increased by 50.6%, and harmful nematodes decreased by 30.9%), the porous structure of biochar in the composite system provides a "sanctuary" for beneficial bacteria, the carbon source of organic materials promotes the proliferation of beneficial bacteria, and the composite microbial agent directly supplements the functional microbial community. The three synergistic effects increase the modularity and clustering coefficient of the soil microbial network by more than 40%, effectively blocking the deterioration trend of "bacterial soil" to "fungal soil". In existing technologies, the viable bacteria loss rate of simple microbial agents reaches 30%-50%, while this application improves the soil microenvironment through pre-fermentation and phased application of microbial agents, thereby increasing the colonization rate of beneficial bacteria by more than 45%. Figure 4 shows that the abundance of beneficial bacteria in the composite treatment group remained stable throughout the planting cycle without significant decline, confirming the high stability of the microbial community. This indicates that the reconstructed microbial network has stronger anti-interference capabilities, providing core support for long-term soil health. The 500-600℃ anaerobic pyrolysis process of functional biochar creates a pore size distribution of 2-50nm and a specific surface area of ​​≥150m² / g, which not only enhances the soil's water and fertilizer retention capacity (reducing water evaporation by more than 30%), but also adsorbs accumulated salts. The heat released during the fermentation of organic materials can raise the soil temperature by 2-3℃ in winter, improving the soil microenvironment. The temperature tolerance range of the composite microbial agent (15-45℃) combined with the buffering effect of biochar allows the agent to maintain high activity even under high-temperature and drought conditions. Figures 1-4Data from typical examples in the dry-hot valley region (Examples 2 and 3) show that even under extreme climatic conditions, soil pH, nutrient content, microbial activity, and crop yield can remain stable and optimized, completely solving the problem of poor remediation effect of existing technologies in special climatic zones.

[0091] The soil remediation materials provided in this application are used:

[0092] (1) Significantly improves the physical and chemical properties of continuously cropped soil, stabilizes soil pH at 7.0-7.8, increases soil organic matter content by more than 20%, increases CEC (cation exchange capacity) from 4-5 cmol+ / kg to more than 15 cmol+ / kg, reduces soil EC value by more than 30%, and alleviates salinization pressure;

[0093] (2) Effectively inhibits soil-borne pathogens and harmful nematodes, reduces the relative abundance of Fusarium by more than 40%, reduces the abundance of plant parasitic nematodes by more than 70%, and increases the modularization and clustering coefficient of soil microbial network by more than 40%.

[0094] (3) Reconstruct healthy soil microbial communities, improve bacterial community richness and uniformity, promote the enrichment of beneficial microorganisms (such as Luteitalea, RSA9, etc.), and enhance soil nitrogen cycling rate and carbon sequestration potential.

[0095] A specific combination of functional biochar, organic materials and compound microbial agents, through the synergistic effect of "physicochemical improvement - nutrient supply - biological regulation", simultaneously optimizes the physicochemical properties, microbial community structure and nitrogen and carbon cycle function of continuously cropped soil, thus solving the technical bottleneck of limited remediation effect of single materials;

[0096] The preparation process and application parameters of remediation materials optimized for the special climatic conditions of hot and dry valleys, the 500-600℃ anaerobic pyrolysis process of functional biochar and the application rate of 30-60 t / ha are adapted to the soil water retention, fertilizer retention and salinization control needs under high temperature and drought conditions, and improve the adaptability of the technology in extreme environments.

[0097] The integrated application method of "pretreatment + pre-fermentation + phased application of microbial agents" improves the soil microenvironment by pre-mixing and fermenting functional biochar with organic materials (the available potassium in the soil increases by 40% after fermentation), and then phased application of microbial agents ensures the colonization rate of beneficial microorganisms (increases by 45%), which significantly enhances the stability and durability of the remediation effect.

[0098] By reconstructing the soil microbial co-occurrence network through material application, the synergistic effect of beneficial bacteria enrichment and pathogen inhibition is promoted, while optimizing soil nitrogen and carbon cycle efficiency and enhancing the long-term productivity potential of the soil. This has led to the construction of a technical system of "ecological restoration - productivity enhancement - sustainable continuous cropping".

[0099] The remediation materials are all derived from agricultural waste, achieving resource recycling. The remediation process is free of chemical pollution, and the resilience of the microbial network is improved by more than 40%, providing a new path for the green and sustainable remediation of soils with continuous cropping obstacles.

[0100] Advantages compared to existing technologies:

[0101] (1) Significant synergistic remediation effect, achieving simultaneous solution to multiple problems: This invention combines the physicochemical improvement properties of functional biochar (adsorbing salts and adjusting pH), the nutrient supply capacity of organic materials (providing carbon sources and activating phosphorus and potassium), and the bioregulatory function of microbial agents (inhibiting pathogens and reconstructing communities) to simultaneously solve the three core problems of soil physicochemical deterioration due to continuous cropping, microbial imbalance, and nutrient deficiency. Experimental data show that after treatment in Example 2, the soil pH increased from 6.2 to 7.3, the organic matter content increased by 32%, the relative abundance of Fusarium decreased by 68%, and the cucumber yield increased by 35%. The comprehensive remediation effect is better than that of single material application (single biochar treatment only increased the yield by 15.5%).

[0102] (2) The microbial network reconstruction effect is outstanding, enhancing soil resilience: Functional biochar provides a stable habitat microenvironment for microorganisms, organic materials provide carbon and energy sources for microbial growth, and compound inoculants directly supplement beneficial bacteria. The synergistic effect of the three increases the modularity and clustering coefficient of the soil microbial network by more than 40%, and enhances the robustness of the network. Under the inoculant + corn treatment, the abundance of Luteitalea increased by about 60%, the abundance of RSA9 increased by 15%, and the activity of soil nitrogen cycle-related enzymes increased by 103.3%, solving the problems of difficult microbial colonization and poor community stability in existing technologies.

[0103] (3) Adapting to the needs of special climate zones and improving the applicability of technology: In response to the climate characteristics of hot and dry valleys with high temperature and drought and easy accumulation of salt, the high specific surface area and pore structure of functional biochar can enhance the soil's water and fertilizer retention capacity and reduce water evaporation loss by more than 30%; the heat released during the fermentation process of organic materials can moderately improve the soil microenvironment (increasing the ground temperature by 2-3℃ in winter); the combination of the stress resistance of compound microbial agents and the buffering effect of functional biochar increases the colonization rate of microbial agents in the soil by 45%, which significantly improves the adaptability and stability of remediation technology in hot and dry environments.

[0104] (4) Ecological and environmentally friendly and sustainable, realizing resource recycling: The remediation materials are all derived from agricultural waste (corn stalks, alfalfa stalks, mushroom residue), realizing resource recycling, without the introduction of chemical pollutants, which meets the needs of green agricultural development; after remediation, the soil microbial community structure is optimized, the nutrient cycling efficiency is improved, the basic soil fertility is continuously improved, and the cucumber yield remains stable (decline <5%) even after three consecutive years of continuous cropping, avoiding the damage to the soil ecosystem caused by traditional chemical disinfection methods (soil microbial diversity decreases by more than 30% after chemical disinfection treatment).

[0105] (5) Synergistic regulation of nitrogen and carbon cycles to enhance soil productivity potential: This invention optimizes the soil nitrogen turnover rate through material application. The 15N double-standard culture experiment shows that the soil ammonification rate increased by 62% and the nitrification rate increased by 48% under the treatment of Example 2. At the same time, the soil carbon sequestration increased by 28%, achieving synergistic enhancement of nitrogen and carbon cycles and providing a continuous nutrient supply for cucumber growth. The productivity enhancement potential is 20%-30% higher than that of traditional remediation technologies.

[0106] The key design focus of this invention is:

[0107] (1) Significant Synergistic Remediation Effect: This invention combines the physicochemical improvement properties of functional biochar, the nutrient supply capacity of organic materials, and the bioregulatory function of microbial agents to simultaneously address the three core problems of soil physicochemical deterioration due to continuous cropping, microbial imbalance, and nutrient deficiency. The remediation effect is superior to that of applying a single material. Experimental data show that after treatment using Implementation Scheme 2, the soil pH increased from 6.2 to 7.3, CEC reached 15.8 cmol / kg, and the organic matter content increased by 32%; the relative abundance of Fusarium decreased by 68%, and the abundance of plant parasitic nematodes decreased by 91%; the aboveground dry matter of cucumber was 2.8 times that of the control, and the yield increased by 35%.

[0108] (2) Outstanding effect of microbial community optimization: functional biochar provides a stable habitat for microorganisms, organic materials provide carbon and energy sources for microbial growth, and compound microbial agents directly supplement beneficial bacteria. The synergistic effect of the three increases the modularization and clustering coefficient of soil microbial network by more than 40%, enhances network robustness, and significantly improves anti-interference ability compared to single remediation technology, solving the problems of difficult microbial colonization and poor community stability in existing technologies.

[0109] (3) Adapting to the needs of special climate zones: In response to the characteristics of hot and dry valley climate, the high specific surface area and pore structure of functional biochar can enhance the soil's water and fertilizer retention capacity, reduce water evaporation and salt accumulation, and the heat released during the fermentation process of organic materials can moderately improve the soil microenvironment. The combination of the stress resistance of compound microbial agents and the buffering effect of functional biochar improves the adaptability and stability of remediation technology in high temperature and drought environments.

[0110] (4) Ecological and environmentally friendly and sustainable: The remediation materials are all derived from agricultural waste (corn stalks, alfalfa stalks, and mushroom residue), realizing resource recycling and without the introduction of chemical pollutants; after remediation, the soil microbial community structure is optimized, the nutrient cycling efficiency is improved, and the basic soil fertility is continuously improved, providing a long-term sustainable soil environment for cucumber continuous cropping and avoiding the damage to the soil ecosystem caused by traditional chemical disinfection methods.

[0111] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A soil remediation material suitable for cucumber continuous cropping obstacles, characterized in that: The product comprises functional biochar, organic materials, and microbial agents. The application rate of functional biochar is 30-60 t / ha, the application rate of organic materials is 6-6.5 t / ha, and the application rate of microbial agents is 15-20 kg / ha. The mass ratio of functional biochar, organic materials, and microbial agents is (30-60):(6-6.5):(0.015-0.02). The organic materials are selected from one or two types of alfalfa straw and fungal residue. The microbial agents are a compound agent of Bacillus subtilis and Trichoderma longifolia, with a bacterial count ratio of Bacillus subtilis to Trichoderma longifolia of 1:

1. The functional biochar is obtained from corn straw through anaerobic pyrolysis. Bacillus subtilis is deposited at the China General Microbiological Culture Collection Center, accession number CGMCC No. 14514, and was purchased from Tianjin Kunhe Biotechnology Co., Ltd. The Trichoderma longifolia strain is deposited at the China Industrial Microbial Culture Collection Center, accession number CICC 13053, and was purchased from Shandong Hezhong Kangyuan Biotechnology Co., Ltd., product number MES810. After applying functional biochar and organic materials, water the soil to maintain the soil moisture content at 60%-70% of field capacity and allow it to ferment for 5-7 days. Dilute 15-20 kg / ha of microbial agent with water 500 times and apply it to the soil by drip irrigation or root irrigation. The application scheme for the soil remediation material when applied to soils with mild continuous cropping obstacles is as follows: 30 t / ha of functional biochar, 6 t / ha of alfalfa straw, and 15 kg / ha of compound microbial agent; the specific characteristics of soils with mild continuous cropping obstacles are: continuous cropping period of 3-5 years, soil pH of 6.5-7.0, relative abundance of Fusarium of 5%-10%, and EC value of <1.0 mS / cm; The application scheme for the soil remediation material when applied to soils with moderate continuous cropping obstacles is as follows: 45 t / ha of functional biochar, 6.5 t / ha of inoculum residue, and 18 kg / ha of compound inoculant. The specific characteristics of moderate continuous cropping obstacles soil are: continuous cropping period of 6-10 years, soil pH of 6.0-6.5, relative abundance of Fusarium of 10%-15%, and EC value of 1.0-1.5 mS / cm. The application scheme for the soil remediation material when applied to soils with severe continuous cropping obstacles is as follows: 60 t / ha of functional biochar, 6 t / ha of alfalfa straw, 3.25 t / ha of inoculum residue, and 20 kg / ha of compound inoculant. The specific characteristics of soils with severe continuous cropping obstacles are: continuous cropping period of more than 10 years, soil pH of 5.5-6.0, relative abundance of Fusarium above 15%, and EC value > 1.5 mS / cm.

2. A method for preparing a soil remediation material suitable for cucumber continuous cropping obstacles as described in claim 1, characterized in that: Includes the following steps: S1. Preparation of Functional Biochar: Using corn stalks as raw material, anaerobic pyrolysis is carried out at 500-600℃ for 2-3 hours. After cooling, the biochar is pulverized and sieved. The resulting biochar has a specific surface area ≥150 m². 2 / g, with a pore size distribution of 2-50 nm, a pH value of 8.5-10.0, and an organic matter content of ≥75%, functional biochar was obtained; S2. Preparation of organic materials: Select alfalfa straw or mushroom residue, crush it to 1-3 cm, wherein the organic matter content of alfalfa straw is ≥80% and the moisture content is ≤15%, and the organic matter content of mushroom residue is ≥75% and the moisture content is ≤20%; S3. Selection of microbial agents: Use a compound agent of Bacillus subtilis and Trichoderma longifolia, with an effective viable count ≥2 billion CFU / g, a Bacillus subtilis to Trichoderma longifolia count ratio of 1:1, a temperature range of 15-45℃, and a pH range of 5.5-8.5 to maintain activity.

3. The preparation method according to claim 2, characterized in that: In step S1, anaerobic pyrolysis is performed at 500-600℃ for 2-3 hours. After cooling, the material is pulverized and sieved. Specifically, a continuous anaerobic pyrolysis furnace is used, with a heating rate controlled at 10℃ / min, raising the temperature to 500-600℃ while maintaining an anaerobic environment with an oxygen content of <5%, and pyrolysis is performed for 2-3 hours. After pyrolysis, the material is allowed to cool naturally to room temperature to avoid rapid cooling that could damage the pore structure. The material is then sieved using a standard 2mm stainless steel sieve, and the undersize material is collected for later use. Large particles on the sieve are returned to the pulverizer for secondary pulverization to ensure particle size uniformity ≥95%.

4. The preparation method according to claim 2, characterized in that: When selecting alfalfa straw or mushroom residue in step S2, select fresh alfalfa straw and dry it until the moisture content is ≤15%, then crush it to 1-3cm; or select waste mushroom residue after edible mushroom cultivation, which is fermented at high temperature, kept at 60℃ for 7 days, and the fermentation degree is tested, with a germination index ≥85%, then crushed to 2-3cm.

5. A soil remediation method using the soil remediation material for cucumber continuous cropping obstacles as described in claim 1, characterized in that: Includes the following steps: First, pretreatment: 10-20 days before planting, spread functional biochar and organic materials evenly on the soil surface in a certain proportion, and use a rotary tiller to plow to a depth of 20-30 cm to fully mix the functional biochar and organic materials with the 0-30 cm topsoil layer, with a mixing uniformity of ≥90%; Second, water regulation: After applying functional biochar and organic materials, water is applied to keep the soil moisture content at 60%-70% of field capacity. This is maintained for 5-7 days for pre-fermentation, during which the soil temperature is controlled at 25-35℃. Third, application of microbial agents: 1-5 days before planting, dilute 15-20 kg / ha of microbial agents with clean water 500 times and apply them to the soil by drip irrigation or root irrigation. The application rate is 20-30 L / ha. Ensure that the microbial agents are evenly distributed in the root growth zone, that is, in the 0-20 cm soil layer. Fourth, field management: After cucumber planting, apply microbial inoculant every 10-20 days. Dilute 15-20 kg / ha of microbial inoculant with water 1000 times. Apply 10-15 L / ha each time, and repeat 2-3 times.

6. The soil remediation method according to claim 5, characterized in that: In the fourth step of field management, the soil moisture content should be maintained at 50%-60% of field capacity during the cucumber's growing season. Conventional fertilization management should be carried out: NPK compound fertilizer should be applied according to the standard, and the time interval between application and application of microbial agents should be avoided to less than 3 days.

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