Agricultural and pastoral interlaced zone covering crop sowing and biogas slurry spraying method

Abstract

The invention provides an agricultural and pastoral zone covering crop sowing and biogas slurry spraying method, and belongs to the technical field of agricultural planting, and the method comprises the following steps: adjusting the soil humidity to a preset humidity range according to the water content, and synchronously applying a fertilizer and turning over; selecting a wide-narrow-row mulching sowing machine, performing main crop wide-narrow-row mulching sowing and inter-row mulching crop synchronous precision sowing, applying seed fertilizer along with sowing, and performing pressing treatment after sowing; in the germination period, the biogas slurry is filtered and diluted and sprayed to covering crop rows; adjusting a biogas slurry dilution ratio and adding nutrients in an elongation stage, and implementing differential application amounts based on a soil nutrient detection result; and in the filling stage, the precipitated biogas slurry stock solution is intensively sprayed around the roots of the crop rows. According to the agricultural and pastoral zone covering crop sowing and biogas slurry spraying method provided by the invention, the agricultural and pastoral zone crop population covering degree and the effectiveness of biogas slurry utilization are improved, and the productivity is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural planting, and more specifically, relates to a method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone. Background Art

[0002] Currently, the agricultural-pastoral transition zone suffers from poor resource endowment, water shortages, coexisting drought, cold weather, and barrenness. Modern crop production is low, and animal husbandry is extensive. These irrational development models have led to severe soil erosion, a fragile ecology, low fertility, and insufficient production capacity. Conserving fertility, increasing production capacity, and integrating agriculture and animal husbandry are key challenges facing high-quality agricultural development in the region. It is estimated that 3.8 billion tons of livestock and poultry manure are produced annually nationwide, with a comprehensive utilization rate of less than 60%. The remainder is lost to the environment, causing eutrophication of water bodies and deteriorating air quality. Improving fertility and production capacity of arable land through a crop-livestock cycle has been a key focus of regional agricultural development strategies in recent years. The orderly utilization of manure resources has important scientific value and practical significance for the high-quality development of regional agriculture, as it protects the ecological environment, improves the efficiency of limited resource utilization, provides environmental benefits, and promotes healthy economic and social development.

[0003] Cover plants are artificially planted grasses or other plants, other than the target crop, to control weeds or cover bare ground. They include all crops that protect the soil from wind and water erosion. In conservation tillage systems, these crops are often planted to protect the soil from erosion when normal crops fail to form a cover layer. After sowing, crops are often unable to grow rapidly and form a cover layer due to regional restrictions (such as drought and low temperatures), resulting in missing seedlings, broken ridges, and low canopy cover in later stages. Furthermore, biogas slurry is sprayed haphazardly in agricultural-pastoral transition zones, and its water content is lost during drying and other tillage operations, ultimately leading to insufficient production capacity. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for sowing cover crops and spraying biogas slurry in the agricultural-pastoral transition zone, aiming to solve the problems of insufficient crop population coverage and disorderly use of biogas slurry in the agricultural-pastoral transition zone, resulting in insufficient production capacity.

[0005] To achieve the above object, the technical solution adopted by the present invention is to provide a method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone, comprising the following steps: S1: Before sowing, the soil moisture is checked and adjusted to the preset range according to the moisture content. Fertilizer is then applied and the soil is tilled. S2: Use a wide-narrow row mulching seeder, set the row spacing and determine the mulching parameters, adjust the sowing depth, plant spacing, and sowing rate according to the main crop type, sow the main crop in wide-narrow rows with mulching and sow the cover crop between the rows simultaneously, apply seed fertilizer during sowing, and perform tamping after sowing; S3: Based on the growth period, the biogas slurry is sprayed in a targeted and phased manner. During the germination period, the biogas slurry is filtered and diluted, and then sprayed on the cover crop rows. During the jointing period, the biogas slurry dilution ratio is adjusted and nutrients are added. Different application amounts are implemented based on the soil nutrient test results. During the filling period, the precipitated biogas slurry is used and concentratedly sprayed around the roots of the cover crop rows.

[0006] In one possible implementation, in step S1, 10-15 days before sowing, a soil moisture meter is used to detect the moisture content of the 0-20 cm soil layer. If the moisture content of the soil layer is less than 10%, the moisture content is increased to 12%-15% through shallow drip irrigation or flooding irrigation. At the same time, 1000-1500 kg / mu of decomposed farmyard manure or 200-300 kg / mu of commercial organic fertilizer is applied and the soil is plowed to a depth of 15-20 cm.

[0007] In one possible implementation, in step S1, if the weed base number in the field is greater than 50 plants / m², 200 ml / mu of 41% glyphosate solution is sprayed 3-5 days before sowing for total weed control.

[0008] In a possible implementation, in step S2, the row spacing is set to 40 cm + 60 cm, the mulch width is 30-40 cm, the main crop sowing depth is 5-6 cm, the plant spacing is 25 cm, and the sowing amount is 4-5 kg / mu.

[0009] In one possible implementation, in step S2, the cover crop seeds are subjected to electrostatic adsorption coating treatment before sowing, and a colloidal solution containing humic acid and microbial agents is evenly coated on the seed surface using an electrostatic spray device to form a charged adsorption layer with a thickness of 0.1-0.3 mm.

[0010] In one possible implementation, in step S2, the operation is carried out at a speed of 3-4 km / h, the ground film is flattened and the overlap between films is 5-10 cm; after sowing, N-P2O5-K2O=15-15-15 fertilizer is applied 5 cm to the side of the main crop row, with an application amount of 10-15 kg / mu and a depth of 8-10 cm.

[0011] In one possible implementation, in step S2, the suppression process uses a vibration-based suppression method. High-frequency vibrations of 20-30 Hz, combined with a porous honeycomb suppressor wheel, form water-retaining microaggregates in the 0-2 cm soil layer. Air-permeable pores are then reserved in the 2-4 cm soil layer, which are then filled with decomposed straw debris. (The suppression device also generates infrasound (frequency <20 Hz) to repel underground pests such as mole crickets and white grubs.) In one possible implementation, in step S3, during the germination period, the biogas slurry is filtered through a 20-mesh screen and diluted with water at a ratio of 1:3, with the EC adjusted to ≤ 2.0 mS / cm and the pH to 6.5-7.5. A fan-shaped narrow-width sprinkler is installed and sprayed at the center of the cover crop row. During the jointing stage, the dilution ratio was adjusted to 1:2 biogas slurry: clean water, 0.1% humic acid water-soluble fertilizer was added and the EC was adjusted to ≤3.0mS / cm. Variable spraying was implemented based on the soil NO3⁻-N content. GPS positioning was matched with the prescription map to ensure a spray width of 15-20cm and a position error of ≤5cm. During the filling period, the biogas slurry that has been settled for more than 7 days is directly applied after being filtered through a 0.5mm pore size filter. The visual recognition system is used to track the covered crop rows in real time and the nozzle angle is hydraulically adjusted to spray the biogas slurry within a range of 10cm around the roots.

[0012] In one possible implementation, during the grouting period spraying in step S3, a neodymium iron boron permanent magnet is integrated at the nozzle of the spraying equipment to form a gradient magnetic field perpendicular to the ground. The charged ions in the biogas slurry generate Lorentz force under the action of the magnetic field and penetrate directionally into the 5-10 cm soil micro-area around the roots of the cover crops.

[0013] In one possible implementation, after step S3, 10-15 days after sowing, if the cover crop seedling shortage rate is greater than 10%, artificial replanting and light watering are performed, the ground film is inspected regularly and damaged areas are compacted with fine soil, the main crop is harvested at the end of milk maturity, leaving a stubble of 10-15 cm and a residual film recovery rate of ≥90%, and the cover crop is used in forage mode or green manure mode.

[0014] The beneficial effects of the method for sowing cover crops and spraying biogas slurry in the agricultural-pastoral transition zone provided by the present invention are as follows: compared with the existing technology, the soil moisture condition needs to be detected before sowing, and according to the detected soil moisture content, the soil moisture is adjusted to a preset range suitable for crop growth through irrigation or drainage, and fertilizer is applied and tillage is performed at the same time to create good soil conditions for sowing. A wide and narrow row mulching seeder is selected, and appropriate row spacing (such as wide and narrow row configuration) and mulching parameters (such as mulching width, mulch type) are set according to the main crop type, and the sowing depth, plant spacing and sowing amount of the main crop are adjusted. While sowing the main crop with wide and narrow row mulching, the cover crops are synchronously sown between the rows. During the sowing process, seed fertilizer is applied as sowing is carried out, and the soil is compacted after sowing to ensure close contact between the seeds and the soil, providing a stable environment for seed germination.

[0015] Based on the crop growth period, the biogas slurry is sprayed in a targeted and phased manner. During the germination period, the biogas slurry is filtered and diluted before being sprayed on the cover crop rows to provide water and nutrients for the germination of the cover crops. During the jointing period, the dilution ratio of the biogas slurry is adjusted and nutrients are added. According to the soil nutrient test results, differentiated application amounts are implemented according to the soil nutrient conditions in different areas to achieve precise nutrient supply. During the filling period, the precipitated biogas slurry concentrate is used and sprayed concentratedly around the roots of the cover crop rows to meet the nutrient needs of the crops in the later growth period and promote the healthy growth of the crops and the formation of yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 The present invention provides a flow chart of a method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] See also Figure 1 , the present invention provides a method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone. The method comprises the following steps: S1: detecting soil moisture before sowing, adjusting soil moisture to a preset moisture range according to water content, applying fertilizer simultaneously and plowing; S2: selecting a wide and narrow row mulching seeder, setting row spacing and determining mulching parameters, adjusting sowing depth, plant spacing and sowing amount according to the main crop type, carrying out wide and narrow row mulching sowing of the main crop and simultaneous precision sowing of inter-row cover crops, applying seed fertilizer during sowing, and performing suppression treatment after sowing; S3: spraying biogas slurry in a targeted and phased manner based on the growth period, filtering and diluting the biogas slurry during the germination period, and spraying it on the cover crop rows; adjusting the biogas slurry dilution ratio and adding nutrients during the jointing period, and implementing differentiated application amounts based on the soil nutrient test results; using the precipitated biogas slurry concentrate during the filling period, and spraying it around the roots of the cover crop rows.

[0020] The present invention provides a method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone. Compared with the existing technology, the soil moisture condition needs to be detected before sowing. According to the detected soil moisture content, the soil moisture is adjusted to a preset range suitable for crop growth through irrigation or drainage, and fertilizer is applied and tillage is performed at the same time to create good soil conditions for sowing. A wide and narrow row mulching seeder is selected, and appropriate row spacing (such as wide and narrow row configuration) and mulching parameters (such as mulching width, mulch type) are set according to the main crop type. The sowing depth, plant spacing and sowing amount of the main crop are adjusted. While sowing the main crop with wide and narrow row mulching, the cover crops are synchronously sown between the rows. During the sowing process, seed fertilizer is applied as sowing is carried out. After sowing is completed, the soil is compacted to ensure close contact between the seeds and the soil, providing a stable environment for seed germination.

[0021] Based on the crop growth period, the biogas slurry is sprayed in a targeted and phased manner. During the germination period, the biogas slurry is filtered and diluted before being sprayed on the cover crop rows to provide water and nutrients for the germination of the cover crops. During the jointing period, the dilution ratio of the biogas slurry is adjusted and nutrients are added. According to the soil nutrient test results, differentiated application amounts are implemented according to the soil nutrient conditions in different areas to achieve precise nutrient supply. During the filling period, the precipitated biogas slurry concentrate is used and sprayed concentratedly around the roots of the cover crop rows to meet the nutrient needs of the crops in the later growth period and promote the healthy growth of the crops and the formation of yield.

[0022] In step S1, a soil moisture meter (such as a TDR time domain reflectometer) is used to conduct multi-point detection of the soil moisture content in the 0-20 cm soil layer of the farmland. 5-10 detection points are set for every 50-100 mu, and the average value is taken as the basis for judgment, reserving sufficient time for subsequent soil moisture adjustments.

[0023] If the soil moisture content is less than 10%, the soil is considered dry and requires water replenishment through shallow drip irrigation or flood irrigation. Shallow drip irrigation is suitable for areas with relatively scarce water resources or complex terrain. Drip irrigation pipes are buried shallowly 10-15 cm into the soil and slowly drip water to raise the soil moisture content to 12%-15%, with a moisture ratio of ≥70%, to avoid wasteful surface runoff. Flood irrigation is suitable for areas with flat terrain and abundant water resources. Irrigation water flows through the soil, rapidly raising the moisture content to the target range. If the soil moisture content is too high (>20%), drain the soil by digging trenches or plow and air dry to reduce humidity and prevent soil hypoxia that affects seed germination. Through testing and water replenishment, the soil moisture content is controlled within the optimal range for seed germination (12%-15%), avoiding insufficient water absorption due to drought or suffocation and rot due to excessive moisture, thereby improving seed germination rate and uniform emergence. Shallow buried drip irrigation technology can save 20%-30% of water and utilize water resources more efficiently than traditional flood irrigation. It is especially suitable for arid and semi-arid agricultural and pastoral transition zones.

[0024] At the same time, apply well-rotted farmyard manure or commercial organic fertilizer and till the soil. Choose well-rotted farmyard manure, such as cow or sheep manure, at a rate of 1,000-1,500 kg per mu (approximately 200-300 kg per mu) of commercial organic fertilizer to replenish soil organic matter and nutrients. Organic fertilizer is rich in humus, microorganisms, and trace elements. When mixed with the soil after tilling, it increases soil organic matter content, improves soil aggregate structure, and enhances water and fertilizer retention, such as increasing soil porosity by 8%-10%.

[0025] Use a rotary tiller or moldboard plow to a depth of 15-20 cm to thoroughly mix the fertilizer with the topsoil. This will also break up clods to a size of less than 5 cm and remove the plow bottom layer, ensuring the soil is flat, loose, broken, and clean for sowing. Tillage breaks up compacted soil, reduces bulk density, enhances soil permeability, and creates a loose environment for crop root growth. Furthermore, tillage can bury surface weed seeds and pest debris deeper into the soil, inhibiting weed germination and reducing the prevalence of soil-borne pests and diseases.

[0026] In step S1, a weed survey is conducted 7-10 days before sowing. Using a sampling method, 5-10 1-meter square plots are randomly selected from the field. The number of weeds in each plot is counted and the average weed density is calculated. If the test results show an average weed count greater than 50 plants / m², it is considered a severe weed infestation and requires weed control.

[0027] A 41% glyphosate aqueous solution is used. It is a systemic, broad-spectrum, and lethal herbicide. By inhibiting the shikimic acid metabolic pathway in weeds, glyphosate effectively controls over 90% of annual grasses, broadleaf weeds, and perennial weeds such as reeds and bermudagrass in the field. This reduces competition between weeds and crops for water, nutrients, and light. Glyphosate is easily decomposed by microorganisms in the soil and has a short half-life (7-14 days). When used at the recommended dose, there is no risk of residue and no phytotoxicity to subsequent cover crops or main crops. Compared to manual tillage and weed control, chemical weed control reduces soil disturbance and the risk of wind and water erosion, making it particularly suitable for ecologically fragile areas in agricultural-pastoral transition zones. Furthermore, it is important to avoid long-term monotherapy with glyphosate. Glyphosate can be rotated or combined with other pesticides such as acetochlor and atrazine to delay the development of weed resistance.

[0028] The dosage for glyphosate per acre is 200ml, diluted approximately 150-fold with 30kg of water. Mix thoroughly and then load into the sprayer. Apply 3-5 days before sowing to ensure ample time for weed absorption and transport, while also preventing residue from affecting subsequent crop germination. Pre-sowing weed control significantly reduces the number of weeding attempts during the growing season, lowering the cost per acre of manual or mechanical weeding.

[0029] Choose calm or light winds (3m / s or less) to prevent droplets from drifting to adjacent crops or non-target areas. Use a fan-shaped nozzle for even spraying, ensuring sufficient coverage of weed stems and leaves, especially perennial weeds with well-developed root systems. Spray 30-40L of liquid per mu. Avoid rainfall within 24 hours after application; re-spray if rain occurs. Check weed control effectiveness 1-2 days before sowing. If a small number of weeds remain, re-spray or manually remove them.

[0030] In step S2, a design with alternating narrow and wide rows of 40 cm and 60 cm is adopted, with adjacent narrow rows spaced 40 cm apart and wide rows spaced 60 cm apart. This configuration increases the light transmittance of the main crop by 15%-20% by expanding the wide row spacing, providing ample growing area for cover crops between the rows. Light intensity in the wide row area is increased by 25%, facilitating photosynthesis of the cover crop. At the same time, the narrow rows ensure a reasonable density of main crops. The main crop (tall-stalked) and the cover crop (short-stalked) form vertical layers. The main crop uses the upper layer to intercept strong light, while the cover crop utilizes scattered light from the lower layer, increasing the leaf area index and accumulating biomass. The main crop roots are concentrated in the soil layer (20-80 cm deep), while the cover crop roots are distributed in the shallow layer (0-30 cm), avoiding nutrient competition. The cover crop roots also stabilize the soil, reducing topsoil loss.

[0031] Choose a biodegradable mulch film with a thickness of 0.01-0.012mm, a degradation cycle of 90-120 days, and a mulch width of 30-40cm. This film is typically placed above narrow rows, leaving the wider row area exposed for sowing cover crops. This 90-120-day biodegradable film will naturally break down during the later stages of the main crop's growth, preventing soil contamination caused by traditional mulch film residue. The broken film fragments also degrade into humus, increasing soil organic matter content. The 30-40cm exposed area within the wide row provides ample sowing space for cover crops. Combined with precision seeding techniques, this improves cover crop emergence and coverage and effectively suppresses weed growth. The edges of the film should be compacted with fine soil, with a 5-10cm overlap between films to prevent moisture loss due to wind. Mulching narrow rows with film can reduce evaporation by 30%-40% and increase soil moisture in the 0-20cm layer by 5%-8% compared to open fields. Furthermore, the exposed areas of wide rows allow rainwater to penetrate, preventing deep soil drying caused by full film coverage.

[0032] In addition, reasonable density planting and the warming effect of mulch film can advance the maturity period of main crops by 5-7 days, which can effectively increase yields.

[0033] Depending on the main crop type, such as corn or oats, the seeder's depth adjustment device controls the sowing depth to 5-6cm, ensuring that the seeds fall into the moist soil layer while avoiding too deep a depth that delays emergence or too shallow a depth that causes dry buds. Plant spacing is set at 25cm. Combined with wide and narrow row spacing, using corn as an example, the main crop planting density is calculated to be approximately 4,000-4,500 plants per mu. A seeding rate of 4-5kg / mu is used, with a single-seed precision sowing using a perforated wheel or pneumatic seed metering device, achieving a void ratio of ≤5% to ensure uniform sowing.

[0034] In step S2, the cover crop seeds are subjected to electrostatic adsorption coating treatment before sowing, and a colloidal solution containing humic acid and microbial agents is evenly coated on the surface of the seeds using an electrostatic spray device to form a charged adsorption layer with a thickness of 0.1-0.3 mm.

[0035] The coating liquid coated on the seed surface contains humic acid, microbial agents, and a colloidal solution matrix. The humic acid content is 50-100g / L, and mineral humic acid or biochemical humic acid is used to enhance the seed's stress resistance. The effective viable count of the microbial agent is ≥1×10 8 CFU / g, with Rhizobia or Bacillus subtilis selected based on crop type. The colloidal solution base uses water as the solvent, with 0.5%-1% gum arabic or carboxymethyl cellulose added as a binder to enhance the coating's adhesion. Humic acid and microbial agents are mixed with the base in appropriate proportions, stirred thoroughly, and passed through a 200-mesh sieve to ensure the solution is free of particulate matter. The pH is adjusted to 6.5-7.5.

[0036] The electrostatic sprayer, with a set voltage of 5-10kV and an atomization pressure of 0.2-0.3MPa, produces negatively charged droplets with a diameter of 50-100μm. These droplets form a strong electrostatic attraction with the seed surface, resulting in an adsorption capacity 2-3 times greater than that of traditional seed dressings. The coating resists shedding, ensuring the continued interaction of humic acid and microbial agents. The humic acid in the coating activates seed enzymes, accelerating seed coat softening, accelerating seed germination by 2-3 days, and increasing seedling emergence by 12%-18% under drought conditions. The colloids in the coating swell upon contact with water to form microgels, capable of holding 5-8 times their own weight in water. This creates localized moist micro-domains in the seedbed, alleviating drought stress. Seeds are transported at a constant speed through the spray zone on a conveyor belt. Electrostatic attraction directs the droplets onto the seed surface, creating a positive charge due to friction, forming a coating 0.1-0.3mm thick. After drying, place the coated seeds in a well-ventilated, dry place to dry in the shade, avoiding direct sunlight. Dry for 4-6 hours to allow the coating to solidify into a film. After drying, control the moisture content of the seeds to below 12%. Place them in a breathable cloth bag or seed bag and store them in a cool, dry place. The storage period is ≤15 days.

[0037] In step S2, adjust the tractor gear to maintain a stable seeder speed of 3-4 km / h. This speed range ensures smooth mulch film laying and uniform seeding depth, avoiding wrinkles in the mulch film, missed seeds, or excessively deep or shallow seeds caused by excessive speed. A trial sowing is conducted before operation, using a marking method to measure the matching of the seeder speed and seed rate, ensuring an error of ≤2% in the number of rows per meter.

[0038] The film reel and pressing wheel at the front of the seeder work together to ensure the film is wrinkle-free and undamaged during laying, keeping it firmly on the ground. The pressing wheel pressure is set to 5-8 kPa, ensuring close contact between the film and the soil, reducing water evaporation caused by air convection beneath the film. The film blocks heat exchange between the soil and the atmosphere, raising the ground temperature in the seeding layer by 2-3°C, effectively shortening the emergence time of the main crop and providing suitable temperature conditions for the germination of cover crops. The overlap width of adjacent film edges is controlled at 5-10 cm, and fine soil is used to compact the overlap and both sides of the film to prevent strong winds from lifting the film and preventing weeds from growing beneath the film. For sandy soils, the topsoil thickness can be increased to 3-5 cm to improve film stability.

[0039] A 15-15-15 compound fertilizer (N-P2O5-K2O) is applied simultaneously with the seed drill's integrated fertilization device 5 cm to the side of the main crop seed row. This distance prevents direct contact between the fertilizer and the seeds, which could lead to seed burn, while ensuring rapid nutrient absorption by the root system after germination. Fertilizer is applied below the root system to avoid direct contact with the seeds. This guides root expansion by leveraging the root system's fertility orientation. This increases root length by 10%-15 cm during the seedling stage of the main crop, and improves nutrient absorption efficiency by 20%. Fertilization is controlled at a depth of 8-10 cm by adjusting the angle of the fertilizer shovel into the soil. This depth, 3-5 cm below the seeds, adheres to the principle of heterotopic stratification of fertilizer and promotes root penetration. The application rate is 10-15 kg per mu, with a 20% fluctuation depending on soil fertility.

[0040] In step S2, a vibrating seed drill press wheel is installed. A porous honeycomb press wheel with a diameter of 30-40 cm is installed, and honeycomb holes with a diameter of 5 mm and a depth of 10 cm are evenly distributed on the wheel surface. A high-frequency vibration device is integrated into the wheel axle. A straw chip spreading device is installed behind the press wheel to evenly spread decomposed straw chips. The straw chips are 1-2 cm long, have a moisture content of ≤15%, and are spread at a rate of 50-80 kg / mu.

[0041] Activate the vibration device and adjust the frequency to 20-30Hz. This will cause the pressing wheel to generate high-frequency micro-vibrations while moving, transmitting the vibrations to a depth of 3-5cm in the soil. Maintain a speed of 1.5-2km / h to ensure the vibrating action of the pressing wheel on the soil is sufficient, with approximately 2-3 seconds per meter of compaction time. By adjusting the pressing wheel counterweight, maintain the pressure of the pressing wheel on the soil at 5-8kPa to avoid excessive compaction that could lead to soil compaction.

[0042] 0-2cm surface suppression: High-frequency vibration rearranges soil particles to form water-retaining microaggregates with a particle size of 0.25-1mm. The capillary action between the microaggregates absorbs water, improves the water holding capacity of the surface soil, and provides continuous moisture for the germination of cover crop seeds.

[0043] 2-4cm middle layer breathable pores are formed: When the porous honeycomb pressing wheel rolls the soil, the honeycomb holes squeeze the soil to form longitudinal breathable pores with a pore diameter of 5-8mm and a depth of 4cm, which promotes seed respiration and root aerobic metabolism, and avoids seed rot caused by soil hypoxia.

[0044] Straw debris filling: During the movement of the pressing wheel, the rear spreading device will simultaneously fill the decomposed straw debris into the air-permeable pores, with a filling rate of 80%-90%, forming a soil-straw air-permeable channel.

[0045] Microaggregates and straw debris provide habitats for soil microorganisms, increasing the number of microorganisms. The activity of functional bacteria such as nitrogen-fixing bacteria and phosphate-solubilizing bacteria is greatly enhanced, accelerating the soil nutrient cycle.

[0046] In addition, the infrasound waves generated by 20-30Hz vibrations can be transmitted through the soil, interfering with the chemical receptors of underground pests such as mole crickets and white grubs, thereby increasing the repellency rate and reducing the problem of missing seedlings and broken ridges caused by insect pests in the seedling stage.

[0047] In step S3, the fresh biogas slurry is filtered through a 20-mesh screen to remove incompletely decomposed solid impurities, such as straw debris and feces, to prevent clogging of the nozzles. The biogas slurry is diluted with clean water at a volume ratio of 1:3. By adding clean water or an acid / alkaline regulator, the conductivity of the mixture is adjusted to ≤2.0mS / cm and the pH value is controlled at 6.5-7.5 to ensure the appropriate solution concentration and avoid high salinity or extreme pH that inhibits seed germination. 5-7 days after sowing, when the cover crop seeds are in the critical germination period, install a fan-shaped narrow-width nozzle with a spray angle of 30°. Aim the nozzle at the center of the cover crop row and spray at a speed of 2-3km / h using a tractor-drawn spraying equipment at a pressure of 0.2MPa. The application rate is 3-5m³ per mu, ensuring that the moisture content of the 0-5cm soil layer in the cover crop row reaches 18%-20%, providing sufficient moisture for the seeds to absorb water, expand, and break through the soil. A 1:3 dilution and EC regulation reduced the salinity of the biogas slurry by 60%-70%, preventing damage to seed cell membranes caused by high salt concentrations. This increased seed germination rates to over 90%, a 15%-20% improvement over the water control. The fan-shaped, narrow-width nozzles focused droplets on the cover crop rows, increasing water utilization efficiency from 30% with traditional spraying to 55%, reducing ineffective evaporation and ensuring the water requirements of seeds during the critical germination period.

[0048] When cover crops enter the jointing stage and the main crop reaches 6-8 leaves, the biogas slurry dilution ratio is adjusted to 1:2 to increase nutrient concentration. A 0.1% humic acid water-soluble fertilizer is added to improve soil aggregate structure and promote root development. The EC of the mixed solution is adjusted to ≤3.0mS / cm to balance nutrient concentration and safety. Based on soil NO⁻-N content test results, the soil is divided into low-nitrogen zones (<10mg / kg), medium-nitrogen zones (10-20mg / kg), and high-nitrogen zones (>20mg / kg), with spray rates set at 7m³, 5m³, and 3m³ per mu, respectively. Using a GPS positioning system aligned with a pre-drawn prescription map, the nozzles are controlled to maintain a spray width of 15-20cm, ensuring a positioning error of ≤5cm. When wind speeds exceed 4m / s, the pressure is automatically reduced to 0.15MPa and the nozzle spacing is shortened to 15cm to minimize droplet drift and ensure precise nutrient delivery. During the filling phase, biogas slurry that has settled for at least seven days is directly applied after being filtered through a 0.5mm pore size filter. A visual recognition system tracks cover crop rows in real time and hydraulically adjusts the nozzle angle to spray the biogas within a 10cm radius of the roots. Differentiated application rates based on soil NO⁻-N detection reduce biogas slurry usage by 20%-40% compared to a one-size-fits-all fertilization approach, increasing nitrogen utilization from 35% to 48% and reducing nutrient leaching losses. GPS matching with prescription maps reduces spray width errors to less than 5cm and the coefficient of variation of nutrient distribution to less than 10%, avoiding growth differences caused by localized excess or deficiency and improving the uniformity of cover crop plant height.

[0049] Biogas slurry that has settled for at least 7 days, with an NH⁺-N concentration of ≥500mg / L and a pH of 7.0-8.0, is filtered through a 0.5mm pore size to retain high nutrient concentrations and remove large impurities. The slurry is applied directly to avoid dilution and reduced nutrient concentrations. During the silking period of the main crop, a visual recognition system is used to track the cover crop rows in real time. A hydraulic mechanism dynamically adjusts the nozzle angle, concentrating the biogas slurry within a 10cm radius around the cover crop roots. The sprayer is moved at a low speed of 1.5-2km / h, with an application rate of 2-3m³ / mu, to ensure sufficient penetration of the slurry into the root absorption zone. If rainfall exceeds 10mm within 24 hours of spraying, an additional 1m³ / mu is sprayed to ensure adequate nutrient supply during the grain filling period and enhance crop resistance to lodging and drought. The settled biogas slurry retains high concentrations of fast-acting nutrients such as NH⁺-N and K⁺, directly affecting the root system. This increases dry matter accumulation during the grain filling period and improves grain plumpness. The dynamic adjustment of the hydraulic nozzle angle allows more than 90% of the biogas liquid to be concentrated within 10cm of the root system. Compared with traditional spraying, this reduces ineffective diffusion, improves root vitality, enhances crop resistance, and reduces the risk of lodging in the later stage.

[0050] During the grouting phase of step S3, a NdFeB permanent magnet (model N52) with a surface magnetic field strength of 100-200 mT is integrated into the nozzle bracket of the biogas slurry spraying equipment. The magnets are arranged perpendicular to the ground, creating a gradient magnetic field with a magnetic field intensity decay rate of ≤15% with increasing depth. This magnetic field promotes ATPase activity in root cell membranes and increases root mitochondrial membrane potential, enhancing active absorption capacity. A magnetic field intensity adjustment device is installed, allowing the magnetic field strength to be flexibly adjusted within a range of 100-200 mT via a knob or electronic control system to adapt to different soil textures and crop needs. Biogas slurry that has settled for at least 7 days, with NH⁺-N ≥ 500 mg / L and a pH of 7.0-8.0, is used. It is then filtered through a 0.5 mm pore size filter to remove suspended impurities and ensure solution fluidity and nozzle patency. Spraying operations begin during the silking phase of the main crop, with a controlled speed of 1.5-2 km / h, a nozzle height of 30 cm above the ground, a spraying pressure of 0.2 MPa, and an application rate of 2-3 m³ per mu. A permanent magnet is activated, causing the charged ions (such as NH⁺, K⁺, and PO⁻) in the biogas slurry to be directionally deflected by the Lorentz force as it passes through the nozzle. By adjusting the nozzle angle, the biogas slurry is precisely sprayed within a 5-10 cm radius around the roots of the cover crop. Magnetic field strength, spray flow rate, and position are monitored in real time. If the magnetic field intensity fluctuates by more than 10% or the nozzle is clogged, the equipment automatically issues an alarm and suspends operation until the fault is resolved. The introduction of permanent magnet magnetic field control technology in agricultural fertilization transcends the traditional nutrient delivery model of gravity diffusion combined with mechanical spraying, establishing a new path of physical field-ion migration-root absorption.

[0051] Within 10-15 days after sowing, conduct a comprehensive inspection of cover crop emergence. Using a random sampling survey, select multiple plots, count the number of seedlings that have emerged, and calculate the missing seedling rate. If the missing seedling rate exceeds 10%, immediately begin manual reseeding. Use seeds of the same variety and treatment as the original sowing, reseeding at 50% of the original sowing rate. After reseeding, water lightly, controlling the amount to 1-2 m³ / mu, to ensure that the reseeded seeds absorb water quickly and germinate smoothly.

[0052] During the crop growth period, regularly inspect the ground film to identify any damage. Once damage is discovered, regardless of the size, immediately compact the damaged area with fine soil to prevent it from being blown away by the wind and affecting its moisture retention and warming properties. If the damaged area exceeds 20%, re-film the ground film by replacing it with a new one and compacting the edges to ensure the integrity of the film cover.

[0053] When the main crop reaches the end of its milky stage, timely harvesting is carried out using specialized harvesting machinery, keeping the stubble height to 10-15 cm. Within seven days of harvesting, residual film recovery equipment is used to reclaim the remaining film. This combined mechanical and manual process ensures a recovery rate of over 90%, preventing residual film from contaminating the soil and impacting subsequent planting.

[0054] Choose the appropriate utilization model based on the type of cover crop and its planting purpose. Grass cover crops like oats and ryegrass should be harvested during the heading phase and used as forage. They can then be dried into hay or stored as silage. Leguminous cover crops like hairy vetch and sedge peas should be plowed and returned to the field during their peak growth phase, with a plowing depth of 15-20 cm. This allows for rapid decomposition, converting them into green manure and increasing soil organic matter. Finally, thoroughly clean the spraying equipment and store it properly. Desilt the biogas tank, compost the cleared sludge, and return it to the field once fully decomposed, thus achieving the recycling of agricultural resources.

[0055] Example 1 (Arid Area) Regional characteristics: average annual precipitation is 300mm, soil moisture content is 6%-8%, mainly sandy loam, severe wind erosion, main crop is silage corn, and cover crops are hairy vetch + oats (1:2 mixed sowing).

[0056] Key steps: Step S1: The moisture content of the 0-20cm soil layer is detected to be 7%. Shallow buried drip irrigation is used to add water at 25m³ / mu to increase the moisture content to 13%; Apply 250kg / mu of commercial organic fertilizer and till the soil to a depth of 18cm. The weed count is 60 plants / m². Spray glyphosate four days before sowing.

[0057] Step S2: row spacing 40 cm + 60 cm, mulch width 35 cm, corn sowing depth 5 cm, plant spacing 25 cm; cover crop seeds were treated with electrostatic adsorption coating (humic acid 80 g / L, bacterial count 1.5 × 10 8 CFU / g).

[0058] Vibration suppression: The vibration frequency is 25Hz, and the porous honeycomb wheel has reserved pores filled with straw debris, and simultaneously generates infrasound waves to repel underground pests.

[0059] Step S3: Spray biogas slurry: clean water at a ratio of 1:3 (4 m³ / mu) during the germination period; spray 7 m³ / mu (with humic acid added) according to the soil NO3⁻-N (9 mg / kg) during the jointing period; and use an integrated permanent magnet (magnetic field strength 150 mT) to directionally infiltrate biogas slurry during the filling period.

[0060] Step S4: The seedling shortage rate is 5%, and no replanting is required; the corn is harvested at the end of the milky stage, and the residual film recovery rate is 92%; the cover crops are used as green manure and turned over and returned to the field.

[0061] Effect data: Cover crop emergence rate: 88% (18% higher than traditional cover crop emergence rate); Soil moisture content (at harvest): 14.2% (+15.5% compared to traditional); Fresh weight of corn ears: increased by 35%; Underground pest damage rate: <5%.

[0062] Example 2 (Semi-arid areas) Regional characteristics: average annual precipitation 450mm, soil moisture content 10%-12%, loess hilly landform, main crop is oats, and cover crop is single sowing of pea.

[0063] Key steps: Step S1: The water content was 11%, and no watering was required. 1200 kg / mu of decomposed farmyard manure was applied, and the soil was tilled to a depth of 16 cm. The weed count was 40 plants / m², and no weeding was performed.

[0064] Step S2: row spacing 40 cm + 60 cm, mulch width 30 cm, oat sowing depth 4 cm; cover crop seeds electrostatic coating (humic acid 50 g / L, bacterial count 1 × 10 8 CFU / g).

[0065] Biodegradable film pressing: Roll-press 0.005mm starch-based film, and form micro-holes with needles to complete pressing and laminating simultaneously.

[0066] Step S3: Spray 3 m³ / mu (1:3 dilution) during the germination period, spray 5 m³ / mu according to NO3⁻-N (15 mg / kg) during the jointing period, and spray 2.5 m³ / mu with the original solution during the filling period. No magnetic field treatment was used.

[0067] Step S4: The seedling shortage rate is 8%, and artificial replanting is performed; the residual film recovery rate after oat harvesting is 90%; the cover crops are harvested as forage, and the fresh grass yield per mu is 1,800 kg.

[0068] Effect data: Cover crop emergence rate: 85% (15% higher than traditional methods); Soil moisture content (at harvest): 13.8% (+12% compared to traditional methods); Oat production: increased by 28%; Weed suppression rate: 65%.

[0069] Example 3 (sub-humid area) Regional characteristics: average annual precipitation is 550 mm, soil moisture content is 13%-15%, the microtopography is mainly sloping, the main crop is corn, and the cover crop is ryegrass sown alone.

[0070] Key steps: Step S1: The water content was 14%, and no watering was required. 200 kg / mu of commercial organic fertilizer was applied, and the soil was tilled to a depth of 15 cm. The weed count was 30 plants / m², and no weeding was performed.

[0071] Step S2: row spacing 50 cm + 50 cm (no mulch), corn sowing depth 6 cm; cover crop seeds are not electrostatically treated.

[0072] Ice pellets mixed with fine sand = 1:1, spread 60kg / mu, and lightly press with a serrated roller (2kPa) to cope with sudden temperature drops after sowing (temperature 4°C).

[0073] Step S3: No spraying during the germination period (rain-fed), spraying 3m³ / mu of NO3⁻-N (22mg / kg) during the jointing period, spraying 2m³ / mu of the original solution during the filling period, and directional infiltration with a magnetic field intensity of 200mT.

[0074] Step S4: The seedling shortage rate is 12%, and artificial replanting is performed; the residual film recovery rate after corn harvest is 88%; the cover crops are turned over as green manure.

[0075] Effect data: Cover crop emergence rate: 82% (12% higher than traditional cover crop emergence rate); Soil moisture content (at harvest): 16.5% (+10.6% compared to traditional); Corn production: increased by 22%; Impact of late spring cold: No obvious frost damage.

[0076]

[0077] In arid areas, vibration suppression and magnetic field technology are used to solve the problems of insufficient soil moisture and insect pests, with significant comprehensive benefits; in semi-arid areas, biodegradable films and electrostatic treatment are used to achieve moisture conservation and efficient seedling emergence; in sub-humid areas, ice suppression and magnetic field penetration are used to deal with sudden low temperatures and nutrient loss, reflecting the environmental adaptability of the solution.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone, characterized in that: The following steps are involved: S1: Before sowing, the soil moisture is checked and adjusted to the preset range according to the moisture content. Fertilizer is then applied and the soil is tilled. S2: Use a wide-narrow row mulching seeder, set the row spacing and determine the mulching parameters, adjust the sowing depth, plant spacing, and sowing rate according to the main crop type, sow the main crop in wide-narrow rows with mulching and sow the cover crop between the rows simultaneously, apply seed fertilizer during sowing, and perform tamping after sowing; S3: Based on the growth period, the biogas slurry is sprayed in a targeted and phased manner. During the germination period, the biogas slurry is filtered and diluted, and then sprayed on the cover crop rows. During the jointing period, the biogas slurry dilution ratio is adjusted and nutrients are added. Different application amounts are implemented based on the soil nutrient test results. During the filling period, the precipitated biogas slurry is used and concentratedly sprayed around the roots of the cover crop rows.

2. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 1, characterized in that: In step S1, 10-15 days before sowing, a soil moisture meter is used to detect the moisture content of the 0-20 cm soil layer. If the moisture content of the soil layer is less than 10%, the moisture content is increased to 12%-15% through shallow buried drip irrigation or flooding irrigation. At the same time, 1000-1500 kg / mu of decomposed farmyard manure or 200-300 kg / mu of commercial organic fertilizer is applied and the soil is plowed to a depth of 15-20 cm.

3. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 2, characterized in that: In step S1, if the weed count in the field is greater than 50 plants / m², spray 200 ml / mu of 41% glyphosate solution 3-5 days before sowing for total weed control.

4. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 1, characterized in that: In step S2, the row spacing is set to 40 cm + 60 cm, the mulch covering width is 30-40 cm, the main crop sowing depth is 5-6 cm, the plant spacing is 25 cm, and the sowing amount is 4-5 kg / mu.

5. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 1, characterized in that: In step S2, the cover crop seeds are subjected to electrostatic adsorption coating treatment before sowing, and a colloidal solution containing humic acid and microbial agents is evenly coated on the surface of the seeds using an electrostatic spray device to form a charged adsorption layer with a thickness of 0.1-0.3 mm.

6. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 1, characterized in that: In step S2, the operation is carried out at a speed of 3-4 km / h, the ground film is flattened and the overlap between films is 5-10 cm; after sowing, N-P2O5-K2O=15-15-15 fertilizer is applied 5 cm to the side of the main crop row, with an application amount of 10-15 kg / mu and a depth of 8-10 cm.

7. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 1, characterized in that: In step S2, the suppression treatment adopts a vibration suppression method. Through the synergistic effect of high-frequency vibration of 20-30 Hz and the porous honeycomb suppression wheel, water-retaining micro-aggregates are formed in the 0-2 cm soil layer, and at the same time, air-permeable pores are reserved in the 2-4 cm soil layer, and the pores are filled with decomposed straw debris.

8. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 1, characterized in that: In step S3, during the germination period, the biogas slurry is filtered through a 20-mesh screen and diluted with water at a ratio of 1:3, with the EC adjusted to ≤ 2.0 mS / cm and the pH to 6.5-7.

5. A fan-shaped narrow-width sprinkler is installed and sprayed at the center of the cover crop row. During the jointing stage, the dilution ratio was adjusted to 1:2 biogas slurry: clean water, 0.1% humic acid water-soluble fertilizer was added and the EC was adjusted to ≤3.0mS / cm. Variable spraying was implemented based on the soil NO3⁻-N content. GPS positioning was matched with the prescription map to ensure a spray width of 15-20cm and a position error of ≤5cm. During the filling period, the biogas slurry that has been settled for more than 7 days is directly applied after being filtered through a 0.5mm pore size filter. The visual recognition system is used to track the covered crop rows in real time and the nozzle angle is hydraulically adjusted to spray the biogas slurry within a range of 10cm around the roots.

9. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 8, characterized in that: During the grouting period spraying in step S3, a neodymium iron boron permanent magnet is integrated at the nozzle of the spraying equipment to form a gradient magnetic field perpendicular to the ground. The charged ions in the biogas slurry generate Lorentz force under the action of the magnetic field and penetrate directionally into the 5-10 cm soil micro-area around the roots of the cover crops.

10. The method for sowing cover crops and spraying biogas slurry in an agricultural-pastoral transition zone according to claim 1, characterized in that: After step S3, 10-15 days after sowing, if the cover crop seedling shortage rate is greater than 10%, artificial replanting and light watering are performed, the ground film is inspected regularly and the damaged parts are compacted with fine soil, the main crop is harvested at the end of milk maturity, leaving a stubble of 10-15 cm and a residual film recovery rate of ≥90%, and the cover crop is used as a forage mode or a green manure mode.

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