Stubble-remaining no-tillage drought-resistant planting method for corn

Abstract

The invention discloses a corn stubble no-tillage drought-resistant planting method which comprises the following steps: for challenges of broken terrain, heavy soil, frequent winter and spring drought and the like in southwest hills and mountains, efficient drought-resistant planting of corn is realized through simplification, intelligentization and ecologicalization integration. The method comprises the core steps that a hilly terrace with the gradient smaller than or equal to 25 degrees is selected, 20-30 cm stubbles are reserved, and shallow rotation is conducted for 5-8 cm in depth; a drought-resistant seed coating agent containing potassium polyacrylate is adopted to coat the middle and early maturing corn variety; a light-weight no-tillage planter is used for synchronously applying high-molecular water-absorbent resin particles, and the planting density is controlled to be 3500-4000 plants per mu; implementing a strip-shaped ridge cleaning and half-covering mode; directional weeding, shallow loosening and topdressing, pest prevention and control and a three-year-one-turning crop rotation system are combined; after harvesting, standing stalks, airing, reserving stubbles, and covering and returning straws to the field; according to the method, the adaptability and safety of seeding operation are improved, the emergence rate is increased through water cooperative regulation and control, the field ecological balance is optimized, and the yield and soil sustainability are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of agricultural planting technology, and in particular to a method for no-till, drought-resistant corn planting with stubble retention. Background Technology

[0002] Corn, as an important food and feed crop in my country, holds an irreplaceable production position in the hilly and mountainous areas of Southwest China. This region features fragmented terrain and generally steep slopes, with arable land mostly existing in the form of terraces or gentle slopes. Coupled with the influence of the subtropical monsoon climate, frequent winter and spring droughts and concentrated summer and autumn torrential rains lead to multiple challenges for agricultural production, including unstable seedling emergence, severe soil erosion, and continuous degradation of soil fertility. Against this backdrop, traditional tillage methods, which exacerbate surface exposure and damage soil structure, are unable to meet the dual needs of ecology and production, prompting the gradual introduction and promotion of conservation tillage concepts. Among these, stubble-retaining no-till technology is considered a sustainable farming approach that aligns with the ecological characteristics of mountainous areas because it effectively reduces soil disturbance, maintains surface cover, inhibits wind and water erosion, and to some extent increases soil organic matter content and biological activity.

[0003] Specifically, stubble retention and no-till farming creates a physical barrier by preserving the residue of the previous crop. This significantly reduces the stripping effect of strong winds on the topsoil during winter and spring, and effectively inhibits ineffective evaporation of soil moisture, thus creating a relatively stable microenvironment for seed germination under drought stress. Simultaneously, this technology avoids the damage to soil aggregate structure caused by frequent tillage, which helps maintain good porosity and root penetration capacity, thereby improving crop growth conditions. For these reasons, numerous studies both domestically and internationally have confirmed its comprehensive advantages in improving soil and water conservation efficiency, enhancing soil carbon sequestration function, and stabilizing crop yields, making it particularly suitable for hilly and mountainous agricultural systems with complex terrain and fragile ecosystems.

[0004] However, with the deepening application of conservation tillage technology, especially under the constraints of frequent extreme weather events, unique soil types (such as purple soil and yellow soil), and highly fragmented plots in Southwest China, existing mainstream technologies have revealed a series of deep-seated compatibility contradictions. While the integrated model of "stubble-retaining no-till + supplemental irrigation sowing," represented by CN112602547B, theoretically achieves the synergistic goals of drought resistance and seedling protection with increased density and yield, its design logic of relying on heavy no-till machinery to complete multiple tasks at once encounters fundamental limitations in the actual scenario of hilly and mountainous areas in Southwest China. On the one hand, the typical slope in the area often reaches 20°–30°, and the plots are small and irregularly shaped, making it difficult for heavy machinery to enter and prone to operational safety risks due to center of gravity shift. On the other hand, soil moisture is already high in spring; if drip irrigation is implemented to supplement moisture, it can easily cause local soil oversaturation, leading to seed rot due to oxygen deficiency, thus weakening the germination rate. More importantly, the purple and yellow soils are heavy and sticky, containing gravel and grass roots, making them prone to tangling and clogging with conventional no-till furrow openers. This leads to uncontrolled sowing depth, uneven seedbeds, and consequently, severe seedling loss and gaps in rows. Meanwhile, while full straw mulching helps retain moisture, it provides a breeding ground for pathogens and pests in high humidity, forcing farmers to burn it, negating the ecological benefits of no-till and creating new environmental pollution problems. Furthermore, varieties touted as "dense-planting tolerant, early-maturing, and machine-harvestable" often exhibit excessive vegetative growth and weak stems under the low light and high humidity conditions of Southwest China, making them highly susceptible to lodging. This makes it difficult to translate the theoretically increased yield from dense planting into actual profits, and mechanized harvesting is also difficult to implement due to plant lodging and terrain limitations.

[0005] Ultimately, the aforementioned predicament does not stem from the failure of a single technological link, but rather from the failure of existing solutions to fully coordinate the inherent tensions between "drought resistance and seedling protection," "ecological conservation," and "agronomic adaptation" in their design philosophy. Particularly in the complex system of the hilly and mountainous regions of Southwest China, where multiple factors are coupled, overemphasizing a single performance indicator (such as full coverage or high-density planting) often comes at the expense of other key elements (such as pest and disease control or machinery adaptability), revealing that the current technological system lacks the dynamic response capability to regionally specific conditions at the principle level. Therefore, how to construct a simplified, intelligent, and ecological maize planting method that can inherit the ecological advantages of stubble retention and no-till farming while addressing the complex challenges of fragmented terrain, heavy clay soils, and the interplay of humid climate and spring drought in the hilly and mountainous regions of Southwest China has become a key challenge and an urgent technical problem for those skilled in the art.

[0006] Therefore, it is necessary to provide a no-till drought-resistant corn planting method with stubble retention to solve the above-mentioned technical problems. Summary of the Invention

[0007] This invention overcomes the shortcomings of the prior art and provides a method for no-till, drought-resistant corn planting with stubble retention.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for no-till drought-resistant corn planting with stubble retention, comprising the following steps:

[0009] S1. Select hilly terraces with a slope of ≤25°, retain 20-30cm of stubble, and shallowly till to a depth of 5-8cm.

[0010] S2. Apply a drought-resistant seed coating agent containing potassium polyacrylate to early-maturing maize varieties;

[0011] S3. Use a lightweight no-till planter and apply superabsorbent polymer granules simultaneously, with a planting density of 3500–4000 plants per acre;

[0012] S4. Adopt strip clearing and half-coverage methods, with a coverage of 40-50%;

[0013] S5. Implement targeted weeding, shallow loosening and topdressing, pest control and a three-year crop rotation system;

[0014] S6. After the straw has been dried, leave a 20-30cm stubble and return the straw to the field as a mulch.

[0015] In a preferred embodiment of the present invention, the shallow rotary tillage is completed within 7 days before sowing. The shallow rotary tillage tool is composed of a combination of a hooked blade and a flat blade. After tillage, at least 70% of the original soil structure remains undisturbed.

[0016] In a preferred embodiment of the present invention, the drought-resistant seed coating agent is prepared by mixing 0.3–0.5% potassium polyacrylate, 0.2% humic acid and 0.1% silicate in a certain mass ratio, and the seed moisture content is controlled below 13% after coating.

[0017] In a preferred embodiment of the present invention, the no-till seeder has a total weight of no more than 150 kg, is equipped with a weeding wheel and a double-edged sliding knife furrow opener, the sowing depth is controlled at 3–4 cm, and the seed-fertilizer separation distance is not less than 4 cm.

[0018] In a preferred embodiment of the present invention, the superabsorbent polymer is potassium polyacrylate or polyacrylamide copolymer, with a particle size of 0.3–0.8 mm, a water absorption ratio of not less than 200 times, and an application amount of 2–3 g per hole.

[0019] In a preferred embodiment of the present invention, the no-till planter is equipped with a slope sensor and lateral stabilizing wheels, and the walking mechanism uses rubber tracks or engineering plastic tracks with a ground pressure not exceeding 25 kPa.

[0020] In a preferred embodiment of the present invention, in step S5, when the number of corn borers per 100 plants reaches or exceeds 100, 15,000 Trichogramma wasps per acre are released, and the release is repeated once every 7 days.

[0021] In a preferred embodiment of the present invention, in the three-year crop rotation system, the shallow plowing depth in the third season is 15cm, and 500kg / mu of well-rotted organic fertilizer is applied simultaneously. The rotation crop is legume, tuber or oilseed crop.

[0022] In a preferred embodiment of the present invention, the curved hook blade is made of 65Mn spring steel with a heat treatment hardness of HRC48–52, and the surface of the flat blade is coated with a wear-resistant ceramic coating.

[0023] In a preferred embodiment of the present invention, superabsorbent polymer granules are delivered to the bottom of the planting hole through an independent application pipeline, with an application amount error of no more than ±0.2g per hole and an effective water retention period of no less than 20 days.

[0024] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0025] (1) This invention provides a method for no-till drought-resistant corn planting with stubble retention. By introducing a lightweight no-till planter and combining it with sowing, the adaptability of the operation in the hilly and mountainous areas of Southwest China is significantly improved, enabling the machine to cope with small plots and steep slopes. This avoids the operational risks caused by the center of gravity shift and terrain limitations of traditional heavy machinery. The lightweight design reduces the compaction of the soil by the machine, while sowing ensures the stability of sowing depth and seed-fertilizer isolation, thereby directly improving the uniformity of sowing and the uniformity of seedling emergence. Compared with the problem that heavy machinery is difficult to work effectively in broken terrain in the prior art, this method not only solves the contradiction of machine adaptability, but also further enhances the safety and efficiency of operation.

[0026] (2) This invention provides a method for no-till drought-resistant corn planting with stubble retention. It adopts a synergistic water regulation method of drought-resistant seed coating agent and superabsorbent polymer, which effectively relieves drought stress during the seedling stage. The seed coating agent coating treatment enhances the drought resistance of the seeds, while the fixed-point application of superabsorbent polymer forms a local water-retaining microenvironment around the seeds, which can absorb and slowly release water, providing continuous support for seed germination, significantly improving the emergence rate and seedling survival rate, and reducing the phenomenon of missing seedlings and broken rows due to drought. Compared with the disadvantages of full irrigation in the prior art, which may cause soil oversaturation and seed rot, this method realizes water management, further reduces water waste, and promotes the robust growth of crops under drought conditions.

[0027] (3) This invention provides a method for no-till drought-resistant corn planting with stubble retention. By combining strip clearing, half-covering straw management with dynamic crop rotation, the ecological balance in the field is optimized. Half-covering retains the moisture-retaining effect of straw and reduces the breeding environment of pests and diseases through clearing. The crop rotation system periodically improves the soil structure, thereby avoiding the risk of high humidity diseases that may be caused by full coverage. At the same time, crop rotation helps nutrient cycling and disease suppression, directly reducing the intensity of pests and diseases and the risk of soil degradation. Compared with the problems of extensive straw management and continuous cropping obstacles in the prior art, this invention provides a method for no-till drought-resistant corn planting with stubble retention. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating a preferred embodiment of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0032] This invention provides a no-till, drought-resistant maize planting method with stubble retention. The technical solution integrates simplified operating equipment, seed treatment, strip clearing with half-coverage, targeted application of high-molecular-weight water-absorbing materials, dynamic crop rotation, and ecological field management to achieve high-efficiency, stable-yield, and drought-resistant no-till maize planting under the unique ecological and production conditions of the hilly and mountainous areas of Southwest China. The following detailed description of the technical solution of this invention is provided in conjunction with specific embodiments.

[0033] In one application scenario of this invention, the planting area is located in a hilly terraced field in Cangxi County, Guangyuan City, Sichuan Province. This area has a subtropical humid monsoon climate with an average annual rainfall of 980 mm. Winter and spring droughts are frequent, while summer and autumn are characterized by concentrated heavy rainfall. The soil type is purple soil, with a heavy, clayey texture, a pH of 6.2–6.8, and an organic matter content of 1.1%–1.5%. The slope ranges from 18° to 23°, and the plots are generally less than 0.2 hm², exhibiting high fragmentation. The previous crop was the "Tongyu 609" maize variety, which was harvested in late September of the previous season.

[0034] like Figure 1 As shown, a no-till drought-resistant corn planting method with stubble retention includes the following steps:

[0035] S1: Select hilly terraces with a slope of no more than 25° and a soil layer thickness of no less than 40cm as the planting area; after the previous corn harvest, retain a stubble structure with an above-ground stem height of 25cm;

[0036] Manually remove weeds from the field and remove plant debris carrying pathogens, including infected corn stubble and moldy straw; use a shallow rotary cutter to perform shallow rotary operations on the surface soil along the contour line, with an operating depth of 6cm and a cutter speed of 220r / min, and the length of a single piece of soil after breaking it up should not exceed 4cm.

[0037] It should be noted that by selecting hilly terraces with a slope of no more than 25° and retaining a 25cm stubble structure, this method cleverly utilizes the synergistic effect of the natural characteristics of the terrain and crop residues. The physical barrier formed by the stubble effectively slows down the surface runoff rate. At the same time, combined with shallow rotary tillage along the contour lines, it significantly reduces the risk of soil erosion and creates a stable microenvironment for subsequent sowing. This not only enhances the erosion resistance of the soil surface but also maintains the biological activity of the soil by preserving the original soil structure.

[0038] The shallow rotary tillage system consists of a combination of a hooked blade and a flat blade. The hooked blade is used to cut grass roots and the topsoil crust, while the flat blade is used to level the working surface. After tillage, at least 72% of the original soil structure remains undisturbed. Shallow rotary tillage is completed 5 days before sowing to avoid premature tillage that could cause the topsoil to compact again. After shallow rotary tillage, the soil bulk density was measured to be 1.22 g / cm³, and the porosity was 47.3%.

[0039] The curved hook blade is made of 65Mn spring steel, and its hardness is HRC50 after quenching and tempering heat treatment. The flat blade is made of Q235 carbon structural steel, and its surface is coated with a thickness of 0.3mm. Composite ceramic coating with a microhardness of HV1200.

[0040] Specifically, the shallow rotary operation uses a combination of curved hook blades and flat blades to efficiently cut grass roots and compacted layers while controlling the depth to 6cm. At the same time, it flattens the working surface. The wear-resistant coating and specific materials of the blades ensure the durability and consistency of the operation, so that the length of a single piece of soil after breaking it up does not exceed 4cm, thereby optimizing the physical properties of the seedbed.

[0041] After land preparation, the soil bulk density is maintained at 1.22 g / cm³, and the porosity reaches 47.3%. This fine soil structure promotes water infiltration and root development, and avoids structural damage caused by excessive disturbance.

[0042] S2: The medium-early maturing maize variety “Tongyu 609”, which has been approved by the Southwest Region of China, is selected. Its growth period is 112 days, ear height is 105cm, and it has the characteristics of being tolerant to rain and resisting ear rot.

[0043] It should be noted that by selecting the mid-early maturing maize variety "Tongyu 609" and combining it with drought-resistant seed coating treatment, the inherent stress resistance of the variety and external protection are deeply integrated. The variety's tolerance to rain and resistance to ear rot provide the seeds with the ability to resist adverse environments.

[0044] Before sowing, the seeds are coated with a drought-resistant seed coating agent, which is prepared by mixing 0.4% potassium polyacrylate, 0.2% humic acid, and 0.1% silicate in a certain mass ratio; among which, potassium polyacrylate is a cross-linked superabsorbent resin powder with an average molecular weight of 1.2 × 10⁻⁶. 6 ;

[0045] Humic acid is in the form of potassium fulvate with a water solubility of 92%; silicate is sodium metasilicate with a purity of 98.5%; the three are dissolved in deionized water in a certain proportion to form a suspension with a solid content of 18%, which is then emulsified by high-speed shearing (8000 r / min for 10 min) and used for seed coating.

[0046] The seed coating process was carried out in a constant temperature and dry environment (temperature 25±1℃, relative humidity 45%) to ensure that the seed coating agent adhered evenly and without clumping; the seed moisture content after coating was 12.7%.

[0047] Among them, potassium polyacrylate, humic acid and silicate in seed coating agents enhance the drought resistance and growth potential of seeds, thereby improving the stability of seeds during the germination stage and creating a favorable microenvironment for seedling growth, effectively coping with the climate fluctuations in the hilly and mountainous areas of Southwest China.

[0048] Specifically, the seed coating agent involves controlled component ratios and high-speed shear emulsification to ensure uniform dispersion of all components and the formation of a stable suspension. Potassium polyacrylate, as a highly absorbent resin, enhances the water retention capacity of the seeds, humic acid promotes root development, and silicates improve the mechanical strength and stress resistance of the seed coat. The entire coating process is completed under constant temperature and dry conditions to avoid clumping and uneven adhesion, thus ensuring that each seed receives a protective layer, significantly improving the uniformity of germination and the robustness of seedlings after sowing.

[0049] S3: When the soil temperature in the 5cm layer remains stable above 10.5℃ for 3 consecutive days and the soil moisture content is 19.2%, a single-row no-till planter can be used for one-time operation. The no-till planter weighs 138kg, is powered by a 6.8kW gasoline engine, operates in 1 row, has a minimum turning radius of 0.85m, and is suitable for a maximum slope of 25°.

[0050] The front end of the machine is equipped with a weed-removing wheel with a diameter of 30cm. Its rotation speed is set to 1.2 times the linear speed of the ground wheel through chain drive. It is used to remove straw and weeds within a 20cm wide area of ​​the sowing strip. The furrow opener adopts a double-edged sliding blade structure with an anti-grafting cover on the blade surface. The sowing depth is controlled at 3.5cm and the seed-fertilizer separation distance is 4.2cm.

[0051] Simultaneously apply 2.5g of superabsorbent polymer (SAP) granules below the sowing location in each hole; the SAP is a potassium polyacrylate copolymer with a particle size of 0.5mm and a measured water absorption ratio of 215 times (distilled water, 25℃, 24h); the planting density is set at 3800 plants / acre, with a row spacing of 65cm.

[0052] The no-till planter is equipped with a MEMS slope sensor (range ±30°, accuracy ±0.5°) and lateral stabilizing wheels. The slope sensor monitors the working slope in real time and feeds back to the ECU control system. The lateral stabilizing wheels adjust lateral displacement through a hydraulic damping mechanism with a damping coefficient set to 12 N·s / m, ensuring that the implement's lateral deviation does not exceed 3 cm when working on slopes. The walking mechanism uses high-strength engineering plastic tracks with a measured ground pressure of 23.6 kPa. The transmission system connects the power output shaft and the working parts through a double-row roller chain and helical gear set, with a torque distribution error of less than 5%.

[0053] The fertilization device uses a screw meter and the fertilizer is a nitrogen-phosphorus-potassium compound fertilizer (N-P2O5-K2O=15-15-15), with a total nutrient content of 45.2% and a particle diameter of 3mm. The soil covering mechanism is located behind the seeder and consists of an arc-shaped soil covering plate and a pressing wheel. The surface of the pressing wheel is covered with a rubber layer with a hardness of Shore A65. It is used to moderately compact the seedbed to ensure contact between the seeds and the soil. The pressing pressure is set to 80N / row.

[0054] The superabsorbent polymer granules are delivered to the seed holes behind the furrow opener through an independent application pipeline. The application pipeline is controlled by a volumetric meter driven by a stepper motor. The metering chamber has a volume of 2.7 cm³. The application rate per hole is ±0.15 g as determined by weighing. After the resin granules absorb water and swell in the soil, they form a gel-like water-retaining layer that continuously releases water to meet the needs of seed germination and early seedling growth. Its effective water-holding period is no less than 22 days as monitored by a field tensiometer.

[0055] It should be noted that by selecting the sowing time, when the soil temperature and moisture content reach a specific threshold, combined with the one-time operation of a lightweight no-till planter, this method achieves a high degree of synchronization between environmental conditions and mechanical operation.

[0056] The lightweight design of the machinery and the slope-adaptive control system ensure stable operation in complex terrain, while the timing of sowing makes full use of soil moisture and heat resources, creating the best starting point for seed germination. This not only avoids the risk of sowing too early or too late, but also improves the consistency of operations through mechanization efficiency.

[0057] During the sowing process, the combined work of the weed-removing wheel and the double-edged sliding knife furrow opener clears obstacles in the sowing zone and controls the sowing depth and seed-fertilizer separation distance. At the same time, the targeted application of superabsorbent polymer resin below the seed hole forms a local water-retaining layer, ensuring that the seeds are placed on a uniform seedbed and receive a continuous water supply, thereby significantly enhancing the drought resistance and uniformity of the seedlings during the emergence stage.

[0058] Furthermore, the real-time adjustment of the slope sensor and stabilizing wheel further ensures that sowing is not affected by terrain fluctuations.

[0059] S4: After the previous corn harvest, the above-ground straw is crushed to a length of 8cm using a small straw crusher; strip clearing and half-covering are used to return the straw to the field, that is, 20cm of bare area is left on each side of the sowing strip, and the crushed straw is evenly spread in the remaining inter-row areas, with the coverage controlled at 45% and the coverage per unit area of ​​320kg / mu.

[0060] Excess straw exceeding this coverage amount (approximately 80 kg / mu) should be removed from the field and composted centrally. The composting should be done using windrow aerobic fermentation, with the C / N ratio adjusted to 25:1. The turning cycle should be 7 days. After the rainy season ends (end of March of the following year), the straw should be fully decomposed and returned to the field before the next season's land preparation.

[0061] The straw mulch layer remains intact during winter until it is partially removed by a straw-removing wheel to form a sowing strip before sowing the following year;

[0062] It should be noted that step S4 achieves a synergistic effect of multiple environmental controls through strip clearing and half-covering, combined with meticulous straw management.

[0063] The previous crop of corn stalks was shredded to 8cm in length, and a strip-shaped clearing strategy was adopted. 20cm of bare area was left on each side of the sowing strip, and the shredded stalks were evenly spread between the remaining rows to control the coverage at about 45%. This achieved a balance between moisture retention and ventilation. The stalk cover effectively inhibited soil moisture evaporation, while the bare areas promoted air circulation, reducing the risk of pathogen growth in high humidity. The cover remained intact during overwintering, providing continuous protection for the soil, until it was partially removed with a straw-removing wheel before sowing the following year, forming an ideal sowing strip and ensuring the stability of the microenvironment for seed germination.

[0064] Furthermore, the combination of partial mulching and strip clearing significantly optimizes field ecological dynamics. The 40-50% mulching setting avoids soil oversaturation and pest and disease risks that may result from full mulching, while the uniform spreading of crushed straw enhances the surface's resistance to erosion and reduces soil erosion.

[0065] Excess straw is removed from the field and composted in windrows using aerobic methods. By adjusting the carbon-nitrogen ratio and turning the pile regularly, it promotes rapid decomposition and is then returned to the field in the next season. This not only recycles organic resources but also avoids fire or pollution problems caused by straw accumulation, supports the enhancement of soil biological activity and nutrient cycling. The long-term integrated effect of this straw treatment method is reflected in soil health and the sustainability of crop growth.

[0066] Half-covering combined with periodic composting gradually improves soil structure and enhances organic matter accumulation, while strip clearing reduces competition from weeds and resistance to mechanical operations.

[0067] In summary, the S4 step maximizes the ecological advantages of stubble retention and no-till farming, providing a solid foundation for maize growth, while also adapting to the unique climate and terrain conditions of the hilly and mountainous areas of Southwest China, demonstrating high practicality and adaptability.

[0068] S5: At the 4th leaf stage after corn emergence, use a suspended sprayer for targeted foliar weeding. The nozzle is installed 15cm above the crop row, and the spraying direction is perpendicular to the plant stem. The nozzle model is TeeJet8002VS, the working pressure is 0.3MPa, the liquid flow rate is 0.8L / min, and the spray width covers a 25cm area between the rows, avoiding contact between the liquid and the heart leaves.

[0069] During the jointing stage, use a mid-tiller to perform shallow loosening operations 10cm from the side of the corn row, with a loosening depth of 6cm, and simultaneously apply 10kg / mu of urea (46% nitrogen content).

[0070] During the early stage of corn borer infestation, a five-point sampling method was used to investigate the number of borers per 100 plants. When the number of borers per 100 plants reached 112, 15,000 Trichogramma wasps per acre were released, and the release was repeated every 7 days. If the infestation developed rapidly (e.g., the number of borers per 100 plants increased to more than 200 within 7 days), then Bacillus thuringiensis (Bt) wettable powder (16000 IU / mg) at a dilution of 800 times was used for foliar spraying.

[0071] After two consecutive planting seasons of no-till operations, shallow plowing is carried out in the third season, with a plowing depth of 15cm. At the same time, all the straw accumulated in the first two seasons is plowed into the soil. The shallow plowing operation uses a chisel plow with a plow body entry angle of 18° and an operation speed of 3.5km / h.

[0072] Simultaneously apply 500 kg / mu of well-rotted organic fertilizer, which is obtained by aerobic fermentation of pig manure for 65 days, with a moisture content of 28.5%, an organic matter content of 47.2%, and a C / N ratio of 22.3; the rotation crop is soybean "Nan Dou 12", which is a non-grass family leguminous crop;

[0073] It should be noted that step S5, through field management measures implemented step by step according to the growth stage, organically links weeding, fertilization, pest control and crop rotation system to form a dynamic response agronomic closed loop.

[0074] Targeted foliar weeding is carried out at the fourth leaf stage after corn emergence. By controlling the height of the nozzle and the direction of spraying, the herbicide is ensured to cover the weeds between rows while avoiding contact with the heart leaves of the crop, thus creating a clean space for seedling growth.

[0075] Specifically, after entering the jointing stage, shallow loosening along the rows combined with topdressing not only breaks up the surface crust and promotes root penetration, but also timely supplements nitrogen nutrition to support robust plant growth. This effectively meets the nutrient requirements and competitive relationship of corn, and significantly improves resource utilization efficiency.

[0076] The pest control system is a deep integration of monitoring and early warning with ecological regulation. During the small trumpet stage, a five-point sampling method is used to monitor the corn borer situation. When the number of insects per 100 plants reaches the threshold, Trichogramma wasps are released first for biological control. If the pest situation worsens, Bacillus thuringiensis spraying is used to form a gradient management strategy. This dynamic control based on insect population density reduces the input of chemical pesticides and maintains the ecological balance in the field through natural enemy insects.

[0077] At the same time, after two consecutive seasons of no-till, shallow plowing is carried out in the third season to return all the accumulated straw to the field and apply well-rotted organic fertilizer to achieve a coordinated supply of carbon and nitrogen.

[0078] The crop rotation system further extends the spatial and temporal dimensions of ecological regulation. By selecting soybeans, a legume crop, as the rotation target, the nitrogen-fixing properties of soybeans are utilized to improve soil fertility. Meanwhile, the depth control of shallow plowing and the design of the angle of the chisel plow ensure that the straw is buried deeply while avoiding damage to the underlying structure.

[0079] S6: After the physiological maturity period of the corn kernel milk line has completely disappeared and the black layer has formed, stand the stalks to dry for 8 days; when the kernel moisture content drops to 28.7%, use a small ear harvester to pick the ears; after harvesting, retain a stubble structure with a height of 25cm for the above-ground stalks;

[0080] After crushing the remaining straw, spread it evenly between the rows according to the S4 method of "strip clearing and half-covering" to cover it for overwintering and provide a surface protection layer for the next season's sowing;

[0081] It should be noted that after the milk lines in the corn kernels have completely disappeared and the black layer has formed, allowing the plants to stand naturally in the field to dry for eight days promotes the slow transpiration of moisture from the kernels through the plant's vascular system, resulting in a uniform reduction in moisture content to approximately 28.7%. At this point, using a small ear harvester for targeted ear picking effectively reduces the risk of mechanical damage to the kernels. Simultaneously, retaining a 25-centimeter stubble structure above ground not only avoids quality deterioration caused by rapid high-temperature drying but also lays a physical foundation for subsequent straw processing.

[0082] The integration of stubble retention and straw mulching constructs a cross-seasonal farmland protection system. The neat stubble retained after harvest and the shredded straw returned to the field together form a three-dimensional protective network. The stubble serves as a permanent support to resist wind erosion, while the shredded straw is laid between the rows in a strip-shaped half-coverage pattern, forming a protective layer with a coverage of about 45%. This effectively inhibits soil moisture evaporation and slows down drastic temperature fluctuations during winter. At the same time, it intercepts raindrop splash and reduces the intensity of surface runoff. The upright nature of the stubble can also capture organic matter particles that migrate with the wind, promoting the natural redistribution of nutrients in the field.

[0083] Experimental example:

[0084] To verify the technical effectiveness of this invention, a comparative experiment was conducted using a comparative example.

[0085] The comparison adopted the local farmers' conventional stubble-retaining no-till farming model: the previous crop stubble height was 35cm, no shallow rotary tillage was carried out, traditional animal-powered seeders were used directly for sowing, the sowing depth fluctuated greatly (2-6cm), no super absorbent polymer materials were applied, straw was fully covered (coverage 70%, coverage amount 550kg / mu), crop rotation was not implemented, no-till farming was carried out for three consecutive years, field management was extensive, and no pest control was carried out.

[0086] The experiment was conducted for three consecutive years on the same plot (0.15 hm²) with consistent soil conditions. The main observation indicators and results are shown in Table 1 below:

[0087] Table 1:

[0088] index Example Comparative Example Seeding depth qualification rate (%) 94.2 68.5 Emergence rate (%) 92.8 76.3 Mean soil moisture content (%) during the seedling stage (0-30 days) 18.6 15.2 Number of corn borers per 100 plants (heads) 85 198 Lodging rate (%) 3.1 12.7 Yield per unit area (kg / mu, dry grains) 486.5 392.3 Soil bulk density (g / cm³, 0-20cm) 1.24 1.41 Annual increase in soil organic matter (%) +0.08 +0.02

[0089] As shown in Table 1:

[0090] This invention significantly improves sowing quality and seedling uniformity by controlling sowing depth, applying high-absorbent polymer materials at specific points, optimizing straw mulching patterns, and implementing ecological pest control. It effectively alleviates drought stress during the seedling stage, reduces the intensity of pests and diseases and the risk of lodging, ultimately leading to a significant increase in yield. Simultaneously, dynamic crop rotation and periodic shallow tillage effectively curb the upward trend in soil bulk density, promote soil organic matter accumulation, and maintain soil fertility sustainability.

[0091] Furthermore, as a preferred embodiment of the present invention, the superabsorbent polymer can be replaced with a polyacrylamide-sodium acrylate copolymer, which has a water absorption ratio of not less than 220 times, higher gel strength, and better anti-degradation performance in heavy clay soils; on plots with a slope of more than 20°, the no-till planter can be equipped with a gyroscope attitude stabilization module, which, combined with slope sensor data, adjusts the hydraulic damping parameters in real time through a PID algorithm to control the lateral tilt angle of the implement within ±2°.

[0092] Specifically, in the application on yellow soil slopes (slope 22°, pH 5.8) in Meitan County, Zunyi City, Guizhou Province, humic acid in the drought-resistant seed coating agent was replaced with potassium humate (88% water-soluble), and the rotation crop was adjusted to potato "Weiyu No. 5". After shallow plowing in the third season, biochar-based organic fertilizer (15% biochar addition) was applied. The average yield per mu over three years reached 462.7 kg / mu, which is 21.8% higher than the local conventional no-till method. The soil pH value increased to 6.1 and the aluminum toxicity activity decreased by 37%.

[0093] In one specific embodiment, the tracked no-till seeder uses rubber tracks (200mm wide, 80mm pitch) with a ground pressure of 21.3kPa, suitable for post-rain operations with low soil bearing capacity; the fertilization device has a screw pitch of 12mm and its rotation speed is controlled by a closed loop based on the seeding speed, ensuring that the coefficient of variation of fertilizer application is less than 8%; the rubber layer of the soil compaction wheel has a Shore A hardness of 68 and a compression set (70℃×24h) of 12%, ensuring stable compaction performance under long-term operation.

[0094] In the blade combination used for shallow rotary tillage, there are 8 curved hook blades per meter of working width, installed at a 15° forward tilt angle, and the flat blade is 50mm wide. The two are arranged alternately. After the operation, the standard deviation of the ground flatness is 1.8cm, which meets the requirements of no-till seeding for the flatness of the seedbed.

[0095] The spatial distribution of superabsorbent polymer (SAP) particles in the soil was verified by CT scan. More than 90% of the particles were concentrated in the soil layer 2–5 cm directly below the planting hole, forming a local high water-holding micro-domain, which effectively avoids the lateral diffusion and loss of water. Its water absorption-release cycle performance was measured by laboratory simulation. After experiencing three cycles of dry and wet, the water holding capacity still maintained 82% of the initial value.

[0096] In the crop rotation system, legumes (such as soybeans) planted after shallow plowing in the third season can fix about 6-8 kg / mu of nitrogen, significantly reducing the nitrogen fertilizer input for corn in the next season; tuber crops (such as sweet potatoes) can loosen deep soil and improve soil structure through tuber growth; and glucosinolates in oil crops (such as rapeseed) have a certain inhibitory effect on soil-borne diseases, forming an ecological disease suppression effect.

[0097] In summary, the no-till, drought-resistant maize planting method with stubble retention of the present invention constructs a simplified, intelligent, and ecological maize planting system highly adapted to the complex terrain and climate conditions of the hilly and mountainous areas of Southwest China through a series of deterministic, quantifiable, and reproducible technical steps. All technical parameters are set based on extensive field trials and engineering verification, ensuring that those skilled in the art can directly implement the method according to this specification and obtain stable and predictable technical results without creative effort.

[0098] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for no-till, drought-resistant corn cultivation with stubble retention, characterized in that, Includes the following steps: S1. Select hilly terraces with a slope of ≤25°, retain 20-30cm of stubble, and shallowly till to a depth of 5-8cm. S2. Apply a drought-resistant seed coating agent containing potassium polyacrylate to early-maturing maize varieties; S3. Use a lightweight no-till planter and apply superabsorbent polymer granules simultaneously, with a planting density of 3500–4000 plants per acre; S4. Adopt strip clearing and half-coverage methods, with a coverage of 40-50%; S5. Implement targeted weeding, shallow loosening and topdressing, pest control and a three-year crop rotation system; S6. After the straw has been dried, leave a 20-30cm stubble and return the straw to the field as a mulch.

2. The method for no-till, drought-resistant corn planting with stubble retention according to claim 1, characterized in that: The shallow rotary tillage operation is completed within 7 days before sowing. The shallow rotary tillage tool consists of a combination of a hooked blade and a flat blade. After tillage, at least 70% of the original soil structure remains undisturbed.

3. The method for no-till, drought-resistant corn planting with stubble retention according to claim 1, characterized in that: The drought-resistant seed coating agent is prepared by mixing 0.3–0.5% potassium polyacrylate, 0.2% humic acid and 0.1% silicate in a certain mass ratio.

4. The method for no-till, drought-resistant corn planting with stubble retention according to claim 1, characterized in that: The no-till seeder weighs no more than 150 kg, is equipped with a weeding wheel and a double-bladed sliding knife furrow opener, and has a seeding depth controlled at 3–4 cm and a seed-fertilizer separation distance of no less than 4 cm.

5. The method for no-till, drought-resistant corn planting with stubble retention according to claim 1, characterized in that: The superabsorbent polymer is a copolymer of potassium polyacrylate or polyacrylamide, with a particle size of 0.3–0.8 mm, a water absorption ratio of not less than 200 times, and an application amount of 2–3 g per hole.

6. The method for no-till, drought-resistant corn planting with stubble retention according to claim 1, characterized in that: The no-till planter is equipped with a slope sensor and lateral stabilizing wheels. The walking mechanism uses rubber tracks or engineering plastic tracks, and the ground pressure is no more than 25 kPa.

7. The method for no-till, drought-resistant corn planting with stubble retention according to claim 1, characterized in that: In S5, when the number of corn borers reaches or exceeds 100 per 100 plants, 15,000 Trichogramma wasps per acre are released, and the release is repeated once every 7 days.

8. The method for no-till, drought-resistant corn planting with stubble retention according to claim 1, characterized in that: In the three-year crop rotation system, the shallow plowing depth in the third season is 10-20cm, and 500kg / mu of well-rotted organic fertilizer is applied simultaneously. The rotation crops are legumes, tubers, or oil crops.

9. A method for no-till, drought-resistant corn planting with stubble retention according to claim 2, characterized in that: The curved blade is made of 60-70Mn spring steel with a heat treatment hardness of HRC48–52, and the surface of the flat blade is coated with a wear-resistant ceramic coating.

10. A method for no-till, drought-resistant corn planting with stubble retention according to claim 5, characterized in that: The superabsorbent polymer granules are delivered to the bottom of the planting hole through an independent application pipeline. The application amount per hole has an error of no more than ±0.2g, and the effective water retention period is no less than 20 days.

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