A method for synergistically reducing ecological regulation of a yellow soil paddy oil wheel farmland composite barrier

Abstract

The present application relates to the field of soil ecological restoration and farmland tillage management, in particular to an ecological regulation method for reducing the combined obstacles of yellow soil rice-oil rotation farmland, which is implemented in stages according to the agricultural time: S1, before rice transplanting, crushing straw, mixing compound functional microbial agent, matured organic fertilizer and calcium-magnesium-phosphorus fertilizer into 0-15 cm; S2, after rice harvesting, deep ploughing 20-25 cm and constructing ridge structure; S3, after ridge construction, interplanting Chinese milk vetch before rape sowing; S4, after rape harvesting, crushing rape straw and Chinese milk vetch into 20-25 cm and applying lime, maintaining higher water holding capacity in a short term; S5, annual circulation. Through the coupling of microorganism-structure-nutrient, the method can alleviate the problems of "thin, flat and sticky" of yellow soil, improve the aggregation and aeration, and promote the growth of root system and stable yield and production.

Description

Technical Field

[0001] This invention relates to the field of soil ecological restoration and farmland management technology, specifically to a method for synergistic reduction and ecological regulation of composite obstacles in yellow soil rice-oil rotation farmland. Background Technology

[0002] Yellow soil is widely distributed in the subtropical mountainous and plateau regions of southern my country. Its formation environment is characterized by high temperature and humidity, and it has undergone intense leaching over a long period. Consequently, it generally exhibits characteristics such as high acidity, heavy texture, high clay content, weak cation exchange capacity, rapid decomposition of organic matter, and unstable aggregate structure. During agricultural cultivation, yellow soil areas are prone to forming a plow pan, leading to soil compaction and poor aeration, which severely restricts crop root growth and nutrient absorption efficiency.

[0003] The rice-oilseed rotation system is an important multiple cropping system in the Yellow Soil region that balances water-dryland rotation with economic benefits, possessing significant ecological and agronomic value. However, in years of rotation practice, the cultivated land in this region generally faces the mutual interference of three overlapping obstacles: "lean, compacted, and sticky." Specifically, "lean" is mainly manifested in low organic matter content in the topsoil, poor basic nutrients, and poor fertilizer retention and supply capacity; "compacted" is characterized by a shallow topsoil, high soil bulk density, low proportion of macropores, and poor permeability, easily forming a physical plow pan; and "sticky" stems from a high proportion of clay particles and poorly developed aggregate structure, resulting in heavy soil, high tillage resistance, and poor drainage.

[0004] Within the crop rotation cycle, the three types of obstacles mentioned above do not exist in isolation, but rather exacerbate each other through a negative linkage mechanism. For example, soil compaction restricts the vertical penetration of rice and rapeseed roots, thereby reducing the efficiency of rhizosphere nutrient utilization; in the reducing environment created by prolonged flooding during the rice season, the heavy clay soil slows down the redox process, which in turn accelerates the mineralization of organic matter and nutrient loss; while during the rapeseed season, if field drainage is poor, frequent heavy tillage and harrowing will further compact the soil, inducing structural deterioration and reduced aeration capacity, forming an irreversible vicious cycle year by year.

[0005] To address the aforementioned problems in yellow soil farmland, existing improvement technologies mostly focus on repairing single obstacles, such as applying organic fertilizer alone to increase organic matter, applying lime to adjust acidity, breaking up compaction through deep tillage, or using water-retaining agents to improve soil structure. However, these technologies often lack systematicity and coordination, making it difficult to comprehensively address the synergistic management needs of the "lean, compacted, and sticky" complex obstacles in yellow soil regions. Furthermore, some measures suffer from high costs, significant potential ecological risks, and operational complexity, thus limiting their practical application. Currently, there is a lack of an integrated ecological regulation pathway that can fully utilize the alternating operation characteristics of the rice and rapeseed seasons to achieve spatiotemporal staged regulation, coordinated material delivery, and multi-dimensional improvement of microorganisms, structure, and nutrients. Therefore, constructing an ecological regulation method for complex obstacles based on the temporal patterns of rice-rapeseed rotation and integrating the synergistic effects of multiple factors has become a key technical problem urgently needing to be solved. Summary of the Invention

[0006] This invention aims to address the problem that existing technologies are insufficient to coordinate the management of the complex obstacles of "lean, flat, and sticky" soil in yellow soil regions.

[0007] To achieve the above objectives, this invention proposes a method for synergistic reduction and ecological regulation of combined obstacles in yellow soil rice-oil rotation farmland, comprising the following steps performed in sequence: S1. Rice seasonal tillage layer conditioning: During the field preparation stage before rice transplanting, crushed straw from the previous crop, compound functional microbial agents, decomposed organic fertilizer and the first mineral conditioner are applied together into the tillage layer soil at a depth of 0-15 cm. S2. Construction of physical structure for rapeseed season: After rice harvest, deep loosening of the field to a depth of 20-25 cm is carried out, followed by the construction of ridge structure, in which the ridge width is 45-55 cm, the furrow width is 25-35 cm, and the ridge height is 20-25 cm. S3, Green manure intercropping: After the ridges are built and before the rapeseed is sown, the seeds of milkvetch are sown in the furrows and on the sides of the ridges, and then rapeseed is sown on the ridges. S4. Rapid fertilization after rapeseed harvest: After rapeseed harvest, crush the rapeseed straw and plow it into the soil layer 20-25 cm deep together with the growing milkvetch, and apply the second mineral conditioner at the same time. S5. Cyclic Operation: Repeat steps S1 to S4 to form a fixed operation cycle for rice-oilseed rotation between years.

[0008] Furthermore, in step S1, the composite functional microbial agent includes phosphorus-solubilizing microorganisms, potassium-solubilizing microorganisms, lignocellulose-degrading microorganisms, and facultative anaerobic growth-promoting microorganisms.

[0009] Further, in step S1, the amount of the decomposed organic fertilizer applied is 300-500 kg / mu; the first mineral conditioner is calcium magnesium phosphate fertilizer, and its application amount is 30-50 kg / mu.

[0010] Furthermore, in step S1, the interval between mixing the compound functional microbial agent with the straw and applying it to the soil does not exceed 24 hours.

[0011] Furthermore, in step S3, the sowing amount of the milkvetch seeds is 1.5~3 kg / mu, and the rapeseed is transplanted in double rows with a row spacing of 20~25 cm and a plant spacing of 15~20 cm.

[0012] Further, in step S4, after plowing and compaction, the soil moisture content is controlled at 80% to 100% of the field capacity and maintained at this moisture content for 7 to 15 days; the second mineral conditioner is lime, and its application rate is 40 to 60 kg / mu.

[0013] This invention also proposes a composite functional microbial agent for the above method, comprising: The microbial active component comprises phosphate-solubilizing microorganisms, potassium-solubilizing microorganisms, lignocellulose-degrading microorganisms, and facultative anaerobic growth-promoting microorganisms; wherein the ratio of viable counts of the phosphate-solubilizing microorganisms, potassium-solubilizing microorganisms, lignocellulose-degrading microorganisms, and facultative anaerobic growth-promoting microorganisms is (1~5):(1~3):(0.5~2):(0.5~2), and the total viable count of the microbial active component is ≥1×10⁻⁶. 8 CFU / g; and agricultural carriers.

[0014] Furthermore, the agricultural carrier has a double-layer encapsulation structure, with the inner carrier being at least one of corn cob powder, wheat bran, and bentonite, and the outer encapsulation material being at least one of sodium alginate, chitosan, and sodium humate.

[0015] Furthermore, the microbial active components are loaded sequentially in stages into the double-layered encapsulation structure; wherein the phosphate-solubilizing microorganisms and the potassium-solubilizing microorganisms are pre-mixed and loaded into the inner carrier, while the lignocellulose-degrading microorganisms and the facultative anaerobic growth-promoting microorganisms are loaded into the outer encapsulation material.

[0016] Furthermore, the lignocellulose-degrading microorganisms include white-rot fungi.

[0017] The present invention has the following beneficial effects: (1) Synergistic reduction of complex obstacles: This invention combines microorganisms, organic nutrients, mineral conditioning and physical structure improvement through a phased and multi-measure coupled regulation method. This achieves the simultaneous activation and replenishment of nutrients, while alleviating the compaction of the plow pan, stabilizing soil aggregates, and improving vertical infiltration and aeration conditions as well as soil acidity. It can systematically address the triple complex obstacles of "lean, compact, and sticky" soil, avoiding the drawbacks of individual measures working independently and neglecting other aspects.

[0018] (2) Simultaneous optimization of fertility and acidity: Through the synergistic effect of "compound functional microbial agent + decomposed organic fertilizer + calcium magnesium phosphate fertilizer / lime" in steps S1 and S4, the insoluble phosphorus and potassium elements in the soil are effectively activated, the humification process is accelerated, and the soil acidity is buffered. As a result, the organic matter content and available nutrient level in the topsoil are significantly improved, and the soil pH value is also stabilized towards the suitable range for crop growth.

[0019] (3) Significantly improves soil structure and promotes root growth: The deep loosening and ridge construction in step S2, combined with the green manure incorporation in steps S3 / S4, effectively increases the proportion of soil aggregates and aeration porosity, and reduces soil bulk density. This enhances the effective thickness of the tillage layer, drainage and water retention capacity, thereby promoting deeper root growth and the formation of a stronger root system.

[0020] (4) Promoting efficient straw conversion and improving heavy clay soil: The white rot fungi and growth-promoting microorganisms in the compound functional microbial agent produce a synergistic effect with the incorporation of milkvetch into the field under controlled release conditions, which accelerates the mineralization and humification process of straw and helps to form stable soil aggregates. This process improves the tillage performance, drainage and aeration of heavy clay soil, and effectively reduces the tillage resistance and root hypoxia risk caused by excessively "sticky" soil.

[0021] (5) Enhance the efficacy and stability of microbial agents through encapsulation and controlled release: The double-layer encapsulation and staged loading technology adopted by the compound functional microbial agents improves the early survival rate, colonization ability and continuous release effect of functional microbial communities in acidic and water-drought alternating field environments, reduces the risk of one-time inactivation or efficacy fluctuation of microbial agents, and thus ensures the stability and repeatability of technical effects.

[0022] (6) Achieve layered and time-based regulation to improve safety and controllability: By controlling the rapid application of microbial agents into the soil within 24 hours after mixing, and setting a short-term high water-holding window in step S4, and simultaneously arranging microbial agents and conditioners such as lime in layers in the vertical direction of the soil, the acidification effect and microbial activity are balanced, reducing the ecological risks and application costs that may be caused by direct application of large doses or strong alkaline materials. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the ecological regulation method of the present invention; Figure 2 A schematic diagram of the double-layer encapsulation structure of a composite functional microbial agent; Figure 3 Normalized radar chart of key indicators for multi-processor groups (B1=1.00). Detailed Implementation

[0024] To facilitate understanding and implementation of the present invention by those skilled in the art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are used to illustrate the present invention and do not constitute a limitation on the scope defined by the claims. Any equivalent substitutions or modifications made without departing from the spirit of the present invention should be considered to fall within the protection scope of the present invention. Example 1

[0025] This embodiment provides a method for synergistic reduction and ecological regulation of combined obstacles in yellow soil rice-oilse rotation farmland, specifically including the following steps S1 to S5: S1. Rice Season Tillage Conditioning: Seven days before rice transplanting, prepare the field. Crush the previous rapeseed straw using machinery (length not exceeding 5 cm) and return it entirely to the field. Simultaneously, apply 3 kg / mu of compound functional microbial inoculant, 350 kg / mu of well-rotted organic fertilizer, and 40 kg / mu of calcium magnesium phosphate fertilizer as the primary mineral conditioner. All materials should be incorporated into the 0-15 cm deep topsoil layer using a rotary tiller within 24 hours of application. The recommended rotary tiller speed is 1.5 km / h to ensure even mixing of the materials with the soil.

[0026] S2. Construction of physical structure for rapeseed season: After rice harvesting, the field is dried and deep-loosened within 3-7 days, with a deep-loosening depth of 22 cm. Subsequently, a ridge structure is constructed with the following parameters: ridge width 50 cm, furrow width 30 cm, and ridge height 22 cm.

[0027] S3. Green manure intercropping: After ridging and before rapeseed sowing, sow milkvetch seeds in the furrows and along the sides of the ridges at a rate of 2.0 kg / mu. Cover with about 1 cm of soil and compact. Then, sow rapeseed in double rows on the ridge tops, with a row spacing of 20 cm and a plant spacing of 15 cm, at a rate of approximately 0.3 kg / mu and a sowing depth of 1.5 cm. After sowing, compact once and irrigate appropriately.

[0028] S4. Rapid Fertilization After Rapeseed Harvest: After rapeseed harvest, crush its straw together with the above-ground parts of the growing milkvetch, and then plow it into the soil to a depth of 20-25 cm. Simultaneously, apply lime as a second mineral conditioner at a rate of 50 kg / mu. Immediately after plowing, perform shallow irrigation to maintain the soil moisture content at 85%-95% of field capacity, and maintain this humidity level for 10 consecutive days to promote the decomposition of straw and green manure.

[0029] S5. Cyclic Operation: After completing soil conditioning for one rapeseed crop, the next rice planting season begins, and steps S1 to S4 above are repeated. Through this inter-year cyclical operation, a fixed ecological regulation process for rice-rapeseed rotation is formed. Example 2

[0030] This embodiment provides a compound functional microbial agent suitable for rice-oilseed rotation systems in yellow soil, and elaborates on its microbial composition, carrier structure, preparation method and application.

[0031] (1) Composition of active microbial components: This microbial agent contains the following four types of functional microorganisms, mixed in a viable count ratio of (3:2:1:1), with a total viable count ≥1×10⁻⁶. 8 CFU / g: Phosphate-solubilizing microorganisms: Bacillus megaterium, accession number CCTCC AB209224, accounting for 3 samples; Potassium-solubilizing microorganisms: Bacillus mucilaginosus, accession number CCTCC KB20082790, accounting for 2 samples; Lignocellulose degrading microorganism: white-rot fungus (Phanerochaete chrysosporium), accession number CGMCC 3.7212, accounting for 1 part; Facultative anaerobic growth-promoting microorganism: Bacillus coagulans, accession number CGMCC1.10823, accounting for 1 copy.

[0032] The strains mentioned above were derived from standard strains or equivalent strains from preservation institutions, but are not limited to these. After activation by slant culture and liquid propagation, the bacterial cells were collected by centrifugation, resulting in viable cell concentrations all exceeding 1 × 10⁻⁶. 9 The bacterial suspension at CFU / mL was then mixed according to the above ratio for subsequent preparation of solid bacterial agents.

[0033] (2) Design of carrier and double-layer embedding structure The bacterial agent adopts a double-layer encapsulation structure, specifically as follows: Inner carrier: It is made of corn cob powder and bentonite mixed at a mass ratio of 2:1, with a particle size controlled at 60 mesh (about 250 μm) and a moisture content controlled at 8%~10%. This inner layer is used to support phosphorus-solubilizing microorganisms and potassium-solubilizing microorganisms.

[0034] The outer controlled-release layer is composed of a 2.0% (w / v) solution prepared by mixing sodium alginate and chitosan in a 1:1 mass ratio. This outer solution is inoculated with lignocellulose-degrading microorganisms and facultative anaerobic growth-promoting microorganisms.

[0035] Encapsulation and Shaping: During the encapsulation process, a 2.5% CaCl2 solution was added dropwise for crosslinking over a period of 12 minutes to form a stable gel layer. The mass ratio of the inner and outer layer materials was 1:0.8. The encapsulated particles were then hot-air dried at 40°C until the moisture content was ≤10%, ultimately yielding double-layered encapsulated particles with a diameter of 1.5~2.5 mm, uniform color, and intact surface.

[0036] (3) Sequential loading and preparation process flow: The propagated Bacillus megaterium and Bacillus mucilaginosus bacterial solutions were mixed at a ratio of 3:2 and loaded onto the inner carrier by spraying. Then, the mixture was stirred for 20 minutes using a roller mixer and allowed to air dry naturally until the moisture content was about 8%. White-rot fungi and Bacillus coagulans were mixed into a 2.0% sodium alginate-chitosan solution and stirred until homogeneous. The carrier particles loaded with the inner layer of bacterial agent were dropped into the outer layer embedding solution containing bacteria, and then transferred to a 2.5% CaCl2 solution for cross-linking and solidification. After sieving, the mixture was dried and shaped at 40°C to obtain the finished composite functional microbial agent.

[0037] (4) Storage and application methods The finished bacterial agent can be stably stored at 4°C for 6 months with a viable bacteria retention rate of no less than 90%.

[0038] Under water immersion conditions at 25°C, the bacterial agent exhibits slow-release characteristics, with a live bacteria release rate of approximately 26% within 24 hours and a cumulative release rate of approximately 41% within 72 hours.

[0039] When applying, mix the inoculant with well-rotted organic fertilizer or crushed straw at a rate of 3 kg / mu, and evenly plow it into the topsoil layer at a depth of 0-15 cm within 24 hours before field preparation.

[0040] After application, the soil should be kept moist to facilitate the rapid activation and colonization of functional microorganisms.

[0041] Comparative Example 1 This comparative example is consistent with Example 1 in key aspects such as crop type, overall operation process, fertilization method, tillage depth and green manure incorporation management. The only difference is that no microbial agents are applied in step S1.

[0042] The specific settings are as follows: Straw treatment: The type of straw used and its crushing length are the same as in Example 1, that is, the previous crop of rapeseed straw, and the crushing length is ≤5 cm.

[0043] Fertilizer application: The application rate of well-rotted organic fertilizer is 350 kg / mu, and the application rate of the first mineral conditioner calcium magnesium phosphate fertilizer is 40 kg / mu.

[0044] Microbial agent setup: In step S1 of this comparative example, no compound functional microbial agents were applied, nor were other types of microbial products used as substitutes.

[0045] Other steps: All operating parameters and procedures in steps S2 to S5 are exactly the same as in Example 1.

[0046] Comparative Example 2 In step S1 of this comparative example, only a single bacterial species, Bacillus megaterium powder, was applied, and the powder was not encapsulated with any carrier. Apart from this, the rest of the operation process was completely consistent with that of Example 1.

[0047] In this comparative example, the application of Bacillus megaterium was based on the viable count, ensuring that the total viable count (CFU / acre) added was equal to the viable count of Bacillus megaterium in the compound microbial agent of Example 1. The specific calculation steps are as follows: a) Determine the total viable count of the compound functional microbial agent used in Example 1 (unit: CFU / g); b) Based on the ratio of live bacteria in the compound microbial agent (3:2:1:1), the proportion of Bacillus megaterium was calculated to be 3 / 7, and then the target number of live bacteria added for Bacillus megaterium in this comparative example (unit: CFU / acre) was obtained. c) Calculate the required amount of powder to be applied based on the measured viable cell concentration (unit: CFU / g) of the single-strain powder used in this comparative example, so as to achieve the equivalent number of viable cells added as in Example 1.

[0048] Except for the difference in the application method of the microbial agent mentioned above, all other operating parameters of this comparative example are consistent with those of Example 1.

[0049] Comparative Example 3 In step S1 of this comparative example, a mixed powder containing four types of functional microorganisms was applied, with a viable count ratio of phosphate-solubilizing microorganisms: potassium-solubilizing microorganisms: lignocellulose-degrading microorganisms: facultative anaerobic growth-promoting microorganisms = 3:2:1:1. This mixed powder did not use any encapsulating carrier. Apart from this, the remaining procedures were completely consistent with Example 1.

[0050] Comparative Example 4 The operation of steps S1, S2, S4 and S5 in this comparative example is consistent with that in Example 1. The difference is that step S3 is cancelled, that is, the intercropping and subsequent turning of milkvetch are not carried out.

[0051] To eliminate interference from differences in material inputs and ensure the fairness of the comparison, this comparative example implements equal carbon / nitrogen compensation in step S4, as follows: The dry matter mass of the aboveground parts of milkvetch measured in Example 1 was used as the target amount to be compensated in this comparative example.

[0052] In step S4 of this comparative example, according to the target amount mentioned above, an equal amount of crushed rice straw or well-rotted farmyard manure is added and mixed with rapeseed straw and pressed into the soil layer at a depth of 20-25 cm.

[0053] Comparative Example 5 The operation of this comparative example in steps S1 to S3 is consistent with that in Example 1, except that lime is not applied in step S4.

[0054] To accurately assess and eliminate the impact of soil acidity differences on the final observed indicators, the following correction scheme was set up for this comparative example: On days 3, 7, and 15 after step S4, topsoil samples were collected from a depth of 0–20 cm, and their pH values ​​were measured. In subsequent statistical analysis, the measured soil pH values ​​were included as covariates in the statistical model to correct for the potential impact of acidity differences on the experimental results.

[0055] To verify the comprehensive effect of the ecological regulation method for synergistic reduction of complex obstacles in yellow soil rice-oil rotation farmland described in this invention on the control of "lean, flat, and sticky" complex obstacles, a small-to-medium-sized field experiment was set up in a typical yellow soil area, and comparative observations were conducted for two consecutive rice-oil rotation cycles.

[0056] (1) Basic information of the experiment: Soil background: The test site is a typical yellow soil, which is obviously acidic, with a pH value (soil-water ratio of 1:2.5) of about 5.0 and a clay content of about 38%.

[0057] The tested crops were: rice variety "Xiangzaoxian 45"; rapeseed variety "Zhongyouza 501"; and intercropped green manure variety "Wanzi 1" (purple clover).

[0058] (2) Experimental design: A randomized block design was adopted, with 10 treatment groups, 3 replicates per group, and a total of 30 plots, each with an area of ​​50 m². 30 cm ditches were set between plots to prevent nutrient or microbial migration; each treatment group completed its corresponding procedures on the same day. All application dosages were measured on a dry basis; viable cell counts were converted to CFU / acre using the dilution plating method for equivalent comparison; straw crushing length was ≤5 cm; the depth of incorporation into the soil was checked at ≥10 sampling points, with a plot pass rate ≥90%. The experimental groupings are shown in the table below: Table 1. Treatment Group Numbers and Brief Descriptions of the Treatment Plan

[0059] (3) Main observation indicators and measurement methods Soil physicochemical properties: Soil samples were collected within 7 days after crop harvest in each crop rotation cycle for testing. Indicators included: soil organic matter (g / kg), available nitrogen / phosphorus / potassium (mg / kg), pH value, and soil bulk density (g / cm³). 3 The content of water-stable aggregates >0.25mm (%) and the air porosity (%).

[0060] Crop growth and yield: The observation indicators include seedling height, progress of key growth stages, and dry weight per plant, and the actual yield per unit area (kg / mu) is measured at maturity.

[0061] Root morphology and topsoil structure: Measurement of root length density (cm / cm) 3 ), root-to-shoot ratio (above-ground dry matter / root dry matter), maximum root penetration depth, and effective tillage layer thickness.

[0062] Microbial characteristics and decomposition process (for T1, C1, C2, C3, and C5 treatment groups): The total amount of soil microorganisms and the number of functional microbial communities such as phosphate-solubilizing bacteria and potassium-solubilizing bacteria (CFU / g) were measured; the straw decomposition rate was assessed by calculating the reduction rate of straw residue dry matter.

[0063] Dynamic monitoring of key processes: Days 3, 7, and 15 after step S4: pH values ​​of the 0-20 cm soil layer in comparative example C5 and implementation group T1 were measured; Day 5 after straw plowing: soil microbial activity and the number of functional bacteria were measured; During step S4: the moisture content of the 0-20 cm soil layer was monitored and converted into a relative percentage of field capacity to verify the implementation of the water management system.

[0064] (4) Monitoring cycle and sample collection and processing Experiment period: The experiment lasted from September 2022 (the start of the first rice season) to June 2024 (the harvest of the second rapeseed season).

[0065] Sampling nodes: Soil samples are collected immediately after each crop harvest; plant samples and soil samples are collected simultaneously before and after step S3; process sampling is carried out at the above-mentioned preset time points after step S4.

[0066] Sample processing and testing methods: Soil samples were collected using the "five-point plum blossom method" and then air-dried before being sieved through a 2 mm sieve. Root samples were collected in layers along the vertical soil profile at 0–10 cm, 10–20 cm, and 20–30 cm depths. Soil bulk density was determined using the ring cutter method. The content of 0.25 mm water-stable aggregates was determined using the wet sieving method. Soil aeration porosity was calculated using the volumetric method. Root length density was determined using stratified root washing combined with image analysis software. Field water holding capacity was converted from the measured moisture content of the 0–20 cm soil layer. The viable microbial count was counted using the dilution plating method and converted to CFU / acre.

[0067] Tables 2-5 summarize the analysis of data collected after two consecutive rice-oilseed crop rotations. The specific calculation results are as follows: Table 2 Soil physicochemical properties (after the second round, 0~20 cm, n=3, mean ± SD) T1 23.8±0.6 6.21±0.05 95±4 31.5±1.2 121±5 1.31±0.02 48.7±1.3 18.5±0.8 T2 23.3±0.5 6.09±0.06 90±3 27.3±1.1 112±4 1.35±0.02 42.6±1.2 17.2±0.7 T3 22.8±0.5 5.92±0.06 88±4 26.8±1.0 109±4 1.37±0.03 41.9±1.1 16.8±0.7 C1 21.2±0.4 5.40±0.05 75±3 23.7±0.9 93±4 1.42±0.03 36.2±1.0 14.0±0.6 C2 21.5±0.5 5.60±0.05 78±3 25.2±1.0 98±4 1.41±0.03 37.5±1.1 14.6±0.6 C3 22.0±0.5 5.75±0.05 82±3 26.1±1.0 105±4 1.39±0.02 39.8±1.1 15.2±0.6 C4 21.4±0.4 5.32±0.05 74±3 21.9±0.9 89±3 1.44±0.03 35.6±1.0 13.8±0.6 C5 21.6±0.5 5.56±0.05 77±3 24.1±0.9 100±4 1.41±0.03 36.8±1.0 14.4±0.6 B1 19.8±0.4 5.05±0.04 70±3 19.8±0.8 85±3 1.47±0.03 33.1±0.9 13.0±0.5 B2 20.3±0.4 5.08±0.04 72±3 20.4±0.8 86±3 1.45±0.03 34.0±1.0 13.5±0.5 The data listed in Table 2 correspond to two obstacles: "lean" and "board". On the one hand, the improvement in nutrient content and pH indicates that the problem of barrenness and acidification has been alleviated; on the other hand, the decrease in bulk density and the increase in the proportion of aggregates indicate that the topsoil is transitioning from dense to loose.

[0068] Table 3 Crop yield and root index (means of two rounds, n=3, mean ± SD) T1 622.5±12.8 148.0±5.0 2.43±0.08 5.8±0.2 29.5±0.8 22.0±0.5 T2 601.2±11.9 145.0±5.0 2.31±0.07 5.3±0.2 28.3±0.8 21.0±0.5 T3 595.6±11.4 143.0±5.0 2.24±0.07 5.2±0.2 27.8±0.7 20.5±0.5 C1 538.4±10.2 136.0±4.8 1.95±0.06 4.7±0.2 24.0±0.7 18.0±0.4 C2 548.6±10.5 138.0±4.8 2.03±0.06 4.9±0.2 24.6±0.7 18.5±0.4 C3 557.5±10.8 141.0±4.9 2.10±0.06 5.0±0.2 25.2±0.7 19.0±0.4 C4 532.5±10.0 135.0±4.8 1.89±0.05 4.6±0.2 23.8±0.6 17.8±0.4 C5 540.3±10.1 137.0±4.8 1.97±0.06 4.8±0.2 24.3±0.7 18.2±0.4 B1 507.2±9.6 126.0±4.5 1.82±0.05 4.5±0.1 22.5±0.6 17.0±0.4 B2 518.0±9.8 129.0±4.6 1.86±0.05 4.6±0.1 23.1±0.6 17.5±0.4 Table 3 further illustrates that the above-mentioned improvements in the topsoil have been transmitted to crop root distribution and yield levels, that is, from soil improvement to actual output.

[0069] Table 4 Functional microorganisms and decomposition processes T1 8.5±0.5 6.2±0.4 5.4±0.3 62±4 41.8±1.6 C1 4.8±0.3 3.0±0.2 2.6±0.2 28±3 24.6±1.4 C2 6.1±0.4 4.8±0.3 2.7±0.2 34±3 31.2±1.3 C3 7.2±0.4 5.6±0.3 4.6±0.3 48±3 36.5±1.5 C5 6.9±0.4 5.1±0.3 4.2±0.3 45±3 34.9±1.4 The results of microorganisms and decomposition rates listed in Table 4 correspond to the problem of "stickiness," that is, the slow decomposition of straw and the easy formation of sticky and heavy slabs after returning it to the field. The compound microbial agent accelerates the decomposition of the returned material, so that the surface residue can be transformed into a source of nutrients that can be used by crops more quickly, providing a continuous source for subsequent loosening of the topsoil and replenishment of organic matter.

[0070] Table 5 Soil pH at different time points after compaction Group T1 6.05±0.06 6.18±0.05 6.21±0.05 Group C5 5.34±0.04 5.38±0.04 5.45±0.05 The data in Table 5 show that by turning over the soil and adjusting the lime-moisture ratio, the pH of acidic yellow soil can be brought back to a suitable range in a short period of time, avoiding further aggravation of the "lean" and "sticky" problems by acidification, and laying the foundation for maintaining a stable topsoil environment in subsequent crop rotation periods.

[0071] The experimental data from each group shown in Table 2-5 are summarized as follows: (1) It enhanced the improvement effect on the "lean" yellow soil. Compared with B1, the soil organic matter content of the implementation group T1 increased from 19.8 g / kg to 23.8 g / kg (an increase of 20%), the available phosphorus content increased from 19.8 mg / kg to 31.5 mg / kg (an increase of 59%), the available potassium content increased from 85 mg / kg to 121 mg / kg (an increase of 42%), and the soil pH value increased from 5.05 to 6.21 (an increase of 1.16 units). This illustrates the synergistic effect of "compound encapsulated microbial agent + decomposed organic fertilizer + calcium magnesium phosphate fertilizer" in step S1: phosphorus / potassium solubilizing microorganisms promoted the activation of insoluble nutrients, white rot fungi accelerated the decomposition and humification process of straw, and lime and calcium magnesium phosphate fertilizer provided effective acidity buffer and phosphorus source. At the same time, "application within 24 hours after mixing the microbial agent" and "maintaining high soil moisture content for 7-15 days" in step S4 together provided a guarantee for the early activation and colonization of microorganisms.

[0072] (2) It enhanced the improvement effect on the "slab" of yellow soil. Compared with B1, the soil bulk density of the implementation group T1 was 1.47 g / cm³. 3 Reduced to 1.31 g / cm³ 3 (A decrease of 11%), the proportion of water-stable aggregates >0.25 mm increased from 33.1% to 48.7% (an increase of 47%), soil aeration porosity increased from 13.0% to 18.5% (an increase of 42%), and correspondingly, crop root length density increased to 2.43 cm / cm². 3 The root penetration depth reached 29.5 cm, and the effective tillage layer thickness increased to 22.0 cm. This indicates that the combined effect of "deep loosening and ridge structure construction" in step S2 and "green manure incorporation and microbial burial" in steps S3 / S4 alleviated the compactness of the tillage layer and plow pan, improved the aggregate structure and porosity, thereby enhancing the root penetration ability and the effective tillage layer thickness.

[0073] (3) It enhanced the improvement effect on the "stickiness" of yellow soil. In the process monitoring after step S4, the implementation group T1 showed better biological activity. Its total soil microbial count reached 8.5 × 10⁻⁶. 7The CFU / g, laccase activity reached 62 U / g, and the straw decomposition rate after 21 days reached 41.8%, all of which were significantly higher than those of control group C1 and control group C2, which only applied a single phosphate-solubilizing bacterium. The accelerated decomposition rate and the increased proportion of large aggregates worked together to improve the microstructure and drainage and aeration performance of heavy clay soils, thereby effectively alleviating the problems caused by excessively "sticky" soil.

[0074] (4) Analysis of the synergy between output performance and technical solutions In implementation group T1, the rice yield reached 622.5 kg / mu (an increase of 22.7% compared to B1), and the rapeseed yield reached 148.0 kg / mu (an increase of 17.5% compared to B1). With an equivalent number of viable bacteria, Comparative Example C3 outperformed Comparative Example C2 (which only had unencapsulated phosphate-solubilizing bacteria) in multiple indicators, indicating that the coupling of multifunctional microbial communities produced a synergistic effect. Although Comparative Example C3 outperformed C2 in various indicators, it was still lower than that of Implementation Group T1, indicating that the double-layer encapsulation structure significantly improved the survival and sustained effectiveness of functional microbial communities in acidic yellow soil and water-dry rotation environments. Even with equal carbon / nitrogen compensation in Comparative Example C4, its improvement effect was still lower than that of T1, proving that the biological functions of milkvetch in improving soil structure and promoting microbial interactions cannot be completely replaced. The soil pH, available phosphorus content, and crop yield of Comparative Example C5 were significantly lower than those of T1, verifying the importance of lime acidification in activating nutrients and indirectly improving soil obstacles. The effects of Implementation Groups T2 and T3 both showed a certain degree of decline, indicating that the dosage and timing of application are necessary to ensure the final effect.

[0075] The key technical path of this invention is: "compound encapsulated microbial agent + precise agricultural timing window of S1 / S4 + deep loosening and ridge structure construction of S2 + intercropping and incorporation of purple clover in S3 + stratified regulation of calcium magnesium phosphate fertilizer / lime". Through the chain reaction of "nutrient activation → organic matter accumulation and decomposition → aggregate formation and structural improvement → root deepening and thickening of the tillage layer", the synergistic treatment of the triple combination obstacles of "lean, flat and sticky" is achieved.

[0076] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for synergistic reduction and ecological regulation of combined obstacles in yellow soil rice-oilseed rotation farmland, characterized in that, The following steps are performed in sequence: S1. Rice seasonal tillage layer conditioning: During the field preparation stage before rice transplanting, crushed straw from the previous crop, compound functional microbial agents, decomposed organic fertilizer and the first mineral conditioner are applied together into the tillage layer soil at a depth of 0-15 cm. The composite functional microbial agent comprises microbial active components and an agricultural carrier. The microbial active components include phosphorus-solubilizing microorganisms, potassium-solubilizing microorganisms, lignocellulose-degrading microorganisms, and facultative anaerobic growth-promoting microorganisms. The ratio of viable counts of the phosphorus-solubilizing microorganisms, potassium-solubilizing microorganisms, lignocellulose-degrading microorganisms, and facultative anaerobic growth-promoting microorganisms is (1~5):(1~3):(0.5~2):(0.5~2), and the total viable count of the microbial active components is ≥1×10⁻⁶. 8 CFU / g; The agricultural carrier has a double-layered embedded structure. The phosphorus-solubilizing microorganisms and the potassium-solubilizing microorganisms are pre-mixed and loaded in the inner carrier layer, while the lignocellulose-degrading microorganisms and the facultative anaerobic growth-promoting microorganisms are loaded in the outer embedded material. S2. Construction of physical structure for rapeseed season: After rice harvest, deep loosening of the field to a depth of 20-25 cm is carried out, followed by the construction of ridge structure, in which the ridge width is 45-55 cm, the furrow width is 25-35 cm, and the ridge height is 20-25 cm. S3, Green manure intercropping: After the ridges are built and before the rapeseed is sown, the seeds of milkvetch are sown in the furrows and on the sides of the ridges, and then rapeseed is sown on the ridges. S4. Rapid fertilization after rapeseed harvest: After rapeseed harvest, crush the rapeseed stalks and plow them into the soil to a depth of 20-25 cm along with milkvetch, which is still in the growth stage. At the same time, apply lime. After plowing, control the soil moisture content to 80%-100% of field capacity and maintain this moisture content for 7-15 days. The amount of lime applied is 40-60 kg / mu. S5. Cyclic Operation: Repeat steps S1 to S4 to form a fixed operation cycle for rice-oilseed rotation between years.

2. The method according to claim 1, characterized in that, In step S1, the amount of the decomposed organic fertilizer applied is 300-500 kg / mu; the first mineral conditioner is calcium magnesium phosphate fertilizer, and its application rate is 30-50 kg / mu.

3. The method according to claim 1, characterized in that, In step S1, the interval between mixing the compound functional microbial agent with straw and applying it to the soil shall not exceed 24 hours.

4. The method according to claim 1, characterized in that, In step S3, the sowing rate of the milkvetch seeds is 1.5~3 kg / mu, and the rapeseed is transplanted in double rows with a row spacing of 20~25 cm and a plant spacing of 15~20 cm.

5. The method according to claim 1, characterized in that, The inner carrier is at least one of corn cob powder, wheat bran and bentonite, and the outer encapsulation material is at least one of sodium alginate, chitosan and sodium humate.

6. The method according to claim 1, characterized in that, The lignocellulose-degrading microorganisms include white-rot fungi.

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