Ecological regulation and control method for synergistically reducing composite obstacles of yellow soil rice-oil rotation cropland

Abstract

The invention relates to the technical field of soil ecological restoration and farmland cultivation management, in particular to an ecological regulation and control method for synergistically reducing compound obstacles of yellow soil rice-oil rotation cropland. The method is implemented by stages according to agricultural time: S1, mixing crushed straw, a composite functional microbial agent, a decomposed organic fertilizer and a calcium magnesium phosphate fertilizer into 0-15cm before rice transplanting; s2, after the rice is harvested, deep scarification is conducted by 20-25 cm, and a ridge culture structure is constructed; s3, interplanting astragalus sinicus after the ridges are built and before the oilseed rape is sown; s4, after the oilseed rape is harvested, the oilseed rape straw and the astragalus smicus are turned and pressed by 20-25 cm, lime is applied, and high water holding capacity is maintained in a short time; and S5, interannual circulation. Through microorganism-structure-nutrient coupling, thin, plate and sticky yellow soil is relieved synergistically, aggregate and air permeability are improved, root growth is promoted, and stable yield is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of soil ecological restoration and farmland management, and particularly relates to a method for reducing ecological regulation of compound obstacles of yellow soil paddy-oil rotation farmland. BACKGROUND

[0002] Yellow soil is widely distributed in the subtropical mountainous and plateau regions of southern China, and its formation environment has the characteristics of high temperature and high humidity, and has long been subjected to strong leaching. Therefore, it generally shows strong acidity, heavy texture, high clay content, weak cation exchange capacity, rapid organic matter decomposition, and unstable aggregate structure. In the process of agricultural cultivation, plough pan is easily formed in the yellow soil region, and problems such as soil compaction and poor aeration occur, which seriously restricts the root growth and nutrient absorption efficiency of crops.

[0003] The paddy-oil rotation mode is an important multiple cropping system in the yellow soil region, which takes into account the water and dry rotation and economic benefits, and has significant ecological and agronomic value. However, in the years of rotation practice, the farmland in this region is generally faced with the mutual interference of the three compound obstacles of "thin, hard, and sticky". Specifically, "thin" mainly shows low organic matter content in the plough layer, poor basic nutrients, poor fertilizer retention and supply capacity; "hard" reflects shallow plough layer, high soil bulk density, low proportion of large pores, weak permeability, and easy formation of physical plough pan; "sticky" is due to high proportion of soil clay and poor development of aggregate structure, resulting in heavy soil, high tillage resistance, poor drainage.

[0004] During the rotation period, the above three types of obstacles do not exist in isolation, but are mutually exacerbated through negative linkage mechanisms. For example, soil compaction limits the vertical penetration of rice and oilseed rape root systems, thereby reducing the utilization efficiency of rhizosphere nutrients; in the reducing environment formed by long-term flooding in the rice season, heavy soil leads to slow oxidation-reduction process, thereby accelerating the mineralization of organic matter and nutrient loss; and in the oilseed rape season, if the field drainage is poor, frequent heavy tillage and harrowing will further compact the soil, inducing structure deterioration and aeration capacity decline, forming a vicious cycle that is difficult to reverse year after year.

[0005] For the above problems of yellow soil, the existing improvement technology focuses on the repair of single obstacle, such as separately applying organic fertilizer to improve organic matter, applying lime to adjust acidity, breaking hardening through deep loosening operation, or using water retaining agent to improve soil structure. However, such technology often lacks systematicness and coupling, and is difficult to comprehensively address the collaborative management needs of the complex obstacles of "thin, hardening, and sticky" in yellow soil area. At the same time, some measures have problems such as high cost, potential ecological risk, and complex operation, and thus are limited in actual promotion. At present, there is still a lack of an integrated ecological regulation path that can fully utilize the alternating operation characteristics of rice and rape seasons, realize temporal and spatial phased regulation, and material collaborative delivery, and multi-dimensional improvement of microorganisms-structure-nutrients. Therefore, it has become a key technical problem to be solved to construct a complex obstacle ecological regulation method based on the time sequence law of rice and rape rotation and the synergistic effect of multiple factors. SUMMARY

[0006] The present application aims to solve the problem that the prior art is difficult to comprehensively address the collaborative management needs of the complex obstacles of "thin, hardening, and sticky" in yellow soil area.

[0007] To achieve the above-mentioned purpose, the present application provides a method for ecological regulation of complex obstacle reduction in yellow soil rice and rape rotation farmland, comprising the following sequentially executed steps: S1, rice season tillage layer conditioning: before rice transplanting, the crushed straw of the previous crop, the composite functional microbial agent, the matured organic fertilizer and the first mineral conditioner are applied to the 0-15 cm deep tillage soil layer; S2, physical structure construction in rape season: after rice harvesting, deep loosening operation with a depth of 20-25 cm is performed on the field, and then ridge culture structure is constructed, wherein the ridge width is 45-55 cm, the ditch width is 25-35 cm, and the ridge height is 20-25 cm; S3, green manure intercropping: after the ridge is built, the purple milk vetch seeds are sown in the ridge ditch and the ridge side before the rape is sown, and then the rape is sown on the ridge; S4, stubble rapid fertilization: after the rape is harvested, the rape straw is crushed and mixed with the growing purple milk vetch, and then the mixture is incorporated into the 20-25 cm deep soil layer, and the second mineral conditioner is applied; S5, cycle operation: steps S1 to S4 are repeated to form a fixed operation cycle between years of rice and rape rotation.

[0008] Further, 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 application amount of the mature organic fertilizer is 300-500 kg / mu; and the first mineral conditioner is calcium magnesium phosphate, and the application amount thereof is 30-50 kg / mu.

[0010] Further, in step S1, the interval time from mixing with the straw to being applied into the soil of the composite functional microbial agent is not more than 24 hours.

[0011] Further, in step S3, the seeding amount of the Astragalus sinicus seeds is 1.5-3 kg / mu, and the rape 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 the turning, the soil water content is controlled to be 80%-100% of the field water holding capacity, and the water content is maintained for 7-15 days; and the second mineral conditioner is lime, and the application amount thereof is 40-60 kg / mu.

[0013] The application further provides a composite functional microbial agent for the method. The microbial active component comprises phosphorus solubilizing microorganisms, potassium solubilizing microorganisms, lignocellulose-degrading microorganisms and facultative anaerobic growth-promoting microorganisms; wherein the ratio of the viable bacterial count of the phosphorus solubilizing microorganisms, the potassium solubilizing microorganisms, the lignocellulose-degrading microorganisms and the facultative anaerobic growth-promoting microorganisms is (1-5) :(1-3) :(0.5-2) :(0.5-2), and the total viable bacterial count of the microbial active component is ≥1×10 8 CFU / g; and an agricultural carrier.

[0014] Further, the agricultural carrier is a double-layer embedding structure, the inner layer carrier of which is at least one of corn cob powder, wheat bran and bentonite, and the outer layer embedding material of which is at least one of sodium alginate, chitosan and sodium humate.

[0015] Further, the microbial active component is loaded in the double-layer embedding structure in a staged sequence; wherein the phosphorus solubilizing microorganisms and the potassium solubilizing microorganisms are pre-mixed and loaded in the inner layer carrier, and the lignocellulose-degrading microorganisms and the facultative anaerobic growth-promoting microorganisms are loaded in the outer layer embedding material.

[0016] Further, the lignocellulose-degrading microorganisms comprise white rot fungi.

[0017] The application has the following beneficial effects: (1) Synergistic reduction of complex obstacles: The present application realizes the simultaneous activation and replenishment of nutrients, the relief of plough pan density, the stabilization of soil aggregates, and the simultaneous improvement of vertical permeability and aeration conditions and soil acidity by organically combining microorganisms, organic nutrients, mineral conditioning and physical structure improvement through phased and multi-measure coupling regulation. It can systematically deal with the threefold complex obstacles of "thin, board, and sticky", avoiding the drawbacks of single measures.

[0018] (2) Simultaneous optimization of fertility and acidity: Through the synergistic effect of "compound functional microbial agent + mature organic fertilizer + calcium magnesium phosphate fertilizer / lime" in steps S1 and S4, the difficult-to-dissolve 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 the level of available nutrients in the plough layer are significantly improved, and the soil pH value also tends to stabilize in the suitable range for crop growth.

[0019] (3) Significant improvement of soil structure and promotion of root growth: The deep tillage of step S2 and the ridge structure construction, combined with the green manure incorporation of steps S3 / S4, effectively increase the proportion of soil aggregates and the aeration porosity, and reduce the soil bulk density. This enhances the effective thickness, seepage and water storage capacity of the plough layer, thereby promoting the downward penetration of crop roots and forming a more robust root group.

[0020] (4) Promote efficient conversion of straw and improve heavy clay soil: White rot fungi and growth-promoting microorganisms in the compound functional microbial agent produce a synergistic effect with the incorporation of Chinese milk vetch under controlled release conditions, accelerating the mineralization and humification process of straw, and helping to form stable soil aggregates. This process improves the tillage performance, drainage and aeration of heavy clay soil, effectively reducing the tillage resistance and root hypoxia risk caused by excessive "stickiness" of the soil.

[0021] (5) Improve the persistence and stability of the microbial agent by embedding and controlled release: The double-embedded and phased loading technology of the compound functional microbial agent improves the early survival rate, colonization ability and sustained release effect of the functional flora in the acid and water-flood alternating field environment, reduces the risk of one-time inactivation or fluctuation of the microbial agent, and thus ensures the stability and repeatability of the technical effect.

[0022] (6) Realize layered and time-controlled regulation to improve safety and controllability: By controlling the rapid application of the microbial agent to the soil within 24 hours after mixing, setting a short-term high soil water holding window in step S4, and arranging the microbial agent and conditioning agents such as lime in layers in the vertical direction of the soil, the acid regulation effect and microbial activity are considered, and the ecological risk and application cost caused by direct application of large doses or strong alkaline materials are reduced. BRIEF DESCRIPTION OF DRAWINGS

[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, stubble rapid fertilization: after the rape is harvested, the straw is crushed together with the above-ground part of the Chinese milk vetch in the growth period, and then is turned into the soil layer of 20-25 cm. At the same time, lime is applied as the second mineral conditioner, and the amount is 50 kg / mu. After the turning operation, shallow irrigation is immediately carried out, so that the soil water content is maintained at 85%-95% of the field water holding capacity, and the humidity condition is continuously maintained for 10 days to promote the humification process of the straw and green manure.

[0029] S5, cycle operation: after completing the soil conditioning of one rape stubble, the next rice planting season is entered, and the steps S1-S4 are repeatedly executed. Through the inter-annual cycle operation, a fixed rice-oil rotation ecological regulation process is formed. Example 2

[0030] The present embodiment provides a composite functional microbial agent suitable for a yellow soil rice-oil rotation system, and specifically describes the microbial composition, carrier structure, preparation method and application mode thereof.

[0031] (1) Microbial active component composition: The microbial agent contains the following four types of functional microorganisms, which are mixed in the proportion of (3:2:1:1) according to the number of viable bacteria, and the total number of viable bacteria is ≥1×10 8 CFU / g: Phosphorus-solubilizing microorganisms: Bacillus megaterium, preservation number CCTCC AB209224, 3 parts; Potassium-solubilizing microorganisms: Bacillus mucilaginosus, preservation number CCTCC KB20082790, 2 parts; Lignocellulose-degrading microorganisms: Phanerochaete chrysosporium, preservation number CGMCC 3.7212, 1 part; Facultative anaerobic growth-promoting microorganisms: Bacillus coagulans, preservation number CGMCC1.10823, 1 part.

[0032] The above strains are derived from standard strains of preservation institutions or equivalent strains, but are not limited thereto. After the slope activation and liquid expansion of each strain, the bacterial bodies are collected by centrifugation to prepare a bacterial liquid with a viable bacterial concentration higher than 1×10 9 CFU / mL, and then mixed in the above-mentioned proportion for the preparation of subsequent solid microbial agents.

[0033] (2) Carrier and double-layer embedding structure design The microbial agent adopts a double-layer embedding structure, and the specific composition is as follows: Inner layer carrier: made of corn cob powder mixed with bentonite at a mass ratio of 2:1, with a particle size controlled at 60 mesh (about 250 μm) and a water content controlled at 8%-10%. The inner layer is used to load phosphorus-dissolving microorganisms and potassium-dissolving microorganisms.

[0034] Outer controlled release layer: made of sodium alginate and chitosan mixed at a mass ratio of 1:1, formulated into a solution with a concentration of 2.0% (w / v). The outer layer solution is inoculated with lignocellulose-degrading microorganisms and facultative anaerobic growth-promoting microorganisms.

[0035] Embedding and molding: in the embedding process, 2.5% CaCl2 solution is used for dropwise crosslinking, and the crosslinking time is 12 minutes to form a stable gel layer. The mass ratio of the inner and outer layer materials is 1:0.8. The embedded particles are hot air dried at 40°C until the water content is ≤10%, and finally the double-layer embedded granules with a diameter of 1.5-2.5 mm, uniform color and complete surface are obtained.

[0036] (3) Sequential loading and preparation process flow: The expanded Bacillus megaterium and Bacillus mucilaginosus bacterial liquid are mixed at a ratio of 3:2, loaded on the inner layer carrier by spraying, then mixed and stirred for 20 minutes using a roller device, and naturally air-dried to a moisture content of about 8%; The white rot fungus and Bacillus coagulans are mixed into a 2.0% sodium alginate-chitosan solution and stirred uniformly; The carrier particles loaded with the inner layer microbial agent are added dropwise into the outer layer embedding solution containing bacteria, then transferred to a 2.5% CaCl2 solution for crosslinking and solidification, screened, and dried and molded at 40°C to obtain the finished product of the composite functional microbial agent.

[0037] (4) Storage and application method The finished product of the microbial agent can be stored stably at 4°C for 6 months, with a viable bacteria retention rate of not less than 90%.

[0038] Under water immersion conditions at 25°C, the microbial agent shows a slow-release characteristic, with a viable bacteria release ratio of about 26% within 24 hours and a cumulative release ratio of about 41% within 72 hours.

[0039] When applied, the microbial agent is mixed with decomposed organic fertilizer or crushed straw, with a dosage of 3 kg / acre, and is evenly turned into the 0-15 cm deep plough layer soil within 24 hours before the whole field.

[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 crop type, overall operation process, fertilization method, tillage depth, and green manure incorporation management, etc. The only difference is that in step S1, no microbial inoculant is applied.

[0042] The specific settings are as follows: Straw treatment: The type and length of the straw used are the same as in Example 1, i.e., the straw of the previous crop of rape, with a length of ≤5 cm.

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

[0044] Inoculant setting: In this comparative example, no complex functional microbial inoculant is applied in step S1, and no other type of microbial product is used as a substitute.

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

[0046] Comparative Example 2 In this comparative example, only a single strain, Bacillus megaterium powder, is applied in step S1, and the powder does not use any embedding carrier. Otherwise, the rest of the operation process is exactly the same as in Example 1.

[0047] In this comparative example, the application of Bacillus megaterium is based on the number of viable bacteria, so that the total number of viable bacteria (CFU / acre) added per acre is equal to the number of viable bacteria of Bacillus megaterium in the complex inoculant of Example 1. The specific calculation steps are as follows: a) Determine the total number of viable bacteria (unit: CFU / g) of the complex functional microbial inoculant used in Example 1; b) According to the proportion of viable bacteria in the complex inoculant (3:2:1:1), the proportion of Bacillus megaterium is calculated to be 3 / 7, and thus the target number of viable bacteria (unit: CFU / acre) of Bacillus megaterium in this comparative example is obtained; c) According to the measured viable bacteria concentration (unit: CFU / g) of the single strain powder used in this comparative example, the mass of the powder required for application is calculated to achieve the equivalent number of viable bacteria of the strain in Example 1.

[0048] Except for the above-mentioned differences in inoculant application methods, all other operation parameters of this comparative example are consistent with Example 1.

[0049] Comparative Example 3 The comparative example 1 is identical with the example 1 in steps S1, S2, S4 and S5, and the difference is that the step S3 is cancelled, i.e. no Chinese milk vetch intercropping and subsequent turning under is performed.

[0050] Comparative example 4 The comparative example 1 is identical with the example 1 in steps S1, S2, S4 and S5, and the difference is that the step S3 is cancelled, i.e. no Chinese milk vetch intercropping and subsequent turning under is performed.

[0051] In order to exclude the interference of the difference in material input on the experimental results and ensure the fairness of comparison, the comparative example 1 is compensated with equal carbon / equal nitrogen in step S4, and the specific scheme is as follows: The dry matter weight of the aboveground part of Chinese milk vetch measured in the example 1 is taken as the target amount to be compensated in the comparative example 1.

[0052] In step S4 of the comparative example 1, an equal amount of crushed rice straw or mature farm compost is added according to the above target amount, and is turned into the soil layer of 20-25 cm together with the rape straw.

[0053] Comparative example 5 The comparative example 1 is identical with the example 1 in steps S1, S2, S4 and S5, and the difference is that the step S3 is cancelled, i.e. no Chinese milk vetch intercropping and subsequent turning under is performed.

[0054] In order to accurately evaluate and exclude the influence of soil acidity difference on the final observation index, the following correction scheme is set in the comparative example 1: On the 3rd day, the 7th day and the 15th day after the completion of step S4 operation, the soil samples of 0-20 cm depth in the plough layer are collected, and the pH values are measured. In the subsequent data statistical analysis, the measured soil pH values are taken as the covariates in the statistical model to correct the potential influence of acidity difference on the experimental results.

[0055] In order to verify the comprehensive effect of the ecological regulation method for reducing the compound obstacles of "thin, flat and sticky" in the compound obstacles of yellow soil rice-oil rotation field, a small-scale field test is set up in a typical yellow soil area, and a comparison observation is made for two consecutive rice-oil rotation periods.

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

[0057] Test crops: the rice variety is "Xiangzaoxian 45"; the rape variety is "Zhongyouza 501"; the intercropped green manure is Chinese milk vetch variety "Wanzi No. 1".

[0058] (2) Test plan: A randomized block design was used, with 10 treatment groups, 3 replicates per group, and a total of 30 plots, each with an area of 50 m². A 30 cm trench was set between the plots to prevent nutrient or microbial migration; the corresponding procedures for each treatment group were completed on the same day. All application doses were measured on a dry basis; the number of viable bacteria was converted to CFU / acre using the dilution plate method for equivalent comparison; the straw was crushed to a length of ≤5 cm; the depth of incorporation was checked at ≥10 points, and the plot pass rate was ≥90%. The test plan grouping is shown in the table below: Table 1 Treatment group number and plan summary

[0059] (3) Main observation indicators and measurement methods Soil physical and chemical properties: Soil samples were collected within 7 days after the harvest of each rotation period crop for determination. The indicators include: soil organic matter (g / kg), available nitrogen / phosphorus / potassium (mg / kg), pH value, soil bulk density (g / cm 3 ), >0.25 mm water-stable aggregate content (%), and air voids (%).

[0060] Crop growth and yield: Observation indicators include seedling stage plant height, key growth stage progress, single plant dry weight, and actual yield per unit area (kg / acre) at maturity.

[0061] Root morphology and tillage layer structure: Root length density (cm / cm 3 ), root-shoot ratio (aboveground dry matter mass / root system dry matter mass), maximum root penetration depth, and effective tillage layer thickness are measured.

[0062] Microbial characteristics and decomposition process (for T1, C1, C2, C3, C5 treatment groups): The total amount of soil microorganisms and the number of functional microbial populations such as phosphorus-dissolving bacteria and potassium-dissolving bacteria (CFU / g) are measured; the straw decomposition rate is evaluated by calculating the dry matter mass reduction rate of straw residues.

[0063] Key process dynamic monitoring: On the 3rd, 7th, and 15th days after step S4, the pH value of the 0~20 cm soil layer of the control group C5 and the implementation group T1 is measured; on the 5th day after straw incorporation, soil microbial activity and functional bacteria numbers are measured; during step S4, the 0~20 cm soil layer moisture content is monitored, and the relative percentage of field water holding capacity is converted to verify the implementation of the water management system.

[0064] (4) Monitoring period and sample collection and processing Test period: The test began in September 2022 (the start of the first rotation of rice season) and continued until June 2024 (the harvest of the second rotation of oilseed rape season).

[0065] Sampling node: Collect soil samples immediately after each crop harvest; Collect plant samples and soil samples synchronously before and after step S3; Collect process samples at the preset time points after step S4.

[0066] Sample processing and determination method: The soil samples are mixed by the "quincunx five-point method", dried naturally, and then passed through a 2 mm sieve for use; The root samples are collected in layers along the soil vertical section according to 0~10 cm, 10~20 cm, and 20~30 cm; The soil bulk density is determined by the cutting ring method; The 0.25 mm water stable aggregate content is determined by the wet screening method; The soil aeration porosity is calculated by the volume method; The root length density is determined by washing roots in layers combined with image analysis software; The field water holding capacity is converted from the actual moisture content of the 0~20 cm soil layer; The number of viable microorganisms is counted by the dilution plating method, and is uniformly converted to CFU / acre.

[0067] Tables 2~5 are analysis summaries of the results collected after two consecutive rice-oil crop rotations, and the specific calculation results are as follows: Table 2 Soil physical and chemical indicators (after the second round, 0~20 cm, n=3, mean ± SD) Group Organic matter (g / kg) pH value Available nitrogen (mg / kg) Available phosphorus (mg / kg) Available potassium (mg / kg) Container weight (g / cm 3 ) > 0.25 mm aggregate (%) Air voids (%) 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 the "thin" and "board" two obstacles: On the one hand, the improvement of nutrient content and pH indicates that the problem of barren acidification is alleviated; On the other hand, the decrease of bulk density and the increase of aggregate proportion indicate that the plough layer is in transition from dense to loose.

[0068] Table 3 Crop yield and root index (two rounds, n=3, mean ± SD) Group Rice yield (kg / mu) Rape yield (kg / mu) Root length density (cm / cm 3 )]]> Root-shoot ratio Root penetration depth (cm) Plough layer thickness (cm) 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 shows that the above-mentioned improvement of the plough layer has been transmitted to the crop root distribution and yield level, i.e., from soil improvement to actual output.

[0069] Table 4 Functional microorganisms and decomposition process Treatment Total amount of soil microorganisms (x10^7 CFU / g) Phosphorus solubilizing bacteria count (x10^6 CFU / g) Potassium solubilizing bacteria count (x10^6 CFU / g) Laccase activity (U / g soil) Straw decomposition rate (21 d, %) 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 microorganism and decomposition rate results listed in Table 4 correspond to the "sticky" problem, i.e., the slow decomposition of straw and the formation of sticky blocks after returning to the field; The compound microbial agent accelerates the decomposition of returned materials, making the surface residues quickly converted into nutrient sources that can be utilized by crops, providing a continuous source for subsequent plough layer loosening and organic matter replenishment.

[0070] Table 5 Soil pH at different time points after ploughing Time 3rd day 7th day 15th day T1 group 6.05±0.06 6.18±0.05 6.21±0.05 C5 group 5.34±0.04 5.38±0.04 5.45±0.05 The data of Table 5 shows that through the process of turning over and lime-moisture regulation, the pH of acidic yellow soil can be pulled back to the appropriate interval in a short period of time, avoiding the further aggravation of the "lean" and "sticky" problems, and laying the foundation for maintaining a stable plough layer environment in the subsequent cropping period.

[0071] The test data of each group shown in Tables 2-5 are summarized as follows: (1) It enhances the improvement effect on the "lean" of yellow soil. Compared with B1, the soil organic matter content of the implementation group T1 is increased from 19.8 g / kg to 23.8 g / kg (20% increase), the available phosphorus content is increased from 19.8 mg / kg to 31.5 mg / kg (59% increase), the available potassium content is increased from 85 mg / kg to 121 mg / kg (42% increase), and the soil pH value is increased from 5.05 to 6.21 (1.16 units increase). It shows that the synergistic effect of "compound embedded microbial agent + mature organic fertilizer + calcium magnesium phosphate fertilizer" in step S1: the function of phosphorus / soluble potassium microorganisms promotes the activation of insoluble nutrients, white rot fungi accelerates the process of straw decomposition and humification, and lime and calcium magnesium phosphate fertilizer provides effective acidity buffer and phosphorus source. At the same time, "application within 24 hours after mixing of microbial agents" and "maintaining high soil moisture content for 7-15 days" in step S4 provide protection for the early activation and colonization of microorganisms.

[0072] (2) It enhances the improvement effect on the "plate" of yellow soil. Compared with B1, the soil bulk density of the implementation group T1 is reduced from 1.47 g / cm 3 to 1.31 g / cm 3 (reduced by 11%), the proportion of >0.25 mm water stable aggregate is increased from 33.1% to 48.7% (increased by 47%), the soil aeration porosity is increased from 13.0% to 18.5% (increased by 42%), and correspondingly, the crop root length density is increased to 2.43 cm / cm 3 , the root penetration depth reaches 29.5 cm, and the effective plough layer thickness is increased to 22.0 cm. This shows that the combined action of "deep loosening and ridge structure construction" in step S2 and "green manure turning over and embedded microorganisms" in steps S3 / S4, relieves the compactness of plough layer and plough bottom layer, improves the aggregate structure and porosity, and thus improves the root penetration ability and effective plough layer thickness.

[0073] (3) It enhances the improvement effect on the "sticky" of yellow soil. In the process monitoring after step S4, the implementation group T1 shows better biological activity. The total amount of soil microorganisms reaches 8.5×10 7CFU / g, laccase activity reached 62 U / g, and the 21-day straw decomposition rate reached 41.8%, which were significantly higher than those of the comparative example C1 and the comparative example C2 in which only a single phosphorus solubilizing bacterium was applied. The acceleration of the decomposition rate and the increase in the proportion of large aggregates together improved the microstructure of the heavy clay soil and its drainage and aeration performance, thereby effectively alleviating the problems caused by the over "stickiness" of the soil.

[0074] (4) Yield performance and technical scheme synergy analysis The rice yield of the implementation group T1 reached 622.5 kg / mu (an increase of 22.7% compared to B1), and the rape yield reached 148.0 kg / mu (an increase of 17.5% compared to B1). Under the same input of viable bacteria, the comparative example C3 was superior to the single phosphorus solubilizing bacterium of the comparative example C2 in many indicators, indicating that the multifunctional bacterial population coupling produced a synergistic effect; although the indicators of the comparative example C3 were superior to those of the comparative example C2, they were still lower than those of the implementation group T1, indicating that the double-layer embedding structure significantly improved the survival and sustained efficacy of the functional bacterial population in the acidic yellow soil and the water-flood rotation environment; even in the comparative example C4, the compensation of equal carbon / equal nitrogen, the improvement effect was still lower than that of T1, which proved that the biological function of Astragalus sinicus in improving soil structure and promoting microbial interaction could not be completely replaced; the soil pH, available phosphorus content and crop yield of the comparative example C5 were significantly lower than those of T1, which verified the importance of lime acid adjustment for activating nutrients and indirectly improving soil obstacles; the effects of the implementation groups T2 and T3 appeared to a certain extent. Backfall, indicating that the use dose and operation time sequence are necessary to ensure the final effect.

[0075] The key technical path of the present application is: "composite embedded bacterial agent + precise agricultural time window of S1 / S4 + deep loosening and ridge culture structure construction of S2 + Astragalus sinicus intercropping and turning of S3 + layered regulation of calcium, magnesium and phosphorus fertilizer / lime", through the chain reaction of "nutrient activation -> organic matter accumulation and decomposition -> aggregate formation and structure improvement -> root deepening and plough layer thickening", the synergistic management of the three combined obstacles of "thin, board and sticky" is realized.

[0076] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

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 0-15cm. S2. Construction of physical structure for rapeseed season: After rice harvest, deep loosening of the field to a depth of 20-25cm is carried out, followed by the construction of ridge structure, in which the ridge width is 45-55cm, the furrow width is 25-35cm, and the ridge height is 20-25cm. 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 turn it into the soil layer 20-25cm 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.

2. The method according to claim 1, characterized in that, In step S1, the composite functional microbial agent includes phosphorus-solubilizing microorganisms, potassium-solubilizing microorganisms, lignocellulose-degrading microorganisms, and facultative anaerobic growth-promoting microorganisms.

3. 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.

4. 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.

5. 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.

6. The method according to claim 1, characterized in that, 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.

7. A composite functional microbial agent for use in the method according to any one of claims 1 to 6, characterized in that, include: 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.

8. The composite functional microbial agent according to claim 7, characterized in that, The agricultural carrier has a double-layered encapsulation structure. 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.

9. The composite functional microbial agent according to claim 8, characterized in that, The microbial active components are loaded sequentially in stages into the double-layered encapsulation structure; wherein the phosphorus-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.

10. The composite functional microbial agent according to claim 7, characterized in that, The lignocellulose-degrading microorganisms include white-rot fungi.

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