Method of land preparation for legume-grass-crop family sequential rotation in soils with continuous cropping obstacles

Abstract

The application discloses a kind of for continuous cropping obstacle soil legume-grass-cabbage family time sequence rotation's method of land reclamation, belong to agricultural soil improvement and crop rotation technical field.The method includes: the first stage planting legume green manure, is pressed into soil in early flowering period after growth 25~30 days, and is idle for 8~10 days;Second stage planting grass green manure, is pressed into soil in early heading after growth 25~30 days, and is idle for 10~12 days;Third stage planting cabbage family green manure, is pressed into soil in full flowering period after growth 25~30 days, and is idle for 14~15 days;Nitrogen fertilizer is supplemented before interplanting crop, and the carbon-nitrogen ratio of soil is adjusted to 20:1.The method is mainly used for the rapid repair and land reclamation of facility vegetable continuous cropping obstacle soil, can be cultivated, improve soil and inhibit bacteria simultaneously in 90 days, and create good growth conditions for interplanting crop.

Description

Technical Field

[0001] This invention belongs to the field of agricultural soil improvement and crop rotation technology, specifically relating to a method for soil improvement through sequential crop rotation of leguminous-grass-cruciferous crops in soils with continuous cropping obstacles. Background Technology

[0002] In the management of soil problems caused by continuous cropping in greenhouse vegetables, the accumulation of soil-borne pathogens, soil structure degradation, and nutrient imbalance are interconnected major issues. In southern greenhouses, due to high multiple cropping indices, continuous cropping for more than three years often leads to soil acidification and a decline in organic matter content. Simultaneously, the number of pathogens such as Fusarium oxysporum increases significantly, resulting in frequent outbreaks of soil-borne diseases such as bacterial wilt and root rot, with yield reductions exceeding 30% in severe cases. To control diseases, farmers often use chemical fumigants such as dazomet and methamidophos, but the cost per acre is as high as 500-800 yuan, and the effect only lasts for one season. Furthermore, fumigation kills beneficial microbial communities in the soil, leading to a more severe rebound of diseases the following year. Measures such as soil replacement or high-temperature fumigation also suffer from high costs and cumbersome operations, making them difficult to sustain. Green manure planting is an eco-friendly soil improvement method, but existing single-species green manure or simple crop rotation methods have limited functions: Leguminosae green manure, while able to improve soil fertility through nitrogen fixation in root nodules, has a shallow root system, resulting in weak improvement of deep soil structure and no pathogen inhibition effect; Gramineae green manure, with its dense fibrous root system, can improve soil aggregate structure, but it cannot fix nitrogen itself, has a high carbon-to-nitrogen ratio, and after being turned over, microbial decomposition easily leads to competition for nitrogen with subsequent crops, and it also lacks antibacterial function; Cruciferous green manure, after being turned over, has glucosinolates hydrolyzed to produce isothiocyanates, which have a certain inhibitory effect on soil-borne pathogens, but the biomass is small, and the effect on improving soil fertility is insufficient. Some studies have attempted binary crop rotation of leguminous and gramineous plants, which can achieve both soil improvement and fertilization, but cannot suppress soil-borne diseases; binary rotation of gramineous and cruciferous plants can partially achieve soil improvement and antibacterial effect, but lacks nitrogen supplementation, requiring the application of additional chemical fertilizers. Therefore, how to simultaneously address the nutrient imbalance, structural degradation, and pathogen accumulation in continuous cropping-impaired soils within a crop rotation cycle that is no longer than the summer fallow period, while avoiding the damage to soil biological communities caused by chemical fumigation, is a long-standing and unresolved technical challenge in this field. Summary of the Invention

[0003] One object of the present invention is to address at least the aforementioned deficiencies and to provide at least the advantages that will be described later.

[0004] This invention provides a method for soil improvement through a legume-grass-cruciferous sequential cropping rotation for soils with continuous cropping obstacles, comprising the following steps: The first stage involves planting leguminous green manure. After 25-30 days of growth, the leguminous green manure is turned into the soil at the initial flowering stage, with a turning depth of 15-20 cm. The land is then left to fallow for 8-10 days. The second stage involves planting grass green manure after the fallow period ends. After 25-30 days of growth, the grass green manure is turned into the soil at the early heading stage, with a turning depth of 15-20 cm. Then, the land is left to fallow for 10-12 days. The third stage involves planting cruciferous green manure after the fallow period ends. After 25 to 30 days of growth, the cruciferous green manure is turned into the soil during the peak flowering period, with a turning depth of 15 to 20 cm. Then, the land is left to fallow for 14 to 15 days. Before transplanting the next crop, apply nitrogen fertilizer according to the soil test results to adjust the soil carbon-nitrogen ratio to 20:1.

[0005] Preferably, the legume green manure is vetch or milkvetch, with a sowing rate of 3-5 kg / mu for vetch or 2-3 kg / mu for milkvetch; Before sowing, inoculate with rhizobium at a ratio of 5 g of rhizobium powder per kilogram of seeds. The viable count of the rhizobium powder should be 5 × 10⁻⁶. 8 ~1×10 9 1 / g; apply 8-12 kg / mu of superphosphate at sowing; maintain soil moisture content at 60%-70% of field capacity during the growing season.

[0006] Preferably, the grass green manure is ryegrass or sorghum, with a sowing rate of 10-15 kg / mu. Before sowing, the seeds are soaked in water at 20-25℃ for 12 hours. Sowing utilizes the residual nitrogen released after the legume green manure is turned over to supply growth. During the growing season, water is added once or twice if there is drought to maintain the soil moisture content at 50%-70% of the field capacity. When turning over the green manure at the early heading stage, the carbon-nitrogen ratio of the grass green manure plants should be 20-30.

[0007] Preferably, the cruciferous green manure is rapeseed or white radish, with a sowing rate of 1-2 kg / mu for rapeseed or 0.5-1 kg / mu for radish. For rapeseed, choose varieties with glucosinolate content greater than 20 μmol / g, and for white radish, choose fleshy, deep-rooted varieties. After sowing, utilize the nitrogen, phosphorus, and potassium nutrients released from the decomposition of the previous two crops of green manure after plowing to supply growth. Do not supplement water during the growing period, or supplement water once in case of drought. Plow and compact the plants when they are in full bloom and the glucosinolate content in the cruciferous green manure plants reaches its peak, with a plowing depth of 15-20 cm. After plowing, maintain the soil moisture content at 60%-70% of the field capacity and leave the land fallow for 14-15 days to allow glucosinolates to hydrolyze into isothiocyanates under the action of soil myrosinase, which inhibits soil-borne pathogens.

[0008] Preferably, irrigation is carried out after each stage of green manure plowing and compaction to bring the soil moisture content of the 0-20 cm soil layer to 60%-75% of the field maximum water holding capacity, and the soil is covered with mulch or straw to maintain this moisture content; the moisture content is maintained for 8-10 days after the first stage of plowing and compaction, for 10-12 days after the second stage of plowing and compaction, and for 14-15 days after the third stage of plowing and compaction.

[0009] Preferably, on the 4th to 5th day after the third stage of plowing and fallowing, calcium peroxide granules are evenly spread on the soil surface at a rate of 2-4 kg / mu. Then, irrigation is carried out until the soil moisture content in the 0-15 cm layer reaches 65%-75% of the field capacity, so that the calcium peroxide reacts with water to produce oxygen and calcium hydroxide. The particle size of the calcium peroxide granules is 1-3 mm, and the decomposition time is 5-7 days.

[0010] Preferably, on the 12th day after the third stage of plowing and fallowing, after the calcium peroxide granules have decomposed, a mixture of phosphate-solubilizing bacteria and molasses powder is evenly spread on the soil surface at a rate of 1 kg / mu to 2 kg / mu of phosphate-solubilizing bacteria and 3-5 kg / mu of molasses powder. Then, shallow rotary tillage is performed on the top 0-10 cm of soil to mix the bacteria with the soil, and the soil moisture content is maintained at 55%-65% of field capacity for 2 days. The phosphate-solubilizing bacteria is a freeze-dried powder of Bacillus megaterium or Pseudomonas fluorescens, with a viable count of 1×10⁻⁶. 9 ~2×10 9 pcs / g; molasses powder is spray-dried sugarcane molasses powder with a total sugar content of 40% to 50%.

[0011] Preferably, when applying the mixture of phosphate-solubilizing agent and molasses powder, mustard seed powder is mixed evenly with the mixture at a ratio of 1-2 kg / mu and then applied together. The mustard seed powder is obtained by crushing white or brown mustard seeds to pass through an 80-mesh sieve, with a glucosinolate content of 50-80 μmol / g and an optimal pH range of 6.5-7.5 for endogenous myrosinase activity. After application, the soil layer is lightly tilled to a depth of 0-10 cm and the soil moisture content is maintained at 55%-65% of the field capacity, so that when the mustard seed powder comes into contact with water, the glucosinolates are hydrolyzed by endogenous myrosinase to form isothiocyanates.

[0012] The present invention has at least the following beneficial effects: First, by rotating and turning over three types of green manure—leguminous, grass, and cruciferous—soil fertilization, structural improvement, and pathogen suppression can be achieved simultaneously within a 90-day cycle. This avoids the problem of insufficient function of a single green manure or the imbalance caused by dual-crop rotation. Furthermore, after turning over, nitrogen fertilizer is applied based on soil test results to adjust the carbon-nitrogen ratio to 20:1, which can effectively prevent microorganisms from competing with the next crop for nitrogen. The next crop can obtain good growth conditions without the need for additional large amounts of fertilizer.

[0013] Secondly, by inoculating leguminous green manure with high-viability rhizobium, applying only superphosphate instead of nitrogen fertilizer, and controlling the soil moisture content at 60%–70% of field capacity, it is possible to promote the formation of a large number of root nodules and maintain high nitrogen-fixing activity. This allows leguminous green manure to fix 5–8 kg of pure nitrogen per acre when it is turned over during the initial flowering stage. After turning over, the organic nitrogen is mineralized and released, providing residual nitrogen for subsequent gramineous green manure and adjusting the soil carbon-nitrogen ratio to 15–20. This avoids the large-scale consumption of available soil nitrogen by microorganisms during the turning over of gramineous green manure, and achieves a smooth succession of nitrogen in time.

[0014] Third, the residual nitrogen released by the mineralization after the previous legume green manure is turned over supplies the growth of gramineous green manure. Combined with seed soaking treatment and appropriate water control, the carbon-nitrogen ratio of gramineous green manure plants reaches exactly 20-30 when they are turned over at the early heading stage without the application of additional chemical nitrogen fertilizer. After turning over, it can quickly decompose to form water-stable aggregates, increasing the proportion of large aggregates to more than 50%, without competing with subsequent crops for nitrogen. At the same time, the dense fibrous root system effectively improves the soil aggregate structure.

[0015] Fourth, by selecting rapeseed varieties with high glucosinolate content or deep-rooted white radishes, and utilizing the nitrogen, phosphorus, and potassium nutrients released after the first two crops of green manure are turned over and decomposed to supply growth, the glucosinolate content reaches its peak during the full flowering period, and the land is left fallow for 14-15 days. This allows glucosinolates to be fully hydrolyzed into isothiocyanates under the action of soil myrosinase, which has a high inhibitory effect on soil-borne pathogens such as Fusarium oxysporum. At the same time, deep-rooted white radishes can break the plow pan and form a spatially complementary structural relay with legumes and grasses. This achieves the synergistic effect of antibacterial and soil improvement without additional fertilization and with less irrigation.

[0016] Fifth, by maintaining soil moisture content at 60%–75% for 8–10 days, 10–12 days, and 14–15 days after each stage of green manure incorporation, and covering with mulch or straw to maintain moisture, differentiated moisture conditions can be provided for green manure residues with three different carbon-nitrogen ratios. This promotes rapid nitrogen mineralization of leguminous green manure, the full entanglement of fibrous roots of gramineous green manure with soil particles to form aggregates, and the efficient hydrolysis and conversion of glucosinolates of cruciferous green manure into isothiocyanates. This avoids insufficient moisture leading to stagnation of decomposition or excessive moisture causing anaerobic environment and nutrient leaching.

[0017] Sixth, by applying calcium peroxide granules on the 4th to 5th day after the third stage of plowing and fallowing, it can slowly release oxygen and calcium hydroxide within 5 to 7 days. This can effectively alleviate the oxygen deficiency problem in the 0-20 cm soil layer caused by the decomposition of a large amount of organic material after three consecutive stages of green manure plowing and avoid the accumulation of anaerobic metabolites such as hydrogen sulfide and organic acids. At the same time, calcium hydroxide can neutralize organic acids and regulate soil pH, providing an alkaline environment for isothiocyanates generated by the hydrolysis of glucosinolates to enhance antibacterial activity and ensure that the soil returns to an aerobic state before the next planting.

[0018] Seventh, by applying phosphorus-solubilizing bacteria and molasses powder on the 12th day after the decomposition of calcium peroxide particles, and then shallowly tilling the 0-10 cm soil layer to maintain a suitable moisture content for 2 days, the problem of calcium hydroxide generated by the reaction of calcium peroxide with water fixing soil phosphorus can be effectively solved. This allows Bacillus megaterium or Pseudomonas fluorescens to secrete organic acids and phosphatases to dissolve calcium phosphate precipitate and mineralize organic phosphorus. Molasses powder acts as a carbon source to promote the rapid reproduction of phosphorus-solubilizing bacteria, thereby increasing the available phosphorus content in the soil and ensuring the phosphorus supply after the next crop is planted. At the same time, it does not antagonize the application of nitrogen fertilizer.

[0019] Eighth, by mixing mustard seed powder with phosphate-solubilizing bacteria and molasses powder, the endogenous myrosinase in mustard seed powder hydrolyzes glucosinolates to generate isothiocyanates upon contact with water. This can precisely inhibit soil-borne pathogens such as Fusarium oxysporum that reactivate using molasses as a carbon source, preventing a rebound in pathogen abundance. Meanwhile, phosphate-solubilizing bacteria have a natural tolerance to isothiocyanates, and their phosphate-solubilizing activity is not affected. Thus, the dual effect of releasing fixed phosphorus and preventing disease rebound is achieved simultaneously in the same operation.

[0020] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0022] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0023] A method for soil conservation through legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles includes the following steps: The first stage involves planting leguminous green manure. After 25-30 days of growth, the leguminous green manure is turned into the soil at the initial flowering stage, with a turning depth of 15-20 cm. The land is then left to fallow for 8-10 days. The second stage involves planting grass green manure after the fallow period ends. After 25-30 days of growth, the grass green manure is turned into the soil at the early heading stage, with a turning depth of 15-20 cm. Then, the land is left to fallow for 10-12 days. The third stage involves planting cruciferous green manure after the fallow period ends. After 25 to 30 days of growth, the cruciferous green manure is turned into the soil during the peak flowering period, with a turning depth of 15 to 20 cm. Then, the land is left to fallow for 14 to 15 days. Before transplanting the next crop, apply nitrogen fertilizer according to the soil test results to adjust the soil carbon-nitrogen ratio to 20:1.

[0024] In another technical solution, the legume green manure is vetch or milkvetch, with a sowing rate of 3-5 kg / mu for vetch or 2-3 kg / mu for milkvetch; Before sowing, inoculate with rhizobium at a ratio of 5 g of rhizobium powder per kilogram of seeds. The viable count of the rhizobium powder should be 5 × 10⁻⁶. 8 ~1×10 9 1 / g; apply 8-12 kg / mu of superphosphate at sowing; maintain soil moisture content at 60%-70% of field capacity during the growing season.

[0025] In another technical solution, the grass green manure is ryegrass or sorghum, with a sowing rate of 10-15 kg / mu. Before sowing, the seeds are soaked in water at 20-25 ℃ for 12 hours. The sowing utilizes the residual nitrogen released by the mineralization of leguminous green manure after it is turned over to supply growth. During the growing period, water is added once or twice in case of drought to maintain the soil moisture content at 50%-70% of the field capacity. When turning over the green manure at the early heading stage, the carbon-nitrogen ratio of the grass green manure plants is 20-30.

[0026] In another technical solution, the cruciferous green manure is rapeseed or white radish, with a sowing rate of 1-2 kg / mu for rapeseed or 0.5-1 kg / mu for radish. The rapeseed variety with a glucosinolate content greater than 20 μmol / g is selected, and the white radish is a fleshy, deep-rooted variety. After sowing, the nitrogen, phosphorus, and potassium nutrients released by the decomposition of the previous two green manure crops are used to supply growth. No watering is required during the growing season, or watering is done once in case of drought. The soil is turned over at the peak flowering period when the glucosinolate content reaches its peak, with a turning depth of 15-20 cm. After turning over, the soil moisture content is maintained at 60%-70% of the field capacity. The soil is left fallow for 14-15 days to allow the glucosinolates to be hydrolyzed into isothiocyanates by myrosinase in the soil, which inhibits soil-borne pathogens.

[0027] In another technical solution, irrigation is carried out after each stage of green manure plowing and compaction to bring the soil moisture content of the 0-20 cm soil layer to 60%-75% of the field maximum water holding capacity, and the soil is covered with mulch or straw to maintain this moisture content; the moisture content is maintained for 8-10 days after the first stage of plowing and compaction, for 10-12 days after the second stage of plowing and compaction, and for 14-15 days after the third stage of plowing and compaction.

[0028] In another technical solution, on the 4th to 5th day after the third stage of plowing and fallowing, calcium peroxide granules are evenly spread on the soil surface at a rate of 2-4 kg / mu. Then, irrigation is carried out until the soil moisture content of the 0-15 cm layer reaches 65%-75% of the field capacity, so that the calcium peroxide reacts with water to produce oxygen and calcium hydroxide. The particle size of the calcium peroxide granules is 1-3 mm, and the decomposition time is 5-7 days.

[0029] In another technical solution, on the 12th day after the third stage of plowing and fallowing, after the calcium peroxide granules have decomposed, a mixture of phosphate-solubilizing bacteria and molasses powder is evenly spread on the soil surface. The application rate is 1 kg / mu to 2 kg / mu of phosphate-solubilizing bacteria and 3-5 kg / mu of molasses powder. Then, shallow rotary tillage is performed on the top 0-10 cm of soil to mix the bacteria with the soil, and the soil moisture content is maintained at 55%-65% of field capacity for 2 days. The phosphate-solubilizing bacteria is a freeze-dried powder of Bacillus megaterium or Pseudomonas fluorescens, with a viable count of 1×10⁻⁶. 9 ~2×10 9 pcs / g; molasses powder is spray-dried sugarcane molasses powder with a total sugar content of 40% to 50%.

[0030] In another technical solution, when applying the mixture of phosphate-solubilizing agent and molasses powder, mustard seed powder is mixed evenly with the mixture at a ratio of 1-2 kg / mu and then applied together. The mustard seed powder is obtained by crushing white or brown mustard seeds to pass through an 80-mesh sieve, with a glucosinolate content of 50-80 μmol / g and an optimal pH range of 6.5-7.5 for endogenous myrosinase activity. After application, the soil layer is lightly tilled to a depth of 0-10 cm and the soil moisture content is maintained at 55%-65% of the field capacity, so that when the mustard seed powder comes into contact with water, the glucosinolates are hydrolyzed by endogenous myrosinase to generate isothiocyanates.

[0031] Example 1 This embodiment provides a soil-nurturing method for legume-grass-cruciferous sequential cropping in soils with continuous cropping obstacles, specifically including the following steps: Phase 1: Planting and Turning of Leguminous Green Manure Select soil plots with continuous cropping obstacles and plant leguminous green manure vetch in the first stage. After the leguminous green manure has grown for 28 days, turn it into the soil in place at the initial flowering stage, with a turning depth of 18 cm, and leave it fallow for 9 days after turning.

[0032] Phase Two: Planting and Turning of Grass Green Manure After the first phase of fallowing, sorghum green manure was planted on the same plot. After 28 days of growth, the sorghum green manure was plowed into the soil at the early heading stage to a depth of 18 cm, followed by 11 days of fallowing.

[0033] Phase 3: Planting and Turning of Cruciferous Green Manure After the second phase of fallowing, cruciferous green manure radishes were planted on the same plot. After the cruciferous green manure had grown for 28 days, it was turned into the soil during its peak flowering period, with a turning depth of 18 cm. After turning, the land was left to fallow for 14 days.

[0034] Pre-planting treatment of successor crops After the third phase of fallow ends and before the next crop is planted, soil samples are taken to test the soil carbon-nitrogen ratio. Based on the test results, nitrogen fertilizer is applied to adjust the soil carbon-nitrogen ratio to 20:1.

[0035] Example 2 This embodiment provides a soil-nurturing method for a legume-grass-cruciferous sequential rotation in soils with continuous cropping obstacles. The first stage of planting and incorporating legume green manure is carried out according to the following specific parameters. The remaining stages (the second stage of grass green manure, the third stage of cruciferous green manure, and nitrogen supplementation before crop rotation) are all operated according to the basic steps of Example 1.

[0036] Phase 1: Planting and Turning of Leguminous Green Manure. Select soil plots with continuous cropping obstacles and plant leguminous green manure vetch at a rate of 4 kg / mu. Before sowing, inoculate with 5 g of rhizobium powder per kilogram of seeds. The viable count of the rhizobium powder used should be 5 × 10⁻⁶. 8 10 kg / g of legume green manure. Apply 10 kg / mu of superphosphate at sowing. During the growing season, maintain soil moisture content at 65% of field capacity through irrigation or mulching. After 28 days of growth, turn the legume green manure into the soil at the initial flowering stage to a depth of 18 cm, and leave it fallow for 9 days after turning.

[0037] The subsequent second and third stages, as well as the application of nitrogen fertilizer before crop rotation, are the same as in Example 1.

[0038] Example 3 This embodiment provides a soil-nurturing method for a legume-grass-cruciferous sequential rotation in soils with continuous cropping obstacles. The planting and incorporation of grass green manure in the second stage are carried out according to the following specific parameters. The remaining stages (legume green manure in the first stage, cruciferous green manure in the third stage, and nitrogen supplementation before crop rotation) are all operated according to the basic steps in Example 1.

[0039] Phase Two: Planting and Turning of Grass Green Manure After completing the first stage of fallow (9 days), plant sorghum green manure (Gramineae) on the same plot at a rate of 12.5 kg / mu. Before sowing, soak the seeds in water at 25℃ for 12 hours. No nitrogen fertilizer is applied after sowing; the plant relies entirely on the residual nitrogen released from the mineralization of the previous leguminous green manure after incorporation. If drought occurs during the growing season, irrigate once to maintain soil moisture at 60% of field capacity. After 28 days of growth, incorporate the sorghum green manure into the soil at the early heading stage. At this time, the plant's carbon-to-nitrogen ratio is 25 (naturally achieved through the aforementioned growth period, lack of nitrogen fertilizer, and controlled watering). The incorporation depth is 18 cm, followed by 11 days of fallow.

[0040] The remaining stages of the operation are the same as in Example 1.

[0041] Example 4 This embodiment provides a soil-nurturing method for legume-grass-cruciferous sequential rotation in soils with continuous cropping obstacles. The planting and incorporation of cruciferous green manure in the third stage are carried out according to the following specific parameters. The remaining stages (legume green manure in the first stage, grass green manure in the second stage, and nitrogen supplementation before crop rotation) are all operated according to the basic steps in Example 1.

[0042] Phase 3: Planting and Turning of Cruciferous Green Manure After completing the second stage of fallow (11 days), plant cruciferous green manure radishes on the same plot, selecting fleshy, deep-rooted varieties, with a sowing rate of 0.75 kg / mu. No fertilizer is applied after sowing; the plant relies entirely on the nitrogen, phosphorus, and potassium released from the decomposition of the previous two crops (leguminous and gramineous) of green manure after plowing. No artificial irrigation is performed during the growing period (water can be added once if drought occurs). After 28 days of growth, plow the radishes at their peak flowering stage, when the glucosinolate content in the plants reaches its peak, to a depth of 18 cm. Irrigate immediately after plowing to ensure the soil moisture content in the 0-20 cm soil layer reaches 65% of field capacity. Cover with mulch or straw to maintain this moisture content, and then allow the land to fallow for 14 days. During this period, glucosinolates are hydrolyzed by soil myrosinase to form isothiocyanates, effectively inhibiting soil-borne pathogens.

[0043] The remaining stages of the operation are the same as in Example 1.

[0044] Example 5 This embodiment provides a soil-nurturing method for legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles. Based on the green manure planting and incorporation operations at each stage described in Embodiment 1, the soil moisture after incorporation at each stage is further controlled as follows: The first stage of water management after plowing: After plowing the legume green manure (vetch) into the soil, irrigate immediately to bring the soil moisture content of the 0-20 cm soil layer to 70% of the field capacity. Cover with mulch or straw to maintain this moisture content for 9 days. This stage of water management ends after the fallow period (9 days).

[0045] The second stage of water management after plowing: After plowing the grass green manure (sorghum and sorghum) into the soil, irrigate immediately to bring the soil moisture content of the 0-20 cm soil layer to 70% of the field capacity. Cover with mulch or straw to maintain this moisture content for 11 days. This stage of water management ends after the fallow period (11 days).

[0046] The third stage of water management after plowing: After plowing the cruciferous green manure (white radish) into the soil, irrigate immediately to bring the soil moisture content of the 0-20 cm soil layer to 70% of the field capacity. Cover with mulch or straw to maintain this moisture content for 14 days. This stage of water management ends after the fallow period (14 days).

[0047] The remaining stages of operation (including the first stage of planting and turning, the second stage of planting and turning, the third stage of planting and turning, and the application of nitrogen fertilizer before the next crop) are the same as in Example 1.

[0048] This embodiment achieves differentiated water support for nitrogen mineralization in leguminous green manure, aggregate formation in gramineous green manure, and glucosinolate hydrolysis in cruciferous green manure by precisely controlling the soil moisture content to 70% of the field capacity after each stage of plowing and compaction, and maintaining this level for 9, 11, and 14 days respectively, thus ensuring smooth functional transitions between each stage.

[0049] Example 6 This embodiment provides a soil-nurturing method for legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles. Based on the water management after each stage of plowing described in Example 5, the following calcium peroxide aeration operation is added during the fallow period after plowing in the third stage (cruciferous green manure): Calcium peroxide application: On the fourth day after the third stage of green manure (white radish) is plowed and left fallow, evenly spread calcium peroxide granules onto the soil surface at a rate of 3 kg / mu. The particle size of the calcium peroxide granules used should be 2 mm. Irrigate immediately after application to bring the soil moisture content in the 0-15 cm layer to 70% of the field capacity. Calcium peroxide reacts slowly with water to produce oxygen and calcium hydroxide, and the decomposition process takes approximately 7 days.

[0050] Subsequent operations: The decomposition process of calcium peroxide is carried out simultaneously with the fallow period. After the fallow period ends (the third stage of fallow lasts for 14 days), the subsequent operations are completed according to Example 5. The operations for other stages (the first stage, the second stage, and the application of nitrogen fertilizer before crop rotation) are the same as in Example 5.

[0051] This embodiment effectively alleviates the oxygen deficiency problem in the 0-20 cm soil layer caused by the decomposition of a large amount of organic material after three consecutive green manure incorporations by applying calcium peroxide granules during the middle of the third fallow period (day 4). It also prevents the accumulation of anaerobic metabolites such as hydrogen sulfide and organic acids. At the same time, the generated calcium hydroxide can neutralize organic acids and regulate soil pH, providing a better alkaline environment for the hydrolysis of glucosinolates to generate isothiocyanates, ensuring that the soil returns to an aerobic state before the next planting.

[0052] Example 7 This embodiment provides a soil-nurturing method for legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles. Based on the calcium peroxide application operation described in Example 6, the following application operations are added during the later stage of fallow after plowing in the third stage (cruciferous green manure): application of phosphate-solubilizing bacteria and molasses powder. Application of phosphate-solubilizing bacteria and molasses powder: On the 12th day after the third stage of green manure (white radish) is plowed and left fallow, when the calcium peroxide granules have completely decomposed, evenly apply the mixture of phosphate-solubilizing bacteria and molasses powder to the soil surface. The application rate is: 1.5 kg / mu of phosphate-solubilizing bacteria and 4 kg / mu of molasses powder. The phosphate-solubilizing bacteria used is freeze-dried powder of Bacillus megaterium with a viable count of 1.5 × 10⁻⁶. 9 Units / g. Molasses powder is spray-dried sugarcane molasses powder with a total sugar content of 45%.

[0053] Shallow rotary tillage and water management: After application, use a rotary tiller for shallow tillage to a depth of 0–10 cm to ensure thorough mixing of the inoculant with the soil. Then adjust the soil moisture content to 60% of field capacity and maintain this level for 2 days. Under these conditions, phosphate-solubilizing bacteria rapidly multiply with the aid of molasses carbon, secreting organic acids and phosphatases to dissolve the phosphates fixed by calcium hydroxide produced from the reaction with calcium peroxide, releasing available phosphorus.

[0054] Subsequent procedures: After the moisture retention period ends, continue with the remaining fallow period. After the fallow period ends, follow the steps in Example 6 to apply nitrogen fertilizer before replanting. The procedures for other stages (first stage and second stage) are the same as in Example 6.

[0055] This embodiment effectively solves the problem of calcium hydroxide, a byproduct of calcium peroxide, fixing soil phosphorus by timely application of phosphorus-solubilizing bacteria and molasses powder after the decomposition of calcium peroxide, combined with shallow rotary tillage and appropriate water management. This allows the available phosphorus content in the soil to return to normal levels, ensuring phosphorus supply after the transplanting of the next crop, and does not antagonize subsequent nitrogen fertilizer application.

[0056] Example 8 This embodiment provides a method for improving soil health through a legume-grass-cruciferous crop rotation in soils with continuous cropping obstacles. Building upon the application of phosphate-solubilizing bacteria and molasses powder described in Example 7, mustard seed powder is further mixed evenly with the above mixture and then applied together. The specific operation is as follows: Preparation of mustard seed powder: White mustard seeds were pulverized using a grinder until they passed through an 80-mesh sieve to obtain mustard seed powder. Testing revealed that the mustard seed powder contained 65 μmol / g of glucosinolates, and the optimal pH range for endogenous myrosinase activity was 6.5–7.5.

[0057] Mixture application: On the 12th day after the third stage green manure (white radish) was turned over and left fallow (the same application time as in Example 7), the calcium peroxide granules had decomposed completely. Take the mustard seed powder prepared above and mix it evenly with the phosphate-solubilizing agent (1.5 kg / mu of freeze-dried Bacillus megaterium powder) and molasses powder (4 kg / mu) from Example 7 at a rate of 1.5 kg / mu to form a mixture. Apply this mixture evenly to the soil surface.

[0058] Shallow rotary tillage and water management: After application, use a rotary tiller for shallow tillage to a depth of 0–10 cm to ensure thorough mixing with the soil. Then adjust the soil moisture content to 65% of field capacity and maintain this level for 2 days. Under these conditions, when mustard seed powder comes into contact with water, the glucosinolates it contains are hydrolyzed by endogenous myrosinase to form isothiocyanates. These isothiocyanates can precisely inhibit soil-borne pathogens such as Fusarium oxysporum, which reactivate using molasses as a carbon source, preventing a rebound in pathogen abundance. Simultaneously, phosphate-solubilizing bacteria exhibit good tolerance to isothiocyanates, and their phosphate-solubilizing activity remains unaffected, continuing to dissolve fixed phosphates and release available phosphorus.

[0059] Subsequent operations: After the moisture retention period ends, continue with the remaining fallow time. After the fallow period ends, perform subsequent operations according to the steps in Example 7 (including applying nitrogen fertilizer before crop rotation). The operations for other stages (first stage, second stage) are the same as in Example 7.

[0060] This embodiment achieves the dual effect of releasing fixed phosphorus and preventing disease rebound simultaneously by mixing mustard seed powder with phosphorus-releasing bacteria and molasses powder during the application of phosphorus-releasing bacteria and molasses powder, thus ensuring the healthy growth and nutrient supply of the next crop.

[0061] Example 9 This embodiment provides a soil-nurturing method for sequential crop rotation of leguminous-grass-cruciferous plants in soils with continuous cropping obstacles, specifically including the following steps.

[0062] Phase 1: Planting and Turning of Leguminous Green Manure Select soil plots with continuous cropping obstacles and plant leguminous green manure vetch at a seed rate of 4 kg / mu. Before sowing, inoculate with 5 g of rhizobium powder per kilogram of seeds, using a rhizobium powder with a viable count of 1×10⁻⁶. 9 / g. Apply 10 kg / mu of superphosphate at sowing, without applying nitrogen fertilizer. During the growing season, maintain soil moisture content at 65% of field capacity through irrigation or mulching. 28 days after the legume green manure begins to grow, at the initial flowering stage, plow it into the soil to a depth of 18 cm. Irrigate immediately after plowing to bring the soil moisture content of the 0–20 cm layer to 70% of field capacity, and cover with mulch or straw to maintain this moisture content for 9 days (the entire fallow period). Leave the soil fallow for 9 days.

[0063] Phase Two: Planting and Turning of Grass Green Manure After the first phase of fallow, plant sorghum green manure (Grassaceae) on the same plot at a rate of 12.5 kg / mu. Before sowing, soak the seeds in water at 25℃ for 12 hours. Do not apply any nitrogen fertilizer after sowing; rely entirely on the residual nitrogen released from the mineralization of the previous leguminous green manure crop after incorporation. If drought occurs during the growing season, irrigate once to maintain soil moisture at 60% of field capacity. After 28 days of growth, in the early heading stage, incorporate the grass green manure into the soil. At this time, the plant's carbon-to-nitrogen ratio is 25 (achieved naturally through growth time, no nitrogen fertilizer application, and controlled watering). The incorporation depth is 18 cm. Irrigate immediately after incorporation to bring the soil moisture content of the 0–20 cm soil layer to 70% of field capacity, and cover with mulch or straw to maintain this moisture content for 11 days (the entire fallow period). Leave the land fallow for 11 days.

[0064] Phase 3: Planting and Turning of Cruciferous Green Manure After the second phase of fallowing, cruciferous green manure radishes were planted on the same plot. A deep-rooted, fleshy variety was selected, with a sowing rate of 0.75 kg / mu. No fertilizer was applied after sowing; the plants relied entirely on the nitrogen, phosphorus, and potassium released from the decomposition of the previous two crops (leguminous and gramineous) of green manure after plowing. No artificial irrigation was carried out during the growing period (watering could be done once in case of extreme drought). Twenty-eight days after the radishes began to grow, plowing was carried out at the peak flowering stage, when the glucosinolate content in the plants reached its peak. The plowing depth was 18 cm. Immediately after plowing, irrigation was carried out to bring the soil moisture content in the 0–20 cm soil layer to 70% of field capacity. The soil was then covered with mulch or straw to maintain this moisture content, and a 14-day fallow period was planned.

[0065] Additional operations during the third phase of fallow: Calcium peroxide application: On the 4th day after plowing and fallowing, evenly spread calcium peroxide granules onto the soil surface at a rate of 3 kg / mu. The particle size of the calcium peroxide granules used should be 2 mm. Irrigate immediately after application to bring the soil moisture content in the 0-15 cm layer to 70% of the field capacity. Calcium peroxide reacts slowly with water to produce oxygen and calcium hydroxide, and the decomposition process takes approximately 7 days.

[0066] Phosphate-solubilizing bacteria, molasses powder, and mustard seed powder are mixed and applied together: On the 12th day after plowing and fallowing (when the calcium peroxide granules have completely decomposed), take mustard seed powder (obtained by crushing white mustard seeds to pass through an 80-mesh sieve, with a glucosinolate content of 65 μmol / g and an optimal pH range of 6.5–7.5 for endogenous myrosinase), and apply it together at a rate of 1.5 kg / mu, evenly mixed with the phosphate-solubilizing bacteria and molasses powder. The phosphate-solubilizing bacteria is Bacillus megaterium freeze-dried powder, applied at a rate of 1.5 kg / mu, with a viable count of 1.5 × 10⁻⁶. 9 The molasses powder is a spray-dried powder of sugarcane molasses, applied at a rate of 4 kg / mu (approximately 0.067 hectares), with a total sugar content of 45%. After application, shallow rotary tillage is performed using a rotary tiller to a depth of 0–10 cm to ensure thorough mixing with the soil. The soil moisture content is then adjusted to 65% of field capacity and maintained for 2 days. During this period, upon contact with water, glucosinolates in the mustard seed powder hydrolyze under the action of endogenous myrosinase to form isothiocyanates, precisely inhibiting soil-borne pathogens that reactivate using molasses as a carbon source. Simultaneously, phosphate-solubilizing bacteria secrete organic acids and phosphatases, dissolving the phosphates fixed by calcium hydroxide generated from the reaction with calcium peroxide, releasing available phosphorus.

[0067] After the aforementioned moisture retention period ends, the remaining fallow time will continue. The total fallow period for the third stage is 14 days.

[0068] Pre-planting treatment for successor crops: After the third stage of fallow and before the transplanting of successor crops, soil samples were taken to test the soil carbon-nitrogen ratio. Based on the test results, nitrogen fertilizer was applied to adjust the soil carbon-nitrogen ratio to 20:1.

[0069] Comparative Example 1 This comparative example only involves planting and tilling leguminous green manure, without planting gramineous or cruciferous green manure. The specific steps are as follows: Select soil plots with continuous cropping obstacles and plant leguminous green manure vetch. After 28 days of growth, at the initial flowering stage, turn the leguminous green manure into the soil to a depth of 18 cm, and then leave the land fallow for 9 days. After the fallow period, directly transplant the next crop. Before transplanting, take soil samples to test the carbon-nitrogen ratio, and apply nitrogen fertilizer according to the test results to adjust the soil carbon-nitrogen ratio to 20:1.

[0070] The difference from Example 1 is that the rotation of grass and cruciferous green manure is missing.

[0071] Comparative Example 2 This comparative example only implements sequential crop rotation of leguminous and gramineous green manure, without planting cruciferous green manure. The specific steps are as follows: The first stage involves planting leguminous green manure vetch, which is then plowed into the soil at the initial flowering stage after 28 days of growth, to a depth of 18 cm, followed by 9 days of fallow. After the fallow period, the second stage involves planting grassy green manure sorghum, which is then plowed into the soil at the early heading stage after 28 days of growth, to a depth of 18 cm, followed by 11 days of fallow. After the fallow period, the next crop is directly transplanted, and nitrogen fertilizer is applied before transplanting to adjust the soil carbon-nitrogen ratio to 20:1.

[0072] The difference from Example 1 is that the third stage of cruciferous green manure rotation is missing.

[0073] Comparative Example 3 This comparative example is basically the same as Example 1, except that the growth period of the first stage of leguminous green manure is extended to 45 days, and it is turned over and mulched during the pod-setting stage; the other steps remain unchanged. Specifically: The first stage involves planting leguminous green manure vetch, which is then plowed into the soil to a depth of 18 cm after 45 days of growth (until pod formation), followed by a 9-day fallow period. The second stage involves plowing sorghum in the early heading stage after 28 days of growth, to a depth of 18 cm, followed by an 11-day fallow period. The third stage involves plowing white radish in the full flowering stage after 28 days of growth, to a depth of 18 cm, followed by a 14-day fallow period. Nitrogen fertilizer is applied before transplanting to adjust the carbon-nitrogen ratio to 20:1.

[0074] The difference from Example 1: the timing of turning in the green manure for leguminous plants is delayed from the initial flowering stage to the pod-setting stage.

[0075] Comparative Example 4 This comparative example is basically the same as Example 1, except that the amount of nitrogen fertilizer applied before transplanting is changed to make the soil carbon-nitrogen ratio 15:1, and the other steps remain unchanged.

[0076] Comparative Example 5 (Shortened fallow period: fallow time at each stage is halved) This comparative example is basically the same as Example 1, except that the fallow time for each stage is shortened: 4 days for the first stage, 5 days for the second stage, and 7 days for the third stage, while the other steps remain unchanged.

[0077] Effect Experiment 1. Soil organic matter Method: Potassium dichromate-external heating method (NY / T 1121.6-2006), air-dried soil sample passed through a 0.25 mm sieve, potassium dichromate-sulfuric acid solution added, heated in an oil bath, and titrated with ferrous sulfate.

[0078] 2. Proportion of water-stable macroaggregates Method: Wet sieve method (Elliott, 1986). Take 100 g of air-dried undisturbed soil sample, place it on a 2 mm and 0.25 mm sieve, shake it in water at 30 times / minute for 30 min, collect aggregates >0.25 mm, dry and weigh them, and calculate the proportion.

[0079] 3. Fusarium oxysporum gene copy number Methods: Real-time quantitative PCR (qPCR) was used to extract total DNA from the soil (e.g., using the MP Bio kit), and specific primers for Fusarium oxysporum were designed. A standard curve was constructed using standard plasmids, and the copy number per gram of dry soil was calculated.

[0080] 4. Incidence of bacterial wilt Methods: Field survey. 60 days after transplanting of tomatoes, the number of diseased plants (typical symptoms of bacterial wilt: wilting, bacterial oozing from stem cut surfaces) was counted. Incidence rate (%) = (number of diseased plants / total number of plants) × 100.

[0081] The results are shown in Table 1 below.

[0082] Table 1. Evaluation results of the effects of each embodiment and comparative example The data in Table 1, based on overall trends, show that in Example 1, which only implemented basic ternary crop rotation and nitrogen supplementation, soil organic matter increased from the initial 1.18% to 1.36% after 90 days, the proportion of large aggregates increased from 35.0% to 48.2%, and the Fusarium oxysporum copy number decreased to 6.0 × 10⁻⁶. 4 With reduced bacterial wilt incidence to 18.0%, this was significantly better than any single or binary crop rotation comparison. With the addition of technical features, the effect continued to improve: Example 2, through optimization of leguminous green manure seeding rate, rhizobium inoculation, and water control, increased organic matter to 1.40% and further reduced Fusarium spore count to 5.2 × 10⁻⁶. 4 Copy / g; Example 3 increased the use of gramineous seed soaking and nitrogen relay management, resulting in organic matter reaching 1.44% and the proportion of aggregates exceeding 50%; Example 4 introduced deep-rooted cruciferous varieties and glucosinolate peak overcrowding, significantly enhancing the antibacterial effect and reducing Fusarium to 4.0 × 10⁻⁶. 4 The copy number / g was reduced, and the incidence of bacterial wilt decreased to 11.0%; Example 5, through precise water control in stages after compaction, promoted aggregate formation and glucosinolate hydrolysis, with the proportion of large aggregates reaching 53.2% and the incidence rate decreasing to 9.5%; Example 6, by adding calcium peroxide for oxygenation, alleviated the hypoxia caused by the decomposition of organic matter, and the Fusarium copy number was further reduced to 3.5 × 10⁻⁶. 4 Copy / g; Example 7 utilized phosphate-solubilizing bacteria and molasses to activate fixed phosphorus, resulting in a slight increase in organic matter and aggregates; Examples 8 and 9 further introduced mustard seed powder to inhibit pathogen rebound, ultimately reducing the incidence of bacterial wilt to 8.0%, and stabilizing the Fusarium copy number at 3.4 × 10⁻⁶. 4 With a copy / g, organic matter reached 1.52%, and the proportion of large aggregates reached 54.0%, achieving comprehensive optimization in fertilization, soil improvement, and antibacterial effects.

[0083] In comparison, the effects of each comparative example were significantly weaker than those of the examples. Comparative Example 1 (single leguminous green manure) only increased organic matter to 1.33%, but the proportion of large aggregates was only 38.0%, and the Fusarium copy number was as high as 11.4 × 10⁻⁶. 4 The incidence rate was 32.0%, indicating that structural modification and antibacterial activity were almost ineffective in the absence of Poaceae and Brassicaceae. Comparative Example 2 (legume + Poaceae binary rotation) increased the aggregate ratio to 52.0%, but without the antibacterial effect of Brassicaceae, Fusarium still reached 10.2 × 10⁻⁶ copies / g. 4 The disease incidence rate was 22.0%, indicating significantly insufficient disease control. Comparative Example 3 (legumes delayed until pod-setting stage with soil turning over) suffered from nitrogen fixation, resulting in only 1.38% organic matter and 45.5% aggregates, which also affected antibacterial activity. Comparative Example 4 (excessive nitrogen supplementation leading to a low C / N ratio) inhibited glucosinolate antibacterial activity, and Fusarium rebounded to 8.0 × 10⁸ copies / g. 4 Copy / g, morbidity rate 28.0%. Comparative Example 5 (half the fallow time) showed insufficient decomposition at each stage, with all indicators being the worst, organic matter content only 1.30%, and morbidity rate as high as 30.0%.

[0084] In summary, the results in Table 1 fully demonstrate that this invention, through the sequential rotation of three functional green manures—legumes, grasses, and cruciferous plants—combined with precise water control, calcium peroxide oxygenation, phosphorus activation by phosphate-solubilizing bacteria, and disease rebound prevention by mustard seed powder, can simultaneously achieve significant improvement in soil organic matter, rapid formation of water-stable aggregates, efficient inhibition of Fusarium oxysporum, and a substantial reduction in bacterial wilt in subsequent crops within 90 days.

[0085] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention. Other modifications can be readily made by those skilled in the art; therefore, the present invention is not limited to the specific details without departing from the general concept defined by the claims and their equivalents.

Claims

1. A method for soil conservation through sequential crop rotation of Leguminosae-Poaceae-Brassicaceae in soils with continuous cropping obstacles, characterized in that, Includes the following steps: The first stage involves planting leguminous green manure. After 25-30 days of growth, the leguminous green manure is turned into the soil at the initial flowering stage, with a turning depth of 15-20 cm. The land is then left to fallow for 8-10 days. The second stage involves planting grass green manure after the fallow period ends. After 25-30 days of growth, the grass green manure is turned into the soil at the early heading stage, with a turning depth of 15-20 cm. Then, the land is left to fallow for 10-12 days. The third stage involves planting cruciferous green manure after the fallow period ends. After 25 to 30 days of growth, the cruciferous green manure is turned into the soil during the peak flowering period, with a turning depth of 15 to 20 cm. Then, the land is left to fallow for 14 to 15 days. Before transplanting the next crop, apply nitrogen fertilizer according to the soil test results to adjust the soil carbon-nitrogen ratio to 20:

1.

2. The method for soil conditioning through legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles, as described in claim 1, is characterized in that... Leguminous green manure can be vetch or milkvetch, with a sowing rate of 3-5 kg / mu for vetch or 2-3 kg / mu for milkvetch. Before sowing, inoculate with rhizobium at a ratio of 5 g of rhizobium powder per kilogram of seeds. The viable count of the rhizobium powder should be 5 × 10⁻⁶. 8 ~1×10 9 pcs / g; Apply 8–12 kg / mu of superphosphate during sowing; During the growing season, maintain soil moisture content at 60%–70% of field capacity.

3. The method for soil conditioning through legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles, as described in claim 2, is characterized in that... The grass green manure is ryegrass or sorghum, with a sowing rate of 10-15 kg / mu. Before sowing, soak the seeds in water at 20-25 ℃ for 12 hours. After sowing, use the residual nitrogen released by mineralization after the legume green manure is turned over to supply growth. During the growing period, water once or twice if there is drought to maintain the soil moisture content at 50%-70% of the field capacity. When turning over at the early heading stage, the carbon-nitrogen ratio of the grass green manure plants should be 20-30.

4. The method for soil conditioning through legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles, as described in claim 1, is characterized in that... Cruciferous green manure can be rapeseed or white radish, with a sowing rate of 1-2 kg / mu for rapeseed or 0.5-1 kg / mu for radish. For rapeseed, choose varieties with glucosinolate content greater than 20 μmol / g, and for white radish, choose fleshy, deep-rooted varieties. After sowing, utilize the nitrogen, phosphorus, and potassium nutrients released from the decomposition of the previous two crops of green manure after plowing to supply growth. Do not supplement water during the growing season, or supplement water once if there is drought. Plow and compact the plants when they are in full bloom and the glucosinolate content in the cruciferous green manure plants reaches its peak. The plowing depth is 15-20 cm. After plowing, maintain the soil moisture content at 60%-70% of the field capacity and leave the land fallow for 14-15 days to allow glucosinolates to hydrolyze into isothiocyanates under the action of soil myrosinase, which inhibits soil-borne pathogens.

5. The method for soil conditioning through legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles, as described in claim 1, is characterized in that... Irrigate after each stage of green manure incorporation to bring the soil moisture content of the 0-20 cm soil layer to 60%-75% of the field capacity, and cover with mulch or straw to maintain this moisture content; maintain this moisture content for 8-10 days after the first stage of incorporation, for 10-12 days after the second stage of incorporation, and for 14-15 days after the third stage of incorporation.

6. The method for soil conditioning through legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles, as described in claim 5, is characterized in that... On the 4th to 5th day after the third stage of plowing and fallowing, apply calcium peroxide granules evenly to the soil surface at a rate of 2-4 kg / mu. Then irrigate until the soil moisture content in the 0-15 cm layer reaches 65%-75% of the field capacity, allowing the calcium peroxide to react with water to produce oxygen and calcium hydroxide. The particle size of the calcium peroxide granules is 1-3 mm, and the decomposition lasts for 5-7 days.

7. The method for soil conditioning through leguminous-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles, as described in claim 6, is characterized in that... On the 12th day after the third stage of plowing and fallowing, once the calcium peroxide granules have decomposed, a mixture of phosphate-solubilizing bacteria and molasses powder is evenly spread on the soil surface at a rate of 1–2 kg / mu for the phosphate-solubilizing bacteria and 3–5 kg / mu for the molasses powder. Then, shallow rotary tillage is performed to mix the bacteria with the soil at a depth of 0–10 cm, maintaining the soil moisture content at 55%–65% of field capacity for 2 days. The phosphate-solubilizing bacteria is a freeze-dried powder of Bacillus megaterium or Pseudomonas fluorescens, with a viable count of 1 × 10⁻⁶. 9 ~2×10 9 The molasses powder is spray-dried sugarcane molasses powder with a total sugar content of 40% to 50%.

8. The method for soil conditioning through legume-grass-cruciferous sequential cropping rotation in soils with continuous cropping obstacles, as described in claim 7, is characterized in that... When applying the mixture of phosphate-solubilizing bacteria and molasses powder, mix mustard seed powder evenly with the mixture at a ratio of 1-2 kg / mu and apply together. The mustard seed powder is made by crushing white or brown mustard seeds to pass through an 80-mesh sieve, with a glucosinolate content of 50-80 μmol / g and an optimal pH range of 6.5-7.5 for endogenous myrosinase activity. After application, lightly till the soil layer to 0-10 cm and maintain the soil moisture content at 55%-65% of the field capacity, so that when the mustard seed powder comes into contact with water, the glucosinolates are hydrolyzed by endogenous myrosinase to form isothiocyanates.

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