An annual crop rotation method for soybeans, rice, and rapeseed

Abstract

The present invention provides an annual rotation method for soybeans, rice, and rapeseed. This method involves continuous cropping of soybeans, rice, and rapeseed (spring soybean - late rice - rapeseed annual rotation system) on the same piece of land within the same year (within 12 months), and adopting the side - deep fertilization technology to regulate the local nutrients in the rhizosphere of crops, improve soil health, increase crop yields, enhance the multiple cropping index, promote high yields of grain, oil, and feed, and achieve multiple improvements in environmental and economic benefits. In the above - mentioned technical solution, through rotation, not only is the single - rice continuous cropping mode broken, but also the extension of the roots during the growth of soybeans and rapeseed can be utilized to improve the soil structure, enhance the air permeability and water retention capacity of the soil, provide an excellent growth environment for the subsequent crops, and increase the comprehensive yields of rice, soybeans, and rapeseed, with high economic benefits. In addition, in the rotation system, the application of side - deep fertilization is closely combined with the growth characteristics of soybeans, rice, and rapeseed, achieving the goals of increasing production and efficiency, reducing costs, and environmental protection.

Description

Technical Field

[0001] The present invention relates to the field of planting technology, and particularly to an annual rotation method for soybeans, rice, and rapeseed. Background Art

[0002] The middle and lower reaches of the Yangtze River region has abundant light, temperature, and water resources, with superior climatic conditions, having significant advantages such as sufficient light radiation, accumulated temperature above 10°C annually exceeding 4500°C, and annual rainfall exceeding 800 millimeters. This region is an important rice production area in China. The frost-free period suitable for safe rice production is 186 to 236 days, forming a planting pattern mainly dominated by rice. In addition, soybeans, as short-day and temperature-loving crops, have a growth period of 195 to 210 days in this region and also have good growth conditions, and can form a rotation complement with rice. Rapeseed, as the second largest oil crop in China and the only oil crop in winter, has an important position in the middle and lower reaches of the Yangtze River region. Planting rapeseed can not only effectively utilize winter land resources but also improve soil structure and fertilize the soil, and is one of the typical representatives of "cultivating the land with the land" and "combining utilization and cultivation". These natural conditions enable the middle and lower reaches of the Yangtze River region to have the basic conditions for the production of rice, soybeans, and rapeseed. Multiple cropping of arable land is a common agricultural planting system in China and is of great significance for increasing the total crop yield. In the context of limited arable land resources in China, increasing the multiple cropping index is an effective way to ensure food security in China.

[0003] However, for a long time, the middle and lower reaches of the Yangtze River region mainly relied on a single continuous rice cropping mode. Along with high-intensity chemical fertilizer input, a series of soil and environmental problems have been caused. Long-term continuous rice cropping has gradually compacted the soil, affecting soil structure and fertility, and causing problems such as nitrogen loss and increased greenhouse gas emissions. These factors not only restrict the increase in rice yield per unit but also affect the quality of rice. In addition, the deterioration of soil health has also led to a severe challenge to the sustainability of agricultural production.

[0004] To solve the above problems, some attempts have been made in the prior art. For example, technical measures such as variety screening, fertilizer-saving experiments, and soil tillage have significantly improved arable land fertility, reduced environmental pollution, increased resource utilization efficiency, and played a positive role in improving product quality and increasing comprehensive benefits. However, although these individual technologies have achieved certain effects, the grain-oil-seed rotation system with higher ecological and economic benefits has not been widely applied. Increasing the multiple cropping index and implementing the annual rotation of soybeans, rice, and rapeseed can also alleviate the land competition contradiction between food crops and cash crops to a certain extent. Especially in the middle and lower reaches of the Yangtze River region, the annual high-efficiency rotation cultivation technology for rice, soybeans, and rapeseed based on full mechanization is still in the initial exploration stage and has not yet formed a mature plan for large-scale promotion and application.

[0005] In view of this, it is necessary to design an improved annual rotation method of soybean, rice and rapeseed to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a year-round crop rotation method for soybean, rice and rapeseed.

[0007] To achieve the above-mentioned object of the invention, the present invention provides a method for annual crop rotation of soybeans, rice, and rapeseed, which is applicable to the middle and lower reaches of the Yangtze River and comprises the following steps:

[0008] S1. Sow soybeans in early May using direct seeding in holes with a hole spacing of 10-13 cm and a row spacing of 40-43 cm. Sow 2-3 seeds per hole, using a seed rate of 7-9 kg per mu and a sowing depth of 3-5 cm. After sowing, perform closed weeding with a mixture of acetochlor and glyphosate.

[0009] S2. Till the soybean rows 2-3 times before closing them. Apply deep lateral fertilization to topdress the soybeans during the second node stage. Apply abamectin and beta-cyfluthrin to control pests and diseases during the second node stage. Apply abamectin, beta-cyfluthrin, Bacillus thuringiensis, and cypermethrin during the flowering and pod stage. Harvest the soybeans in mid-August.

[0010] In mid-August, transplant the 20-25-day-old rice seedlings from the nursery to the rice field. The row spacing during transplanting is 30 cm, the plant spacing is 13.3 cm, and there are two rice seedlings per root. Use a rice transplanting and side deep fertilization machine to apply base fertilizer to one side of the rice seedlings while transplanting. After transplanting, maintain a 2-3 cm shallow water layer to protect the seedlings and promote their growth.

[0011] S4. Seven days after transplanting, when the rice has returned to green, irrigate the field to maintain a 3-5 cm water layer and apply rice tillering fertilizer, broadcasting 3 kg of nitrogen fertilizer per mu. Mix benzylsulfuron-methyl into the fertilizer to control weeds in the rice field. Drain and sun-dry the field after the rice reaches the peak tillering stage to control ineffective tillering.

[0012] Topdressing before rice panicles: Apply rice panicle fertilizer during the rice panicle differentiation period, spreading 3kg of nitrogen fertilizer and 2.14kg of potassium fertilizer per mu; before topdressing, irrigate the field to a depth of 8cm to maintain moisture, which is conducive to rice filling. After the rice is filled, alternate dry and wet irrigation can be used;

[0013] During the S5 rice seedling period, tebuconazole, abamectin and pymetrozine were applied; during the rice cracking period, jinggangmycin, kasugamycin, abamectin and beta-cyfluthrin were applied; in early November, the rice was harvested with low pile retention;

[0014] In early November, transplant 35-40 day old rapeseed seedlings into the rapeseed field with a row spacing of 35-40 cm and a plant spacing of 20-23 cm, with one seedling per hole. Apply base fertilizer using deep lateral fertilization at the same time as transplanting.

[0015] S7. Topdress rapeseed during the seedling stage. 9 days after transplanting, apply fertilizer for greening and growth, broadcasting 2.80 kg of nitrogen fertilizer per mu. During the seedling stage, stalk stage, and before initial flowering, spray boron fertilizer 2-3 times per mu each time, using 3 packets of Solubor per mu. Mix 1 bucket of water per packet and spray on the leaves.

[0016] Thinning and topdressing of rapeseed seedlings is usually done twice in the seedbed. The first time is when the cotyledons are flat; the second time is when the first true leaf appears. It is required that the leaves do not overlap with each other and the seedlings do not lean against each other, and the seedlings are evenly dense and thinned. According to the seedling conditions, when the rapeseed seedlings have 3 leaves and 1 heart, paclobutrazol diluted with water is sprayed evenly, with a dosage of 30g per mu.

[0017] S8. Apply cypermethrin, thiamethoxam and ethoprop during the seedling stage; apply fluazifop, chlorpyrifos and procymidone during the bud stage; harvest rapeseed in late April of the following year and start a new round of soybean, rice and rapeseed rotation.

[0018] Furthermore, in step S2, the topdressing position is 10-12 cm deep between the two rows; 1.86 kg of nitrogen fertilizer and 1.50 kg of potassium fertilizer are applied per mu during the topdressing.

[0019] Furthermore, in step S3, the topdressing position is 5-8 cm deep between the two rows; when topdressing, 10.00 kg of nitrogen fertilizer, 2.84 kg of potassium fertilizer, and 11.41 kg of phosphorus fertilizer are applied per mu as base fertilizer.

[0020] Furthermore, in step S6, the topdressing position is 8-10 cm deep between the two rows; the application rule of base fertilizer is: 6.00 kg of nitrogen fertilizer, 3.44 kg of phosphorus fertilizer, 1.20 kg of potassium fertilizer, and 0.75 kg of borax per mu.

[0021] Furthermore, the cultivation of rice seedlings is carried out as follows: in late July, the rice seeds are soaked in warm water at about 40°C until they turn white, and then the seeds are kept warm and germinated. When the buds are about 1 cm long, they are sown. The seed rate is about 3.5 kg per mu for conventional seeds and about 1.5 kg for hybrid seeds. Rice seedlings are sown and raised. The soaked rice seeds are sown in a pre-prepared nursery field to cultivate seedlings. The nursery bed width is about 1.5 m, and the nursery bed furrow depth is 25 cm.

[0022] Further, in late September, rapeseed is sown 35 days before rice harvesting. The rapeseed is sown in the seedbed that has been prepared in advance. The width of the seedbed is 1.4 - 1.6 m, the width of the ditch is 25 - 30 cm, the depth of the surrounding ditch is 20 - 25 cm, and the depth of the middle ditch is 15 - 20 cm, which is conducive to draining waterlogging. The ratio of the field area to the seedbed area is 1:(0.1 - 0.12), that is, for 100 mu of rapeseed, 10 - 12 mu of seedbed is prepared. When sowing, the seeds and urea are evenly mixed in a weight ratio of 1:4 and then broadcast. After sowing, 100 grams of carbendazim is mixed with 30 kg of water per mu of the seedbed and evenly sprayed to prevent diseases.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The rotation method provided by the present invention involves continuous cropping of soybeans, rice, and rapeseed on the same land within the same year (within 12 months). This not only breaks the single rice continuous cropping pattern but also utilizes the root extension during the growth of soybeans and rapeseed to improve the soil structure, slow down the soil compaction problem, enhance the soil permeability and water retention capacity, and provide an excellent growth environment for the subsequent crops. In addition, rotation helps to restore the microbial activity in the soil, improve the soil fertility, and thus promote the high-yield stability of crops, increase the comprehensive yields of rice, soybeans, and rapeseed, and have high economic benefits.

[0025] 2. The rotation method provided by the present invention regulates the local nutrients in the rhizosphere by adopting the side deep fertilization technology. According to the differences in the rooting depth and nutrient requirements of different crops during the growth process, the fertilizer is accurately applied to a specific depth near the roots, increasing the nutrient concentration around the crop roots, thereby significantly improving the fertilizer utilization rate and crop absorption efficiency. The above fertilization method not only reduces the amount of chemical fertilizer used and environmental pollution but also improves the soil nutrient retention capacity, reduces soil nutrient loss, and enables the long-term maintenance of soil health and productivity. At the same time, side deep fertilization can be carried out synchronously with sowing, simplifying the operation process and improving production efficiency. In addition, in the rotation system, the application of side deep fertilization is closely combined with the growth characteristics of soybeans, rice, and rapeseed, thus achieving the goals of increasing production and efficiency, saving costs and protecting the environment.

[0026] 3. The rotation method provided by the present invention involves annual rotation of rice, soybeans, and rapeseed. By optimizing the planting pattern of soybeans in the rice rotation system (that is, the pattern of planting soybeans after harvesting rice), it makes full use of the natural resource advantages in the middle and lower reaches of the Yangtze River. While ensuring the stable production of rice, it significantly increases the yield of soybeans. The introduction of the rotation system provides a more suitable growth environment for soybeans, effectively extends the growth cycle of soybeans, and ensures the yield stability. In addition, this technology relies on full mechanization operations, simplifies the planting management process of soybeans, reduces labor costs, and further improves production efficiency.

[0027] 4. The crop rotation method provided by the present invention uses soybeans as the previous crop of rice. The unique biological nitrogen fixation effect of soybeans can fix nitrogen elements in the atmosphere and provide partial nitrogen nutrition for the subsequent rice crop. This process effectively reduces the amount of nitrogen fertilizer used in the rice planting process, reduces the planting cost, and effectively reduces the negative impact of nitrogen fertilizer on the soil and environment. By introducing the rotation system of spring soybeans - late rice - rapeseed, the natural climate conditions throughout the four seasons of the year are fully utilized, ensuring year-round plant coverage and maximizing the utilization rate of land. Through year-round plant coverage, not only the sustainable and efficient utilization of land resources is achieved, but also the occurrence frequency of weeds and pests is reduced, thereby reducing the amount of pesticides used and further achieving the goal of green agriculture. Brief Description of the Drawings

[0028] Figure 1 It shows the key growth stages of soybeans, rice and rapeseed in the annual rotation system of spring soybeans - late rice - rapeseed and brief cultivation management information. Detailed Embodiment

[0029] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the drawings and specific embodiments.

[0030] Here, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0031] In addition, it should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0032] Please refer to Figure 1 As shown, the annual rotation method of soybeans, rice and rapeseed provided by the present invention is applicable to the middle and lower reaches of the Yangtze River and includes the following steps:

[0033] S1. Soybean planting: The plot is plowed and leveled in advance, with a tillage depth of 22 - 25 cm, and the whole field is plowed and ridged, with a ridge width of 1.2 - 1.8 m. Soybeans are sown in early May, and the sowing method is direct seeding. Seeds are sown in holes, with a hole spacing of 10 - 13 cm and a row spacing of 40 - 43 cm. 2 - 3 seeds are sown in each hole, and the seeding rate per mu is 7 - 9 kg. The sowing depth is 3 - 5 cm. After sowing, 140 g of isopropyl acetochlor and 180 g of glyphosate are mixed and diluted with 60 kg of water for spraying to conduct closed weeding;

[0034] S2. Field management and harvesting: Conduct 2 - 3 cultivations before the soybeans close their rows (when the leaves of the soybean plants completely cover the ground, forming a continuous green cover layer). This not only removes weeds but also loosens the soil, enhancing root development, improving the plant's stress resistance, and regularly conduct weeding during the entire growth period of soybeans;

[0035] At the two - node stage of soybeans, use side - deep fertilization machinery to apply top - dressing 10 - 12 cm deep between two rows. Apply 1.86 kg of nitrogen fertilizer (using urea as the fertilizer source) and 1.50 kg of potassium fertilizer (using potassium chloride as the fertilizer source) per mu as top - dressing to promote the strong stems and long branches of soybeans and enhance their lodging resistance. At the pod - filling stage of soybeans, scatter 0.93 kg of nitrogen fertilizer per mu as top - dressing to promote the plump growth of pods, increase yield and quality;

[0036] At the two - node stage of soybeans, mix 10 ml of abamectin and 60 ml of beta - cyfluthrin, then dilute with 60 kg of water and spray for pest and disease control. At the flowering and pod - setting stage, mix 10 ml of abamectin, 60 ml of beta - cyfluthrin, 200 ml of Bacillus thuringiensis, and 10 ml of polybenzyl benzoate, then dilute with 60 kg of water and spray to strengthen pest and disease control, reducing insect - damaged pods and disease - spotted pods. Harvest soybeans with machinery in mid - August. After harvesting, dry the soybean grains to the storage moisture content and store them properly. Remove the soybean straw from the field;

[0037] S3. Rice planting: Irrigate the field where soybeans have been planted for 1 day, then use a rotary tiller to till to a depth of 20 - 25 cm, and use a leveling machine to level the rice field, maintaining a 1 - cm shallow water layer. In mid - August, transplant the seedlings that have been cultivated for 20 - 25 days from the seedling nursery to the rice field. The row spacing during transplantation is 30 cm, the plant spacing is 13.3 cm, and the number of seedlings per hill is two. Use an integrated rice transplanter and side - deep fertilization machine to apply basal fertilizer 5 - 8 cm deep on one side of the seedlings during transplantation, that is, apply 10.00 kg of nitrogen fertilizer, 2.84 kg of potassium fertilizer, and 11.41 kg of phosphate fertilizer (using superphosphate as the fertilizer source) per mu as basal fertilizer. After transplantation, maintain a 2 - 3 - cm shallow water layer to protect the seedlings and promote their growth;

[0038] S4. Fertilization: After the rice seedlings turn green 7 days after transplantation, irrigate the field to maintain a 3 - 5 - cm water layer and apply rice tillering fertilizer, that is, scatter 3 kg of nitrogen fertilizer per mu, and at the same time mix 80 g of bensulfuron - methyl in the fertilizer for weed control in the rice field. After the rice reaches the peak tillering stage, drain the field and sun it to control ineffective tillering;

[0039] Topdressing before the rice ear stage: At the rice young panicle differentiation stage (when 80% of the stems in the whole field reach this stage and white small villi can be seen by peeling open the inside of the rice stem), apply rice ear fertilizer, spreading 3 kg of nitrogen fertilizer and 2.14 kg of potassium fertilizer per mu; 8 cm of deep water can be irrigated before topdressing, and maintaining water retention in the field is beneficial for filling. After the rice filling is completed, the wet-dry alternate irrigation method combining shallow irrigation and natural drying can be adopted for irrigation, with the irrigation depth of 3 - 5 cm each time, and irrigation is carried out again 5 - 7 days after the surface water layer of the soil disappears, reducing the risk of lodging;

[0040] S5. Pest and disease control and harvesting: During the rice seedling stage, mix 10 ml of tebuconazole, 10 ml of abamectin, and 8 g of pymetrozine per mu and spray after diluting with 60 kg of water for pest and disease control; For pest and disease control at the rice booting stage, at the rice booting stage, mix 35 g of jinggangmycin, 40 ml of kasugamycin, 10 ml of abamectin, and 40 ml of beta-cyfluthrin per mu and spray after diluting with 60 kg of water for pest and disease control such as sheath blight, rice blast, and rice planthoppers, ensuring a smooth passage through the rice booting stage;

[0041] Use a harvesting machine to harvest the rice in early November with a stubble height of 5 - 8 cm. Dry the paddy to the storage moisture content and store it properly, and remove the rice straw from the field;

[0042] S6. Rapeseed planting: After harvesting the rice, use a tiller to till and crush the rapeseed field soil. After tilling, dig ditches and ridges. The width of the ridge is 1.8 - 2 m, the width of the ditch is 25 - 30 cm, the depth of the surrounding ditch is 20 - 25 cm, and the depth of the middle ditch is 15 - 20 cm;

[0043] In early November, transplant rapeseed seedlings with a seedling age of 35 - 40 days into the rapeseed field at a row spacing of 35 - 40 cm, a plant spacing of 20 - 25 cm, and one seedling per hole; At the same time of transplanting, use a side - deep fertilization machine to apply basal fertilizer 8 - 10 cm deep between two rows, applying 6.00 kg of nitrogen fertilizer, 3.44 kg of phosphate fertilizer, 1.20 kg of potassium fertilizer, and 0.75 kg of borax per mu as basal fertilizer;

[0044] S7. Rapeseed topdressing: For rapeseed topdressing at the seedling stage, 9 days after transplanting, apply a green - turning and growth - promoting fertilizer, that is, spread 2.80 kg of nitrogen fertilizer per mu; At the rapeseed seedling stage, bolting stage, and before the initial flowering stage, spray boron fertilizer 2 - 3 times, using 3 packs of Solubor per mu each time, and spray on the leaf surface after diluting each pack of Solubor with 30 kg of water;

[0045] Thinning and spacing of rapeseed (which means selectively removing some overcrowded seedlings after the rapeseed seedlings grow to a certain height to reduce competition among seedlings and ensure that each plant has sufficient growth space and resources), topdressing. Generally, thin the seedlings in the seedbed twice. The first time is to thin and pile up the seedlings when the cotyledons are flat; the second thinning is carried out when the first true leaf appears, requiring that the leaves do not overlap and the seedlings do not lean on each other, thinning the dense and filling the sparse; according to the seedling situation, generally when the rapeseed seedlings have three leaves and one heart, spray evenly with paclobutrazol diluted with water, with a dosage of 30 g per mu, to promote root growth and cultivate strong seedlings;

[0046] S8. Pest and disease control and harvesting: During the seedling stage, mix 8 ml of deltamethrin, 15 ml of thiamethoxam and 5 ml of ethyl garlicin per mu and spray after diluting with 60 kg of water for pest and disease control; during the budding and bolting stage, in addition to basic control, 20 ml of fluxapyroxad and 50 ml of coniothyrium minitans can be added per mu, mixed and sprayed after diluting with 60 kg of water on the base of the rapeseed stem to control sclerotinia rot; in late April of the following year, when 90-95% of the pods of rapeseed are mature, use a combine harvester for harvesting and start a new round of rotation of soybean, rice and rapeseed.

[0047] As an embodiment of the present invention, soybean seeds need to be dressed before sowing, and the dressing is carried out as follows: Select plump and undamaged soybeans as seeds, mix the soybean seeds evenly with the dressing agent for the first dressing. After the dressing is completed, dry them in a cool and ventilated place, and the seeds can be stored for up to 30 days; wait for at least 24 hours after the first dressing and then carry out the second dressing. To ensure better play of the role of the dressing agent, the seeds after the second dressing need to be sown within 1-3 days and avoid being exposed to wind and sun. Among them, the dressing agent for the first dressing is a thiamethoxam type, and the dressing agent for the second dressing is a soybean rhizobium agent.

[0048] As an embodiment of the present invention, before sowing soybeans, use a rotary tiller to plow and level the land, with a tillage depth of 20-25 cm, plow and form ridges across the whole field, and the ridge width is 1.2-1.8 m. This step improves the soil conditions and provides a suitable growth environment for soybeans.

[0049] As an embodiment of the present invention, the cultivation of rice seedlings is carried out as follows: In late July, soak the rice seeds in warm water at about 40 °C until they show white and then carry out heat preservation and germination. When the bud length is about 1 cm, sow them. The seeding rate is about 3.5 kg per mu for conventional seeds and about 1.5 kg per mu for hybrid seeds; for rice seeding and raising seedlings, sow the soaked rice seeds into the seedbed prepared in advance to cultivate seedlings. The width of the seedbed ridge is about 1.5 m, and the depth of the seedbed ditch is 25 cm. During the seedling raising process, attention should be paid to water management to ensure the healthy growth of seedlings.

[0050] As an embodiment of the present invention, the cultivation of rapeseed seedlings is carried out as follows: in late September, rapeseed seeds are sown 35 days before rice harvest, and the rapeseed is sown in a pre-prepared seedbed with a bed width of 1.4m, a ditch width of 25-30cm, a side ditch depth of 20-25cm, and a middle ditch depth of 25-20cm, which is conducive to draining water; the ratio of the field to the seedbed area is 1:(0.1-0.12), that is, 100 mu of rapeseed prepares 10-12 mu of seedbed; when sowing, the seeds and urea are mixed in a weight ratio of 1:4 and then sown. After sowing, 100 grams of carbendazim and 30 kilograms of water are evenly sprayed per mu of seedbed to prevent diseases.

[0051] The annual crop rotation method of soybean, rice and rapeseed proposed by the present invention is further described below with reference to specific embodiments:

[0052] Example 1

[0053] In this example, the annual rotation method of soybean, rice and rapeseed proposed by the present invention is applied to Xiaogan City, Hubei Province. In Examples 1-3, Zhongdou 68 is used as the mid-spring soybean, Taiyou 398 is used as the late rice variety, and Huayouza 62R is used as the rapeseed variety.

[0054] Specifically, the crop rotation method includes the following steps:

[0055] S1. Select plump, intact spring soybeans as seeds. Mix the soybean seeds with a thiamethoxam seed dressing agent evenly. After dressing, air-dry the seeds in a cool, ventilated place. The seeds can be stored for up to 30 days. Wait at least 24 hours after dressing before dressing the seeds with a soybean rhizobium agent. To ensure the best effect of the seed dressing agent, sow the seeds within 1-3 days after dressing and avoid exposure to wind and sun.

[0056] The land was plowed and leveled in advance to a depth of 25 cm, and the entire field was plowed and ridged to a width of 120 cm. Soybeans were sown on May 3rd, using direct seeding in holes with a spacing of 10 cm and a row spacing of 40 cm. Two seeds were sown per hole, with a seed rate of 7.5 kg per mu and a sowing depth of 3 cm. After sowing, 140 g of acetochlor and 180 g of glyphosate were mixed and diluted with 60 kg of water and sprayed per mu for closed weed control.

[0057] S2. Before closing the soybean rows, carry out 2-3 intertillages to remove weeds and loosen the soil, which can enhance root development and strengthen the plant's resistance to stress. Intertillage and weeding should be carried out regularly throughout the soybean growth period.

[0058] During the second node stage of soybeans, use a side deep fertilization machine to apply topdressing fertilizer at a depth of 10 cm between the two rows. Apply 1.86 kg of nitrogen fertilizer and 1.50 kg of potassium fertilizer per mu as topdressing to promote strong stalks and branches and enhance lodging resistance of soybeans. During the soybean pod and grain filling stage, apply 0.93 kg of nitrogen fertilizer per mu as topdressing to promote full growth of pods and improve yield and quality.

[0059] Apply avermectin and beta-cyfluthrin to control pests and diseases during the second soybean node stage. Apply avermectin, beta-cyfluthrin, Bacillus thuringiensis, and cypermethrin to strengthen pest and disease control during the flowering and pod stage to reduce insect-infested pods and disease-ridden pods. Harvest soybeans mechanically in mid-August. After harvesting, dry the soybeans to the storage moisture content and store them properly.

[0060] In late July, soak the rice seeds in warm water at about 40°C until they turn white, then keep warm and germinate them. Sow the seeds when the buds are about 1 cm long. The seed rate is about 3.5 kg per mu for conventional seeds and about 1.5 kg for hybrid seeds. Sow the soaked rice seeds in a pre-prepared nursery field to cultivate the seedlings. The nursery bed width is about 1.5 m, and the furrow depth is 25 cm. During the seedling cultivation process, pay attention to water management to ensure the healthy growth of the seedlings.

[0061] After soaking the soybean fields for one day, a rotary tiller was used to plow the fields to a depth of 25 cm. The rice fields were leveled with a harrow, maintaining a 1 cm shallow water layer. In mid-August, the rice seedlings, which had been cultivated for 24 days, were transplanted from the nursery fields to the rice fields. The row spacing during the transplanting process was 30 cm, the plant spacing was 13.3 cm, and there were two seedlings per plant. A rice transplanting and side deep fertilization machine was used to apply base fertilizer to a depth of 5 cm on one side of the seedlings during transplanting. 10.00 kg of nitrogen fertilizer, 2.84 kg of potassium fertilizer, and 11.41 kg of phosphorus fertilizer were applied per mu as base fertilizer. After transplanting, a 2-3 cm shallow water layer was maintained to protect the seedlings and promote their growth.

[0062] S4. Seven days after transplanting, when the rice has returned to green, irrigate the field to maintain a 3-5 cm water layer and apply rice tillering fertilizer, broadcasting 3 kg of nitrogen fertilizer per mu. Mix benzylsulfuron-methyl into the fertilizer to control weeds in the rice field. Drain and sun-dry the field after the rice reaches the peak tillering stage to control ineffective tillering.

[0063] Topdressing before rice panicles: Apply rice panicle fertilizer during the rice panicle differentiation period, spreading 3kg of nitrogen fertilizer and 2.14kg of potassium fertilizer per mu. Before topdressing, irrigate the field to a depth of 8cm to maintain moisture, which is conducive to grain filling. After the rice grain filling is completed, alternate dry and wet irrigation can be used to reduce the risk of lodging.

[0064] During S5 and rice seedling period, tebuconazole, avermectin and pymetrozine were used for pest and disease control;

[0065] During the rice-breaking period, pest and disease control measures such as Jinggangmycin, Kasugamycin, Avermectin, and Beta-cyfluthrin are used to control sheath blight, rice blast, and rice planthoppers to ensure a smooth passage through the rice-breaking period. In early November, rice is harvested using harvesting machinery at low piles, dried to storage moisture content, and then properly stored.

[0066] S6. In late September, rapeseed is sown 35 days before rice harvest. The rapeseed is sown in the pre-prepared seedbed. The width of the seedbed is 1.4 m, the width of the ditch is 30 cm, the depth of the surrounding ditch is 25 cm, and the depth of the middle ditch is 20 cm, which is conducive to draining waterlogging. The ratio of the field area to the seedbed area is 1:(0.1 - 0.12), that is, for 100 mu of rapeseed, 10 - 12 mu of seedbed is prepared. When sowing, the seeds and urea are evenly mixed in a weight ratio of 1:4 and then broadcast. After sowing, 100 grams of carbendazim is mixed with 30 kg of water per mu of the seedbed and evenly sprayed to prevent diseases.

[0067] After rice harvest, a rotary tiller is used to plow and crush the soil in the rapeseed field. After plowing, the ditch beds are opened. The width of the bed is 2 m, the width of the ditch is 30 cm, the depth of the surrounding ditch is 25 cm, and the depth of the middle ditch is 20 cm.

[0068] In early November, rapeseed seedlings with a seedling age of 35 days are transplanted into the rapeseed field at a row spacing of 40 cm, a plant spacing of 20 cm, and one seedling per hole. At the same time of transplantation, a side deep fertilization machine is used to apply basal fertilizer 8 cm deep between two rows. 6.00 kg of nitrogen fertilizer, 3.44 kg of phosphate fertilizer, 1.20 kg of potassium fertilizer, and 0.75 kg of borax are applied per mu as basal fertilizer.

[0069] S7. Topdressing for rapeseed seedlings. 9 days after transplantation, a greening and growth-promoting fertilizer is applied, and 2.80 kg of nitrogen fertilizer is broadcast per mu. During the rapeseed seedling stage, bolting stage, and before the initial flowering stage, 3 times of boron fertilizer are sprayed. Each time, 3 packages of Solubor are used per mu, and each package of Solubor is mixed with 1 bucket of water and sprayed on the leaf surface.

[0070] Thinning, spacing, and topdressing for rapeseed. Generally, the seedbed is thinned 2 times. The first thinning is to thin the crowded seedlings when the cotyledons are flat. The second thinning is carried out when the first true leaf appears, and it is required that the leaves do not overlap and the seedlings do not lean on each other, thinning the dense and filling the sparse. According to the seedling situation, generally when the rapeseed seedlings have 3 leaves and 1 heart, 30 g of paclobutrazol is evenly mixed with water and sprayed per mu to promote root growth and cultivate strong seedlings.

[0071] S8. Use deltamethrin, thiamethoxam, and ethyllicin to prevent and control diseases and pests during the seedling stage. During the bolting stage, in addition to basic prevention and control, flutriafol, coniothyrium minitans, and procymidone can be added and sprayed on the base of the rapeseed stem to prevent sclerotinia rot. In late April of the following year, when 90 - 95% of the rapeseed pods are mature, a combine harvester is used for harvesting.

[0072] Furthermore, in order to select the best soybean variety suitable for paddy field planting during the rotation process, the rotation results of Zhongdou 68, Zhongdou 52, and Edou 10 are compared, and the results are shown in Table 1. In addition, the growth periods of Zhongdou 52, Zhongdou 68, and Edou 10 are 106 days, 92 days, and 99 days respectively. Considering the above factors, Zhongdou 68 is selected as the best soybean variety for rotation.

[0073] Table 1 Yields of Different Soybean Varieties When Planted as Spring Soybeans

[0074]

[0075] In Example 1, the yields and fertilizer utilization rates of various crops are shown in Table 2. In the table, the rice yield equivalent = (the yield of the crop * the energy content per unit weight of the crop's grains) / the energy content per unit weight of rice grains. Among them, the energy contents per unit weight of rice, soybean, and rapeseed grains are 14.7, 23.7, and 27.6 MJ / kg respectively.

[0076] Table 2 Yields and fertilizer utilization rates of various crops in Example 1

[0077]

[0078] Comparative Example 1

[0079] The difference between Comparative Example 1 and Example 1 is only that: when topdressing soybeans, rice, and rapeseed, the side - deep fertilization method is not used, but topdressing is carried out in the conventional way. That is, fertilizers are applied to the roots of soybean and rapeseed plants, and fertilizers are directly spread in the rice paddy field. The weight of fertilizers used for topdressing in this step is the same as that in Example 1, and other steps and parameters are the same as those in Example 1, so they will not be elaborated here.

[0080] Comparative Example 2

[0081] The difference between Comparative Example 2 and Example 1 is only that: rapeseed is not planted during the crop rotation process. That is, after rice is harvested, the land is left idle in winter, and soybeans are directly planted in the next spring. Other steps and parameters are the same as those in Example 1, so they will not be elaborated here.

[0082] Comparative Example 3

[0083] The difference between Comparative Example 3 and Example 1 is only that: soybeans are not planted during the crop rotation process. That is, after rapeseed is harvested, rice is directly planted. Other steps and parameters are the same as those in Example 1, so they will not be elaborated here.

[0084] The yields of various crops in Example 1 and Comparative Examples 1 - 3 are shown in Table 3. In the table, the rice yield equivalent = (the yield of the crop * the energy content per unit weight of the crop's grains) / the energy content per unit weight of rice grains. Among them, the energy contents per unit weight of rice, soybean, and rapeseed grains are 14.7, 23.7, and 27.6 MJ / kg respectively.

[0085] Table 3 Yields of various crops in Example 1 and Comparative Examples 1 - 3

[0086]

[0087]

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for annual crop rotation of soybean, rice and rapeseed, characterized in that: The method is applicable to the middle and lower reaches of the Yangtze River and comprises the following steps: S1. Sow soybeans in early May using direct seeding in holes with a hole spacing of 10-13 cm and a row spacing of 40-43 cm. Sow 2-3 seeds per hole, using a seed rate of 7-9 kg per mu and a sowing depth of 3-5 cm. After sowing, perform closed weeding with a mixture of acetochlor and glyphosate. S2. Till the soybean rows 2-3 times before closing them. Apply deep lateral fertilization to topdress the soybeans during the second node stage. Apply abamectin and beta-cyfluthrin to control pests and diseases during the second node stage. Apply abamectin, beta-cyfluthrin, Bacillus thuringiensis, and cypermethrin during the flowering and pod stage. Harvest the soybeans in mid-August. In mid-August, transplant the 20-25-day-old rice seedlings from the nursery to the rice field. The row spacing during transplanting is 30 cm, the plant spacing is 13.3 cm, and there are two rice seedlings per root. Use a rice transplanting and side deep fertilization machine to apply base fertilizer to one side of the rice seedlings while transplanting. After transplanting, maintain a 2-3 cm shallow water layer to protect the seedlings and promote their growth. S4. Seven days after transplanting, when the rice has returned to green, irrigate the field to maintain a 3-5 cm water layer and apply rice tillering fertilizer, broadcasting 3 kg of nitrogen fertilizer per mu. Mix benzylsulfuron-methyl into the fertilizer to control weeds in the rice field. Drain and sun-dry the field after the rice reaches the peak tillering stage to control ineffective tillering. Topdressing before rice panicles: Apply rice panicle fertilizer during the rice panicle differentiation period, that is, apply 3kg of nitrogen fertilizer and 2.14kg of potassium fertilizer per mu; before topdressing, irrigate the field to a depth of 8cm to maintain moisture, which is conducive to rice filling. After the rice is filled, alternate dry and wet irrigation can be used; S5, during the rice seedling period, tebuconazole, avermectin and pymetrozine were applied; During the rice rupture period, jinggangmycin, kasugamycin, avermectin and beta-cyfluthrin were applied; in early November, the rice was harvested with low pile retention; In early November, transplant 35-40 day old rapeseed seedlings into the rapeseed field with a row spacing of 35-40 cm and a plant spacing of 20-23 cm, with one seedling per hole. Apply base fertilizer using deep lateral fertilization at the same time as transplanting. S7. Topdress rapeseed during the seedling stage. 9 days after transplanting, apply fertilizer for greening and tree growth, i.e., broadcast nitrogen fertilizer 2.80 kg per mu. During the seedling stage, stalk stage, and before initial flowering, spray boron fertilizer 2-3 times per mu each time, using 3 packets of Solubor per mu. Mix 1 bucket of water per packet of Solubor and spray on the leaves. Thinning and topdressing of rapeseed seedlings is usually done twice in the seedbed. The first time is when the cotyledons are flat; the second time is when the first true leaf appears. It is required that the leaves do not overlap with each other and the seedlings do not lean against each other, and the seedlings are evenly dense and thinned. According to the seedling conditions, when the rapeseed seedlings have 3 leaves and 1 heart, paclobutrazol diluted with water is sprayed evenly, with a dosage of 30g per mu. S8. Apply cypermethrin, thiamethoxam and ethoprop during the seedling stage; apply fluazifop, chlorpyrifos and procymidone during the bud stage; harvest rapeseed in late April of the following year and start a new round of soybean, rice and rapeseed rotation.

2. The crop rotation method according to claim 1, characterized in that In step S2, the topdressing position is 10-12 cm deep between the two rows; 1.86 kg of nitrogen fertilizer and 1.50 kg of potassium fertilizer are applied per mu.

3. The crop rotation method according to claim 1, wherein In step S3, the topdressing position is 5-8 cm deep between the two rows; when topdressing, 10.00 kg of nitrogen fertilizer, 2.84 kg of potassium fertilizer, and 11.41 kg of phosphorus fertilizer are applied per mu as base fertilizer.

4. The crop rotation method according to claim 1, characterized in that In step S6, the topdressing position is 8-10 cm deep between the two rows; the application rule of base fertilizer is: 6.00 kg of nitrogen fertilizer, 3.44 kg of phosphorus fertilizer, 1.20 kg of potassium fertilizer, and 0.75 kg of borax per mu.

5. The crop rotation method according to claim 1, characterized in that: The cultivation of rice seedlings is carried out as follows: in late July, the rice seeds are soaked in warm water at about 40°C until they turn white, and then kept warm to germinate. When the buds are about 1 cm long, they are sown. The seed rate is about 3.5 kg per mu for conventional seeds and about 1.5 kg for hybrid seeds. For rice sowing and seedling cultivation, the soaked rice seeds are sown in a pre-prepared nursery field to cultivate seedlings. The nursery bed width is about 1.5 m, and the nursery bed furrow depth is 25 cm.

6. The crop rotation method according to claim 1, characterized in that: In late September, rapeseed seeds are sown 35 days before rice harvest. The rapeseed is sown in the pre-prepared seedbed with a bed width of 1.4-1.6m, a ditch width of 25-30cm, a side ditch depth of 20-25cm, and a middle ditch depth of 15-20cm to facilitate the drainage of waterlogging. The ratio of field area to seedbed area is 1:(0.1-0.12), that is, 100 mu of rapeseed prepares 10-12 mu of seedbed. When sowing, the seeds and urea are mixed in a weight ratio of 1:4 and then sown. After sowing, each mu of seedbed is evenly sprayed with 100 grams of carbendazim diluted with 30 kilograms of water to prevent diseases.

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