Technology model of fertilizer and pesticide reduction in rapeseed rotation

1. Background and main target issues of the modeThe three cropping rice rice oil rotation planting area in southwestern Jiangxi has the characteristics of late harvest of previous late rice, tight planting time of rapeseed, and excessive rainfall during the growth period of rapeseed, resulting in easy loss of soil nutrients. In addition, farmers generally burn straw during late rice harvesting, which not only fails to make reasonable use of organic straw energy, but also increases atmospheric pollution. The area has a high use of fertilizers and pesticides, resulting in a decrease in soil organic components year by year, The problems of acidification and hardening are becoming increasingly serious. The implementation of this technology model is based on the requirements of adapting to the development of modern rapeseed industry, focusing on green production, high-yield cultivation, high-quality and efficient, and ecological optimization. Key technologies such as “full straw return to the field, seed coating or soaking, increasing density control height, reducing fertilizer and pesticide dosage, pesticide atomization use, and full mechanized planting” are assembled and integrated, achieving a reduction of more than 25% in the use of rapeseed fertilizers and pesticides compared to conventional conventional usage, The goal of producing 130 kilograms of rapeseed per mu.2. Key technical components and operating methods of the pattern2.1 Pre broadcast requirementsThe previous crop was double season late rice, which was harvested using a tracked harvester from October 20th to 25th. The rice straw is fully crushed and covered for returning to the field, with a crushing length of about 10 cm and a stubble height of about 30 cm on the rice pile; Returning straw to the field can not only inhibit grass growth and reduce fertilizer usage, but also increase soil organic matter content through winter insulation and moisture preservation, reduce soil acidification, and optimize soil ecological structure.2.2 Variety selectionAccording to the conditions in the region, varieties such as Yangguang 131 and Fengyou 730 that have early maturity, strong disease and insect resistance, lodging resistance, short plant shape, strong branching ability, good stable yield, and are suitable for mechanized harvesting are selected.2.3 Seed treatmentSelect seed treatment methods based on the prediction and prediction of aphid occurrence by the local plant protection department. When predicting the occurrence of aphids as a high-risk year, seed coating agents (with an effective ingredient of 600 ml/L of imidacloprid) are used for seed coating treatment (10 ml of seed coating agents are used for every 300 grams of rapeseed seeds); When predicting the occurrence of aphids in lighter years, seed treatment is not necessary.2.4 Sowing and fertilizationFrom October 25th to 30th, the rapeseed precision sowing integrated machine will be used for rotary tillage and sowing; Non tillable fields use mechanical trenching for live streaming. Using precision rotary tillage seeders to complete multiple tasks such as rotary tillage, stubble removal, sowing, furrowing, ridging, fertilization, pesticide application, soil covering, and compaction in one go, with seeds sown per mu ranging from 350 to 400 g/mu; 35~40 kg of rapeseed specific slow-release fertilizer (25-7-8) is applied per mu, and the seeds and fertilizer are simultaneously sown in different locations. The fertilizer is applied by side application method, with a depth of 5cm.No-tillage direct seeding machine trenching: Mechanical sowing or manual sowing methods are used, with a sowing rate of 350-400 g/mu. A one-time application of rapeseed specific relief fertilizer (25-7-8) of 35-40 kg is used as the base fertilizer, and the fertilizer is sown simultaneously or applied together with the sowing machine to reduce operating costs and increase work efficiency. After sowing, a 35 disc trenching machine is used to open deep trenches, paired with an 80-90 horsepower tractor for power operation. The ridge width is 1.8-2 m, the trench width is 25-30 cm, and the trench depth is 25-30 cm. The surrounding areas of the field are manually repaired to ensure that the trenches are connected for easy drainage.2.5 Chemical weedingDuring sowing or before emergence, use 40 ml of 89% acetochlor and 16 ml of 48% isoxamethasone per acre to mix with 30 kg of water for soil enclosed weeding. Using a precision rapeseed seeder, it can be sprayed simultaneously with the seed fertilizer, achieving closed weeding; For those who use a zero tillage direct seeding machine for trenching and sowing, manual spraying and closed weeding can be carried out 2-3 days after sowing.2.6 Disease and pest controlWhen the occurrence of aphids is relatively severe during the seedling stage, key prevention and control measures can be taken for fields with different degrees of occurrence. During the initial flowering period, drones were used to melt 37.5 ml of 45% prochloraz and 20 ml of additives per acre. A new type of nozzle was used for atomization control of sclerotinia sclerotiorum, reducing pesticide use and increasing control effectiveness.2.7 Timely HarvestingIn late April, when more than 90% of the entire plant’s pods are yellow and the maturity of rapeseed reaches over 90%, it is the appropriate time for harvesting and can be harvested using a one-time threshing harvester. For some fields with late maturity, in order to avoid affecting early rice production in the later stage and facilitate unified harvesting, special rapeseed ripening and drying agents (standing oil) can be sprayed about 10 days before harvesting, which can be harvested in advance.3. Case study of mode application effectExperimental demonstrations were conducted in Anfu County, Jiangxi Province from 2018 to 2019 and from 2019 to 2020 to compare the reduced application of chemical fertilizers and pesticides in rapeseed under the full return of straw from the southern triple cropping late rice system with the customary planting mode of local farmers (see Table 1 for specific operations of the two treatments). Compared with the traditional planting mode of farmers (straw not returning to the field, pure nutrient input of fertilizer 22.6 kg/mu, pesticide input 326 ml/mu, manual fertilization twice a year, and application twice a year), applying this technical mode (full straw returning to the field, pure nutrient input of fertilizer 15.0 kg/mu, pesticide input 113.5 ml/mu, manual fertilization 0 times, manual application 0 times, and drone application 1 time) reduces the total nutrient input of fertilizer by 33.6% per year, On the basis of a 65.2% reduction in pesticide input, the average annual yield of rapeseed has reached 138.6 kg/mu, which is an average increase of 8.96% compared to the traditional planting mode of farmers. From the perspective of economic benefits, the annual average cost of the late rice straw full return rapeseed fertilizer and pesticide reduction technology mode is 316 yuan/mu, the total annual benefit is 970.2 yuan/mu, and the net annual income is 654.2 yuan/mu; The average annual cost of farmers’ habitual planting mode is 505 yuan/mu, the total annual benefit per mu is 890.4 yuan/mu, and the net annual income is 385.4 yuan/mu. Through comparison, the application of this project’s technical model can not only achieve the goal of saving fertilizer, reducing drugs, high yield, and efficiency, but also benefit the improvement of the ecological environment, with significant cost saving and efficiency increasing effects.