Ministry of Agriculture and Rural Affairs issues 2019-2020 autumn and winter technical guidance for rapeseed

Autumn and winter rapeseed planting is about to get fully underway. Based on this year's climate characteristics and actual production conditions, the Oilseed Expert Guidance Group of the Ministry of Agriculture and Rural Affairs, together with the National Agricultural Technology Extension Service Center, has studied and proposed the 2019—2020 autumn and winter rapeseed planting technical guidance.

(1) Adapt to local conditions and select good varieties suited to the region. According to the natural conditions and cropping systems of different regions, and under the premise of mechanized production, select rapeseed varieties that are suitable for the region and have high yield, high oil content, and suitability for mechanical harvesting. Among them: in the middle and lower reaches of the Yangtze River production area, where sclerotinia stem rot has occurred at a high rate for many consecutive years, special attention should be paid to selecting varieties resistant to sclerotinia stem rot; the southwestern region is an area where clubroot occurs, so attention should be paid to selecting new varieties resistant to clubroot, adopting delayed sowing (transplanting) dates and soil improvement to reduce the occurrence of clubroot; in the lower reaches of the Yangtze River, new high-yield, high-oil varieties that tolerate late sowing and resist sclerotinia stem rot should be selected. For direct-seeded rapeseed in the rice-rapeseed double-cropping system, medium-maturity rapeseed varieties with high yield, high oil content, and resistance to lodging and disease should be selected; for direct-seeded rapeseed in the rice-rice-rapeseed triple-cropping system in the central-southern region and early-maturing rapeseed in the Yunnan-Guizhou Plateau, new extremely early-maturing rapeseed varieties with disease resistance and lodging resistance should be selected; for dryland rapeseed, rapeseed varieties with high yield potential and resistance to lodging and disease should be selected.

(2) Sow while preserving soil moisture and improve sowing quality. The meteorological department predicts that during this year's autumn sowing period, precipitation in the main rapeseed production areas of the Yangtze River Basin may be flat or below normal, while in the rapeseed production areas of the central-southern region and the Yunnan-Guizhou Plateau it may be 20%-50% below normal, and temperatures may also be higher than in previous years. All localities should seize the favorable opportunity of residual soil moisture after rice harvest or around precipitation events, increase the sowing rate by 20%, and promptly sow while preserving soil moisture and cover with soil to conserve moisture. The southwestern region should pay attention to direct seeding and seedling raising before the Huaxi autumn rain, drain water promptly to reduce the impact of waterlogging, and for transplanted rapeseed it is recommended to use “two plants per hole” to increase transplanting density to 6000—10000 plants per mu. To ensure the quality of sowing and seedling emergence, it is recommended to use seed dressing with chemicals or seed coating, which can effectively control striped flea beetles, aphids, diamondback moths, and others during the seedling stage. Seed treatment should strictly follow the pesticide instructions to control the dosage, and after treatment the seeds should be dried promptly to prevent phytotoxicity from affecting the germination rate.

(3) Integrate agricultural machinery and agronomy to advance full-process mechanized production. Promote and apply new equipment such as rapeseed combined seeders, seeding drones, plant protection drones, and combine harvesters to accelerate full-process mechanized rapeseed production. Vigorously promote green, high-quality, and efficient rapeseed production technologies such as appropriate soil moisture management, increased planting density, one-time fertilization with slow- and controlled-release complete nutrition, seed coating, simultaneous seeding and fertilizing, and drone aerial application, so as to achieve the integration of agricultural machinery and agronomy, reduce the application of chemical fertilizers and pesticides, lower production costs, and improve rapeseed yield levels and benefits. For rice-rapeseed rotation production areas, guide rice harvesters to be equipped with synchronized straw crushing equipment to realize comprehensive utilization of rice straw returned to the field, increase soil organic matter, improve cultivated land quality, and facilitate rapeseed sowing.

(4) Fertilize scientifically to promote fertilizer reduction. It is recommended to use rapeseed-specific slow-release fertilizer, generally without the need for topdressing. Determine the fertilization amount according to the soil fertility of the previous crop and the target yield level. Generally, for rapeseed in paddy fields, apply 40—50 kg per mu of special slow-release fertilizer as base fertilizer, and for dryland rapeseed and triple-cropping rapeseed, apply 35—40 kg per mu as base fertilizer. If traditional fertilization methods are used, generally apply 10—12 kg of pure nitrogen, 3—4 kg of phosphorus pentoxide, 3—5 kg of potassium oxide, and 0.75 kg of borax per mu. Among these, 60% of the total nitrogen and potassium fertilizers and all of the phosphorus and boron fertilizers are used as base fertilizer, 20%—30% of the nitrogen fertilizer is used for pre-winter seedling promotion, and 10%—20% of the nitrogen fertilizer and 40% of the potassium fertilizer are used as bolting fertilizer.

(5) Prevent disease and resist disasters to ensure high and stable yields. First, open the “three ditches” well. Ensure the matching of the “three ditches” - the field ditch, waist ditch, and surrounding ditch - to drain water and prevent waterlogging in a timely manner; for low-lying fields and cold waterlogged fields, the depth of drainage ditches should also be increased to eliminate waterlogging stress. Second, prevent autumn and winter diseases, insects, and weeds. Use acetochlor for closed weeding or selective rapeseed herbicides for seedling-stage weeding; for seeds that have not been coated or dressed, apply pesticides promptly after emergence to control cabbage caterpillars, aphids, and flea beetles. Third, ensure safe overwintering. Some early-sown rapeseed may grow too vigorously before winter, so the amount of topdressing should be reduced and growth regulators sprayed to control excessive growth and prevent early bolting and early flowering; for fields with early bolting and early flowering, the “one vegetable, two uses” technique can be combined with picking tender stems to increase income. Fourth, strengthen “one promotion and four preventions.” In response to the year-by-year worsening trend of sclerotinia stem rot, pesticides such as prochloraz or carbendazim can be mixed with potassium dihydrogen phosphate and water-soluble boron fertilizer and sprayed on the leaves from bolting to early flowering.

(6) Expand uses and improve comprehensive planting benefits. Actively promote multifunctional development and utilization technologies for rapeseed to achieve “one rapeseed crop, multiple uses; one planting, multiple harvests,” thereby improving planting benefits and farmers' income. First, vigorously develop ornamental rapeseed. In suburban areas and areas rich in tourism resources, develop sightseeing tourism, leisure agriculture, and the beekeeping industry by planting varieties with different flower colors, designing landscape patterns, and extending the flowering period. Second, develop green manure rapeseed. Select varieties with vigorous vegetative growth and relatively high stem and leaf yields, direct-seed 500 grams per mu, and at the final flowering stage crush and incorporate the rapeseed into the field. Third, promote “dual use for vegetable and oil.” Select high-quality, high-yield, early-maturing varieties that are easy to establish early and have strong ratooning ability, sow and transplant early, and pick about 15 cm of tender stems from the top of the main stem as a vegetable to increase income from tender stems. Fourth, promote forage rapeseed. It is advisable to select “double-low” forage rapeseed varieties with low glucosinolate content, high protein content, and high green forage yield. According to feeding methods and processing requirements, carry out mechanical harvesting from the bud-bolting stage to the early pod-forming stage.