Drought in the middle and lower reaches of the Yangtze River: how to plant winter rapeseed without being affected? Experts offer advice

During this year's rapeseed sowing period, rainfall in some areas of China's Yangtze River Basin was lower than the same period last year, with persistent drought occurring, which has had a certain impact on rapeseed sowing and emergence. So how can winter rapeseed be planted in the drought-affected middle and lower reaches of the Yangtze River without being affected? To guide drought-affected areas in promptly implementing autumn field management measures for winter rapeseed and vigorously advancing scientific drought resistance, the Oil Crops Expert Steering Group of the Ministry of Agriculture and Rural Affairs, together with the National Agricultural Technology Extension Service Center, studied and proposed technical guidance on drought resistance for winter rapeseed in the Yangtze River Basin. Let's hear what the experts have to say.

1. Methods for planting winter rapeseed: choose good varieties

Choose the leading varieties recommended by the agricultural authorities of each province. Leading varieties have better stress resistance and stable yield, stronger drought tolerance, can significantly increase the emergence rate, and reduce the cost of drought resistance.

2. Methods for planting winter rapeseed: sow while there is still soil moisture

Immediately after the rice harvest, sow while there is still soil moisture, making full use of the residual moisture in the paddy field to achieve rapeseed emergence. For sowing while there is still soil moisture, no-till techniques such as drone aerial seeding or manual broadcasting followed by trenching and soil covering can be used, or a combined rapeseed seeder can be used to sow seed and fertilizer together; after sowing, compaction is needed to preserve soil moisture. To cope with the possible decline in rapeseed emergence rate under drought conditions, the sowing rate should be appropriately increased to ensure the emergence rate and basic seedling number, laying the foundation for stable yield.

3. Methods for planting winter rapeseed: actively prevent disasters

Before sowing, seed treatment with a coating agent can be used; at the seedling stage, a drought-resistance agent can be sprayed on the leaves to promote root development and seedling growth and enhance drought tolerance at the seedling stage. Drought may also cause early-sown rapeseed to grow excessively; paclobutrazol can be sprayed to control excessive growth.

4. Methods for planting winter rapeseed: balanced fertilization

Under drought conditions, the fertilizer utilization capacity of rapeseed declines, causing slower growth, but for fields with sufficient basal fertilizer, it can recover quickly after soil moisture improves. Therefore, when topdressing to promote seedlings, pay attention to balanced fertilization of nitrogen, phosphorus and potassium, and avoid increasing and biased application of nitrogen fertilizer, so as to prevent lodging later and aggravate the occurrence of diseases and pests.

5. Methods for planting winter rapeseed: strengthen prevention and control

Drought can lead to insufficient early accumulation of boron nutrition in rapeseed. A mixed solution of water-soluble boron, potassium dihydrogen phosphate and carbendazim can be sprayed once each at the budding and bolting stage and the early flowering stage to promote growth and development. Under drought, biological disasters such as aphids, cabbage caterpillars, diamondback moths and viral diseases may also occur more severely, so forecasting must be strengthened and prevention and control carried out promptly to avoid outbreaks and epidemics.