When did winter wheat start jointing in the middle and lower reaches of the Yangtze River?

The sowing date of winter wheat in the middle and lower reaches of the Yangtze River is prolonged, the seedling situation is complicated, the sowing of wheat after rice is late, the seedling situation is weak, and the soil in some areas is wet. It is necessary to do a good job in promoting the weak to become strong, applying jointing fertilizers, clearing ditches and regulating soil moisture, preventing waterlogging, preventing "late spring cold" and preventing diseases, weeds and pests in time.

(1) applying tiller fertilizer to strengthen the weak. For fields with insufficient basal seedling fertilizer and small population (tiller number per mu is less than 3,), especially for weak seedlings sown late, 1-15 kilograms of ternary high-efficiency compound fertilizer (15% for N, P2O5 and K2O respectively) can be topdressing per mu, and 5 kilograms of urea should be added per mu for those with large straw returning amount and weak seedling condition, so as to promote the transformation and upgrading of seedling condition.

(2) applying jointing fertilizer to strengthen stalks and ears. For the first-class and second-class seedling wheat fields with suitable number of tillers, when the leaf color fades normally and the first internode at the base of the plant is close to a fixed length, jointing fertilizer is applied topdressing. Generally, 5 kg of urea and 1-15 kg of ternary high-efficiency compound fertilizer are applied per mu. For wheat fields with too large population and abnormal leaf color fading, the application of jointing fertilizer should be appropriately delayed to prevent lodging. For the three kinds of seedlings with too small population and insufficient tillers, and the wheat fields with serious fertilization and yellowing, jointing fertilizer should be applied appropriately early.