北京地区大白菜栽培技术（四）２莲座期管理（１）浇水、中耕和蹲苗大白菜在莲座期生长速度和生长量都较大，是产量形成的重要阶段，是为包心打基础的时期，外叶的形成，球叶的分化，根系扎深和主、侧根增粗均在此时期。管理上主攻目标是促进外叶健壮发育，心叶正常分化... Cultivation Techniques of Chinese Cabbage in Beijing (Ⅳ) 2. Management of Rape Senescence (1) Watering, cultivating and squatching Chinese cabbage grow faster and more in the rosette stage, which is an important stage of yield formation, Period, the formation of the outer leaves, the differentiation of the cotyledons, roots tie deep and the main, lateral root thickening are in this period. The main goal of management is to promote the vigorous development of the outer leaves, heart leaves normal differentiation ...