不论直播或移栽,凡越冬期只有4～5片绿叶的苗,都应列为迟发油菜。据田间苗情观察,有的绿叶嫩小,主要是迟播造成;有的叶大红黄,主要是老苗迟栽造成;有的株小叶红,新叶滞发,常是苗差、迟栽、干旱、渍涝、病虫害、缺肥、粗管等多方面因素造成。迟发油菜主要表现为:苗热瘦弱,体内积累营养少,春后易抽早薹,而且薹细茎矮,总分枝和有效分枝数减少,导致角果数和实粒数下 Whether live or transplanted, where winter only 4 to 5 green leaves of the seedlings, should be classified as delayed rape. According to field observation of seedlings, and some green leaves small, mainly caused by late sowing; some reddish brown leaves, mainly caused by late planting seedlings; some strains of small red leaves, new leaves stagnation, often poor seedlings, late planting , Drought, waterlogging, pests and diseases, lack of fat, thick tube and other factors. Delayed rapeseed mainly as: thin seedling fever, less accumulation of nutrients in the body, easy to pull early spring after sedge, and thin stalks Sedge, the total number of branches and effective branches reduced, resulting in the number of pectin and the number of real particles