油菜在冬前苗期生长过程中，如果遇到外界不良因素的影响，会导致油菜叶片由绿变红，油菜发生红叶后，绿叶面积减少，光合作用降低，严重影响产量。因此，必须针对造成红叶不同原因，对症下药，及时采取措施挽救。1苗密红叶　　直播油菜，如果播种量过大，出苗过密，单株营养不 During the growth of winter rapeseed rape, if it encounters the influence of adverse factors, it will cause the rape leaves turn from green to red. After the rape leaves fall, the area of ​​green leaves will decrease and the photosynthesis will decrease, which will seriously affect the yield. Therefore, we must take into account the different causes of red leaves, the right medicine, timely measures to save. 1 Miao dense leaves broadcast rape, if the sowing is too large, the emergence of over-dense, nutrition is not single plant