我省冬油菜为白菜型油菜。常年种植面积40-50万亩,产量低而不稳。主要原因是越冬死苗严重,保收面积小,一般只占播种面积的三分之一左右。因此,抓好以越冬保苗为中心的技术措施,争取保种保收,是发展我省油菜生产的主攻目标。几年来,我们研究分析了冬油菜越冬死苗的主要原因和壮苗安全越冬的形态指标,初步确定了我省冬油菜的适宜播种期和密度。一、死苗的主要原因和壮苗的形态指标: 我省冬油菜越冬死苗有两类:一类是高脚苗、 My provincial winter rape cabbage rape. Perennial planting area of ​​40-50 mu, low yield and instability. The main reason is that the overwintering dead seedlings are seriously damaged and the area under cover is small, accounting for only about one third of the sown area. Therefore, do a good job in the winter to protect the seedlings as the center of technical measures for preservation and collection, is the development of rapeseed production in our province the main target. In recent years, we studied and analyzed the main reason of overwintering dead seedlings of winter rape, and the morphological indexes of strong seedlings overwintering, and initially determined the appropriate sowing date and density of winter rapeseed in our province. First, the main reason dead seedlings and strong seedling morphological indicators: My winter winter rape winter dead seedlings have two categories: one is the tall seedlings,