油菜渍害的成因:油菜渍害在菜苗移栽到大田后的各个生长时期都可能发生。因江南一带一般年份秋、冬、春季均雨水较多,特别是在持续阴雨,地下水位高的条件下,油菜发生渍害的可能性极大。因此,渍害是油菜正常生长的一大障碍。油菜田间发生渍害的主要表现是土壤含水量过高, Cause of rape stains: rape stains in vegetable seedlings transplanted to the field after the growth period may occur. Due to the general year in the south of Yangtze River in autumn, winter and spring are more rain, especially in the continuous rainy weather, high groundwater conditions, the possibility of rape stains is extremely likely. Therefore, the stain is a major obstacle to the normal growth of rape. The main performance of rapeseed stains occurred in the field is the soil moisture content is too high,