郊区油菜多数与水稻轮作,土壤粘湿,加之冬早春雨多,对油菜生长发育不利。为此我们于1976年进行了油菜田不同深度的一条沟试验,结果表明,开深沟可降低地下水位,提高土温,有利油菜的生长(见表)。油菜“一三五”生长情况(单位:厘米、克、月/日) Suburb rape mostly with rice rotation, soil sticky wet, combined with rainy winter early spring, rape growth and development adversely. To this end, we carried out a trench test at different depths in a rape field in 1976. The results show that the open ditch can reduce the water table and increase the soil temperature to facilitate the growth of the rape (see table). Rape “one three five” growth (unit: cm, g, month / day)