油菜在轮作中普遍认为是好茬口,但在解释其原因时,却存在种种争议,主要有“培肥养地”和“还肥省地”之说。也有人认为,油菜既无根瘤菌固氮,又是需肥较多的作物,养分取之于土,何以肥地?由此认为,油菜本身不能增加土壤中的氮素和其它营养物质。因此,搞清楚油菜培肥养地原因,在理论和实践上均有一定的意义。 试验设小麦、油菜(白菜型)、豌豆和休闲(头年7月至次年8月共休闲14个月)四个处 Rape is generally regarded as a good crop rotation in the rotation, but there are various controversies when explaining its causes, mainly including “cultivation of fertilizers and raising of fertilizers and land”. Some people think that neither rape rhizobium nitrogen fixation, but also need more fertilizer, nutrients from the soil, why fat? Therefore, the rape itself can not increase soil nitrogen and other nutrients. Therefore, figuring out the reasons for rapeseed cultivation and raising has certain significance both in theory and in practice. The experiment set wheat, rape (cabbage type), pea and leisure (July to August next year a total of 14 months of leisure) four