水分-氮肥配合对油菜水分生产效率的影响

Effects of Soil Water and Nitrogen Fertilizer Couplingon on Water Use Efficiency of Rape(Brassica rapa L.)

[目的]研究不同水氮条件对油菜(Brassica rapa L.)水分生产效率的影响,探索其合适的水肥供应水平。[方法]采用盆栽试验方法。设置4种水分处理和4种氮素水平。水分处理分别为50%θf、60%θf、70%θf、80%θf(θf代表土壤田间持水量,各设计水平为浇后灌水上限);施氮量分别为纯氮0、0.12、0.24和0.36 g/kg(土),肥料为尿素(含氮46.2%)。[结果]油菜水分生产效率与氮肥用量、灌水控制水平关系极为密切,且水肥交互效应明显。油菜水分生产效率随着氮肥用量的增加而增加,但超过某一氮肥用量后,则表现为下降的趋势;随灌水控制水平的变化亦表现出相同趋势。各水氮处理中,水分生产效率与油菜产量具有高度的协同性,水肥协调供应是高产和提高水分生产效率的重要措施。综合考虑,灌水水平控制在田间持水量的80%、施氮量为0.24 g/kg(土)的组合是最优的。[结论]该研究可为油菜的合理灌溉和施肥提供理论依据。

[ Objective ] The purpose was to study the effects of soil water and nitrogen fertilizer conditions on water use efficiency of rape, and discuss its suitable applying level of water and fertilizer. [ Method] A pot culture experiment was conducted in greenhouse. Four water treatments were 50% θf, 60% θf, 70% θf, 80% θf（θf stood for the field moisture capacity, and each design level was the irrigation upper limit after irriga- ting） respectively; Amount of pure nitrogen fertilizer were 0, 0.12, 0.24, 0.36 g/kg （soil）, and fertilizer was urea （Nitrogen content of 46.2% ）. [ Result] The results showed that the water use efficiency of rape had a close relation with soil water content and nitrogen fertilizer ap- plication amount, and there was also a significant interaction between soil water content and nitrogen fertilizer application amount. The water use efficiency of rape increased with increasing of nitrogen fertilizer application amount, but it would decrease when nitrogen fertilizer application a- mount exceeded a certain dosage, and its trend with soil water was similar. Among different water and nitrogen fertilizer treatments, the change of water use efficiency and rape fresh weight were highly synchronous. The coordinating supplying of soil water and nitrogen fertilizer was impor- tant measures to get higher fresh weight and higher water use efficiency. Taking into accounts in all factors, the combination that soil water was controlled 80% field capacity and nitrogen rate was kept 0, 24 g/kg（soil） was the best. [ Conclusion] The study provides a theoretical basis for reasonable irrigation and fertilization in rape cultivation.