甘蔗/木薯间作系统中氮素的固定与转移

Biological Nitrogen Fixation in Sugarcane and Nitrogen Transfer from Sugarcane to Cassava in the Intercropping System

为探讨甘蔗/木薯间作系统中甘蔗的固氮量变化及氮素向木薯的转移情况。利用15N同位素稀释法进行田间示踪试验。结果表明:单作下甘蔗的固氮百分率为29.50%,固氮量为11.31 g/m2。间作下甘蔗的总固氮百分率为36.43%,它包括供甘蔗自身生长需要的固氮百分率29.90%和转移到木薯的固氮百分率6.53%;间作下甘蔗的固氮量为17.82 g/m2,其中82.07%用于自身生长需要,17.93%转移给木薯利用。间作木薯的总氮量中21.42%来自甘蔗固氮。此结果表明在单作和间作下甘蔗固氮对自身贡献的大小基本一致。甘蔗/木薯间作对甘蔗固氮有促进作用,但促进部分转移给木薯利用。

The biological nitrogen fixation in sugarcane and the fixed nitrogen transfer from sugarcane to cassava in an intercropping system were investigated.15N isotope dilution technique was used in this experiment.The experimental results showed that the nitrogen fixation rate and the nitrogen fixation amout was 29.50%,11.31 g/m2 respectively under sole sugarcane planting.In the sugarcane-cassava intercropping system,the nitrogen fixation rate was 36.43%,including 29.90% in sugarcane for its growth utilization and 6.53% in cassava transferred from sugarcane;and the nitrogen fixation amount was 17.82 g/m2,in which 82.07% for sugarcane growth and 17.93% for utilization in cassava.It is concluded that sugarcane plants received the same amount of nitrogen from biological fixation in both sole planting and intercropping systems,but it could fix more nitrogen and transfer to cassava in the sugarcane-cassava intercropping system.