Yield and Nitrogen Uptake of Residual Wheat in Rice - Wheat Cropping System as Influenced by Greenmanures

摘要

Influence of greenmanure on yield and N uptake of residual wheat was studied under greenhouse condition. Three urea enriched greenmanures, viz., dhaincha (Sesbania aculeata L.), cowpea (Vigna unguiculata L.) and guar (Cyamopsis teragonoloba L.) and split application of urea was compared under rice - wheat cropping sequence. Residual effect of greenmanures and their enriched counter parts in terms of yield and N uptake of wheat was better than that of urea treated soil during preceding rice season. Negative correlation existed with both lignin content and C/N ratio whereas positive correlation existed with N content of greenmanures with grain yield, dry matter yield, grain N uptake and total N uptake of residual wheat. Efficiency of residual N utilization in terms of grain yield, dry matter yield, grain N uptake and total N uptake by wheat could be determined by the N content, lignin content and C/N ratio of greenmanures. Lignin content was found to be a better index than N content and C/N ratio inpredicting the grain yield, dry matter yield, grain N uptake and total N uptake of residual wheat. The linear regression equations involving lignin content could effectively describe 80.78 to 87.35 per cent of total variations in grain yield, dry matteryield, grain N uptake and total N uptake of residual wheat.