Effects of Bt Cotton-Based Cropping Systems and Their Fertility Levels on Succeeding Wheat Crop

Indian Agricultural Research Institute scientist Raman Jeet Singhab and I. P. S. Ahlawat conducted a study to evaluate and quantify the residual effect of two tiered intercropping of Bt cotton and groundnut with substitution of 25-50 percent recommended dose of nitrogen (RDN) for cotton by farm yard manure (FYM), on productivity and soil fertility in Bt cotton-wheat system. The study took place in New Delhi, India from 2006 to 2008.

Results showed that wheat following groundnut intercropped Bt cotton receiving 50percent RDN substitution through FYM had significantly 5 percent higher grain yield than that after sole cotton. Residual soil fertility was improved under cotton and groundnut–wheat system with substitution of 50 percent RDN for cotton by FYM. Apparent nitrogen balance in the wheat harvest was negative in most of the treatments, with greater loss recorded under pure stand of cotton–wheat system with 100 percent RDN for cotton through urea.

Based on the results, it was concluded that including a legume and organic manure in Bt-cotton-wheat system is a sustainable practice to address the increasing prices of N-fertilizers with environmental effects.

Read the abstract at http://www.tandfonline.com/doi/abs/10.1080/00103624.2014.912291#.U41dufmSwvI.