Sustainability of maize-wheat cropping system by different legume intercropping and nitrogen level treatments on light distribution, soil temperature and crop productivity

Agriculture designs for cropping system with legume intercropping for increased resource use efficiency, profitability, productivity and reduced adverse environmental impact are urgently required. A three-year field experiment consisting of six cropping treatments applied during both seasons was conducted during 2008-2009 to 2010-2011 to study the effect of nitrogen and legume intercropping with maize for sustainability of maize-wheat cropping systems. Results indicate that the photosynthetic active radiation was at noon reaching nearly 1940 μmol m-2 s-1 for maize and 1620 μmol m-2 s-1 for intercropped legumes. Intercropping can increase light interception, shading and reduce evaporation as compared to sole maize. Maize intercropped had higher values of stomatal conductance and leaf temperature than pure crop. The grain yield and yield attributing characters of wheat crop increased significantly under intercropping treatments when compared with wheat only. Wheat yield significantly increased up to 160 kg N ha-1. However, there was no significant increase in yield of maize beyond 120 kg N ha-1. Sole maize-wheat rotation showed a decline in soil organic carbon by 3.7%, while black gram and cowpea intercropping with maize in paired rows (2:2 row ratio) followed by wheat had increased contents of per cent organic carbon in soil as 0.63 and 0.67, respectively, as compared to initial values of 0.54%. Plots treated with intercrops/farm yard manure (FYM) during the rainy season sustained the wheat yield while the control plot showed a decline in wheat yield by 4-9%. Key words: Sustainability, intercropping, soil temperature, crop productivity.