Legume residue and N management for improving productivity and N economy and soil fertility in wheat (Triticum aestivum)-based cropping systems

With the objective of improving productivity, N economy and soil fertility in wheat-based cropping systems, a fixed plot field experiment was conducted during 2009-2011 with two grain legumes, viz. groundnut and soybean for residue management (stover removed and stover incorporated in the succeeding wheat crop) and maize as main plots during rainy season. Wheat was grown in winter season with four levels of N, viz. 0, 50, 100 and 150 kg N ha(-1) as subplots. Grain legumes (groundnut and soybean) as previous crops had a positive effect on growth and yield of succeeding wheat compared to the maize. Wheat grain yield was 4.59-5.02% higher under groundnut and soybean residue incorporation than residue removal. Groundnut and soybean as preceding crops recorded 9.57-10.32% more yields than maize as preceding crop to wheat. Nitrogen economy in wheat through grain legume residue incorporation was 44.5-54 kg N ha(-1). Groundnut-wheat cropping system with residue incorporation recorded the highest system productivity (WGEY) (8.84 t ha(-1)) and net returns (INR 77.5 x 10(3) ha(-1)) followed by groundnut-wheat with residue removal. Maximum soil organic carbon (0.46%) and soil available N (242 kg ha(-1)) and P (15.73 kg ha(-1)) were recorded under groundnut-wheat + groundnut residue incorporation, but the highest available K (246.3 kg ha(-1)) was recorded in soybean-wheat + soybean residue incorporation and minimum under maize-wheat. From this study, it is concluded that the inclusion of legumes in wheat-based rotations and their residue incorporation saved the N fertilizer and improved the wheat productivity and soil fertility at the end of 2-year cropping cycle.