Evaluation of summer legumes for their economic feasibility, nutrient accumulation and soil fertility

A field experiment was conducted during 2007–08 at the research farm of the Indian Agricultural Research Institute, New Delhi to study summer legumes grown as a sandwich crop in ricewheat cropping system for their economic feasibility, nutrient accumulation and their residual effect on soil fertility. Cowpea residues accumulated significantly higher amount of N (97.7 and 4.56 kg/ha in shoot and root, respectively) over that in mungbean. P, K, Mn and Zn accumulation in cowpea residues were significantly higher than those in mungbean. Cowpea also performed significantly better in terms of gross return, net return and B: C ratio. Residual nutrient status in terms of available N, K, Mn and Fe in soil after harvest of dual purpose summer legumes was also higher in cowpea grown plot. However, system productivity of aromatic hybrid rice-wheat-summer legume was highest with mungbean compared to cowpea and summer fallow.