The role of mungbean residues and Sesbania aculeata green manure in the nitrogen economy of rice-wheat cropping system

Abstract

Field experiments were carried out to determine the effect of Sesbania aculeata L. green manuring and mungbean, Vigna radiata (L.) residue incorporation on the response of rice to urea-N and their residual effects on a subsequent spring wheat. Compared with a pre-rice fallow, Sesbania green manuring and mungbean residue increased grain yield of rice by 0.4 and 0.3 t ha⁻¹, respectively and of spring wheat by 0.6 and 0.7 t ha⁻¹, respectively when no urea-N was applied to rice and 40 kg urea-N ha⁻¹ as a basal starter dose was applied to wheat. Sesbania green manure and mungbean residue substituted for 43 and 30 kg urea-N ha⁻¹ in rice and subsequently gave a beneficial effect in spring wheat equal to the residual effect of 89 and 112 kg urea-N ha⁻¹ applied to rice, respectively. Mungbean residue remaining after the picking of pods, was found to be at par with Sesbania green manuring towards N contribution to “rice-wheat” cropping system but had an additional advantage of 0.5 to 1.3 t ha⁻¹ seed yield of protein rich mungbeans.