Residual Effect of Pigeonpea (Cajanus cajan) on Yield and Nitrogen Response of Maize

Field experiments during 1979 and 1980 on a Vertisol soil at ICRISAT Centre, Hyderabad, India, examined the residual effect of pigeonpea (Cajanus cajan) on growth and yield of a following maize crop. Pigeonpea was grown alone or as an intercrop with sorghum fertilized or not with 80 kg N ha−1. Sorghum alone and fallow treatments were included for comparison. In the first year, the sorghum/pigeonpea intercrop produced the largest grain and dry matter yields, but the yield of intercropped pigeonpea was about 50% less than that produced by the sole crop. Pigeonpea alone had a large residual effect on maize, increasing grain yield by 57% and total plant dry matter by 32% compared with corresponding values after fallow. In comparison, intercrop pigeonpea had little residual effect. Maize following either fallow, sorghum grown alone, with or without N, or the sorghum/pigeonpea intercrop, again with or without N, required fertilizer equivalent to 38–49 kg N ha−1 in order to attain yields similar to that of unfertilized maize following sole crop pigeonpe