Contrasting phosphorus responses of pigeonpea genotypes differing in maturity duration

Abstract

To better understand interactions between crop duration and P nutrition of pigeonpea, response of a range of pigeonpea genotypes to P application was studied on an Alfisol and a Vertisol in peninsular India. Time to flowering was advanced by P application, more so in shorter duration genotypes and on Vertisol than Alfisol. In the Alfisol, P response of shoot biomass and grain yield was greater for extrashort-duration (ESD) than for short-duration (SD) genotypes. On this soil, P application depressed yield of the medium-duration (MD) genotypes. This occurred because the crops ran out of water. Plants were made more sensitive to water stress because there was less root proliferation at depth in P-fertilized, compared to unfertilized, treatments. By contrast, in the Vertisol extent of P response increased with crop duration. This was because of the greater water-holding capacity of this soil and thus increasing biomass formation, and demand for P, with increasing crop duration.