Effect of different sources of phosphorus on summer mungbean (Vigna radiata) in alkaline soil of Delhi

Abstract

The field experiments were conducted at the Indian Agricultural Research Institute, New Delhi for 3 years from 2002 to 2004 to study the effects of incorporation of 6 tonnes/ha of residue of wheat crop on the efficiency of diammonium phosphate (DAP) and Mussoorie rock phosphate plus inoculation of phosphorus-solubilizing bacteria (MRP + PSB) on summer mungbean var. ‘PS 16’. Application DAP @ 17.5 and 35 kg P/ha significantly increased seed yield over control by 16–34 and 39–49%, respectively, P uptake by 18–26 and 35–44%, respectively, gross returns by 13–25 and 32–41%, respectively and net return of mungbean by 23–288 and 87–278%, respectively, whereas application MRP + PSB @ 17.5, 35 and 52.5 kg P/ha increased seed yield over control by 9–17, 24–31 and 40–70%, respectively, P uptake by 7– 16, 23–35 and 38–51%, respectively, gross returns by 8–13, 18–28 and 37–56%, respectively and net returns of mungbean by 14–138, 43–146 and 85–678%, respectively. Thus, MRP + PSB at 35 and 52.5 kg/ha was at par with DAP at 17.5 and 35 kg/ha, respectively in terms of seed yield, P uptake and gross and net returns of mungbean. Agronomic efficiency ranged between 5.3 and 10.1 kg seed/kg P for DAP and between 3.1 and 6.3 kg seed/kg P for MRP + PSB. Similarly, apparent recovery of MRP + PSB was lower (3.4–7.0%) than that of DAP (7.0–10.2%). However, incorporation of residue of preceding wheat crop significantly increased the efficiency of MRP + PSB and thus MRP + PSB along with residue incorporation can be used for P fertilization in mungbean crop.