Effect of rates and sources of phosphorus on productivity and economics of rice (Oryza sativa) as influenced by crop-residue incorporation

Abstract

A field experiment was conducted at New Delhi for 3 years during rainy season ( kharif) of 2001 to 2003 to study the effect of crop-residue incorporation on the relative efficiency of di-ammonium phosphate (DAP) and Mussoorie rock phosphate (MRP) in rice ( Oryza sativa L.). Phosphorus application generally increased the growth and yield parameters, yields as well as gross and net returns of rice. The increase of these parameters was however signifi- cant when the rate of P application was increased from 0 to 35 kg P/ha. At 35 kg P/ha MRP in conjunction with phosphate solubilizing bacteria (PSB) was statistically on a par with DAP, increasing the grain yield by 10-17%, P uptake by 26-54%, available P content in soil by 12-99% and net profit by 15-37% over the control. Agronomic effi- ciency and apparent recovery of DAP were higher than those of MRP at 17.5 kg P/ha, but on a par with those at 35 kg P/ha. Crop-residue incorporation had no significant effect on grain yield but it significantly increased the appar- ent recovery of applied P and available P content of soil. Thus, the combined application of MRP, PSB and crop residue proved a good practice that can be used as P fertilizer for rice.