Influence of sources and rates of phosphorus on plant growth, productivity and economics of aerobic rice (Oryza sativa)

A field experiment was conducted at New Delhi in rainy (kharif) season of 2013 to study the effect of 2 sources of phosphorus, viz. rock phosphate (RP) and di-ammonium phosphate (DAP), 2 levels of phosphorus viz. 15 and 30 kgP/ha and 2 microbial inoculants viz. phosphate-solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF) in different combination along with control on growth, productivity and economics of aerobic rice (Oryza sativa L.). Seed was inoculated with liquid formulation of PSB @ 250 ml/ha before sowing and AMF was applied @ 12 kg/ha in the furrows at the time of sowing. Recommended doses of N (120 kg/ha) and K (40 kg/ha) were applied in all the treatments. Results revealed that plant height, tillers/plant, dry-matter/plant, panicle/plant and yield (5.62 t/ha) of aerobic rice increased significantly due to application of 30 kg P/ha through RP + PSB + AMF. There was significant increase in plant height, tillers, dry-matter, number of panicles and grain yield of aerobic rice with increase in P application rate from 15 kg P/ha to 30 kg P/ha applied either through DAP or RP. The application of 30 kg P/ha through RP + PSB + AMF resulted in highest net return (139.0 × 10³/ha) of aerobic rice.