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 sa- tiva 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 ap- plied 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.