RESUMEN
A field experiment was conducted to study the effect of top dressing of phosphorus through complex fertilizers on rice during kharif 2009 on clayey soil at Agricultural college farm Bapatla. Phosphorus uptake was significantly influenced due to sources of P at different times of application. Significantly higher P uptake in grain and straw was recorded with application of P as basal and at maximum tillering stages either through DAP or by 20:20:0 which was on a par with three splits of DAP and 20:20:0 and basal application of DAP, SSP and 20:20:0. The available P in soil was found significant among the treatments at 30 DAT, whereas, at 60 and 90 DAT and at maturity, it was non significant. The available nitrogen and potassium in soil after the harvest of rice crop was found non significant. Gross and net returns and benefit cost ratio were higher with application of P through DAP in two equal splits at basal and maximum tillering stages followed by 20:20:0; whereas, BCR was the highest with DAP in three splits.