Effect of phosphorus enriched organic manures on p-uptake and p-availability to onion crop in Vertisol

The experiment was conducted in Kalaburagi district, which belongs to North Eastern Dry Zone (Zone-2) of Karnataka state. The experiment was laid out in split-plot design with three main plot treatments viz., control (0 Kg P2O5 ha-1), 50 per cent of recommended dose of P (30 Kg P2O5 ha-1) and 100 per cent of recommended dose of P (75 Kg P2O5 ha-1) and seven sub-plot treatments viz., no organic manure, farmyard manure @ 12 t per ha-1, vermicompost @ 6 t per ha-1, poultry manure @ 6 t per ha-1, P enriched farmyard manure @ 6 t per ha-1, P enriched vermicompost @ 3 t per ha-1 and P-enriched poultry manure @ 3 t per ha-1. Application of P-enriched organic manures at different levels of P-fertilizers had significantly increased the P-uptake of onion crop. Among different P-enriched organic manures, poultry manure gave highest uptake and available status of phosphorus.