Phosphorus management in rice (Oryza sativa)-wheat (Triticum aestivum) cropping system

The trials on rice (Oryza sativa L.)-wheat (Triticum aestivum L. emend. Fio ri & Paol.) cropping system were conducted during 1991-95 at Palampur, R.S. Pura and Varanasi centres of All-india Go-ordinated Research Project on Cr opping Systems for determining the frequency of phosphorus application, so as to make judicious use of P fertilizer. Application of P2O5 @ 90 kg/ha to both rainy season (kharif) and winter (rabi) season crops every year gave maximum system productivity of 8.6 tonnes/ha. However, farmers may apply 60 kg P2O5/ha every year to rabi crops with greater net returns of Rs 22,705/ ha/year at Palampur, whereas application of 60 kg P2O5/ha to both kharif an d rabi crops every year recorded higher net returns of Rs 26,298/ha/year at R.S. Pura. Similarly, application of 60 kg P2O5/ha to rabi crops in altern ate year resulted in maximum net returns of Rs 29, 213/ha/year at Varanasi.