Phosphorus management in rice (Oryza sativa jwheat .(flzticum aestivum) cropping system

The trials on rice (Oryza sativa L.)-wheal (Tritcum aestivum L emend. Fiori & Paol.) cropping system were conducted during 1991-95 at Palampur, R.S. Pura and Varanasi centres of All-India Co-ordinated Research Project on Cropping Systems for determining the frequency of phosphorus application, so as to make judicious use of P fertilizer. Application of P,O,@ 90 kglha to both rainy season (khariq and winter (rabq season crops every year gave maximum system productivity of 8.6 tonneslha. However, fanners may apply 60 kg P20@a every year to rabi crops with greater net returns of Rs 22,705lhdyear at Palampur, whereas application of 60, kg P20Jha to both kharif and rabi crops every year recorded higher net returns of Rs 26,298lhdyear at R.S. Pura. Similarly, application of 60 kg P,OJha to rabicrops in alternate year resulted in maximum net returns of Rs 29,213/ha/year at Varanasi.