Yield stability in rice (Oryza sativa)-wheat (Triticum aestivum) system under long-term fertilizer use

Field trials were conducted during 1978-79 to 1988-89 at Palampur and 1977- 78 to 1994-95 at Pantnagar while at RS Pura from 1981-82 to 1994-95 to stud y the long-term effect of inorganic fertilizer application on yield sustain ability and soil fertility in rice-wheat cropping system. The results showe d that the system's productivity could be stable over years with the applic ation of 40-80-40 kg NPK/ha at Palampur, 80-40-40 kg NPK/ha at R S Pura and 120-40-40 kg NPK/ha at Pantnagar. The soil fertility build-up was not obse rved at any of the sites with the application of NPK due to continuous crop ping of rice (Oryza sativa L.)- wheat (Triticum aestivum L. emend. Fiori & Paol.) sequence except at Palampur and Pantnagar where increase in availabl e phosphorus was noticed over the initial soil status.