A field experiment was carried out during kharif season of 2002 and 2003 to assess the extent of reductions in yield due to application of inorganic fertilizers below the recommended level. The NPK levels applied were @ 100%, 75% and 50% of recommended fertilizers through inorganic fertilizers. The higher values of NPK elements are required for identical increase in yield if the sources are organics. Among organics, higher amounts for Bagasse NPK are required for same increase in the yield. The NPK was twice as effective as FYM, NPK and about 4 times as effective as Bagasse NPK in terms of  increasing the yield of rice. The fertilizer P was about 4 times as efficient in increasing P uptake by rice as FYM P and more than 10 times higher as compared to Bagasse P. The fertilizer K was about 6 times and 10 times more effective than FYM and Bagasse K, respectively in enhancing the K uptake by rice.  

Keywords: Replacement value of inorganic; Organic; Rice.