EVALUATION OF LONG TERM DIFFERENT NUTRIENT MANAGEMENT PRACTICES ON CROP PRODUCTIVITY AND SOIL QUALITY IN RICE (ORYZA SATIVA)-POTATO (SOLANUM TUBEROSUM)-GROUNDNUT (ARACHIS HYPOGAEA) CROPPING SYSTEM IN NEW ALLUVIAL SOIL ZONE OF WEST BENGAL, INDIA

Abstract

We analyzed data from a long-term rice-potato-groundnut cropping sequence to evaluate the effects of different nutrient management practices on yield trends, economics and soil fertility of the system. In this study, most of the organic and integrated treatments showed significantly higher mean system yield in terms of rice-equivalent yield (REY) of the 13th and 14th crop cyclethan that of with purely inorganic source. Highest mean rice-equivalent system yieldwas obtained in the treatment with 33% of recommended N each from FYM, vermicompost and Neem cake along with Azospirillum, Azotobacter, Rhizobium and PSB (14.96 t ha-1). In contrast with the yield result, purely inorganic treatment showed better performance compare to all other organic and integrated treatments from the economical point of view during last two 13th and 14 th cropping year. The organic nutrient-management packages increased the mean soil organic carbon and soil macronutrients (available N, P and K) at the end of 13th and 14 th cropping system cycle over the control (fallow land) and the buildup was maximum in the soil, applied with 33% of recommended N each from FYM, vermicompost and Neem cake along with Azospirillum, Azotobacter, Rhizobium and PSB (0.98%, 301.8, 61.1 and 173.3 kg/ha for organic carbon, N, P and K). The mean microbial population after thirteenth and fourteenth cropping year in terms of colony forming units increased in a higher rate in soils with organic nutrient supply system (bacteria 3.7 to 14.5 cfu g-1, fungi 3 to 12.3 cfu g-1) compared to the control as against the respective increases of 1.2 cfu g-1 and 1.8 cfu g-1 in the soils receiving nutrients through chemical fertilizers. Application of 33% of recommended N each from FYM, vermicompost and Neem cake along with Azospirillum, Azotobacter, Rhizobium and PSB was the best organic nutrient management practice compare to other studied management practices for rice–potato–groundnut cropping system in new alluvial zone of West