Effect of concentrate manure and nutrient levels on enzymatic activities and microbial population under submerged rice in alluvium soil of Varanasi

A field experiment was conducted in kharif season of 2009 at Agricultural Research Farm, BHU, Varanasi. The aim of this study was to focus the effect of concentrated manure (wellgrow grain and wellgrow soil) and nutrient levels on microbial population of bacteria, fungi, actinomycetes and enzymatic activities in submerged rice soil of Varanasi. The experiment consisting nine treatments was laid out in randomised block design with three replications. Maximum dehydrogenase activity (188 μgTPF/g soil/day), urease (445 μg urea hydrolyzed/g soil/h) and phosphatase (114 μg PNP/g soil/h) at panicle initiation stage of rice were recorded with 100% RDF+200 kg wellgrow grain/ha. Enzymatic activities were positively and significantly correlated with content of organic carbon. Judicious use of 75% RDF along with 200 kg wellgrow/ha was the best combination in the applied treatments.