Assay of Urease Activity and Effect of Application of Neem, Shal Cakes on Urease Activity in Soils of Sundarbans Ecosystem

Urease play a key role in conversion of Urea – N to ammonium –N in soil treated with Urea. Rapid urease activity causes gaseous loss as NH3, NO2, N2O is a concerns for environment, whereas low urease activity renders most of the applied urea nitrogen unavailable to plants. In the present study the level of urease activity in six costal soils of Sundarban namely Bidya, Sudhanyakhali, Herobhanga, Kultali, Patharpratima & Netidhopani were examined Soil urease activity was correlated with soil organic carbon (O.C. %), pH, C.E.C, Clay and Silt percentage to understand whether they have any effect on urease activity of soil. Urease activity was found to be negatively correlated with O.C. %, but no significant correlation with pH, C.E.C, Clay and Silt % was found. It was further observed that addition of neem cake and Shal cakes slightly increased urease activity, and as such, no urease inhibition activity of these two cakes were found on costal soils of Sundarbans.