干旱区生态环境知识资源中心

A study was undertaken in the established benchmark soil series in different agro-ecological sub-regions of Black Soil Regions of India with the objective to assess the urease activity as a function of soil depth, bio-climate, cropping system and land use type. The urease activity declined with increase in soil depth. Maximum activity was restricted within 0-30 cm of soil depth. Cropping systems and bio-climates significantly (p < 0.01) influenced the urease activity in soil. The average urease activity in different bio-climates was in decreasing order viz. sub-humid (moist) > sub-humid (dry) > semi-arid (dry) > arid. The activity in different cropping systems was in decreasing order viz. legume- > sugarcane- > cereals- > cotton-based cropping system. Higher urease activity was observed in irrigated agro-systems as compared to the rainfed agricultural systems. High management practices increased urease activity as compared to low management. In physical properties, urease activity was negatively correlated with sand, fine clay, bulk density and available water content. Electrical conductivity, calcium carbonate and cation exchange capacity showed negative correlation in chemical properties at all the soil depths.