RT - Journal Article T1 - Factors Affecting, Urease Enzyme Activity in some Soils in Isfahan Province JF - JCPP YR - 2001 JO - JCPP VO - 5 IS - 3 UR - http://jcpp.iut.ac.ir/article-1-67-en.html SP - 95 EP - 106 K1 - Urease activity K1 - Soil characteristics K1 - Correlation. AB - The urease enzyme plays an important role in the efficient use of urea fertilizer and some environmental risk assessment. Urease activities in 20 different soil samples of arid to semi-arid regions of Isfahan Province were determined and their correlations with some soil physical, chemical and biological characteristics were studied. Urease activities range from 5.3 to 79.2 µg NH4+ g-1 soil 2hr-1. Results indicated that soil organic carbon was significantly correlated with urease activity (r=0.899***). None of sand, silt and clay percentages were significantly correlated with urease activity. Total nitrogen was significantly correlated with urease activity (r=0.797***). Electrical conductivity of saturated paste extracts were also negatively correlated (r=-0.499*) but sodium adsorption ratio (SAR), pH, equivalent calcium carbonate and cation exchange capacity failed to be correlated significantly with urease activity. No significant correlations were found between urease activity and total bacteria (on nutrient agar) or total fungi (on potato dextrose agar), but the bacteria that could colonize urea-agar media were significantly correlated with urease activity (r=0.47*). Multiple stepwise regression analysis showed that organic carbon accounted for most of the variation in urease activity. LA eng UL http://jcpp.iut.ac.ir/article-1-67-en.html M3 ER -