ENZYME-ACTIVITIES IN APPALACHIAN SOILS .2. UREASE

The urease enzyme in many soils plays an important role in the efficient use of urea fertilizer. Urease activities in fourteen hill land soils of the Appalachian region were determined. The two top horizons from each of the soils were sampled in early spring and stored at field moist conditions at 4-degrees-C. Observed urease activities varied with soil types, and magnitude of activities were comparable to reported urease activities in other soils. Surface horizons had 1.6 times higher urease activities than subsurface horizons. Relationships between urease activities and soil pH, sand, silt and clay content were nonsignificant. Urease activities were positively related to soil C, N, forms of P and S. CEC, and original moisture content. Each soil type had its own inherent level of urease activity. The urease levels found in these hill-land soils would suggest that urea could be effectively used as N fertilizer source in the Appalachian region.