Submitted to: Wildland Shrub Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2003
Publication Date: February 1, 2004
Citation: Blank, R.R. 2004. Enzyme activity in temperate desert soils: influence of microsite, depth, and grazing. In: Seed and Soil Dynamics in Shrubland Ecosystems. Wildland Shrub Symposium Proceedings. p. 51-53. Interpretive Summary: Soil enzymes control mineralization and therefore influence nutrient availability of N, S, and P. I investigated the influence of plant microsite and depth on soil enzyme activities in a temperate desert environment. Relative to unvegetated interspaces, plant growth overall increased soil enzymes responsible for the mineralization of N, S, and P. Enzyme activities generally decline with soil depth. Enzyme activity is an important soil attribute and may serve as a robust measure of soil health.
Technical Abstract: The enzyme status of soil influences mineralization kinetics, and thus, the supply of nutrients to plants. I quantified urease, asparaginase, glutaminase, aryl-phosphatase, and aryl-sulfatase activity in an Artemisia tridentata ecosystem northeast of Reno, NV. Enzyme activity was evaluated by depth (0-5 cm, 5-10 cm, 10-20 cm), microsite (A. tridentata, Agropyron desertorum, Bromus tectorum, microphytic crust, shrub interspace), and treatment (grazed and ungrazed). For most enzymes evaluated, there was a significant depth x microsite interaction. In general, enzyme activity declined with depth. Moreover, the interspace microsite usually had the lowest enzyme activity. In the 10-20 cm depth increment of the B. tectorum microsite, the grazed treatment had significantly higher urease activity as compared to the ungrazed treatment. Enzyme activity may be an important component in the health of rangeland soil. Future research should more intensively address temporal and microsite aspects of soil enzyme activities.