Wednesday, November 7, 2007
329-3

Influence of Land Management Practices on Selected Enzyme Activities.

Meiko Thompson, Elica M. Moss, Zachary N. Senwo, and Robert W. Taylor. Plant and Soil Science, Alabama A&M University, 4900 Meridian Street, ARC Room 158, Normal, AL 35762

All biochemical reactions are catalyzed by enzymes, which are proteins that increase the rate of chemical reactions without undergoing permanent alterations. Land use and resulting environmental impacts influence the ability of soils to process nutrients and affect soil quality. Soil enzymes, which arise from microorganisms in the soil, act as an indicator of soil change. Enzymes respond to changes in soil management practices more quickly than other soil variables; the ease of measurement and the rapid response to change make them the most useful indications of biological changes. Enzymatic assays are simple, quick, and effective ways to measure activities of soil samples, identify pathways, and identify groups of organisms. The rhizoshpere, where most microbial activity occurs, is known for increased microbial enzyme activity. However, fire often results in effects on organic matter and microbial community structure that can be detected by quantifying enzyme activity. Amidohydrolases are enzymes involved in N cycling and include amidase, urease, asparaginase, glutaminase, aspartase, which are most important in forest soils. They hydrolyze organic N substrates added to the soil to produce NH4. Soils from the Bankhead National Forest were sampled before and after treatments were applied to evaluate enzyme activity of the soils with different land management practices. Amidase, urase, asparaginase, and glutaminase activities were assayed by the methods described by Tabatabai and aspartase activity as described by Senwo and Tabatabai.