PARENT SESSION
Poster Session #5: Soil Ecology.
Monday, August 6, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall
125
Analysis of soil microbial activity at three spatial scales in an Ohio deciduous forest landscape.
Knorr, Melissa 1, Brinkman, Jennifer1, Dress, William1, Thiet, Rachel1, Strachan, Ryan1, Swinehart, Beth1, Boerner, Ralph1, 1
ABSTRACT- Quantification of underlying patterns of variation in ecosystem parameters at multiple scales prior to application of restoration treatments is a key to subsequent evaluation of the efficacy of those treatments. In preparation for the application of a suite of fire and mechanical thinning treatments for ecosystem restoration in deciduous forests of southern Ohio, we quantified the activity rates of three soil exoenzymes (acid phosphatase, chitinase, and phenol oxidase) as measures of microbial activity in soils at three spatial scales: (1) Regional scale: three separate forested areas of 100-200 ha within 1000 km2, (2) Local scale: four neighboring watershed-size treatment units of 15-25 ha within each forested area, and (3) Topographic scale: along gradients of elevation and aspect within each treatment unit. Soil organic C and activity of all three enzymes varied significantly at the regional scale, presumably in response to parent material-driven variations in soil chemistry and fertility. Acid phosphatase activity varied significantly and consistently among watershed-size treatment units within forested areas, while variations in chitinase, phenol oxidase, and soil organic C at this scale differed greatly among forested areas. Soil moisture and acid phosphatase activity were the only parameters that varied consistently at the topographic scale. Over all scales, acid phosphatase was the most sensitive and chitinase the least sensitive indicator of underlying landscape variations in microbial activity.
KEY WORDS: soil enzymes, microbial activity, landscape, forest