EFFECT OF SOIL AMENDMENTS ON SOIL ENZYME ACTIVITIES AND ACTIVE CARBON ON A MANAGED DOUGLAS-FIR FOREST ECOSYSTEM
Natural Resources/Aquaculture
Sam Angima
Agricultural Program Leader
OREGON STATE UNIVERSITY
Corvallis
Abstract
Effects of soil amendments on soil enzyme activities and active carbon were examined on a 25-year old forested ecosystem consisting of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) in Central Western Oregon. Five treatments were developed based on most common forest practices. The treatments were: full soil test recommended rates with weed control, half soil test recommended rates with weed control, full soil test recommended rates without weed control, weed control only, and the control. These recommendations were applied in 2004, 2005, and 2006. Soil samples were collected in 2007 and analyzed for pH, organic matter, three soil enzyme activities, and active carbon (C). Enzyme analyses were β-glucosidase, arylsulfatase, and acid phosphatase. pH range was 5.1 to 5.5 and organic matter was between 5% and 6%. Dunnett’s ANOVA indicated significant differences in β-glucosidase from soils receiving full recommendation with weed control versus the control plots. Although control plots resulted in greater numerical values, no other statistically significant differences among the treatments for the measured enzyme activities or active C were noted. Adding soil amendments to forest ecosystems helps boost nutrient content of soils and does not adversely suppress the microbial community responsible for nutrient cycling in the short term.
Authors: Angima, S. , Woodruff, T., Reeb, J., Green, S., Bouldin, J.
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Angima, S. Lincoln County Extension Agent, Oregon State University, Oregon, 97365
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Woodruff, T. Graduate Student, Arkansas State University, Arkansas, 72401
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Reeb, J. Lincoln County Extension Agent, Oregon State University, Oregon, 97365
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Green, S. Associate Professor, Arkansas State University, Arkansas, 72401
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Bouldin, J. Assistant Professor, Arkansas State University, Arkansas, 72401