Abstract
Soil microbial activity contributes to soil and environmental quality. A detailed description of a laboratory exercise is provided that provides direct measures of soil microbial activity in 3 soil treatments: control (soil only), alfalfa (soil + alfalfa meal) and redwood (soil + redwood sawdust) is laid out and discussed. Students assess microbial activity in several ways: by comparing the odor generated, by observing the presence of fungal mycelia and by measuring NO3 - levels in the treated soil by two methods. Measuring NO3 - levels in two ways enables students to gain an understanding of how to compare benefits and deficits of different methods used to determine the same parameter. Measures of microbial activity are related to carbon and nitrogen cycles so that students may better understand how their experimental observations relate to the cycling of organic matter and nutrients. Understanding gained by students leads to a better appreciation of how organic matter and microorganisms affect the overall health of the ecosystem. Students earned a 60% average score on a pre-laboratory quiz. Students earned a 77.1% average score after completing the laboratory and writing a laboratory report. The gain in average student score was interpreted as significant as assessed by Cohen’s D (1.27).
 10 Appel_2014 NACTA Journal.pdf | [ ] | 255 kB |
