| An understanding of the effect of disturbance on ecosystems is needed for development of a concept of soil quality. Changes in nematode community structure and nitrogen mineralization are potential indicators of soil quality. The carrot ecosystem was used for this research. It was postulated that physical, chemical, and biological disturbances change nematode community structure and nitrogen dynamics affecting carrot growth. Three Michigan ecosystems; an organic carrot site, woodland, and corn-soybean field were evaluated in a descriptive survey of soil characteristics and nematode community structure. Three soil core disturbance trials (physical, chemical, and biological), and a microcosm study were used. Soil characteristics and nematode community structure were ecosystem and disturbance specific. Addition of an organic amendment resulted in increases in nitrogen mineralization and population densities of bacterivores. Physical disturbance caused a decrease in population densities of fungivores. The general hypothesis for this project was supported by these research findings. |
