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UNDERSTANDING PLANT-SOIL RELATIONSHIPS USING CONTROLLED ENVIRONMENT FACILITIES
Citation:
Andersen, C P. AND P T. Rygiewicz. UNDERSTANDING PLANT-SOIL RELATIONSHIPS USING CONTROLLED ENVIRONMENT FACILITIES. ADVANCES IN SPACE RESEARCH 24(3):309-318, (1999).
Description:
Although soil is a component of terrestrial ecosystems, it is comprised of a complex web of interacting organisms, and therefore, can be considered itself as an ecosystem. Soil microflora and fauna derive energy from plants and plant residues and serve important functions in maintaining soil physical and chemical properties, thereby affecting net primary productivity (NPP), and in the case of contained environments, the quality of the life support system. We have been using 3 controlled-environment facilities (CEF's) that incorpoate different levels of soil biological complexity and environmental control, and differ in their resemblance to natural ecosystems, to study relationships among plant physicology, soil ecology, fluxes of minerals and nutrients, and overall ecosystem function. The simplest system utilizes growth chambers and specialized root chambers with organic-less media to study the physiology of plant-mycorrhizal associations. A second dystem incorporates natural soil in open-top chambers to study soil bacterial and fungal population response to stress. The most complex CEF incorpoates reconstructed soil profiles in a "constructed" ecosystem, enabling close examination of soil foodweb. Our results show that closed ecosystem research is important for understanding mechanisms of response to ecosystem stresses. In addition, repsonses observed at onelevel of biological complexity may not allow prediction of response at a different level of biological complexity. In closed life support systems, incorporating soil foodwebs will require less artificial manipulation to maintain system stability and sustainability.