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2007 Soil and Water Conservation Society - Soil Quality Workshop

"Soil Quality: the Foundation for Natural Resource Quality"


Cindy Cambardella

Ecosystems perform fundamental services that function to recycle nutrients, regulate hydrological processes, control erosion, and detoxify wastes. Renewal processes are carried out by communities of microorganisms that interact with plants, animals, and the physical environment. The ability of an ecosystem to continue to provide these services depends on the maintenance of biological diversity. Functional biodiversity may be more critical to ecosystem stability than taxonomic biodiversity. An important service provided by belowground ecosystems is the heterotrophic decomposition of organic matter and the concomitant recycling of plant available nutrients. Energy, carbon and nutrients are cycled through soil organic matter, primarily through the activity of bacteria and fungi. Soil nematodes, protozoa and amoebae contribute to nutrient recycling and translocation subsequent to ingesting bacteria and fungi. Decomposition processes are controlled by soil microclimate variables, such as moisture, temperature, and oxygen content, by intrinsic soil properties, such as soil texture and pH, and by the quality of the organic substrate available to the decomposers. High-input, intensive management tends to produce ecologically simplified systems that favor bacterial-pathways of decomposition, dominated by labile substrates and opportunistic, bacterial-feeding fauna. Low-input management tends to produce a more heterogeneous, complex habitat and resource base and systems that favor fungal-pathways dominated by fungal-feeding soil microfauna. The enhancement of functional biodiversity is an important ecological strategy in the development of long-term sustainable management strategies.

Cynthia Cambardella - Cynthia A. Cambardella is a Research Soil Scientist with the USDA-ARS at the National Soil Tilth Laboratory in Ames, IA, and Associate Professor of Soil Science in the Department of Agronomy at Iowa State University. She earned her PhD in Soil Science and Ecology from Colorado State University in Ft. Collins, Colorado. Research interests include understanding how changes in land-use and agricultural management impact agroecosystems through effects on C accumulation and partitioning in soil, N-use efficiency, and the formation and stabilization of soil aggregates.