ARS | Publication request: INFLUENCE OF FUNGAL AND BACTERIAL METABOLISM OF SOIL CARBON ON C SEQUESTRATION

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2000
Publication Date: N/A

Technical Abstract: The enhanced sequestration of C in soil is one way to reduce rising CO2 concentrations in the atmosphere. Previous work has focused on the enrichment of soil organic matter (SOM) in an effort to increase the productivity of different land use systems. The novelty of this new research is derived from an interest in optimizing C storage to reduce greenhouse gas emissions without compromising land productivity. We seek here to establish the role of soil microbial structure and function in the metabolism of freshly added C in four soils of different origin. The soils studied were collected from agricultural, desert, grassland, and forest ecosystems and have well documented management histories. The paired samples represent contrasting management histories, location along a climate gradient, or establishment age. The relative contributions of fungal and bacterial metabolism of a model C substrate were quantified. As a group, fungi have greater C use efficiencies than bacteria and therefore are more likely to govern long-term storage of C in soil. Thus, identifying the contributions of these two taxa of organisms in soils of different origin may be a fundamental piece of information necessary to designing land management strategies for enhancing C sequestration in soil. In addition to classical biochemical techniques for measuring fungal and bacterial contributions to soil respiration, we have also pursued alternate measures of the two groups: direct microscopy and phospholipid fatty acid (PLFA) analysis. The comparison of soils of different ecosystems will aid in the identification of terrestrial ecosystems best suited to being managed for the sequestration of C away from the atmosphere.