ARS | Publication request: FUNGAL AND BACTERIAL CONTRIBUTIONS TO POTENTIAL C STORAGE IN SOILS

Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: November 28, 2000
Publication Date: N/A

Technical Abstract: The storage of carbon in soils has been proposed as one way to reduce the increasing amount of CO2 in the atmosphere. The indigenous soil microbial community may transform C into soil organic matter, stabilizing and increasing its persistence in soil. To enhance this activity the main organisms of interest must first be identified. In general, it is predicted that fungi will store C in more persistent and recalcitrant forms than will bacteria. As an initial step to examining these mechanisms of C storage we used antibiotics to selectively inhibit activities of the fungal and bacterial communities in whole soils. Study sites represented a range of ecotypes; by choosing well-documented sites we were able to select sites that further contained contrastable plots. We have five study sites, each with two contrasting plots: tallgrass prairie restoration vs. neighboring farmland, agricultural land managed to zero and conventional tillage, forest plots that have received fertilization vs. those that have not, and a desert mountain that has a change in climate with a change in elevation. We found significantly higher fungal to bacterial activity ratios in soils from the cooler, moister higher position of the desert mountain (1.97) than in the hotter, drier lower position (1.64); similarly, the 21 year old prairie had a higher proportion of fungal activity (13.5) than the neighboring farmland of the same soil type (0.85). We were able to compare these results not only among ecotypes, but also between treatments within these ecotypes. Based on the data shown, we found that more intrusive land management strategies, as well as climate changes that decrease moisture and increase temperature, reduce the potential for long-term C sequestration.