Kerri Steenwerth, Louise Jackson, Mark Stromberg, Kate Scow
To determine which factors are most important in distinguishing sites with different land use histories, and to study how microbial communities affect soil processes, several experiments are underway to examine the changes in soil microbial community composition and nutrient dynamics, including trace gas efflux from soil, in response to:
The following questions are addressed in this research: Does a resource-rich soil tend to respond less dynamically and show little displacement from its present state from one season to another, or after the perturbation caused by rewetting dry soil? Is a frequently disturbed, resource-poor soil more likely to respond rapidly and strongly to changes in resource availability? How do plants affect soil microbial communities and activity? What are the effects of perturbations and rainfall on C and N loss in grassland and cultivated soils?
The approach of this work has been to describe soil quality, nutrient retention and microbial ecology including microbial biomass and activity, nutrient pools, plant biomass and composition, and CO2 and N2O efflux from soil under different sets of environmental conditions. These environmental and site factors and biological processes will be related to soil microbial community composition as determined by PLFA analysis.
References
Steenwerth, K.L., L.E. Jackson, E.A. Carlisle, and K.M. Scow. 2006. Microbial
communities of a native perennial bunchgrass do not respond consistently
across a gradient of land-use intensification. Soil Biology and Biochemistry 38:
1797-1811. ucce.ucdavis.edu/files/filelibrary/5472/28052.pdf
Steenwerth, K.L., L.E. Jackson, F.J. Calderón, K.M. Scow, and D.R. Rolston. 2005.
Response of microbial community composition and activity in agricultural and
grassland soils after a simulated rainfall. Soil Biology and Biochemistry 37:
2249-2262. ucce.ucdavis.edu/files/filelibrary/5472/28053.pdf