SOIL ORGANIC MATTER AND NUTRIENT CYCLING TO SUSTAIN AGRICULTURE IN THE SOUTHEASTERN USA
Location: Athens, Georgia
Title: Soil bacterial community composition and diversity as affected by animal manure application in pasture and cropping systems of the Southern Piedmont USA
Submitted to: Soil Biology and Biochemistry
Publication Type: Abstract Only
Publication Acceptance Date: September 16, 2006
Publication Date: September 23, 2006
Citation: Kamlesh, J., Williams, M., Franzluebbers, A.J., Jenkins, M., Endale, D.M., Coleman, D.C., Whitman, W.B. 2006. Soil bacterial community composition and diversity as affected by animal manure application in pasture and cropping systems of the Southern Piedmont USA [abstract]. Academy of the Environment Conference, January 28-February 1, 2007, Savannah, Georgia. 40:2843-2853.
While land management practices are known to have a tremendous impact on agro-ecosystems and their microbial activities, its effects on prokaryotic diversity are not well described. Seven management systems at the J. Phil Campbell, Sr., Natural Resource Center near Watkinsville, Georgia, were investigated: (1) control forest without agriculture since the Civil War, (2) cropping with inorganic fertilizer, (3) cropping with poultry litter fertilizer, (4) bermudagrass hay with inorganic fertilizer, (5) bermudagrass hay with poultry litter fertilizer, (6) bermudagrass grazed by cattle receiving inorganic fertilizer, and (7) bermudagrass grazed by cattle receiving poultry litter fertilizer. Mixed community DNA was extracted from soil, and the bacterial 16S rRNA genes were amplified in 15-cycle PCR, cloned, and then sequenced. The resulting 3706 sequences were used to analyze the community composition and diversity by RDPquery, LIBSHUFF, and other methods. LIBSHUFF analyses indicated that the bacterial communities from soils under all seven treatments were significantly different. However, the reasons for the differences are only apparent in only a few cases at this stage of the analyses. While the forest soils (1) contained the highest numbers of Acidobacteria, the poultry litter treated soils (3, 5 and 7) contained the least. Similarly, the gamma Proteobacteria were unusually abundant in soils from cropland with inorganic fertilizer (2). Interestingly, the Nitrospira were specifically present in the poultry litter treated soils (3, 5 and 7). Seasonal differences were also observed for the communities from the cropland (2 and 3) and grazed pasture receiving inorganic fertilizer (6), but not at the other treatments. The Gemmatimonadetes occurred more frequently in the inorganic fertilizer treated summer soils from both the cropland (2) and the grazed pasture (6).