|Koger Iii, Clifford|
Submitted to: American Society of Agronomy Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/25/2004
Publication Date: 6/30/2004
Citation: Patterson, M., Zablotowicz, R.M., Weaver, M.A., Koger Iii, C.H., Wahome, J. Effect of winter flooding of rice fields on soil microbial activity and community structure. [Abstract]. American Society of Agronomy Branch Meeting.
Technical Abstract: Winter flooding of rice fields is a promising management practice that may provide a wetland habitat, promote degradation of rice straw, and reduce winter weeds. The effect of winter flooding on soil microbial populations and processes are poorly understood. This study evaluated soil microbial community structure and enzyme activity under four flooding regimes compared to non-flooded soil. Soils (0 to 2.5 cm) were sampled monthly from October 2003 to March 2004. Soil microbial communities were assessed using fatty acid methyl esters (FAMEs). Microbial activity was assessed using fluorescien diacetate (FDA) hydrolysis and triphenyl tetrazolium chloride (TTC) dehydrogenase enzyme assays. No consistent effect of flooding was observed on FDA activity, while long durations of flooding increased TTC activity compared to activity found in non-flooded plots. Long-term flooding likewise resulted in significant changes of FAME profiles as analyzed by principal component analysis indicating changes in soil microbial community in response to flooding. Major responses to flooding include a decrease in fungal FAME (18:2?6), and gram-negative bacterial FAME (18:1?9) and an increases in gram-positive bacterial FAMEs (iso16:0, antiiso15:0, iso14:0) respectively. These alterations in soil microbial community and activity are being investigated in relation to ability of soil microbial community to support the anaerobic degradation of rice straw.