Development of microbial community structure in turfgrass rootzone mixtures varying by amendment, age, presence of plants, and environment.

摘要

The stability of turfgrass golf green rootzone mixtures depends on the development of a stable microbial community structure. Factors affecting microbial community development are age of the turfgrass, the location of golf greens, and the amendments added. The objective of this study was to evaluate methods for assessment of turfgrass rootzone microbial community structure and function and to apply them to field situations. Methods were identified to evaluate the microbial community in these rootzone mixtures. Metabolic diversity (BIOLOG), dehydrogenase activity, bacterial plate counts, and phospholipid fatty acid analysis were performed on turfgrass green rootzone mixture samples collected from a bench top study, established golf courses, a greenhouse study, and replicated field plots.;The utility of each of the measures of microbial communities in evaluating turfgreen stability varied between the levels of complexitiy of the study (i.e. laboratory vs. greenhouse vs. field situation). In the bench top study, BIOLOG, dehydrogenase activity, and bacterial plate counts revealed differences in the microbial community as affected by the base material of the rootzone (sand, soil) and rate of peat moss amendment. In sampling of established golf courses, BIOLOG showed differences in the microbial community, based on age of the rootzone; it was not clear if these differences were due to age or other factors such as management. In a greenhouse study, BIOLOG showed differences in the microbial community, in rootzones varying by amendement and presence of turfgrass. Fatty acid data indicated some grouping based on amendment. Dehydrogenase and bacterial plate counts did not correlate to amendment or presence of turfgrass. Dehydrogenase did show correlation with bacterial signature fatty acids detected. A final study evaluated replicate field plots varying by amendment and microclimates. BIOLOG showed grouping based on microclimate and amendment. Fatty acid data did not vary based on amendment, yet showed slight, seasonal differences in the microbial community. Dehydrogenase did show correlation with bacterial fatty acids detected.;This research demonstrated that the selected methods of microbial community activity and function were useful for evaluating rootzone mixtures, although it appears that the specific combination of tests used will depend upon the system examined.