Fine root dynamics in the upper 45 cm of the soil were monitored for one year in a laurel oak (Quercus laurifolia) community on the Coosawhatchie River floodplain, Jasper County, South Carolina. Approximately 74% of the fine root biomass was located in surface soils (0--15 cm). Minirhizotron and in-situ screen methods were used to monitor fine root production in floodplain systems and production estimates were compared among three distinct microsite types; a well-drained (WD), an intermediately drained (ID), and a poorly drained (PD) soil. Both methods proved to be useful tools for tracking fine roots in floodplain soils and revealed that greater quantities of fine roots were produced and turned over annually in better-drained soils. Fine roots in better-drained soils contributed greater quantities of higher quality root detritus to decomposer communities compared to poorly drained soils.; Decomposition dynamics were compared among four floodplain communities located throughout the southern United States. Leaf litter was combined into mixtures representative of the tree species litterfall in each community. A single-species litter collected from one site was also placed in three of these communities to assess edaphic and geographic influences on decomposition processes. After 100 weeks, the percentage of original mass remaining in litterbags ranged from five to 33 percent and from seven to 54 percent for mixed- and single-species litter, respectively. Although a number of studies have emphasized the importance of litter quality in governing decomposition, results from this study indicated that flooding, which severely alters the decomposition environment, was also important. However, variation in litter quality among the four litter mixtures was relatively low which may have served to obscure clear differences based on litter quality alone. Single-species litter varied in terms of quality but decay rates and extents for this substrate varied dramatically among the floodplain communities. This suggests that site-specific (i.e., edaphic, hydroperiod) factors also were responsible for divergent decay patterns. Litter quality differed between mixed- and single-species litter on one floodplain, and faster decay rates for the higher-quality mixed-species litter strongly suggested litter quality controls. My results did agree with other studies in which a few, brief flooding events stimulated mass loss of leaf litter to a greater extent than longer- duration flooding. Although brief periods of N and P immobilization were observed, each litter type exhibited net mineralization after 100 weeks.
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