THE EFFECT OF CHRONIC NUTRIENT ADDITION FROM WASTEWATER ON FOREST ECOSYSTEMS AT THE RICE RIVERS CENTER

Beck, Michael.  MS Thesis

Wastewater application to land can be a useful tool for mitigating impacts of nutrient enrichment on aquatic systems. A land application treatment system at VCU’s Rice Rivers Center in Charles City County, VA provided an opportunity to study the impact of wastewater addition on the biogeochemistry of forests representative of the Mid-Atlantic Coastal Plain. Nutrient concentrations in throughfall and leachate were measured at Treatment and Control sites to assess differences in nutrient deposition and retention. Wastewater amended plots from the Walter L. Rice education building received 20-fold (N) and 6-fold (P) higher inputs relative to Control plots and plots located at the Virginia Department of Game and Inland Fisheries building. Despite higher inputs, leaching losses of P from the Rice Treatment plots were comparable to Control plots, indicating that the land-based application system effectively mitigated wastewater loads. Leaching losses of nitrate were two-fold higher from Treatment plots relative to Controls, suggesting a potential N saturation effect and a reduction in N retention capacity of the treated forest. Nitrogen effects on vegetation were indicated by lower root biomass and greater root N content among Treatment plots relative to Control plots. Overall, these results suggest that wastewater–amended plots near the Rice education building receive appreciably higher nutrient inputs and could, therefore, serve as a model system for assessing effects on forest ecosystems.

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