IMPACTS OF FERTILIZER ADDITIONS ON WATER QUALITY OF A DRAINED PINE PLANTATION, LOWER COASTAL PLAIN OF NORTH CAROLINA

Intensive plantation forestry will be increasingly important in the next 50 years to meet the high demand for domestic wood products in the US. However, forestry management practices can substantially influence downstream water quality and ecology. One of the major problems associated with poor management practices is eutrophication of surface water bodies due to excess concentrations of nitrates and phosphates. In this project, the importance of fertilization and biomass on water quality at a drained coastal pine plantation located in Carteret County, North Carolina is being studied. The pine plantation consists of three sub-watersheds, two with mature (31-year old) stands and one with a young (nine-year old) stand. One of the mature stands was commercially thinned in 2002. The un-thinned mature stand was designated as a control site and was not fertilized. The young and thinned sub-watersheds, located downstream of the control site, were fertilized with diammonium phosphate, urea, potassium sulfate and boron. Water quality monitoring sites are located at the outlet of each sub-watershed to measure nutrient (phosphates and nitrates) concentrations and surface and groundwater parameters. It is hypothesized that nutrient export from the control site will be significantly lower than the treatment watersheds because no fertilizers were applied. The nutrient concentrations as a function of seasonal outflow at the outlet of each sub-watershed will be measured. In addition, statistical analyses will be conducted to evaluate the effects of fertilization on the mature and recently planted and fertilized sub-watersheds. The overall goal of this study is to increase our understanding of nutrient transport from fertilized pine plantations. This research has further implications to issues related to Total Maximum Daily Load (TMDL) measures that are of interest to regulatory agencies and forestry managers.