Recycling Wood Ash in Established Loblolly Pine Plantations in Eastern North Carolina, 1992 Environmental Conference Proceedings

This study evaluated the use of loblolly pine (Pinus taeda L.) plantations to recycle paper mill wood-derived boiler ash as an alternative to landfilling. To date, cumulative ash applications have been made at rates of 0, 6.4, 13.8, and 26.9 dry metric tons/ha in a loblolly pine stand that was established in 1974. Cooperation with the North Carolina State University, Department of Agricultural Engineering and the North Carolina Department of Environment, Health and Natural Resources-Solid Waste Division led to the development of an environmental monitoring program to assure compliance with groundwater quality standards and limits on metal loading rates of soil. Soil pH, percent base saturation, and extractable Mg and K have increased significantly 15 months after initial ash applications. Calcium availability increased with increasing ash application rates, although increases were not significant. Heavy metals concentrations in shallow groundwater samples have not been affected by ash applications. Sufficient time has not elapsed to collect the data required to adequately evaluate foliar uptake of nutrients or possible differences in tree growth.