Tuesday, November 6, 2007
216-6

Potential for Soil Nutrient Mobility After Prescribed Burning in >40-yr-old Loblolly Pine Forest in the Sumter National Forest, South Carolina, USA.

Marco Galang, Larry Morris, and Daniel Markewitz. Warnell School of Forestry and Natural Resources, The University of Georgia, DW Brooks Drive, Athens, GA 30602

In pine ecosystems in the Southeastern Untied States, prescribed burning is utilized for site preparation, species control, nutrient recycling, and wildlife management. Effects of prescribed burning on soil and solution chemical attributes have been assessed using paired-watersheds or plot-scale studies. As both of these are dependent on rain events which could occur either shortly after burning or not until the burned area has been covered with fresh fallen litter, results often vary. We conducted an assessment of nutrient mobility in soil before, immediately after, and three months after prescribed burning through an artificial leaching experiment. Sampling was done in a >40-yr-old loblolly pine stand at the Long Cane Ranger District, Sumter National Forest, which was thinned in 1994 and 1998 and prescribed burned in 2004. Intact soil core samples were taken before and after the most recent burn treatment of March 2007. Deionized water equivalent to 5 cm of rainfall was added and leachate extract was analyzed for pH, conductivity, dissolved reactive P, Ca, Mg, and K. Separate soil samples were also collected and analyzed for the same soil properties following standard techniques. A soil P fractionation was also included. Results reveal increased soil concentrations of extractable P and cations after prescribed burning with a potential for nutrient mobility at the site in the event of immediate rainfall after prescribed burning.