Soil carbon was measured on a Short Rotation Woody Crop study located on the U. S. Department of Energy's Savannah River Institute outside Aiken, SC.  This study was a three-way, complete factorial, split-plot design including fertilization, irrigation and five tree species.  The tree species were sweetgum (Liquidambar styraciflua L.), loblolly pine (Pinus taeda L.), sycamore (Platanus occidentalis L.) and two eastern cottonwood (Populus deltoides Bartr.) clones.  The predominant soil series on the site is the Blanton series (thermic, Grossarenic Paleudults).  Prior to study installation, the previous pine stand was harvested and the remaining slash and stumps were pulverized and incorporated 30 cm into the soil by a RS-500 Reclaimer/Stabilizer.  Three years after study installation, site preparation increased total soil carbon and mineral associated carbon at all depths except the 45 – 105 cm depth, where there was carbon loss.  During tilling, stumps were uprooted and the residue was concentrated in the upper soil depths; thus, diminishing necromass at lower depths.  When utilizing the full statistical model, no significant difference in soil carbon contents, at any depth, between the treatments or tree species were detected.  However, when we examined tree response to the individual treatments, one cottonwood clone (ST66), when irrigated and fertilized, had higher soil carbon and mineral associated carbon in the upper 30 cm compared to the other tree species.  This suggests that root development in ST66 may have been stimulated by the irrigation plus fertilization treatment.  This effect was not observed for any other tree/treatment combination.  The observed difference between the two cottonwood clones may be a result of their origin.  The S7C15 clone originated from east Texas and may be more tolerant of low soil moisture and nutrient content than the ST66 clone which originated along the Mississippi River in Issaquena County, Mississippi.