Forms of Extractable Fe and Al in Forest Soils Subjected to Prescribed Burning and Thinning Treatments.

Prescribed logging and burning treatments may influence changes in forest soil chemical and physical properties. The extent of change in soil properties depends on factors such as soil characteristics and fire intensity. Some factors that affect the soil physical and chemical properties after burning include coarsening in soil texture, changes in soil pH, changes in soil mineralogy, availability of soil nutrients, and formation of recalcitrant forms of organic carbon. Fire induced soil properties may have influence in changing the extractable forms of Fe and Al in such ecosystems. Little information is available on effect of fire on changing extractable forms of Fe and Al in soils. This study was conducted to investigate the effect of prescribed burning and thinning treatments on extractable Fe and Al forms in a forest ecosystem in Bankhead National Forest, Alabama. Dithionate, oxalate, and pyrophosphate extractable Fe in the soils were analyzed from different treatment sites to differentiate crystalline, amorphous, and organically bound Fe forms. Dithionite extractable Fe and Al were in soils from all treatment sites were found to be relative high compared to  oxalate and pyrophosphate extractable Fe and Al.