Organic Matter and Clay Mineral Redistribution in Fire-Managed Alabama Ultisols.

Forest managers use prescribed burning and logging to manage forests. Logging provides fuel (charcoal), needed timber, land for other uses, and facilitates establishment of new species. Prescribed fires on the other hand helps to maintain fire dependant species, reduce the rate of spread and the intensity of wildfires, and improve forest species population dynamics. But the impact of these practices on soil properties is not well understood. The objectives of the study were to evaluate the impacts of prescribed forest fires and logging practices on soil organic matter distribution, and soil mineralogy. Nine field plots were located (3 burning patterns, 3 logging patterns) at the Bankhead National Forest, Alabama, to investigate the impacts of the practices on soils. Soils at the sites are Ultisols in the Sipsey series (Fine-loamy, siliceous, semiactive, thermic Typic Hapludults). One soil profile pit, three auger cores, and litter samples were sampled from the locations before and after treatment. Routine soil analysis, Carbon and Nitrogen analysis, and clay mineralology analysis were carried out on samples from the site. Immediate impacts of prescribed treatments to SOM were primarily restricted to soil surface horizons. Changes in exchangeable cations concentrations and pH were variable among the sites. Mineralogically, common minerals of the soils included Kaolinite, Vermiculite, Hydroxy-interlayered vermiculites, and Quartz. Other less well identified peaks at 22.5, 7.92 Å, are suspected to be reflections of a mica-vermiculite-layered mineral (hydrobiotite), a weathering product of mica. It is not clear which mineral that the peak reflects or how burning resulted in the peaks.