Effect of Prescribed Burning and Logging Treatments On Distribution of Soil Phosphorus Forms in a Forest Ecosystem.

Prescribed fires and logging treatments applied to forest ecosystems have short and long-term effects on changes in forest soil chemical and physical properties that impacts the soil nutrient cycle essential to the long-term sustainability of forest ecosystems. Phosphorus is an important plant nutrient in forest ecosystems, specifically in highly weathered soils such as ultisols and oxisols where P is considered as a major limiting nutrient. Forest thinning and burning practices have effects on altering soil phosphorus (P) cycle in forest ecosystems. This study was carried out on soils from Bankhead National Forest, Alabama, subjected to several prescribed burning and thinning treatments. A soil P fractionation method was utilized to identify predominant inorganic P pools in soil. Findings indicate that major P form in these soils at all depths (0-50 cm) comprises of Al/Fe bound P.  Significant changes in water soluble P and bicarbonate-P  forms were found in soils from areas subjected to certain burning and thinning treatments.Generally, thinning or burning treatments did not have any effect on Ca-P pools.  For all treatments, most of the P pools did not show any significant variations with soil depth, except for some instances, where significant accumulation of water or bicarbonate P was found in 0-10 or 10-20 cm levels. This study indicates that thinning and burning treatment has certain impacts on increasing certain P pools in soil relative to no thinning/no burn or burning only treatment.