Phosphorus Forms in Forest Soils Impacted by Prescribed Burning and Logging.

Disturbances caused by fire and logging could affect the type of organic compounds of C, N, S, and P that prevails in the soil which determine important physical and chemical characteristics of forest soil. These changes can affect the availability of some nutrients to the forest biota of the eco-system. This study is focused on identifying the changes in P forms in forest soils impacted by prescribed fires and logging disturbances using chemical extractions and ³¹P NMR studies. Soils for this study were collected from Bankhead National Forest in Alabama subjected to several prescribed thinning and burning treatment cycles. Labile forms of organic P in surface soils were extracted with 0.5 M NaHCO₃ while total organic P was extracted using NaOH/EDTA. Both extracts were analyzed using ³¹P NMR.  The data was compared with control soils to evaluate the impact of prescribed treatments on phosphorus forms in forest soil. Some differences were observed in P forms present in NaHCO₃ and NaOH/EDTA extracts. Pyrophosphates and polyphosphates were detected in some of the NaHCO₃ extracts. Pre-dominant organic P forms in the extracts consist of phosphate monoesters.