Clay Mineral Transformation In Fire-Affected Forest Soil of Northern Alabama.

Forest management practices such as prescribed burning are commonly used to restore degraded forest communities in southern forest regions. While influence of prescribed burning on soil chemical properties is generally well studied, less is known about fire impact on mineral suite transformations. This study was conducted to investigate effects of prescribed burning on mineralogy of a Typic Hapludults in Northern Alabama. Prescribed burning was carried on during wetter winter months, resulting in low-intensity, low-temperature burn with surface temperatures reaching 150-200ºC. Composite soil samples were collected from four depths (0-5, 5-10, 10-15 and 15-20 cm) at three locations prior to and following the burning. Oriented clay samples were prepared and analyzed with XRD using a Panalytical X’Pert Pro MPD diffraction system. Pre-burn soil mineralogy was dominated by kaolinite, halloysite, vermiculite-hydroxy-interlayered vermiculites. Comparisons between pre- and post-treatment samples were made, and changes in mineralogical composition of fire-affected soil were identified.