Tuesday, November 14, 2006

Clay Mineral Distribution and Transformation Patterns in Fire-Managed Ultisols in Alabama.

Monday Mbila, Maria Nobles, Ngowari Jaja, and Coleman Tommy. Alabama A&M Univ, 4900 Meridian St, Normal, AL 35762

Several forests in Alabama are routinely burned as a means for forest floor fuel load reduction which in turn reduces the rate of spread and the intensity of wildfires. Many of the forests within the Cumberland Plateau grow on ultisols that are intensely weathered due to Alabama’s warm temperate climate (high temperatures and leaching). Thus, kaolinite, a highly weathered clay and other less weatherable minerals predominate the forest soil mineralogy. Although forest fires have been shown to affect soil pH, and cation exchange capacity, still there is a paucity of information regarding soil mineralogy transformation patterns under drastic conditions caused by forest fires. This study investigates the mineralogy suites and transformation patterns in ultisols that are routinely managed with prescribed burning. Soil samples will be collected from treatment plots that are managed by different cycles of prescribed burning as well as control plots at the William Bankhead National Forest in Alabama. XRD analysis of soil samples from the sites will be performed to identify the clay minerals and their vertical distribution in soil. Total chemical analyses of the samples will be conducted to determine the clay mineral characteristics and transformation patterns. Data of pre-fire treatment, post-fire treatment, and a control (no-burning treatment within the forest) will be compared to determine the impact of the fires on soil clay mineralogy.