Soil properties as indicators of disturbance in forest ecosystems of Georgia, USA

The objective of this study was to examine spatial variability and the effects of forest ecosystem disturbance, caused by military training, on soil organic matter (SOM) and related soil properties. Six 5th to 6th order watersheds were sampled at the Fort Benning military reservation, Georgia, USA. Sampling locations were categorized as either upland or bottomland, and sites were classified as low, moderately or severely impacted according to the level of ecosystem disturbance. Total carbon (C) and nitrogen (N), and extractable iron (Fe) and aluminum (Al) were greater in bottomland sites. Extractable-cations were affected by disturbance on upland soil. Severely impacted sites showed lower total C and N concentrations in both landscape positions. This is likely due to the physical disruption of soil structure due to the traffic of heavy military vehicles, resulting in the removal of forest floor. This pattern was more evident in upland sites. Conversely, soil properties in the bottomland sites were less affected by the level of impact.