Response of soil organic carbon dynamics to disturbance from military training

ABSTRACT:

A field study was conducted at Fort Benning, Georgia (USA) to evaluate changes in soil organic carbon storage and partitioning in response to site disturbance from ground-based military training. Our primary goal was to investigate the utility of selected soil biogeochemical parameters for monitoring and assessment of land condition in conjunction with restoration and other management activities. Soil was sampled at sites representing a wide range of intensity of land disturbance due to mechanized training, foot and light vehicle traffic, and related activities. Soil chemical and microbial analyses included total carbon (C), total nitrogen (N), dissolved organic C, microbial biomass C, and soil respiration. All of these, with the exception of dissolved organic C, showed relatively consistent decreasing trends (significant at P≤0.05) with increasing site disturbance, consistent with increased loss of topsoil in uplands and sedimentation in bottomlands. Concomitant increases in dissolved organic C:total C and microbial biomass C:total C appear to indicate that the relative bioavailability of soil C increased with soil disturbance despite a decrease in C storage.