Above and Below Ground Biomass Effects On Soil Strength and Trafficability.

Multiple anthropogenic activities take place on Army training lands concurrently, including, but not limited to, military training, forestry operations, agricultural out leasing, and various recreational activities. Inevitably, this use leads to natural resource disturbance.  For example, the use of military vehicles, during training, results in soil disturbance and vegetation loss, with subsequent increases in soil erosion rates, sedimentation in streams, and habitat degradation. Similarly, forestry activities such as timber harvest and prescribed burns can result in soil disturbance and/or loss of vegetation and similar, subsequent impacts to varying degrees. The overall objective of this research is to quantify and develop an understanding of the interactions between training impacts and land management practices on above and below ground biomass and the effect vegetated soils have on vehicle performance and trafficking impacts on training lands.

In 2011 An experiment was conducted at Camp Guernsey, WY to investigate the effects of multiple land use practices on the trafficability and recovery of a mixed grass training range.  Vegetated plots were subjected to combinations of training land stressors, such as trafficking, burning, and mowing. Biomass, soil strength and vehicle mobility parameters were collected over two growing seasons.  Prior to and following trafficking the test area was characterized for various strength measurements (drop cone, Clegg Impact Hammer, Cone Penetrometer, and Pilcon shear strength), and vegetation biomass.  The biomass measurements included above and below ground density as well as classification of root length and diameter. A Heavy Expanded Mobility Tactical Truck (HEMTT) was used to simulate military training, and the disturbance effect on the soil strength and vegetation was also quantified. The experimental approach and results are presented.