| Popis: |
There is a need for greater understanding of the relationship of dust emission levels to disturbances of soil and vegetation indices that occur during military vehicle activities in Department of Defense training areas. A replicated field experiment was conducted in the fall of 2010 on two soils that dominate the military training grounds at Fort Riley, Kansas. Treatments consisted of two vehicle types, and three levels of vehicle passes. An Abrams M1A1 tank, representing tracked vehicles, and a Humvee representing wheeled military vehicles were used. Bulk density, above ground standing biomass, and plant cover were among the parameters measured before and after vehicular traffic. Samples were taken from curved, straight, and cross-over sections of the vehicle tracks. A mixed-model analysis of variance of the data indicates that the overall mean bulk density under the M1A1 were significantly higher than under the Humvee (p=0.05). In general, as the number of passes increased the bulk density under the M1A1 increased significantly (p=0.05), but the increases under the Humvee were not significant (p=0.05). Bulk densities were significantly larger in the curved part of the tracks than the straight part of the track. Large differences in biomass and vegetation cover between different treatments were observed. Comparison of spring and fall bulk density data showed significant difference at the 0-5 cm depth; indicating that the winter freeze and thaw cycles loosened the top soil layer. |
