Foot Traffic Effects on Grassland Soil Properties at the United States Air Force Academy, Colorado USA

摘要

Soils and vegetation are subjected to stress and disturbance under human foot traffic. This study was conducted to determine whether cadet and other training activities at the United States Air Force Academy adversely impacted soils and vegetation. In the summer of 1998, the effects of the cadet and other training on bulk density, infiltration, soil water holding capacity, soil total C and N concentrations, soil C:N ratio, total aboveground biomass, and litter layer were comparatively studied at the Air Force Academy's Jack's Valley Training Area, on Pring sandy loam (coarse-loamy, mixed Aridic Haploborolls) and Tomah loamy sand (coarse-loamy, mixed Boralfic Argiborolls). In May-June 1998 after 2 years of intensive training use, bulk densities of the top 6 cm of soil were measured. Mean bulk densities on the high use site (1.37 g cm(exp -3)) and moderate use site (1.30 g cm(exp -3)) were significantly different from the mean bulk density of the low use (reference) site (1.04 g cm(exp -3)). Adjusted bulk densities (adjusted for coarse fragment content) followed a similar pattern. In August 1998, following the 3rd basic cadet training encampment on the research area, bulk density samples were collected (post-encampment) and compared to the samples from earlier in the summer (pre- encampment). Post-encampment mean bulk densities and adjusted bulk densities were significantly higher than the pre-encampment bulk densities. Mean infiltration rates on the high use site (0.63 cm min(exp -1)) and the moderate use site (0.67 cm(exp -1)) were significantly different from the mean infiltration rate on the low use site (3.83 cm min(exp -1)) Mean soil water holding capacities of the three sites were not significantly different.