Patterns of soil erosion and redeposition on Lucky Hills Watershed, Walnut Gulch Experimental Watershed, Arizona.

摘要

Degradation of semiarid and arid rangelands is a major concern and is usually described in terms of soil movement and changing plant communities. The purpose of this paper was to determine the patterns and rates of soil erosion and redistribution from measurement of the distribution of fallout 137Cesium on the Lucky Hills Watershed, a semiarid rangeland watershed in southeastern Arizona. Soil redistribution ranged from a loss of -9.8 t ha-1 yr-1 to the deposition of +7.0 t ha-1 yr-1. Net soil loss occurred at 54 of the 74 sample sites or approximately 73% of the watershed. Soil erosion rates were significantly correlated to the percent of rock fragments in the surface 25-cm soil layer with erosion decreasing as rock fragments increased. Soil redistribution was not significantly related to vegetation cover at the sample sites. This study supports earlier research on Walnut Gulch Watershed that showed the importance of rock fragments in estimating soil loss..