Hydrologic characteristics immediately after seasonal burning on introduced and native grasslands.

Abstract

Fire on rangelands used as a management tool or as an unwanted wildfire removes vegetation cover. Vegetation cover is thought to be a dominate factor controlling surface runoff and erosion. Vegetation removal by a burn should have an immediate effect on runoff and erosion. Surface runoff and sediment production were evaluated immediately after fall and spring season burns at 2 locations with different soil and vegetation types for 2 years in southeastern Arizona. The evaluations were conducted with a rainfall simulator at 2 precipitation intensities. Immediately after a burn there was not a significant change in runoff and erosion, therefore, vegetation cover by itself was concluded not to be a dominate factor controlling surface runoff and erosion. The increase found in surface runoff and sediment production from the burn plots was not significantly greater than the natural variability for the locations or seasons. Significantly higher surface runoff and sediment production was measured in the fall season compared to the spring at 1 location.