Soil movement following an intense burn

Abstract

A study was conducted from June to August, 1967 to evaluate the effects of an intense burn on soil and ash movement from steep mountain slopes. Twenty study plots were established on the burn. The soil on each plot was tagged at five points with Cs-134. Rates and patterns of actual soil particle movement were established by measuring changes in radiation intensity following three summer thunderstorms. Tagging of the soil with Rocket Red fluorescent dye provided a means of tracing soil particle movement throughout the study period. Dispersion of dye spots located on 0-1 per cent slopes provided an estimate of soil particle transport by raindrop splash. Summer soil loss was measured on each study plot. The results indicated that rock cover is more important than slope when rainfall intensities are insufficient to produce surface runoff. However, when surface runoff is produced, slope is the controlling factor of soil movement. Raindrop splash was also found to be a prime factor in initiating soil particle movement. Comparison of the two methods of tracing soil particle movement indicated that analogous data were obtained with either method.