PARTITIONING SMALL-SCALE SPATIAL VARIABILITY OF RUNOFF AND EROSION ONSAGEBRUSH RANGELAND

Most hydrologic models require input parameters which represent the va riability found across an entire landscape. The estimation of such par ameters is very difficult, particularly on rangeland. Improved model p arameter estimation procedures are needed which incorporate the small- scale and temporal variability found on rangeland. This study investig ates the use of a surface soil classification scheme to partition the spatial variability in hydrologic and interrill erosion processes in a sagebrush plant community. Four distinct microsites were found to exi st within the sagebrush coppice-dune dune-interspace complex. The micr osites explained the majority of variation in hydrologic and interrill erosion response found on the site and were discernable based on read ily available soil and vegetation information. The variability within each microsite was quite low and was not well correlated with soil and vegetation properties. The surface soil classification scheme defined in this study can be quite useful for defining sampling procedures, f or understanding hydrologic and erosion processes, and for parameteriz ing hydrologic models for use on sagebrush rangeland.