EFFECT OF SLASH on SOIL EROSION on A PINYON-JUNIPER WOODLAND

Pinyon-Juniper encroachment has had a profound impact on hydrologic and ecologic features throughout the intermountain west. These trees can come to dominate the vegetation cover leaving little to no understory, which results in there being a high risk for erosion during and after a rainfall event. This study assessed the response of the two forms of overland flow: sheet and concentrated flow. Three water application rates (15, 30 and 42 L min^-1) and two slope steepnesses were evaluated (10 and 30%) on a total of twelve plots. Detachment equations show a limited applicability, which may be because current equations do not account for soil armoring and assume that there is an unlimited detachment capacity of water. Current detachment equations show a low correlation for both concentrated flow and sheet flow on this rangeland hillslope. Experimental results indicated that adding slash can reduce soil loss and total sediment yields on slopes up to 30%. This study was based on unbound channels which allowed the flow paths to develop naturally.