This indicator assesses the resistance of the surface of the soil to erosion. Resistance depends on soil stability, microtopography, and on the spatial variability in soil stability relative to vegetation and microtopographic features. The stability of the soil surface is key to this indicator. Soil surfaces may be stabilized by soil organic matter which has been fully incorporated into aggregates at the soil surface, adhesion of decomposing organic matter to the soil surface, and biological crusts. The presence of one or more of these factors is a good indicator of soil surface resistance to erosion.