Hydrologic responses to simulated small ranch conditions of horse grazing/trampling and flood irrigation

Small ranch practices of flood irrigation and horse grazing cause changes in soil characteristics, affecting hydrologic responses. Hoof impact increases soil bulk density, which decreases infiltration rates. This increases runoff, which may degrade water quality as nutrients, chemicals, and sediment are transported in off-pasture drainage. This study simulated small ranch practices to determine the effects of moderate and heavy grazing intensities.; Small plots with heavy grazing/trampling had the highest quantities of surface runoff and total suspended solids, followed by moderate and control plots. Control plots had the highest soil water contents following irrigation. Amounts of subsurface drainage, soil moisture storage, aboveground biomass production, and basal area cover were also highest for control plots followed by treatments at moderate and heavy intensities. Control and moderate plots were not significantly different for the majority of parameters measured. This indicates that moderate or lesser intensity grazing will have minimal effects on hydrologic response.