The benefits of changing cattle grazing practices on native plant communities in the western United States remain controversial, due in part to a lack of experimentation. In 1997, we initiated an experimental study of two rangeland alternatives, cattle removal and short duration, high-impact grazing and compared grassland soil and plant responses with more conventional, moderate grazing practices.  Soil nutrient supply rates were measured with PRS™ - probes and the plant community was monitored in 2001-2003 in a high-elevation, semi-arid grassland near Flagstaff, Arizona.  The soil nitrate (NO₃^--N) supply rate responded to grazing treatments as well as to seasonal variation in moisture.  A lab incubation in 2001 showed that high-impact grazing had a 30% greater potential NO₃^- supply rate than the moderate grazing treatment.  We then buried the PRS™ - probes in the field during the fall season and the high-impact grazing treatment showed the greatest NO₃^- supply rate in 2 of the 3 years.  We also observed a trend of higher H₂PO₄^-/HPO₄^2- supply rate during the wet season in the high intensity grazing treatment, however, this was not statistically significant.  Increased availability of soil nutrients may help explain a two-fold increase in plant cover by exotic plant species in the high-impact grazing plots despite a treatment duration of only 24 hours.  In contrast, the cattle removal treatment showed a trend of decreased NO₃^-, but the plant community was not significantly different from the moderate-grazing treatment.  Soil nutrient supply may be an important predictor of exotic plant invasion and an indicator for livestock management.