We develop three quantitative indicators of the physical/biological aspect of sustainability. They are based on depletion of resources, dependence on outside subsidies, and disruption of natural cycles. We apply the indicators to an agricultural county in Kansas, using energy, water, soil, and nitrogen as numeraires. 9/10 of Chase County is dedicated to range beef cattle grazing and 1/10 to row-cropping and confinement animal feeding. Range production is relatively non-depleting, independent, and non-disrupting. Cropping is more depleting, dependent, and disrupting, but comparable with that in other agricultural areas. We discuss how this pattern, mediated by absentee land-holding and low human population density, trades off against [...]