Ecosystems, Sustainability, and Grassland Management

The long-term sustainability of modern agriculture is examined in an ecological context. As an aid to defining agriculture, animal agriculture, and sustainable agriculture, a broad overview of the structural and functional aspects of ecosystems is presented. The longterm sustainability of two corn production systems and four beef cattle production systems is then examined relative to energy output/cultural energy input ratios. Results indicate that as corn yields increase, ecological efficiencies decrease dramatically. But analyses of the four beef cattle production systems show an even more startling effect in that cultural energy inputs (i.e. fossil fuels) far exceed energy outputs. This low level of efficiency was found to be largely the result of the interaction effects of the high levels of cultural energy required to maintain a productive cow herd and grow and finish calves in the rather harsh environment of the Northern Great Plains. Results pointedly reveal the high level of dependency of the U.S. beef cattle industry on fossil fuels. These findings in turn bring into question the ecological and economic risks associated with the current technology driving North American agriculture.