LAUSR

This article presents an energy analysis of Quebec agroecoystems at five periods of time: 1871, 1931, 1951, 1981, and 2011, calculating for each year the various energy flows and their resulting Energy Return on Investment (EROI). In the nineteenth century, Quebec agroecosystems were typical examples of historical organic agriculture, with a low dependence on external Inputs but a high dependence on biomass reused, mainly livestock feed and crop seeds. Following the full industrialization of Quebec agriculture by the 1960s, there have been massive injections of external inputs, but also steadily rising amounts of biomass reused due to livestock specialization and the decoupling of domesticated animals from crop farming. As a result of this transformation, the energy efficiency of agroecosystems diminished, despite the significant increases in both final produce and area productivity that were achieved.