Is the organic cropping system more sustainable than the best alternative in the semi-arid southern Alberta

There is increasing demand for organic products, likely due to perceived differences in product quality and environmental impacts associated with production. This paper attempts to define key, measurable characteristics that can be used to determine the relative sustainability of different agricultural systems. It provides an extensive literature review followed by a model comparing energy efficiencies, input cost efficiencies and nutrient balances of two hypothetical farms, an organic system and a zero-tillage system, in southern Alberta. Results indicated that the organic farm was more energy efficient (1.45 vs. 2.39 MJ/kg) but had higher production costs ({dollar}0.11/kg vs. {dollar}0.08/kg) and a less balanced nutrient budget. The zero-tillage farm had higher yields, required less capital for equipment and burned less fuel. Zero-tillage reduces water loss, soil erosion and the risk of crop failure. This study did not support the view that organic agriculture is more sustainable than a zero-till system.