Influence of organic management with different crop rotations on selected productivity parameters in a long-term Canadian field study.

The Glenlea long-term rotation study, located near Winnipeg, is Canada’s oldest conventional vs organic crop comparison study. Since 1992, three farming systems (grain only; grain with green manure crops; combined grain-forage rotation) were evaluated under two management systems (organic and conventional). Organic system ranked higher than conventional systems in energy efficiency and biodiversity while conventional system ranked higher in yield, weed management and soil nutrient status. However, significant farming system by management interactions were observed for many variables. The basis for these interactions was enhanced performance of organic production in the combined grain-forage system compared with the grain only system. Organic crop production is sustainable provided combined grain-forage rotations and livestock manure recycling are used.