SUSTAINABILITY OF ORGANIC DAIRYING IN CANADA

Kurzfassung

The distinctive production characteristics and economic performance of organic dairy farms in central Canada has been documented, but the sustainability of these systems with respect to farm nutrient flows is less well understood. We have assessed farm management, livestock productivity, and nutrient status of fifteen long term (>10y) certified organic dairy farms in Ontario, Canada. Farm size, herd size and herd productivity averaged 110 ha, 52 cows and 8207 kg milk cow yr-1, respectively. Cropping composition differed little between farms, with pasture and forage accounting for an average of 65% of the cropped landbase. Annual farm nutrient budgets (inputs-outputs) over two years (2003-2005) for N, P and K were 52, 1 and 11 kg ha-1 yr-1, respectively. The majority (13) of farms had positive K budgets with half of the farms recording negative annual P budgets. Nutrient budget results were supported by soil fertility data generated by sampling 80% of farm fields (n=225). Overall, these results contrast strongly with large nutrient surpluses reported for more intensive, confinement-based dairy farms throughout N. America, but suggest a challenge to remain sustainable over the longer term for the 50% of these farms adopting a broadly ‘self-sufficient’ approach, and importing little P (0 - 2.5 kg ha-1 yr-1) as feed and feed supplements.