麻豆传媒

Organic Agriculture Centre of Canada

Many Canadians will argue that the substantial environmental benefits of organic agriculture make it a more ecologically and socially responsible system than its conventional counterpart. Unfortunately, in North America at least, a conclusive body of research with which to back up these claims is largely unavailable. Traditionally, North American scientists and organic advocates alike, in their search for authoritative and complete studies, have looked to Europe where the bulk of research related to organic agriculture exists. Curiously enough, these European studies, devoid of Canadian organic farms and farmers, tend not to influence Canadian agricultural policy makers, despite their positive implications.

In response, and with the aim of encouraging further research and influencing policy, Dr. Derek Lynch, Canada Research Chair in Organic Agriculture, at the Nova Scotia Agricultural College has published a paper, 鈥溾�� that compiles recent North American and Canadian organic agricultural research, especially as it relates to the principles of the Canadian organic standard. Given the recent climate change summit in Copenhagen and the global community鈥檚 push to reduce CO₂ emissions, the sections of Lynch鈥檚 paper that compare the energy use and the greenhouse gas emissions on both organic and conventional farms is of particular interest.

Several organic management practices, especially the tillage required for weed control and the legume rotations utilized for fertility, have been criticized for their energy consumption and the CO₂ emissions they release. Lynch, in an effort to substantiate or disprove the mounting criticism, assembled those studies that dealt with the comparative net energy balance of organic management systems in Canada and North America. Of the three energy use studies reviewed in the paper, all of them concluded that energy use in organic farms was lower than that of conventional farms.

Lynch cites a 12 year Manitoba study of two forage and grain crop rotations managed either organically or conventionally. After the data was compiled and compared, including crop yield, crop inputs, fuel usage and machinery, the study concluded that energy use was 50% lower and energy efficiency was higher in the organic versus conventionally managed systems. A similar study out of Washington, comparing organic and conventional apple production, found that the organic system used 9% less energy inputs and was 7% more energy efficient than the conventionally managed orchard. Finally, Lynch presents a study, conducted from 1981 to 2002, that compares the energy inputs for corn and soybeans grown in organic and conventional systems. The study found that fossil energy inputs were, on average, 30% lower for the organic than the conventional systems.

Lynch then proceeds to examine those studies that compare the greenhouse gas emissions on organic and conventional operations. He concedes that while research is relatively scarce and in its infancy, that which is available is 鈥渋ntriguing鈥� and certainly deserving of more investigation.

One notable study, conducted in an orchard system in Washington, found that after 9 years, the soil in the organically managed orchard not only exhibited greater soil organic matter and soil microbial activity, but also fostered a much larger and more efficient denitrification community than in the conventionally managed orchard. These denitrifiers perform a 鈥渧aluable ecosystem service鈥� by converting excess nitrates into benign N₂.

Another significant study out of Atlantic Canada, examines the effect of crop, timing of forage tillage and potato fertility regime (preceding the crop with or without the addition of an inorganic N fertilizer) on N₂O emissions. Although the study is still in the early stages, preliminary results indicate that potato and forage crops relying on organic sources of nitrogen (legume or animal manure) emit less N₂O than those crops supplemented with inorganic fertilizers.

Derek Lynch, citing a study by MacRae and others (2007), notes that if the true costs of food production were to include the costs to the environment, organic food and agricultural systems would command a greater presence in both the marketplace and in the Canadian agri-political arena. Unfortunately, organic agriculture鈥檚 attributes have been largely absent from Canada鈥檚 political agenda, despite the fact that "costs" like climate change will directly and adversely impact our agricultural industry. Lynch鈥檚 paper, which he admits is by no means exhaustive, is a vital first step in compiling the information and evidence necessary to convince Canada鈥檚 policy makers of the undeniable environmental and ecological benefits of the Canadian organic system.

This article was written by Tanya Brouwers on behalf of the OACC with funding provided by Canada鈥檚 Organic Science Cluster (a part of the Canadian Agri-Science Clusters Initiative of Agriculture and Agri-Food Canada's Growing Forward Policy Framework).聽 The Organic Science Cluster is a collaborative effort led jointly by the OACC, the and industry partners. For more information: oacc@dal.ca or 902-893-7256.

This article is Part 1 of a series based on Derek Lynch's 2009 paper, "". Click here to see Part 2, Part 3 and Part 4.

Posted January 2010