Earth Talk: Is organic agriculture really unsustainable?

Dr. Henry I. Miller's May 15, opinion piece in theWall Street Journalhas indeed made waves in the organic farming community. Miller, former director of the Office of Biotechnology at the U.S. Food & Drug Administration, argues that conventional farming — which uses synthetic pesticides, herbicides and fertilizers and often genetically modified (GM) seed stock to maximize yields— is actually better for the environment, producing more food and using less water compared to organic farming.

"Organic farming might work well for certain local environments on a small scale, but its farms produce far less food per unit of land and water than conventional ones," says Miller. "The low yields of organic agriculture — typically 20% to 50% less than conventional agriculture — impose various stresses on farmland and especially on water consumption." Miller adds that organic methods can cause significant leaking of nitrates from composted manure — the fertilizer of choice for most organic farms — into groundwater, polluting drinking water. He also cites research showing that large-scale composting generates significant amounts of greenhouse gases and "may also deposit pathogenic bacteria on or in food crops, which has led to more frequent occurrences of food poisoning in the U.S. and elsewhere."

"If the scale of organic production were significantly increased," says Miller, the "lower yields would increase the pressure for the conversion of more land to farming and more water for irrigation, both of which are serious environmental issues." He adds that conventional farming's embrace of GM crops — a no-no to organic farmers — is yet another way we can boost yields and feed more people with less land.

But, the Washington, DC-based Organic Center takes issue with Miller's allegations about nitrates polluting groundwater: "Most studies that examine nutrient runoff show that organic production methods result in reduced nitrogen losses when compared to conventional crop production," reports the group.

The Organic Center also disputes Miller's claims about the organic farming's carbon footprint, arging that overall energy usage and greenhouse gas emissions are much less from organic farming than for conventional agriculture. The group also says that taking into account the greenhouse gas emissions that come from the production (not just the use) of synthetic fertilizer changes the equation entirely. The group cites a recent study by the UN Food and Agriculture Organization which found that organic agriculture can potentially reduce overall greenhouse gas emissions by 20% compared to conventional farming.

Also, Miller's statements about GM crops overlook the ecological problems associated with their use. "For example," the Organic Center reports, "transgene movement from GM crops to wild, weedy relatives could increase the invasiveness of weeds." Also, genetic modification has led to higher pesticide use in agricultural systems and an increase in herbicide-resistant weeds. Some worry this is leading to a vicious cycle whereby farmers use more and more chemical herbicides to battle hardier and hardier weeds.

As the price of organic food continues to drop, more and more people will be able to afford it and the increased demand may well drive the conversion to organic agriculture more than policy or philosophy.

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