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Ask the Conservationist

October 2011: Is Organic Better for the Environment?


One reader questions the trade-offs between buying organic foods and using less land through conventional farming practices.

We asked one of our in-house experts. Read his answer below, then send us your questions on any conservation subject for one of the Conservancy's 550 staff scientists. (Note: We regret that we can only answer one or two questions each month and that we cannot answer the others offline.)

Lisa Bonack of Milwaukee, WI writes:

I try to buy organic when possible because I believe it is better for the environment, but I read somewhere that the use of chemicals allows more crops to be grown on less land, thus preserving more natural habitat for area wildlife. Could you please shed some light on why going organic outweighs habitat preservation?

Joe Fargione, lead scientist with the Conservancy’s North America Region, replies:

Great question. Growing crops has several impacts on the environment. Crop production takes land, water, and other inputs which can include synthetic fertilizers, herbicides, and pesticides (all of which can be either synthetic or natural). Let's discuss each in turn.

Organic crops do generally have lower yields and therefore require more land. This has been shown in randomized experimental designs and on real farms. In 2008 the USDA (US Dept. of Agriculture) conducted its first ever survey of organic producers, collecting data on acreage and production from over 20,000 organic farms. The results of this survey were published in 2010, allowing a comprehensive, crop by crop, comparison of yields between conventional and organic production for the first time. The data are conclusive: comparing 62 crops – from almonds to watermelons – conventional yields are 10% - 360% higher than organic yields. There are a few (four) exceptions: organic tomatoes, sweet potatoes, canola, and hay are higher yielding than their conventional counterparts.

This means that if all of our crops were organic, they would take substantially more land. For example, if all of the corn grain, winter wheat, and soybeans in the United States were grown organically, it would require about 93 million more acres of farmland, a 30% increase in total crop acres.

For water use, I’m not aware of studies comparing conventional and organic farming. But since organic certification doesn’t require lower water use, I see no reason to expect any difference between water usage in organic versus conventional crops. Similarly, both conventional and organic methods can cause soil erosion that contributes to sediment pollution in rivers. One of the best solutions to sediment pollution is no-till farming. But organic farmers have traditionally used tillage as a form of weed control, making it difficult for them to switch to no-till farming.

For water use, I’m not aware of studies comparing conventional and organic farming. But since organic certification doesn’t require lower water use, I see no reason to expect any difference between water usage in organic versus conventional crops. Similarly, both conventional and organic methods can cause soil erosion that contributes to sediment pollution in rivers. One of the best solutions to sediment pollution is no-till farming. But organic farmers have traditionally used tillage as a form of weed control, making it difficult for them to switch to no-till farming.

When it comes to toxic pesticides, organic farming is the clear winner. In a comprehensive nationwide USGS study of 186 streams and over 5,000 shallow wells, pesticides (or their byproducts) were detected in every stream and more than half of shallow wells in agricultural and urban areas. Conventional agriculture used 877 million pounds of pesticides in 2007, the last year for which data are available. The USFWS found that pesticides kill at least 72 million birds per year. In addition, these pesticides are generally not good for anything that lives in or drinks water. For example, the European Union ranks pesticides according to their impacts to aquatic organisms; essentially all of our conventional pesticides are considered either harmful, toxic, or very toxic to aquatic organisms. Encouragingly, conventional agriculture has doubled the proportion of pesticides that are only "harmful or toxic" from 20 to 40% between 1999 and 2007 (reducing the proportion of "very toxic" pesticides from 80 to 60%). And the total amount of pesticide that is used every year has decreased by 8% between 1999 and 2007, even though food production has increased. But on balance, conventional food can’t compete with organic food when it comes to environmental impacts of pesticide use.

Life is full of trade-offs, and this is no exception: Organic foods require more land, but don’t use synthetic pesticides.


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