As food riots in places like Haiti and Egypt are reminding us, there are many, many hungry people in the world. Supporters of industrialized agriculture have argued for years that the only way to feed billions of mouths is by raising crops and livestock in large-scale specialized systems reliant on petroleum-based fertilizers and pesticides. Diversified agricultural systems—organic in particular—are a luxury the world can ill afford at a time when the population has surpassed six billion people, say scientists like Nobel Prize-winning plant breeder Norman Borlaug. John Emsley, a chemist at Cambridge University, has called organic farming “the greatest catastrophe that the human race could face,” according to World Watch magazine. Ouch. Well at least the good professor doesn’t beat around the bush. The basis for such sharp criticism is that organic crop production, for example, simply cannot produce high yields because it relies on natural sources of fertility such as animal manure. But a lot of false assumptions and lack of data are the basis for such arguments.
For example, it’s often stated as fact that if the U.S. switched to organic farming, this country would produce only about one-fourth of what it produces today. That’s based on a USDA study showing that all the manure in the U.S. could only meet one-quarter of the country’s crop fertility needs. But that study ignores the fact that organic farmers depend heavily on other sources of fertility besides manure—rotations, nitrogen-fixing legumes and plowing down crops to provide “green manure,” for example.
Assumptions about organic farming’s inherently low yields are also biased by the fact that during the first few years of transition from a chemical-intensive system, yields do often drop as the soil adjusts to pesticide and fertilizer withdrawl and develops its own natural systems once again.
In recent years, sophisticated research comparing organic and conventional crop yields has shown that many beliefs about chemical-free food production are simply wrong. For example, the Wisconsin Integrated Cropping Systems Trial (WICST) project recently concluded 13 years of research comparing conventional and organic crop yields in the southern part of that state.
According to the results, which were published in the Agronomy Journal earlier this year, in good years (more later on what constitutes a good year) organic systems produced corn and soybean yields that were 90 to 98 percent as good as their conventional counterparts. An analysis of similar field trial studies done during the past several years in Iowa, Minnesota, Pennsylvania and Michigan shows that on average in good years organic and low-chemical corn yields were 98 to 114 percent of conventional corn yields; soybean yields under sustainable systems averaged 94 percent to 111 percent of their conventional counterparts.
“Clearly, field research has answered the question, ‘Can biologically diverse, low-input cropping systems be as productive as conventional systems?’ with a qualified yes and has refuted the most dire warnings against wide-adoption of low-input cropping systems,” concludes the WICST paper.
Now for that “qualified yes” the WICST scientists talked mentioned. Numerous research projects confirm what organic farmers already know: organic systems can be particularly vulnerable to wet conditions early in the season. Since organic systems cannot utilize herbicides to kill weeds, they must rely on mechanical weed control such as rotary hoeing to control unwanted invasives.
If excessive wet weather at the wrong times of the year makes it difficult to get weed-killing steel out in the field, yields suffer. Field trials show that when weather conditions prevent good mechanical weed control, corn and soybean yields averaged about 74 percent of their conventional counterparts. During about a third of the years studied, weed problems significantly knocked yields back for sustainably-raised crops.
However, research at land grant universities, on farms, and in places like the Rodale Institute is helping farmers deal with weed problems in organic systems more consistently. For example, Rodale has developed a system that uses cover crops and a roller to create a weed-suppressing, soil-saving mulch in organic systems. Research on this system is creating quite a stir at the U of M’s Southwest Research and Outreach Center in Lamberton. Last summer I sat in a room full of Minnesota farmers during a video demonstration of the roller system and the excitement was palpable. Field trials as well as on-farm use show the system can help organic row-crops match and even exceed the yields of their conventional counterparts.
Another important point to keep in mind is that purveyors of the “organics will starve us” myth often lay the scenario out in stark, all-or-nothing terms. One popular polemic goes something like this: which two billion people will be chosen to die when pesticides are banned tomorrow? Scientists who study organic farming systems say in reality the sustainable agriculture of the future may in some cases be a mix of systems: a farmer may use rotations, cover crops and steel to control weeds during the two-thirds of the time that weather conditions allow, for example. Otherwise, they can use spot spraying of herbicides to deal with weeds that take advantage of inclement weather to get a jump on crops.
Blending organic and conventional systems can pay off. For example, multi-year research by the University of Minnesota shows that one typical four-year organic rotation—corn, soybeans, alfalfa and oats—can produce 3 to 6 percent higher yields for conventional farmers who are sticking with at least some chemicals for the time being.
Farming systems that rely more on sustainable techniques have gained so much respect in recent years that many scientists are beginning to see them as the only way to feed people long into the future. Last month, a commission of more than 400 agricultural experts from around the world released a series of reports that called for a major shift to sustainable farming methods such as crop diversification and use of organic fertilizers. Without such a shift, concluded this group, conventional agriculture’s destruction of the very resources needed to produce food will only worsen the current humanitarian and environmental crisis. We may already see some shifts this planting season brought about by pure economics—I’m guessing the current shortage of nitrogen fertilizer will cause more than a few conventional farmers to consider cutting back or seeking alternative sources of fertility.
We’ve tried the all-chemicals, all-the-time-strategy. How about plugging a little sustainable hybrid vigor back into the system?