The organic movement's claims about the sustainability of its methods are dubious. For example, a recent study found that the potential for groundwater contamination can be dramatically reduced if fertilizers are distributed through the irrigation system according to plant demand during the growing season; organic farming, however, depends on compost, the release of which is not matched to plant demand. Moreover, though composting receives good press as a "green" practice, it generates a significant amount of greenhouse gases (and is often a source of pathogenic bacteria in crops).
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The study also found that "intensive organic agriculture relying on solid organic matter, such as composted manure that is mixed in to the soil prior to planting, resulted in significant down-leaching of nitrate" into groundwater. Increasing the nitrate levels in groundwater is hardly a hallmark of sustainability, especially with many of the world's most fertile farming regions in the throes of drought.
A fundamental reason that organic food production is far less "sustainable" than many forms of conventional farming is that organic farms, though possibly well adapted for certain local environments on a small scale, produce far less food per unit of land and water. The low yields of organic agriculture – typically 20-50% below conventional agriculture – impose various stresses on farmland, especially on water consumption.
A British meta-analysis published in 2012 identified some of the stresses that were higher in organic agriculture. For example, it found that "ammonia emissions, nitrogen leaching, and nitrous oxide emissions per product unit were higher from organic systems," as were "land use, eutrophication potential, and acidification potential per product unit."
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Lower crop yields in organic farming are largely inevitable, owing to the arbitrary rejection of various advanced methods and technologies. Organic practices afford limited pesticide options, create difficulties in meeting peak fertilizer demand, and rule out access to genetically engineered varieties. If organic production were scaled up significantly, the lower yields would lead to greater pressure to convert land to agricultural use and produce more animals for manure, to say nothing of the tighter squeeze on water supplies – all of which are challenges to sustainability.
Another limitation of organic production is that it works against the best approach to enhancing soil quality – namely, the minimization of soil disturbance (such as that caused by plowing or tilling), combined with the use of cover crops. Such farming systems have many environmental advantages, particularly with respect to limiting erosion and the runoff of fertilizers and pesticides. Organic growers do frequently plant cover crops, but in the absence of effective herbicides, they often rely on tillage (or even labor-intensive hand weeding) for weed control.
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At the same time, organic producers do use insecticides and fungicides to protect their crops, despite the green myth that they do not. More than 20 chemicals (mostly containing copper and sulfur) are commonly used in growing and processing organic crops – all acceptable under US rules for certifying organic products.
Perhaps the most illogical and least sustainable aspect of organic farming in the long term is the exclusion of "genetically engineered" (also known as "genetically modified," or GM) plants – but only those that were modified with the most precise techniques and predictable results. Except for wild berries and wild mushrooms, virtually all the fruits, vegetables, and grains in European and North American diets have been genetically improved by one technique or another – often as a result of seeds being irradiated or undergoing hybridizations that move genes from one species or genus to another in ways that do not occur in nature.
The exclusion from organic agriculture of organisms simply because they were crafted with modern, superior techniques makes no sense. It not only denies farmers improved seeds, but also denies consumers of organic goods access to nutritionally improved foods, such as oils with enhanced levels of omega-3 fatty acids.
In recent decades, conventional agriculture has become more environmentally friendly and sustainable than ever before. But that reflects science-based research and old-fashioned technological ingenuity on the part of farmers, plant breeders, and agribusiness companies, not irrational opposition to modern insecticides, herbicides, genetic engineering, and "industrial agriculture."
Commentary by Henry I. Miller and Richard Cornett. Miller is a physician and molecular biologist, and a fellow in scientific philosophy and public policy at Stanford University's Hoover Institution. He was the founding director of the Office of Biotechnology in the US FDA and is the author of "The Frankenfood Myth." Richard Cornett is Communications Director for the Western Plant Health Association, a California-based nonprofit agricultural trade group.
Copyright: Project Syndicate, 2014.