Organic farming has long been considered healthier for the consumer and better for the planet than conventional farming. But a new study by a team of researchers from Cranfield University in the UK is now challenging this green doctrine.
Researchers include Dr. Adrian Williams, who studies greenhouse gas emissions, and Dr. Laurence G. Smith, who studies environmental policy and development, among others. Funding for this study and Smith’s PhD program in agricultural systems modeling was provided by the Ratcliff Foundation and the Engineering and Physical Sciences Research Council.
Smith began his career in agriculture working on organic farms in New Zealand, then returned to England and joined the organic research business.
The researchers looked at all crops grown in England and Wales and – using Optimal Land Use Modeling (OLUM), a linear programming model – suggested that if all conventional agriculture were converted to organic methods, the latter’s low crop yield would lead to more land dedicated to agriculture, which could increase greenhouse gases.
The authors of the study, published in the peer-reviewed journal Nature Communication, projected greenhouse gas emissions would increase by 21%.
Organic farming initially reduces emissions through decreasing agricultural inputs, such as fertilizers, and increasing carbon storage. However, according to this study, it also reduces crop and livestock yields by about 40 percent. To produce the same amount of food, much more land is needed.
Clearing additional land to compensate for yield loss produces more greenhouse gases than are reduced by the initial organic farming practices, according to the study.
Smith was surprised by the magnitude of yield loss found in the study. He deemed the research all the more important because of this. “It’s my role to challenge the assumptions we have and see how much they are based on fact or reality,” Smith said. WhoWhatWhy.
For crops, conventional agriculture uses fertilizers, pesticides and genetically modified organisms. Organic farming depends on natural materials and methods, such as using animal manure and compost as fertilizer, and rotating crops with legumes (which provide nitrogen).
The organic method produces less greenhouse gases than the synthetic fertilizers used in conventional agriculture.
For livestock, conventional agriculture uses hormones, supplements and feeds that increase yields. Organic methods allow animals to graze for a longer period of time.
Grazing reduces emissions associated with conventional feeds and stimulates plant growth and subsequent carbon storage.
Although in the nascent phase organic methods produce fewer emissions, according to the Cranfields University study, the problem remains – yields are lower and more land is needed. 1.5 times more land, to be exact.
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But other organic farming experts point out the limitations of the study’s statistical model. For example, the study does not include the environmental impact of the creation, distribution and use of fertilizers, or their residual impact on the land and the food chain, said Abby Youngblood, executive director of the National Organic Coalition. “Fertilizers release nitrous oxide, which is a greenhouse gas three times more potent than carbon dioxide,” Youngblood said.
And another expert says the study contains faulty assumptions. Dr Yichao Rui, a soil scientist at the Rodale Institute, says the main finding of this study, that yields will drop by 40% if there is a large-scale switch from conventional to organic methods, is not not true.
The Farming Systems Trial, a nearly forty-year longitudinal study that compares results for 12 acres side-by-side of organic and conventional farming methods, shows that there is no statistical difference between organic and conventional yields, has explained Dr. Rui.
“In arid years – climate change scenarios – organic farming can produce 50% more wheat and 100% more soybeans,” he said. WhoWhatWhy.
The farming systems trial – which began in 1981 – showed that in the first five years of transition from conventional to organic, yields declined. “You need time for soil biology and biological activity to be restored.”
After the first five years, organic farming systems produce equal or better yields than conventional methods.
“This document is one-sided,” Dr. Rui said. “It doesn’t take a holistic perspective of what is needed to make a fundamental transition to a sustainable system.”
The divergent points of view show that this question is not settled and merits further study. Time is running out, however, as solutions are urgently needed to address this looming crisis.
Panoramic photo credit associated with the first page: Adapted by WhoWhatWhy from Sethoscope / Flickr (CC BY-SA 2.0)