New research out of the University of Cambridge affirms what many production farmers and ag communicators have said about the environmental sustainability benefits of modern high-yield farming techniques, at least as compared with organic and other “regenerative” methods.
There is mounting evidence that the best way to meet rising food demand while conserving biodiversity is to wring as much food as sustainably possible from the land we do farm, so that more natural habitats can be “spared the plough,” the Cambridge researchers said in the journal Nature Sustainability. So even though organic farming may superficially appear more eco-friendly to the public, the reality is that its overall environmental costs are much greater.
That said, the data in this study was limited, and there is much more research to be done. Not to mention that if your motivation is simply to increase short-term profits by increasing yield (and you’re not focused on the long-term health of your farm), then you’re doing it wrong, and this study doesn’t apply to you.
The results
Scientists have put together measures for some of the major “externalities” — such as greenhouse gas emission, fertiliser and water use — generated by high- and low-yield farming systems, and compared the environmental costs of producing a given amount of food in different ways.
Previous research compared these costs by land area. As high-yield farming needs less land to produce the same quantity of food, the study’s authors say this approach overestimates its environmental impact.
Their results from four major agricultural sectors suggest that, contrary to many people’s perceptions, more intensive agriculture that uses less land may also produce fewer pollutants, cause less soil loss and consume less water.
“Our results suggest that high-yield farming could be harnessed to meet the growing demand for food without destroying more of the natural world,” said study lead author Andrew Balmford, Professor of Conservation Science from Cambridge’s Department of Zoology. “However, if we are to avert mass extinction, it is vital that land-efficient agriculture is linked to more wilderness being spared the plough.”
Organic groups told the BBC that they are not impressed with the study’s conclusions. They argue that the world produces enough food already and that the issues with feeding populations are economic and political, not agricultural.
Research details
The study analysed information from hundreds of investigations into four vast food sectors, accounting for large percentages of the global output for each product: Asian paddy rice (90 percent), European wheat (33 percent), Latin American beef (23 percent), and European dairy (53 percent).
Examples of high-yield strategies include enhanced pasture systems and livestock breeds in beef production, use of chemical fertilizer on crops, and keeping dairy cows indoors for longer.
The scientists found data to be limited, and say more research is urgently needed on the environmental cost of different farming systems. Nevertheless, results suggest many high-yield systems are less ecologically damaging and, crucially, use much less land.
For example, in field trials, inorganic nitrogen boosted yields with little to no greenhouse gas “penalty” and lower water use per tonne of rice. Per tonne of beef, the team found greenhouse gas emissions could be halved in some systems where yields are boosted by adding trees to provide shade and forage for cattle.
The study only looked at organic farming in the European dairy sector, but found that — for the same amount of milk — organic systems caused at least one third more soil loss, and take up twice as much land, as conventional dairy farming.
Conservation expert and co-author Dr David Edwards, from the University of Sheffield, said: “Organic systems are often considered to be far more environmentally friendly than conventional farming, but our work suggested the opposite. By using more land to produce the same yield, organic may ultimately accrue larger environmental costs.”
The study authors say that high-yield farming must be combined with mechanisms that limit agricultural expansion if they are to have any environmental benefit. These could include strict land-use zoning and restructured rural subsidies.
The Cambridge scientists conducted the study with a research team from 17 organisations across the UK and around the globe, including colleagues from Poland, Brazil, Australia, Mexico and Colombia.
