Agriculture that appears to be more eco-friendly but uses more land may actually have greater environmental costs per unit of food than “high-yield” intensive farming that uses less land, finds a new study published in Nature Sustainability – The environmental costs and benefits of high-yield farming.
The new findings by Cambridge scientists suggest that more intensive agriculture is the “least bad” option for feeding the world while saving species, provided use of such “land-efficient” systems prevents further conversion of wilderness to farmland. Researchers suggest intensive farming could meet rising food demand in a limited area and allow more natural habitats than other lower yielding systems. Intensive farming techniques have been criticised for creating pollution, water scarcity and soil erosion. However, the study shows this is not necessarily the case.
More intensive agriculture that uses less land may also produce fewer pollutants, cause less soil loss and consume less water.
Scientists compared the environmental costs of producing a given amount of food in different ways – such as greenhouse gas emission, fertiliser and water use. 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. However, the team behind the study, led by scientists from the University of Cambridge, caution that if higher yields are simply used to increase profit or lower prices, they will only accelerate the extinction crisis we are already seeing.
“Agriculture is the most significant cause of biodiversity loss on the planet,” said study lead author Andrew Balmford, Professor of Conservation Science from Cambridge’s Department of Zoology. “Habitats are continuing to be cleared to make way for farmland, leaving ever less space for wildlife. “However, if we are to avert mass extinction it is vital that land-efficient agriculture is linked to more wilderness being spared the plough.” The Cambridge scientists conducted the study with a research team from 17 organisations across the UK and around the globe – including Poland, Brazil, Australia, Mexico and Colombia.
In field trials, inorganic nitrogen was found to boost 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.
In the European dairy sector the study 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.
Co-author Prof. Phil Garnsworthy from the University of Nottingham, who led the dairy team, said: “Across all dairy systems we find that higher milk yield per unit of land generally leads to greater biological and economic efficiency of production. “Dairy farmers should welcome the news that more efficient systems have a lower environmental impact.”
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.”
Source – Agriland