'High-yield' farming costs the environment less than previously thought—and could help spare habitats

September 14, 2018, University of Cambridge
Credit: CC0 Public Domain

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" farming that uses less land, a new study has found.

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 , so that more natural habitats can be "spared the plough".

However, this involves intensive farming techniques thought to create disproportionate levels of pollution, water scarcity and soil erosion. Now, a study published today in the journal Nature Sustainability shows this is not necessarily the case.

Scientists have put together measures for some of the major "externalities—such as , fertiliser and water use—generated by high- and low-yield farming systems, and compared the 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.

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."

"Our results suggest that high-yield farming could be harnessed to meet the growing demand for food without destroying more of the natural world. 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 colleagues from Poland, Brazil, Australia, Mexico and Colombia.

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%), European wheat (33%), Latin American beef (23%), and European dairy (53%).

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 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.

Co-author Professor 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 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."

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.

"These results add to the evidence that sparing by using high-yield farming to produce food is the least bad way forward," added Balmford.

"Where agriculture is heavily subsidised, public payments could be contingent on higher yields from land already being farmed, while other land is taken out of production and restored as natural habitat, for wildlife and carbon or floodwater storage."

Explore further: To keep more carbon on the ground, halting farmland expansion is key

More information: Andrew Balmford et al, The environmental costs and benefits of high-yield farming, Nature Sustainability (2018). DOI: 10.1038/s41893-018-0138-5

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5 / 5 (1) Sep 14, 2018
Another hit against "organic" farming. Two many people conflate the term with things like quality, sustainability and environmentally friendly, yet organic farming practices can be wasteful and damaging to the environment. These practices can't be classified with broad labels. Sustainable farming requires much more nuance than that.
5 / 5 (1) Sep 14, 2018
"if higher yields are simply used to increase profit or lower prices, they will only accelerate the extinction crisis we are already seeing"
of course they will, that's how the world economy works
Thorium Boy
2.8 / 5 (4) Sep 15, 2018
Enviro-Oragokooks want to take us back to a time when an acre of land could barely feed 10 people. If we completely reverted, we'd be looking at starvation for at least 1/2 the planet. It's time to begin heavily taxing the organic food industry because they do not make efficient use of land, which should be illegal.
5 / 5 (1) Sep 15, 2018
Enviro-Oragokooks want to take us back to a time when an acre of land could barely feed 10 people. If we completely reverted, we'd be looking at starvation for at least 1/2 the planet. It's time to begin heavily taxing the organic food industry because they do not make efficient use of land, which should be illegal.

I don't think such enforcing is really necessary. Organic food is a small piece of all the food produced. Besides, there are fuel crops too, which are way more important than organic ones in terms of surface.
not rated yet Sep 15, 2018
When the big push came to sell fertilizer to Indian farmers it was discovered that using more space between the plants allowed a better yield than crowding the plants and adding fertilizer. Real as opposed to computer models.
5 / 5 (2) Sep 15, 2018
In my view, the possible future of agriculture will look something like this:

Agri 1: Current agriculture. Energy efficiency EE (light to stored reserves) is around 0.2-0.5%: https://en.wikipe...ficiency

Agri 1.1: Further improvements in terms of fertilizers, water, pesticides, and today's crops. Average yields may grow to or above current top levels.

Agri 1.2: Crop optimization in terms of environmental conditions by growing plants inside greenhouses with heat and humidity control. Also artificial light may be fed to plants.

Agri 2 var. 1: Instead of whole plants, plant (and animal) tissues are grown with energy from the Sun, LEDs or even with electricity. EE may go up to 8-16% with artificial light or electricity fed in. Yields grow 10-20 times from Agri 1. Land utilization is no longer necessary. Vertical farming at massive industrial scale is possible with nuclear energy.
5 / 5 (2) Sep 15, 2018
Agri 2 var. 2: People stop eating plants and replace them with microorganisms (bacteria, fungi, yeast). These are grown in bioreactors, being fed with hydrocarbons from fossil fuels or from conversion of existing CO2 with nuclear power. No need for land surface use. Growth can be achieved underground. EE is around 5-20% (I don't exactly recollect the efficiency of microorganisms). Light is not necessary; electricity may be fed as an energy source. The whole process is quite simple. Maximum production is orders of magnitude above Agri 1.

Agri 3: People synthesize chemically most of the food they need with chemical reactors. Basic substances produced (glucose, aminoacids/proteins, fatty acids) are combined with vitamins and algae-produced flavours to give different meals. EE around 50%.

Latter steps are more detailed in substeps. Also Agri 2 may take one of 2 variants. All these steps can be envisaged within current scientific knowledge / technology. Details need to be developed.
not rated yet Sep 16, 2018
"Agriculture is the most significant cause of biodiversity loss on the planet,"

-Followed closely by invasive species. The only solution for both earth and mars is GMO plants specifically designed for the purpose.

And we need to start from scratch, ie start with the pleistocene plants we evolved to eat, and modify them for increased yield and environmental utility.

The crap we are currently eating is the result of millenia of consistently selecting for quantity at the cost of quality, in the desperate attempt to feed pops that were growing faster than the food supply. Many human diseases might be traced to the lack of nutrients found only in paleo foods, both living and extinct.
not rated yet Sep 18, 2018
Otto, I hope you do not subscribe to the paleo diet. That seems nonsensical. The paleo diet was, after all, whatever humans could find, because they were often at risk of starving. Humans of the times only lived a few decades, if they were lucky. Consider that most of the ancient crops were nothing like what we have in the present day. Corn was nothing much more than somewhat larger seeds on tall grass. Our current bananas dwarf their pathetic progenitors.

What makes more sense than starting over at the paleo point is to simply determine what is best for us Now. Humanity has evolved since paleo times, more precisely co-evolved with our food supplies. Consider our ability to handle dairy products which (most) humans evolved once animal husbandry came into effect.
not rated yet Sep 18, 2018
I agree that large scale farming of the last century or two may leave things to be desired in the rush to quantity (which we need too!) Hopefully new technologies will improve the situation. Much has been lost in the effort to make food not spoil in transit and on store shelves (again an important attribute.) I hope GMO techniques will allow us to bring back quality and taste which has been sacrificed, while still reducing spoilage and other waste which we cannot afford.
3 / 5 (2) Sep 19, 2018
Humans of the times only lived a few decades, if they were lucky. -carbon_unit

No. That's what happens when infant mortality is averaged in. If you made it past childhood, even back then, there was a decent chance you'd make it to old age.

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