Nav: Home

A very small number of crops are dominating globally. That's bad news for sustainable agriculture

February 06, 2019

A new U of T study suggests that globally we're growing more of the same kinds of crops, and this presents major challenges for agricultural sustainability on a global scale.

The study, done by an international team of researchers led by U of T assistant professor Adam Martin, used data from the U.N.'s Food and Agricultural Organization (FAO) to look at which crops were grown where on large-scale industrial farmlands from 1961 to 2014.

They found that within regions crop diversity has actually increased - in North America for example, 93 different crops are now grown compared to 80 back in the 1960s. The problem, Martin says, is that on a global scale we're now seeing more of the same kinds of crops being grown on much larger scales.

In other words, large industrial-sized farms in Asia, Europe, North and South America are beginning to look the same.

"What we're seeing is large monocultures of crops that are commercially valuable being grown in greater numbers around the world," says Martin, who is an ecologist in the Department of Physical and Environmental Sciences at U of T Scarborough.

"So large industrial farms are often growing one crop species, which are usually just a single genotype, across thousands of hectares of land."

Soybeans, wheat, rice and corn are prime examples. These four crops alone occupy just shy of 50 per cent of the world's entire agricultural lands, while the remaining 152 crops cover the rest.

It's widely assumed that the biggest change in global agricultural diversity took part during the so-called Columbia exchange of the 15th and 16th centuries where commercially important plant species were being transported to different parts of the world.

But the authors found that in the 1980s there was a massive increase in global crop diversity as different types of crops were being grown in new places on an industrial scale for the first time. By the 1990s that diversity flattened out, and what's happened since is that diversity across regions began to decline.

The lack of genetic diversity within individual crops is pretty obvious, says Martin. For example, in North America, six individual genotypes comprise about 50 per cent of all maize (corn) crops.

This decline in global crop diversity is an issue for a number of reasons. For one, it affects regional food sovereignty. "If regional crop diversity is threatened, it really cuts into people's ability to eat or afford food that is culturally significant to them," says Martin.

There is also an ecological issue; think potato famine, but on a global scale. Martin says if there's increasing dominance by a few genetic lineages of crops, then the global agricultural system becomes increasingly susceptible to pests or diseases. He points to a deadly fungus that continues to devastate banana plantations around the world as an example.

He hopes to apply the same global-scale analysis to look at national patterns of crop diversity as a next step for the research. Martin adds that there's a policy angle to consider, since government decisions that favour growing certain kinds of crops may contribute to a lack of diversity.

"It will be important to look at what governments are doing to promote more different types of crops being grown, or at a policy-level, are they favouring farms to grow certain types of cash crops," he says.
-end-
The study, which is published in the journal PLOS ONE, received funding from the Natural Sciences and Engineering Research Council of Canada (NSERC).

University of Toronto

Related Diversity Articles:

Revealing Aspergillus diversity for industrial applications
In a Feb. 14, 2017 study published in Genome Biology, an international team report sequencing the genomes of 10 novel Aspergillus species, which were compared with the eight other sequenced Aspergillus species.
Important to maintain a diversity of habitats in the sea
Researchers from University of Gothenburg and the Swedish University of Agricultural Sciences (SLU) show that both species diversity and habitat diversity are critical to understand the functioning of ecosystems.
Discovering what shapes language diversity
A research team led by Colorado State University is the first to use a form of simulation modeling to study the processes that shape language diversity patterns.
Making the switch to polarization diversity
New silicon photonic chip that offers significant improvement to the optical switches used by fiber optic networks to be presented at OFC 2017 in Los Angeles.
Deciphering the emergence of neuronal diversity
Neuroscientists at UNIGE have analysed the diversity of inhibitory interneurons during the developmental period surrounding birth.
Epigenetic diversity in childhood cancer
Tumors of the elderly carry many DNA mutations that can influence disease course.
Diversity without limits
Now, researchers at Temple and Oakland universities have completed a new tree of prokaryotic life calibrated to time, assembled from 11,784 species of bacteria.
Threatened by diversity
Psychologist Brenda Major identifies what may be a key factor in many white Americans' support for Donald Trump.
Diversity as natural pesticide
Monoculture crops provide the nutrient levels insect pests crave, explains a study led by the University of California, Davis, in the journal Nature. Returning plant diversity to farmland could be a key step toward sustainable pest control.
A missing influence in keeping diversity within the academy?
A new study of science Ph.D.s who embarked on careers between 2004 and 2014 showed that while nearly two-thirds chose employment outside academic science, their reasons for doing so had little to do with the advice they received from faculty advisors, other scientific mentors, family, or even graduate school peers.

Related Diversity Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...