How science could spark a second Green Revolution
To fight poverty and overpopulation, crops need coaxing. Advances in deep-root food plants may trigger a new Green Revolution.
Jonathan Lynch wants to get at the roots of the problem of producing enough food for humanity. Literally.Skip to next paragraph
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In projects around the world, the professor of plant nutrition at Pennsylvania State University and his colleagues are trying to develop crops whose root systems can resist drought and take up fertilizer from the soil more efficiently.
With world population expected to grow by nearly 50 percent to more than 9 billion people by midcentury, farmland is going to need to be much more productive. Even today, nearly 1 out of every 6 people in the world – more than 1 billion – are going hungry, according to the United Nations Food and Agriculture Organization.
With most good farmland already under cultivation, any new acreage would likely be in marginal land with either poor soil conditions or little rainfall. What's more, climate change is expected to make some regions drier or hotter, which may send crop yields plummeting.
What the world needs, say Dr. Lynch and others, is a new Green Revolution that can increase yields in the face of challenging and changing conditions.
"The idea that we could fertilize and irrigate our way out of this problem was the first Green Revolution" led by Nobel Peace Prize-winner Norman Borlaug and others, Lynch says. The second Green Revolution is going to be how we get plants to grow productively with less water and artificial fertilizer, he says.
That's where Lynch's idea for improving roots comes in. He calls the concept "steep, cheap, and deep" – developing crop roots that grow steeper and deeper into the soil, making them able to find more moisture and nutrients, thereby reducing need for irrigation and nitrogen fertilizers. (With crops that rely on phosphorus, he's breeding shallow roots, since phosphorus is typically found in topsoil.)
Working with bean breeders around the world, for example, Lynch's team has identified root traits that can produce "two or three times more food without fertilizer," he says, using conventional breeding techniques that select for superior root traits.
His work on new varieties of corn is less advanced. But Lynch has published a paper that identified a previously unrecognized trait that improved yields eight times in experimental corn lines grown under drought conditions.
A key component in raising American corn yields in recent decades, nitrogen fertilizer, is more expensive in Africa than in the United States, Lynch says. In addition, as it runs off fields it can contaminate water supplies and produce nitrous oxide, a potent greenhouse gas.
While Lynch employs traditional cross-breeding methods, genetically modified (GM) crops seem likely to play an important role in the second Green Revolution. Concerns about safety and unexpected consequences have led to a slow rate of adoption in Europe and parts of Africa, although GM crops are already widely planted and consumed in the US.
"There's incredible debate over to what extent you can achieve these productivity goals without [GM crops]," says Mark Rosegrant, an economist at the International Food Policy Research Institute in Washington.
GM crops will be an "essential" part of increasing yields in Africa, says Calestous Juma, a professor of international development at Harvard University and the director of the Agricultural Innovation in Africa Project funded by the Bill & Melinda Gates Foundation. "In the medium to long run, genetic engineering is going to become inevitable," he says.