왜 옥수수가 가뭄을 대비하지 못했나

For more than a decade, academic and industry scientists have promised crops that would endure hot, dry weather. That weather has arrived. The crops have not. In a land where corn is king, the king is stunted and withered.

How could this be? The answer offers a window into some of the fundamental tensions of modern agriculture, with no easy scapegoats nor obvious solutions.

“We need a systems approach to doing this — improved genetics, improved agronomy, adopting some organic methods,” said Doug Gurian-Sherman, a food expert at the Union of Concerned Scientists, a nonprofit advocacy group. “If we just rely on the companies, we’re not going to get there.”

“It’s arguably the most important trait for world food stability that there is,” said Joe Keaschall, director of maize research at Pioneer Hi-Bred, the world’s largest corn seed producer.

In the United States, corn covers an area the size of California, and nearly all the seed comes from Pioneer and Monsanto. It’s been a biotechnological bonanza: 88 percent is genetically engineered, primarily for resistance to pests and herbicides.

The first drought-tolerant varieties, however, bred by Pioneer and branded collectively under the Optimum AQUAmax trademark, only went on sale in 2011, as did Syngenta’s AgriSure Artesian corn. Another variety, developed by Monsanto and called DroughtGard, was approved by the USDA this year and is expected to go on sale in 2013.

None have been tested in large-scale, real-world conditions, and the claims made for them are cautious: They won’t flourish during droughts, but might do a bit better than existing plants, hopefully surviving for one more rainfall.

'There will be no silver bullet.'

If they work as advertised, the varieties could be quite useful in droughts of low to moderate intensity. Their utility in the crucible that much of the central and western United States is expected to become, however, will likely be limited.

It’s a far cry from traits like Bt pesticide production and Roundup herbicide tolerance. Those are powerful and ubiquitous, the agricultural analogues of blockbuster drugs, and have dominated company research efforts. “They are incredibly large products, and that’s why the companies have emphasized them,” said agricultural economist Greg Graff of Colorado State University.

Given the costs of developing new products, agriculture companies, just like drug companies, focus on those with the biggest payoffs. As for drought tolerance, said Graff, “We haven’t been trying that hard for that long.”

Yet even if drought tolerance hasn’t been a central commercial priority, it hasn’t been ignored. As Keaschall noted, Pioneer has worked on it since 1977, and so have hundreds of academic scientists. A more fundamental problem is sheer biological intractability.

Unlike pest or herbicide resistance, drought tolerance doesn’t come from a few easily added genes. It’s the result of complex traits involving hundreds of genes, their activity difficult to orchestrate. “Drought is not going to be a single-gene solution,” said Keaschall.

Even when the genetics can be grasped, they’re often antithetical to farmers’ aims. A slow-growing plant with tiny leaves that shutters its metabolism in the absence of rain would do fine during a drought, but for farmers it’d be slightly more useful than a cactus.

Indeed, inasmuch as high productivity is required of drought-resistant corn, the limitations of genetics may be inescapable. “If you add it all up, what it says to me is that there are limitations to what you can do in a plant like corn,” said Gurian-Sherman.

That makes non-genetic approaches, such as using cover crops to manage soil characteristics and fine-tuning planting times, all the more important. But those methods are knowledge-based, and it’s much harder to monetize knowledge than genes.

As a result, research in those areas has lagged, said Gurian-Sherman. “We need to invest public research into those things that companies are not doing as much, such as agroecology and breeding other crops that are promising but neglected,” he said. “The efficiency of these methods could be greatly improved, and they need to be. But the result is going to be methods farmers can use, not products.”

Pioneer’s Keaschall said the company does work with these methods. “We’re doubling the number of agronomists working directly with customers,” he said. “The idea is to work with growers to get the right product on the right acre with the right management.”

The drought is expected to last through October.Image: National Weather Service

In some ways, this disagreement resembles that around new crops genetically engineered to resist multiple herbicides, a controversial approach prompted by industrial over-reliance on a single approach to pest control. Companies say they’ve learned their lesson, but that remains to be seen.

According to Graff, there’s another, subtler challenge to confront: limited consumer demand.
“When you sit down and talk with the farmers about this kind of thing, and with the companies that develop new seeds for them, I think the single most important insight is that market demand for this kind of trait is weak,” he said.

For all the social catastrophe caused by drought, and all the hardships that farmers do endure, farmers can buy insurance, Graff said. They can buffer themselves against the risk of drought — not completely, but enough to reduce the commercial value of drought tolerance.

“There’s a lot of traits for which there’s not enough incentive on the table for private investors,” Graff said. “It’s not a smart investment for anyone — except for society at large, because it improves the productivity of our agricultural base and keeps the price of food down.”

Graff suggests subsidizing farmers to purchase drought-tolerant seeds and focusing public research on market deployment rather than basic research. The public return on investment, he said, would be between 20 and 50 percent. Gurian-Sherman put that figure around 200 percent.

But even if all this advice were taken, the genetics and agronomy and economic facts perfected, the possibility remains that a drought like this summer’s — the worst since the Dust Bowl, emblematic of weather patterns predicted to result from climate change — might be too much to handle.

“Once it’s really bad, nothing is going to help,” Graff said.

“We need to acknowledge that there are limits to what we can do,” said Gurian-Sherman. “We need to be much more forthcoming that climate change is real, that it will make these situations worse, and that we need to do something about it.”