U.S. corn yields are increasingly vulnerable to hot, dry weather


May 2, 2014 |

Corn yields in the central United States have become more sensitive to drought conditions in the past two decades, according to Stanford research.

The study, which appears in the journal Science, was led by Stanford’s David Lobell, associate professor of environmental Earth system science and associate director of the Center on Food Security and the Environment. “The Corn Belt is phenomenally productive,” Lobell said, referring to the region of Midwestern states where much of the country’s corn is grown. “But in the past two decades we saw very small yield gains in non-irrigated corn under the hottest conditions. This suggests farmers may be pushing the limits of what’s possible under these conditions.”

He predicted that at current levels of temperature sensitivity, crops could lose 15 percent of their yield within 50 years, or as much as 30 percent if crops continue the trend of becoming more sensitive over time.

As Lobell explained, the quest to maximize crop yields has been a driving force behind agricultural research as the world’s population grows and climate change puts pressure on global food production. One big challenge for climate science is whether crops can adapt to climate change by becoming less sensitive to hotter and drier weather.

“The data clearly indicate that drought stress for corn and soy comes partly from low rain, but even more so from hot and dry air. Plants have to trade water to get carbon from the air to grow, and the terms of that trade become much less favorable when it’s hot,” said Lobell, also the lead author for a chapter in the U.N. Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, which details a consensus view on the current state and fate of the world’s climate.

The United States produces 40 percent of the world’s corn, mostly in Iowa, Illinois, and Indiana. As more than 80 percent of U.S. agricultural land relies on natural rainfall rather than irrigation, corn farmers in these regions depend on precipitation, air temperature and humidity for optimal plant growth.

corn image

According to the research, over the last few decades, corn in the United States has been modified with new traits, like more effective roots that better access water and built-in pest resistance to protect against soil insects. These traits allow farmers to plant seeds closer together in a field, and have helped farmers steadily raise yields in typical years.

But in drought conditions, densely planted corn can suffer higher stress and produce lower yields. In contrast, soybeans have not been planted more densely in recent decades and show no signs of increased sensitivity to drought, the report noted.

Drought conditions are expected to become even more challenging as temperatures continue to rise throughout the 21st century, the researchers said.

Lobell said, “Recent yield progress is overall a good news story. But because farm yields are improving fastest in favorable weather, the stakes for having such weather are rising. In other words, the negative impacts of hot and dry weather are rising at the same time that climate change is expected to bring more such weather.”

Extensive data

Lobell’s team examined an unprecedented amount of detailed field data from more than 1 million USDA crop insurance records between 1995 and 2012.

“The idea was pretty simple,” he said. “We determined which conditions really matter for corn and soy yields, and then tracked how farmers were doing at different levels of these conditions over time. But to do that well, you really need a lot of data, and this dataset was a beauty.”

Lobell said he hopes that the research can help inform researchers and policymakers so they can make better decisions.

“I think it’s exciting that data like this now exist to see what’s actually happening in fields. By taking advantage of this data, we can learn a lot fairly quickly,” he said. “Of course, our hope is to improve the situation. But these results challenge the idea that U.S. agriculture will just easily adapt to climate changes because we invest a lot and are really high-tech.”

Lobell and colleagues are also looking at ways crops may perform better under increasingly hot conditions. “But I wouldn’t expect any miracles,” he said. “It will take targeted efforts, and even then gains could be modest. There’s only so much a plant can do when it is hot and dry.”

28 Responses to U.S. corn yields are increasingly vulnerable to hot, dry weather

  1. Kagiso(13355377) May 5, 2014 at 6:50 am #

    I think its going to be a bit difficult to modify corn into withstanding extreme weather conditions that are mentioned in the above article, for this reason; not only many plant can survive the hot dry weather conditions except for the well known desert trees. However, the state should start looking for new sites in which they will farm corn, and start implementing things that will support and sustain the climate from there forth. Thus these can be building dams, planting more trees and providing the soil with sufficient amount of nitrogen.

  2. Rakhuduwe Mantsha 14152402 May 5, 2014 at 2:11 am #

    From the above discoveries it shows that in the next coming years not only corn will be the only crop that can grow on both hot and cold conditions but other crops will also have the same traits as that of the corn if they are also treated in the same way of modifying them.And it also shows that even in some regions crops with traits that includes drought tolerant, resistance to pests can grow and will lead to the reduction of poverty.

  3. u14043892 May 5, 2014 at 12:08 am #

    The temperatures are rising globally, convicting a huge problem for all farmers globally. Crops all around the world are experiencing hardships, and so new ideas need to be created. Yields still need to be on standard, to feed our world. Traits are the most important aspect of our new technology industry, and is used all over the world.. These traits are stronger and can overcome more and more hardships, still giving a the yield of crops that we want, batteling all kinds of deseases that can decrease the yields. For example the Zea Maize plant, that adapted to bad weather conditions, and still give the yield that we want. Farmers plant these maize between there original crops, so that traits can make the original crops stronger….So the need for new traits in the crop industry, is compulsery.. And so we are striving for newer better perfection, to adapt to the future behond.

  4. Karabo (14046874) May 4, 2014 at 10:08 pm #

    I think the problem should not lie on maximizing the crop production but on how they can produce enough crop under such unfavourable conditions. Mono-culture could be one of the reason why the ground has been so unproductive. Instead of forcing great production they should find solutions if it shows such problems. I do not believe in genetically modified seeds/products and it might the reason behind all the negative outcomes. I say this because if one of them gets infected the whole of them can suffer just as much.

  5. u14127212 May 4, 2014 at 1:27 pm #

    I agree with Rudolf and Chanel. Corn plants need to be genetically modified with new traits to withstand the hot and dry weather conditions. The biggest challenge for agricultural research is whether the corn plant will adapt and become less sensitive to draught.

    As a long term solution, is it not possible to start building dams in the area for the future when our climate inevitably will become more challenging because of climate change. The corn plants may adapt to warmer weather, but they will still need water to grow.

  6. 14127212 May 4, 2014 at 12:57 pm #

    I agree with Rudolf and Chanel. Corn plants need to be genetically modified with new traits to withstand the hot and dry weather conditions. The biggest challenge for agricultural research is whether the corn plant will adapt and become less sensitive to draught.

    As a long term solution, is it not possible to start building dams in the area for the future when our climate inevitably will become more challenging because of climate change. The corn plants may adapt to warmer weather, but they will still need water to grow.

  7. u14184096 May 4, 2014 at 12:26 pm #

    By modifying this corn yields genetically it will actually give them a lot more benefits , is it really that bad for the human’s health ?

  8. u14184096 May 4, 2014 at 12:02 pm #

    Genetic modified foods and nanotechnology in foods are things that is already being used with plants and foods , it is bad for your health and that is not a secure solution for this corn , I would not recommend it but on the other hand , it does have a few benefits like helping the corn “survive” this drought and keeping products fresh for longer as well as providing a more secure income for farmers that was struggling with droughts that killed the corn before.

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