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


May 2, 2014
Earth, Energy & Environment

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.

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.”



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

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.

  9. Christie Nel (u14022852) May 4, 2014 at 10:04 am #

    The climate is unfortunately not one of the factors that can be altered by humans and therefore the only solution to increase the production of corn is to continue with genetic modification. Scientists will just have to keep on doing what they do best and interfere with the natural world if we want to survive in this changing circumstances.

  10. Panashe(u14239419) May 4, 2014 at 8:00 am #

    Leaving more space between the plants would help remove stress on plants as less water is available in hot conditions. It would be better to use genetics in introducing genes that are adapted to hot and drought conditions so that the corn can be more drought resistant and therefore better yields are obtained.

  11. Rudolf (u14379572) May 4, 2014 at 6:56 am #

    Another solution to fighting the effects of heat/drought on corn, could be to use nano-technology in the plants. This will then help them store more water when it is available, and use it more efficiently when it is not. Nano-technology is already being used to fight cancer in the human body, why not use it on something as simple(compared to a human) as a plant.

  12. Rudolf (u14379572) May 4, 2014 at 6:31 am #

    Thanks Tod Skinny. Didn’t know that.

  13. u14184096 May 4, 2014 at 6:10 am #

    I do not think that this problem can be solved by planting corn on fields that is not being used as the temperature will be the same. Due to climate change , we can only expect that the drought will get worse or remain the same . So that is an aspect that we do not have control of but they can also try to manage it by considering using isolated areas with conrtolled temperatures and watering systems . It may not be very cost efficient but it will protect the corn against these unexpected weather conditions. So what I am trying to say is , I think it would be better to manage or manipulate the environment than genetics.

  14. karabo (14046874) May 4, 2014 at 5:17 am #

    Why should the main focus only be on be maximizing the corn? I think that the issue should be more on how can they produce enough corn with unfavorable weather conditions. Mono-culture could also be the reason why the corn production has decreased , meaning that its either they must use fertilizers or find new land to plant on. I strongly disagree with the use of genetically modified seeds/products, as I see it as creative more problems rather than creating a solution.

  15. 14098106 May 4, 2014 at 4:26 am #

    I am against genetic modified products, it is not natural at all and bad to your health. rather produce 100% organic products wich is much more safer for humans to use. The U.S. produces 86% genetic modified corn and many countries in the world have banned genetic modified products, wich leaves America with a problem.Professor J Cummins of the University of Western Ontario said that “there is evidence that GM products will impact directly on human health through damage to the ileum.” GM products can also be the cause of birth defects in animals and cancer in humans. Therefore I am against the use of GM products, even though they can produce more food it is harmful to the enviroment and on the long term it will not be sustainable for human health

  16. u14138060 May 4, 2014 at 2:54 am #

    They can also try to take a few crops and isolate them,change the temperature to check which temperature they cannot withstand over a period of time. Then take that information and try to modify their genes as well as repeat the experiment with the modified crops to see if whether they will grow better or not. By modifying the crops, I mean they can look for a gene in the xerophytes plants that make them to survive the dry habitat they live in and put it in the crops.they should not forget to check different soils where the modified crops will grow better and produce more crops at those temperatures. That way they will be prepared for the future.

  17. u14153972 N Mankganoto May 4, 2014 at 2:36 am #

    Solution that will maximise the decrease in yield of corn in U.S is the use of both genetically modified plants and fertilisers , recent studies have shown that genetically modified plants are resistant to harsh weather conditions, and they are well adapted to to such harsh weather conditions. Stats from food security in Brasil have shown that indeed the use of both GMF and fertiliser are the solution to decrease in yields of agricultural product.

    I strongly do not support the idea that U.S should consider to plant corn in unused or different area, because the effect of EL`nino affects over wide area and it threaterning the survival of our crops

  18. u14153972 N Mankganoto May 4, 2014 at 2:09 am #

    The solution to maximize the yields of corn of in U.S the use of genetically modified food /plants because these type of plants resistant to harsh weather conditions and they are well adapted to such conditions. the use of fertilisers is also effective in maximising the yields of crops. planting of corn in different area will not bring any difference since the effect of EL`nino is threaterning the survival of our crops.
    I firmly do not support the idea of planting corn in unused area because these plants will experience the same effect of climate change.

    The solution to this problem is the use of genetically modified plants and fertilisers so that the yield corn in U.S can be increased.

  19. Todd Skinner u14182948 May 4, 2014 at 12:13 am #

    Rudolph with your idea regarding the genetic modification of corn so that there is more corn on each cob is a great idea, however this has already been done. Corn actually comes from a plant called teosinte, which looks alot like corn however it is only one row of corn. Farmers genetically modified this plant so that there is more corn on each cob.

  20. Todd Skinner u14182948 May 4, 2014 at 12:09 am #

    The United States is said to contribute to 40 percent of the worlds corn production, this generates a large amount of income for the farming industry as most of the corn is exported. However, the worlds average temperature has been on the rise over the past few years due to global warming, thus the temperatures are too high to grow corn sustainably. This has led to a decrease in percentage yield of corn crops. This has become an issue as the worlds population is on a constant increase resulting in a higher demand on the amount of food. The only solution to compensate for the large demand of corn is to genetically modify it so that it can be grown anywhere. Genetically modified crops have become more and more popular, although they are more expensive than organic crops, they generate more income as the percentage yield is far greater.

  21. Ranier U14013950 May 3, 2014 at 1:20 pm #

    The U.S. is the largest exporter of corn in the world today, shipping about 40 percent of the world’s corn. In the 2012/2013 the United States grew nearly 10.8 billion bushels (273.8 million metric tons) .That’s why I support the idea of genetically modifying the corn. Recent studies dun by organization have shown a transgenic drought tolerance trait in a line of corn hybrids . Why not use genes like that , on a large scale to produce more corn, that can prevent death of the plant in hot/drought climates ,and more scientist’s can become part of this developing world to solve problems . I also support Rudolf’s idea . Genetically modifying the crops. This can have a positive outcome and open a world for new young scientists.

  22. Maike (14005345) May 3, 2014 at 8:15 am #

    Recent studies on more than one crop, including apples prooved the effect of climate change. I think that developing crop which are better adapted to these conditions will definitely be the first step, but changing the farming method might also be a temporary solution, for eg. Using No-till methods where plant material are left on the fields and helps to lock moisture in the soil and lower the average temperature in the land.
    Another factor which can also be taken into concideration in this study is the soil quality. If the same crop is planted on the same fields year after year, it might also have an effect on the yield, despite of the change in climate.

  23. Rudolf (u14379572) May 3, 2014 at 5:15 am #

    Why not genetically modify the corn to produce more (corn cobs) on a single plant?
    (Like the new grape vine, that produces more than double the amount of Murbine [ton per ha.] as an average.)
    That way the corn can still be planted further apart, and so prevent the decrease in production during hot/drought conditions.[as mentioned, if soy beans were planted further apart, they didn’t stress/suffer] This is a short term solution but if it buys 20-30 years of more good (normal) production then at least there will be time to find a long term solution

  24. 14303273 May 3, 2014 at 5:03 am #

    Rather than to spend money on the genetic modification to improve corn to withstand temperature changes, they should plant more corn in fields that is unused, thus compensating to the loss of the corn yielding percentage.

  25. Rudolf May 2, 2014 at 12:23 pm #

    Just some “problems” that I see with your version Mr.Phalatsi
    If the farmers planted barley, and thus decreasing the volume of corn that could be produced, they would actually worsen the problem, since the corn, as it is, loses “15 percent of their yield” (U.S. corn yields are increasingly vulnerable to hot, dry weather) in unusually hot conditions. and that amount increases because of, as you mentioned, climate change.
    The goal is not to vary the crop production but to try and keep it constant, at a high amount for as long as possible.Thus making the crop (corn) drought or heat “resistant” would help that cause along quite well.So by using experience and data gained from making barley drought resistant, they can try and make corn crops drought resistant.

    Well said Chanel.

  26. Chanel May 2, 2014 at 12:12 pm #

    Instead of focussing so much on maximizing crop yields, the focus can be placed on modifying the corn to withstand the drought conditions and challenging temperatures. This would lead to a sustainable yield over time. More of these modified crops can be planted to satisfy the needs of the people rather than spending more money on finding new ways to maximize yields and still having the decrease because of the changing climate and conditions.

  27. J Phalatsi (u14252768) May 2, 2014 at 10:17 am #

    I agree with you Rudolf, why cannot they manipulate the concerned traits so that the corns can survive to produce a larger yield. It is apparent that conditions will get worse due to climate change it would also be am option to reduce the corn rotation and replace it with barley or similar plants that are drought resistant. this might also increase the variation in crop production.

  28. Rudolf May 2, 2014 at 6:49 am #

    Why not genetically modify the corn to produce more (corn cobs) on a single plant?
    (Like the new grape vine, that produces more than double the amount of Murbine [ton per ha.] as an average.)
    That way the corn can still be planted further apart, and so prevent the decrease in production during hot/drought conditions.[as mentioned, if soy beans were planted further apart, they didn’t stress/suffer] This is a short term solution but if it buys 20-30 years of more good (normal) production then at least there will be time to find a long term solution.

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