Corn is the number one crop grown by American farmers, accounting for more than 95% of total production and use. The crop, which was a human invention and cannot be found in the wild, is also one of the most dependent on ideal weather conditions to grow. In a world with an ever-warming climate, these two factors do not play well with one another.
Now scientists from Stanford University have found another “oh, goody” moment to insert into the conversation. A new study, published in Nature Food, has found that the staple crop has become significantly more sensitive to drought conditions.
New technologies are able to help raise yields in a variety of weather conditions. That’s the good news.
“The bad news is that these technologies, which include some specifically designed to withstand drought, are so helpful in good conditions that the cost of bad conditions are rising,” said study lead author David Lobell, the Gloria and Richard Kushel Director of the Center on Food Security and the Environment at Stanford. “So there’s no sign yet that they will help reduce the cost of climate change.”
Corn production in the U.S. is a seemingly unstoppable juggernaut. Despite concerns about resistant weeds, a changing climate and many other factors, the industry has set record yields in five of the last seven years. Likely drivers of these bumper crops include changes in planting and harvesting practices, such as adoption of drought-tolerant varieties, and changes in environmental conditions, such as reduced ozone levels and increased atmospheric carbon dioxide concentrations that generally improve the water-use efficiency of crops.
As climate change intensifies, however, the cost to maintain crop yields will likely increase. A variety of factors enter into the equation, such as increased crop water needs due to increased plant sowing density. What is clear is that despite robust corn yields, the cost of drought and global demand for corn are rising simultaneously.
The Stanford scientists akin it to “a baseball slugger whose home run totals rise despite missing more curveballs each season.”
To accomplish the study, scientists used county soil maps and satellite-based yield estimates, among other data, to examine fields in the Corn Belt, the nine-state region of the Midwest which account for roughly two-thirds of the nation’s corn production. By comparing fields along gradients of drought stress each year, researchers could identify how sensitivity to drought is changing over time.
Even within a single county, they found a wide range of soil moisture retention, with some soils able to hold twice as much water as others. As might be expected, there were generally higher yields for soils that held more water. They found yield…