A University of Illinois study has revealed that the U.S. corn and soybean varieties have become increasingly heat and drought resistant as agricultural production adapts to a changing climate.
It further revealed that the focus on developing crops for extreme conditions has negatively affected performance under normal weather patterns.
“Since the 1950s, advances in breeding and management practices have made corn and soybean more resilient to extreme heat and drought. However, there is a cost for it. Crop productivity with respect to the normal temperature and precipitation is getting lower,” Chengzheng Yu, a doctoral student in the Department of Agricultural and Consumer Economics (ACE) at the University of Illinois and lead author on the new paper, published in Scientific Reports said.
The study co-author Madhu Khanna, ACES distinguished professor of environmental economics in ACE further explained that climate projections indicate a mix of extreme and normal weather patterns in the next 50 years, adding that crops must perform well under a variety of conditions.
While noting that it is not enough to just focus on extreme weather conditions, Khana said the impacts of climate change in a piecemeal fashion alone can’t be looked at alone but to develop varieties only to cope with certain aspects of it.
Yu, Khanna, and co-author Ruiqing Miao, Auburn University, studied corn and soybean yield from 1951 to 2017 in the eastern part of the U.S., an area where crops can grow without irrigation. The authors said crop yield increased significantly during the present period due to a wide range of technological and breeding improvements. But when the researchers isolated the effect of climate-related adaptations, they found significant negative impacts on yield.
The study further revealed that heat and drought tolerance increased yield by 33 percent for corn and 20 percent for soybean over this period, while the gain was offset by reduced productivity under normal conditions. The researchers then concluded that maladaptation due to climate-related factors reduced corn and soybean yield by 8 percent and 67 percent, respectively.
“There’s been this trade-off; crops become better adapted to extreme weather, but less adapted to normal conditions. Overall, crop yields went up by 100 percent to 200 percent over the past decades. We break this down into the components that happened because of climate-related changes, and components that happened irrespective of climate change. And we find the impact of climate-related adaptation has been negative,” she explains.
In their findings, the researchers projected net effects of climate change adaptation on crop yields by 2050 under a range of warming scenarios. They noted that weather-adapted variations will perform better in the most extreme scenarios. But under less extreme scenarios varieties that perform well in normal climate would be more productive.
They advised crop breeders to focus on developing crop varieties for diverse weather patterns, adding that flexibility is important for agricultural producers to be well prepared for future conditions.