b'POST-2050: A CORN BELT WITHOUT CORN?New study predicts the impact of a changing climate on crop yields in the Corn Belt, and the results are daunting.Madeleine BaergNEW RESEARCH FROM Soybeans are harder to predict. While the University of Connecticutscorn will suffer sooner from heat stress, Department of Civil and Environmentalsoybeans may benefit from temperature Engineering outlines how a changing cli- increases in the short term and, more mate is likely to impact corn and soybeannotably, from higher CO2 levels. After yields in one of Americas most produc- 2050, however, the impact of heat stress tive growing regions: the Corn Belt.is likely to counteract higher C02s fertili-Post-doc Meijian Yang and professorzation effect. of civil and environmental engineering,The [predictive] models have con-Guiling Wang, used a simulation modelsensus in producing a future climate that called the Decision Support System forwould cause yield for soy at mid-century Agrotechnology Transfer to track howto go up, Wang says. different physiological processes in keyThats the good news. On the later side crops would respond to changing envi- of 2050, however, as greater heat stress ronmental conditions. The model took asbegins to impact soybeans more signifi-inputs the CO2 concentration, the amountcantly, yields could nosedive drastically. of fertilizers applied and the projectedIf you look at soy based on climate climate variables (including sunlight, pre- predictions from individual models, cipitation, temperature and wind speed)there is a very large variation among on each day through the growing seasonGuiling Wang, lead researcher on the cornthe models. Some climates would cause under a given climate at a very localisedand soybean yield modeling project. a huge decrease in yield, others would (2.5 mile) spatial resolution.cause little change, Wang says. Based on the simulated growth andThe models show not just that the stress of the crop, the model then calcu- average yield goes down, but much lated estimated yield for each crop. Tengreater fluctuations in yield than have projections of future climates were con- been seen until now. sidered, each corresponding to a differentYou end up with a lot more extreme climate model. years where yield loss is a problem. That has implications for insurance compa-Whats Ahead? nies. How will that influence farmers Farmers in the Corn Belt wont beability to get insurance? Wang says.pleased by the models projections. ToThe researchers found that soy and begin with, the model shows a 40% dropmaize yields were limited mostly by in maize yield by late in the century. water availability into the 2040s and For maize, the consensus is really2050s. After the 2050s, however, the strong, and I therefore have confidence formodel showed that heat will become the maize response, both in mid-centurythe primary yield limiting factor, first for and late-century. We see a 12% decreasemaize and later for soybeans. That has [in yield] for maize by mid-century andbig implications, not just for farmers, but 40% by late-century, Wang says. also for plant breeding. Breeding for heat Climate will cause corn to be less pro- tolerance must be a top priority even ductive. We are confident in the directionPost-doc researcher Meijian Yang. now, as variety development typically of the trend.takes many years.36/ SEEDWORLD.COMDECEMBER 2023'