Climate Impacts on Corn Yield in the North American Corn Belt

Weather and climate conditions define the environment in which agricultural crops grow and produce yield. The question of how variations of these conditions affect the yield of various crops has long been the focus of research in agricultural meteorology and climatology as well as in agronomy.

Effects of climate conditions and their seasonal variations on corn yield at one of the oldest experimental sites in the USA, the Sanborn Field in Columbia, Missouri were evaluated using the established datasets of climate and yield of 104 years. The claypan soil profiles, the management and practice in the production process, and the climate at this experiment site have representativeness of the growing conditions in the rest of the North American Corn Belt.

In the analysis, climate conditions were composited according to yield. There are three major results from the study. First, the climate effect is essential in determining the corn yield in the region. This was demonstrated by the same dependence of the yield on the growing season precipitation and temperature variations from two very different treatments/managements. Both treatments produced yield below their long-term averages in years with unfavorable climate conditions. Their yields were higher than those averages in the same years with climate conditions favorable for corn growth. Three climate sub-regimes were established in the region separated by the yield variations

Secondly, precipitation and temperature variations within the growing season had a dominant impact on the corn yield. The seasonal average conditions are not as important. This was particularly the case for temperature variations. It was found that what separated the high yield from the low yield was the within-season variation of temperature anomalies.

Thirdly, the planting season temperature and precipitation were the most effective parameters on the corn growth and yield. Opposite anomalies of both temperature and rainfall in that period were found for high and low yield years. In particular, high yield years were dry and warm in that period of time while low yield years were wet and cool/cold. Additionally, there is a lag between the time of change of precipitation and temperature at the end of this period. In high yield years, the precipitation change from dry to wet started 2 to 4 weeks earlier than the temperature change from warm to not warm. This feature is shown critical for corn yield.