Forming Expectations for the 2015 U.S. Average Winter Wheat Yield: What Does History Teach Us?

Abstract

The main factors determining spring wheat yield will unfold over the next few months. For the time being, yield expectations are generally based on trend yield analysis that might also incorporate specific views on prospects for growing season weather. This raises the perennial issue of what, if anything can be learned from the historical trends and patterns of U.S. average spring wheat yields. Here, we examine the history of spring wheat yields from 1960 through 2014 as a basis for forming an expectation of the U.S. average yield in 2015. The analysis follows the same format as our farmdoc daily articles on 2015 corn yields (February 26, 2015), 2015 soybean yields (March 19, 2015), and 2015 winter wheat yields (March 26, 2015). The analysis of spring wheat yields is motivated by the differing patterns of average spring and winter wheat yields experienced since 1960 (Figure 1). The divergent patterns reflect differences in geographic areas of production and differences in planting seasons. Average spring wheat yields have typically been lower than average winter wheat yields, but the difference varies considerably year-to-year. In addition, the ratio of winter wheat yields to spring wheat yields has declined slowly over time (Figure 2).