title: Climate-induced reduction in US-wide soybean yields underpinned by region- and in-season-specific responses.
abstract: The United States is one of the largest soybean exporters in the world. Production is concentrated in the upper Midwest(1). Much of this region is not irrigated, rendering soybean production systems in the area highly sensitive to in-season variations in weather. Although the influence of in-season weather trends on the yields of crops such as soybean, wheat and maize has been explored in several countries(2-6), the potentially confounding influence of genetic improvements on yields has been overlooked. Here we assess the effect of in-season weather trends on soybean yields in the United States between 1994 and 2013, using field trial data, meteorological data and information on crop management practices, including the adoption of new cultivars. We show that in-season temperature trends had a greater impact on soybean yields than in-season precipitation trends over the measurement period. Averaging across the United States, we show that soybean yields fell by around 2.4% for every 1 °C rise in growing season temperature. However, the response varied significantly among individual states, ranging from -22% to +9%, and also with the month of the year in which the warming occurred. We estimate that year-to-year changes in precipitation and temperature combined suppressed the US average yield gain by around 30% over the measurement period, leading to a loss of US$11 billion. Our data highlight the importance of developing location-specific adaptation strategies for climate change based on early-, mid- and late-growing season climate trends.
authors.affiliation: Department of Agronomy, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Mourtzinis
authors.affiliation: Department of Agronomy, University of Nebraska, Lincoln, Nebraska 68583, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Specht
authors.affiliation: Department of Horticulture and Crop Science, Columbus, Ohio 43210, USA.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Lindsey
authors.affiliation: Department of Plant Sciences, University of Missouri, Columbia, Missouri 65211, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Wiebold
authors.affiliation: University of Arkansas Division of Agriculture, Little Rock, Arkansas 72204, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Ross
authors.affiliation: Department of Crop Sciences, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Emerson D
authors.initials: ED
authors.lastname: Nafziger
authors.affiliation: Department of Plant Sciences, North Dakota State University, Fargo, North Dakota 58108-6050, USA.
authors.forename: Herman J
authors.initials: HJ
authors.lastname: Kandel
authors.affiliation: Department of Plant Sciences, South Dakota State University, Brookings, South Dakota 57007, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Mueller
authors.affiliation: Director of the Purdue Crop Performance Program, 4540 U.S. 52 west, West Lafayette, Indiana 47906, USA.
authors.forename: Philip L
authors.initials: PL
authors.lastname: Devillez
authors.affiliation: Department of Soil Science, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Arriaga
authors.affiliation: Department of Agronomy, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Shawn P
authors.initials: SP
authors.lastname: Conley