Author
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Hatfield, Jerry |
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WRIGHT-MORTON, LOIS - Iowa State University |
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HALL, BETH - Midwestern Regional Climate Center (MRCC) |
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Submitted to: Climatic Change
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/15/2017 Publication Date: 6/12/2017 Citation: Hatfield, J.L., Wright-Morton, L., Hall, B. 2017. Vulnerability of grain crops and croplands in the Midwest to climatic variability and adaptation strategies. Climatic Change. doi: 10.1007/S10584-017-1997-x. Interpretive Summary: Maize and soybean are the dominant crops grown in the Midwest and with wheat and oats as the minor grain crops. There continue to be questions asked about the potential impacts of climate change on the viability of maize and soybean production across the Midwest. To address that question, we evaluated the concept of a yield gap defined as the difference between the yield we could attain with no weather limitations and the actual observed yield for each county in the Midwest. These data were combined with different meteorological variables and we found July maximum, August minimum temperatures and July-August total precipitation provided the best description for the yield gaps across the different counties in the Midwest. To determine the potential impact of climate change we extracted these values from projected scenarios through the remainder of this century and found for maize there is a strong gradient from south t0 north in the Midwest. This gradient showed that yield gaps would continue to increase and in maize in the southern part of Illinois yields would be less than 25% of the attainable yield while in soybean for the same areas was near 70%. Maize will suffer large yield losses with projected climate change due the high summer temperatures. This information will help crop geneticists to identify traits and crop producers to begin to explore adaptation strategies to reduce stress. Technical Abstract: Maize (Zea mays L.) and soybean (Gylcine max (L.) Merr.) are the dominant grain crops across the Midwest and are grown on 75% of the arable land with wheat (Triticum aestivum L.) and oats (Avena sativa L.) small but economically important crops. Historically there have been variations in annual yields for maize and soybean related to the seasonal weather patterns. Key concerns are the impacts of future climate change on maize and soybean production and their vulnerability to future climate changes. To evaluate these, we analyzed the yield gaps as the difference between the attainable and actual yield at the county level using county level yield data and observed meteorological data to determine which seasonal variables were dominant in quantifying the actual/attainable yields. July maximum temperatures, August minimum temperatures and July-August total precipitation were found to be the factors affecting the yield gap. These relationships were used to estimate the change in the yield gap through 2100 using both the RCP 4.5 and 8.5 climate scenarios for these variables for selected counties across the Midwest. Yield gaps increased with time for maize across the Midwest with the largest increases in the southern portion of the Corn Belt showing a large north-south gradient in the increase of the yield gap and minimal east-west gradient. Soybean was not as sensitive as maize because the projected temperatures do not exceed the temperature ranges and reductions in production are more sensitive to precipitation changes during the reproductive stages. Adaptation strategies for maize and soybean will require more innovation than simple agronomic management and require the linkage between geneticists, agronomists, and agricultural meteorologists to develop innovative strategies to preserve production in the Midwest. |
