USDA’s National Agricultural Statistical Service has released projected 2012 Crop Reporting District (CRD) yields for Illinois, Indiana, Iowa, Kansas, and Missouri. These projected CRD yields are compared to trend yields so as to find areas where the 2012 drought caused the largest yield declines in corn and soybeans. Overall, yields are most below trend yields in eastern Kansas, northern Missouri, southern Illinois, and southwest Indiana.
Each 2012 yield is stated as a percent of trend yield. For example, the Southeast CRD has a projected 2012 corn yield of 55 bushels per acre. Based on yield data from 1972 through 2011, the Southeast CRD has a 2012 trend yield of 142 bushels per acre. This trend yield represents the expected yield for 2012 – if 2012 could be repeated ten times, the average yield across those 10 replications would be close to 142 bushels per acre. The Southeast CRD actual yield is 39 percent of trend yield (39 percent = 55 bushel 2012 yield / 142 bushel trend yield). This is a very low yield that is 61 percent below trend yield.
CRDs whose 2012 yields are between 0 and 50 percent of trend yields occur in an area beginning in eastern Kansas, continuing across much of the northern two-thirds of Missouri, extending across southern Illinois, and ending in the southwest Indiana (see Figure 1). From a corn yield perspective, this area has the largest percentage decline in 2012 yields. CRDs next to these hardest hit areas tended to have low yields. There were a number of CRDs that had yields 50 to 60 percent of trend yield in Kansas, Illinois, and Indiana. Relative to trend, CRDs with the highest yields are located in Iowa, southwest Kansas, and southeast Missouri. However, there are no CRDs where 2012 projected yield exceed 90% of trend yield, indicating that yield losses occurred across all these states.
CRDs with the lowest projected soybean yields are located in Kansas (see Figure 2). All reporting CRDs in Kansas have trend yields that are 70% or below trend yields. Other areas of lower yields include the northern two-thirds of Missouri, southern Illinois, and southwest Indiana. The area of low soybean yields overlap with the area of low corn yields with some differences. In Illinois, lower soybean yields are projected to occur not as far south as lower corn yields. Moreover, lower soybean yields are located further west than are low corn yields.
There are a number of areas were soybean yields are not projected to be decreased by large amounts. CRDs in northern Illinois and southeast Missouri are projected to have 2012 yields that are 90% or more of trend yields. The Southeast CRD’s 2012 yield is projected to be at trend yield.
Except for some northern Iowa CRDs, 2012 corn yields as a percent of trend are lower than soybean yields as a percent of trends. Except in northern Iowa, corn yields have more losses as a result of the drought as compared to soybean yields.
In the states with projected 2012 CRD yields, the 2012 drought has its largest negative impacts on Kansas, Missouri, southern Illinois, and southwest Indiana. In terms of lower yields, the epicenter of the drought appears to have been in Missouri. Yields generally increase the further from this area. In general, corn yields were lower as a percent of trend than soybean yields.
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