Drought 2012: searching for ground zero
Over at farmdocdaily.illinois.edu, ag economist Dr. Gary Schnitkey crunched the numbers from USDA’s 2012 yield projections as grouped in Crop Reporting Districts (CRD) for Illinois, Indiana, Iowa, Kansas, and Missouri. In the graphics he prepared, the CRD yields are compared to trend yields. The result is a general look at levels of severity for 2012’s drought.
“Overall, yields are most below trend yields in eastern Kansas, northern Missouri, southern Illinois, and southwest Indiana,” reported Schnitkey. You can read the full report here.
While late-season rains may have tempered soybean losses, the corn season was contained within historic hot and dry conditions and give a solid picture of just how bad the drought was.
From Schnitkey’s research:

Corn Yields
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.

