County yield estimates were issued recently by the Indiana Ag Statistics Service. Vital to those with GRIP crop insurance policies, they also reveal interesting trends. One of those is that average numbers can be misleading.
In central Indiana, for example, the final county estimate was just over 99 bushels per acre, right at the Indiana statewide estimate. However, several of the counties with the lowest yields statewide were in that sample, including Morgan, Johnson, Shelby and Hendricks. All of those posted yields below 65 bushels per acre. So how did the average rise to 99? – that was what farmers staring at burnt-up fields wondered last summer when the statistics first began to come out.
It's not what happens in your backyard, but across the entire area when you begin to talk averages. Jim Newman, former Purdue University ag climatologist, often made the point that what happens outside your back door is one of the worst ways to guess trends and make marketing decisions, which depend upon what happened over a wide area.
In this case, yields north and east of Indianapolis were much better, led by Hamilton County, with an average yield over 120, and other nearby counties..
The situation was similar in west-central Indiana, which averaged 88 bushels per acre. Yet some of the lower-yielding counties were in that sample. However, yields in counties on the northern end of the district fared better, due to better rainfall and better soils. That helped pull the average yield up.
South-central and southwest Indiana posted the lowest average yields, and many counties within those districts were some of the lowest yielding in the state. Southeast Indiana had better rainfall last spring, but soils and drier weather later drug it down as well. Corn yield in southeast Indiana was still below the statewide average in 2012.