There are consulting firms in Indiana that have storage sheds full of corn stalks, at least eight inches long, suspended from racks and drying this time of year. Once they're ready, the samples will be sent to labs for analysis.
The main thing most consultants look for when sampling late-season stalks are nitrate levels. (This is an entirely separate discussion from testing corn that will be chopped for silage or baled for hay for nitrates in the stalk. In that case the purpose is to determine if there are possibly harmful levels of nitrate in the stalks that could be harmful when fed to livestock.)
In this case, the corn typically isn't chopped. It's harvested for grain. The stalk sampling is used as a tool to help fine-tune nitrogen programs for the following year. It's a way to see if stalks ran deficient on N, or if they had an excess of N, meaning more N was applied than the plant could use to make grain.
At least that's what it usually means. Lisa Holscher, watershed coordinator for the West Central Indiana Watershed Alliance, has been taking stalk samples as part of various projects where the protocol calls for stalk samples before harvest.
One of those is part of an On-Farm Network group. There are several On-Farm Network projects within Indiana. Each one consists of a group of like-minded farmers who want to test a practice. Each conducts the same experiment in their field. Then in the off-season they compare results. Many of these projects call for stalk sampling before harvest as an extra insight into what effect the practice might be having on the corn plant.
Holscher says this year will be interesting. She says what might happen this year is that the results will simply set the bar for what levels to expect in a bad year.
The On-Farm Network concept is partially sponsored by the Indiana State Department of Agriculture. The idea started in Iowa several years ago. The Iowa program is now so large that many groups of farmers cooperate, and test a wide variety of practices each year.