There aren’t great answers to contend with the root cause (pun intended) of the uneven corn this season. The unusual weather conditions that started last winter and extended into this spring, and long periods of stress magnify small differences within fields and improves the odds of seedling disease, insect injury, chemical injury, etc. Any of these factors can make the plant more susceptible to slow root and top growth. Small management changes like floating trash whippers, higher dose seed treatments, slower planting speeds, and straw choppers/spreaders on combines can help with some of these issues. It’s always a good idea to look over the field as a whole for any patterns to the uneven corn that may help determine causes.
Many of the stunted/uneven areas can (and probably will) improve to a degree, especially if we can get some moisture in some of the areas where the upper soil profile could use it. I know, it sounds crazy to be talking about needing moisture after we fought an excess of it all spring in many areas, but while the subsoil is still full of moisture, in many areas the upper rooting zone is drying out. So, with limited root systems, stunted plants will continue to suffer more than the good parts of the field if we have extended dry weather. If we get moisture where we need it, things will likely look better… until tasseling time. Then the uneven growth and development of the field will show up again as compromised plants typically tassel later than the rest of the field.
While it depends on the field, here is some general advice when it comes to taking management steps for uneven corn:
1. Uneven corn seems to be more prevalent in corn on corn again this year. Agronomists are asking if the rotation to a different type of root system, like tap-rooted soybeans, helped to offset this somewhat. Field observations are agreeing with this. The flip side is that rotation decisions are tough to base on one really odd winter freeze/thaw cycle. The grain markets aren’t helping us much with rotation decisions lately either.
2. Some are asking if we should do some sort of mid-level or deep-tillage to correct this. What I have found has been so variable within fields that tillage may not address the issue as well as a “real” Iowa winter. Hard to have a guy run through a lot of acres burning diesel, time, and risking erosion for spotty and shallow, tight soil issues. Best we can advise right now is to work with your agronomy team and make an area-by-area evaluation of this when you have a chance this fall.
3. Since each case is different, the best idea would be to work with your local dealers and ISU agronomists to see what management factors can help out in the future.