What to Know Post Flooding
Due to major flooding over the last week in Indiana and other areas of the Corn Belt, many fields have had most of last season’s crop residue removed. What impact will this have on the 2025 crop, and what adjustments should be made?
The answer to this question depends on field topography and location because that will determine where the crop residues go. In flatter fields, most residues will have simply decomposed in the flooded field, just a bit earlier than expected. In such cases, little is lost beyond the protection against soil drying through V6. In cases where torrential rain washed it off of slopes, that residue mitigated some erosion and loss of surface nutrients. So, it did its job. And, where active flooding lifted it away, those same waters likely also deposited some nutrient-rich silt.
In the case of bottom fields, the benefits of periodic flooding often balance out the occasional losses. The timing relative to other events upstream remains relevant. As noted, the delivery of “nutrient” rich, silty water with floods can be a mixed blessing as it all depends on what the upstream landowners and sewer districts did in the weeks before flooding.
Too much potassium or herbicide applied upstream might stress early emergence in bottom lands that flooded and drained in the weeks before planting takes place. Excessive crusting/soil sealing, if it is a problem, can be addressed post-flooding with a pelletized gypsum product, e.g. at 250-500 lbs/ac, but this might only be needed in heavier / high CEC soils. If flooding lasted more than a week, and planting is just a few weeks away, applications of balanced nutrition and a biostimulant in furrow to reactivate the native soil biology will be beneficial.
Of course, the most important thing is to delay field operations and planting in flooded areas until well after the soil can take the equipment. Not mudding in the crop is first priority. It’s important to know that delayed planting up to a week after the typical target date (or two weeks after an early target planting date) is very rarely a yield limiter, as the elevated soil temperatures promote faster and more vigorous emergence.
