The high number of prevented-planting fields in some areas, the late start to harvest, and the inability to apply P and K fertilizer as planned last fall or this past spring combine to raise a number of questions about fall application of P, K, and lime over the next few months, writes Emerson Nafziger, University of Illinois Extension Specialist, Crop Production.
Prevented-planting fields
If P and K fertilizers were applied last fall or this past spring but no crop could be planted, there’s no reason not to count all of the applied P and K as available for the 2020 crop. The same goes for any lime applied over the past 12 months. Any nitrogen (N) that was applied with MAP or DAP is likely no longer available, and shouldn’t be counted in the 2020 supply.
If the plan was to sample soil last fall or this spring to determine how much P, K, and lime to apply but that didn’t get done, these fields can be sampled now in preparation for fall or spring application. If the plan was to sample after the 2020 crop, there’s no reason to move that up to this fall; these nutrients didn’t (and won’t) go anywhere. By the same token, there’s no reason not to apply after two years based on estimated removal using the same P and K rates set to be applied a year ago. Unless a cover crop has been or will be harvested from a prevented-planting field this fall, removal will be zero.
Continue reading at the University of Illinois Extension.
