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| You could figure removal of your proposed corn crop and apply that much N, P, and K. You'll probably over apply N and the P and K won't leach much so they won't hurt other than cost to put them into the ground "bank." People apply from .6 to 2 pounds of N per bushel of corn expected depending on how they apply, when they apply, and their production history. 0.6 pound is for two applications or more with one at planting and one sidedressed. 2 is most common when putting the N down as anyhdrous in the fall. There are practical variations depending on the N source but ALL these rates are debated widely here and in extension reports. Some give beans credit, some don't. Most give alfalfa much credit as an N source for corn. But one ISU extension bulletin was withdrawn after a few years. It said no N was needed the first year and maybe the second year.
You can do a late season stalk test for N to see what the N rate did for the crop, whether it was too little, just right, or too much. You can do an earlier season tissue test to see about other nutrients, macro and micro.
Without this year's soil test, I'd probably put down 130 pounds of N in a split application (planter and side dress), 100 pounds of MAP and 150 pounds of potash. These numbers I think are enough to give the crop a decent chance, maybe not enough for a bumper crop, but enough to get a useful crop. Then refine with tissue and stalk tests for future years. And remember that soil, tissue, and stalk tests are tiny samples and may not be actually representative of the whole field or its extremes.
Gerald J. | |
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Soil sampling questions.
