Adapt-N User Group:

Here are a few more perspectives on Adapt-N:

  • The low rainfall in much of the Corn Belt is generating questions about the generally low Adapt-N recommendations. Research has shown that in dryer years the actual recommended sidedress rate can indeed be as low as 0 lbs/ac, especially in corn after soybeans. Farmers don’t normally realize that, because they always fertilize at a higher rate. A recent Ohio State University study showed that in 2 out of 12 years no sidedress N was needed beyond a 40 lbs/ac starter application. We don’t believe that Adapt-N underestimates N rates, but farmers can always decide to deviate if they are uncomfortable with the recommended rate. Of course, those who participate in our formal trials should still include the Adapt-N recommended rate to verify its correctness. We would recommend that you are not too conservative with the yield potential, so you don’t unnecessarily push the recommendation too low.
  • The issue of field variability is also important. If the field is uniformly managed, but has a lot of inherent soil variability, then one should apply N at the highest rate for the field. I.e., don’t assume an average organic matter content or soil texture for an entire field, but do the simulations for different parts of the field (that differ in soil types and organic matter contents) and then take the highest recommended rate. After all, you cannot afford to under-fertilize in some areas of the field. The better approach, of course, is to vary the rates based on the different soil conditions in the field.

As always, we welcome questions and feedback. Also please note that previously sent updates and tips are generally posted on our blog for reference: http://blogs.cornell.edu/adaptn/.

All the best,

The Adapt-N Team