I was asked how to correct a nitrogen deficiency today. The table posted gives rates of ammonium sulfate based on days after planting. The following is the text I sent:

As we advance into the season, here is a recommendation on ammonium sulfate (AMS) rates based on days after planting. I don’t have strong data on this, but this seems like a logical approach. The farmer you were working with today got some of the yield back with 125 pounds of AMS but needs more over the crop cycle. Most of our work in new ground was when the farmer first noticed yellow peanuts and no nodules in mid to late June. That’s when the 500 pounds can get a lot of the yield back. I think over the cropping cycle, if the total amount of AMS is about 500 pounds, the farmer has done all that is possible. Sometimes with split applications it’s hard to get a farmer to make the second application. One can easily talk themselves out of the second trip.

*Once we get later in the cropping cycle, even if we have had yellow peanuts for a month or so, the higher rate is not helpful. The rate recommended in the table at a given point in time reflects the maximum amount of nitrogen we need with the shorter amount of season remaining. As mentioned, if you catch the deficiency early (45 days after planting) and apply 500 pounds AMS, you likely will cover the cost of AMS and gain more income above that cost. Responding quickly is critical.