Nitrogen and Peanuts Peanut Notes No. 98 2020
I’m noticing some pale green to almost yellow peanuts. Some have 5-10 nodules but still not looking so great. If the decline in living nodules continues and approaches 5, is it too early to apply ammonium sulfate? When is it “too late” to apply?
The general rule is you need 15 nodules on the tap root at 45 days after planting. Ten is marginal and 5 is poor. If you have 10 that are active, once fields dry out they may get going again and peanuts likely will green up. My experience has been that about the time you can get in the field for a ground rig the peanuts improve. The issue is likely water and not nodules, although there is an interaction. This is a hard call. If I applied ammonium sulfate i would go ahead and commit to it as the source of nitrogen the peanuts will use for the year. That means 500 pounds AMS/acre. Time is often the essence. The crop is moving slowly this year and it does not need to miss a beat. Earlier is better if there is a true N deficiency. But I would give the peanuts a little more time to see if it dries out and they nodules get going again. However, if they do not green up in the next two weeks I would apply the AMS. It is just an expensive option.