Each year some fields will begin to show nitrogen deficiencies. There is often a pattern associated with this issue. Often times it is a problem with one planter unit and can be seen across the field. The issue can also be associated with dry soil at planting which allows the soil to cave in after seed drop but before the inoculant is sprayed in the seed furrow.

At about 45 days after planting, roots should have 15 nodules. Anything below 15, and application of nitrogen might be warranted. The challenge is the expense of products like ammonium sulfate. Based on yield data from nitrogen deficient peanuts over the entire season, inoculated peanut, and improvement in yield when ammonium sulfate was applied (at 500 pounds per acre, our recommended rate,) at least half of a field needs to be expressing nitrogen deficiency to economically justify a broadcast application over the entire field. If you have a way to apply ammonium sulfate only to the deficient rows, it is well worth the application. But that is challenging to do.

We cover this topic in detail in 2024 Peanut Information.