Question:
I recently received a complaint about yellow peanuts from a farmer. I have attached a picture of one of their fields. There is a field that is more yellow than this, but their other fields have yellow spots on sandy patches. The fields have been out of peanut production for fifteen to twenty years. The roots have some active nodules, but not a great number. The farmer used a 2 by 2 fertilizer application at planting. The peanuts are showing interveinal chlorosis consistent with manganese deficiency, but the farmer made an application last week. Additionally, they have been very hot and dry in this location. I tell you all this information to see what you thought may be causing the peanuts to be so yellow, and what you suggest to address this.
Jordan:
This looks like a nitrogen deficiency given it is so general. Manganese is typically more spotty because soil pH, the driver on Mn availability can vary. You could run a tissue analysis. By this time of the year, a green peanut crop would have an abundant number of nodules. These peanuts likely need applied nitrogen. While expensive, I recommend 400 pounds of AMS. See page 27 in Peanut Information. The 2 by 2 likely did not cause a problem but it was not enough to help into the season. There could be a number of reasons why (in the other field) the deficiency is in sandy areas. In a dry spring, soil can cave in the furrow after seed drop but before liquid application. If the inoculant is above the seed, it can never catch up to the roots. Fluffy, sandy areas are more likely to cave in. The sandy soil could also have been drier (and hotter) than the areas with more OM and a finer texture. That could kill the bacteria in inoculant. The economic return on applied nitrogen is hard to pencil out with N prices this year unless the deficiency is across the entire field. Page 27 has an example of the financial return from 500 pounds AMS at various percentages of N deficiency across the field. A broadcast application will likely not pay for itself unless half or more of the field is N deficient.