Addressing Yellow Peanuts Peanut Notes No. 109 2019

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Yellow peanuts this time of year could be caused by nitrogen deficiency as a result for poor nodulation, from a manganese deficiency or from water-logged areas of fields. Yellow peanuts from little to no nodulation will improve only by adding sufficient nitrogen. This issue generally occurs in newground fields are fields where peanuts have not been grown for many years. Apply 500 pounds/acre of ammonium sulfate as soon as possible to correct this issue. This is expensive but necessary if a true nitrogen deficiency caused by poor nodulation exists. If manganese deficiency is present a foliar application of manganese will correct this issue. If peanuts are yellow due to water-logged soils, the only way they will improve is by drying of soil. In my experience when soil begins to dry peanut foliage will become green as N fixation begins under favorable conditions. See chapter 3 in 2019 Peanut Information for more details on these issues. Timely application of ammonium sulfate or manganese (when needed) will resolve the issue more effectively than delays in application. Ammonium sulfate is expensive, so make sure nodulation is the issue before applying this fertilizer. A nitrogen-deficient peanut requires as much N as a corn crop. Certainly, biological nitrogen fixation is the least expensive way to provide this to peanut (a legume that fixes its own N) but at this point if nodulation is inadequate a substantial amount of applied N is needed to correct the deficiency. Correcting a manganese deficiency is much less expensive, but make sure the product applied provides adequate manganese and is cost effective.