Optimizing Manganese Supplementation for Soybeans with Ammonium sulfate.
Manganese deficiency is the most common nutrient deficiency seen in soybeans. Manganese sulfate can be applied in a two-by-two band at planting when soil test levels are low. Foliar application of manganese sulfate at one to two pounds per acre of actual manganese is the most economical and effective method for correcting manganese deficiency. Apply one pound per acre of actual manganese when the first deficiency symptoms appear (six-inch tall plants) and apply another pound per acre in 10 days if deficiency symptoms reappear.
Manganese sulfate should not be tank-mixed with glyphosate as the performance of both products will be reduced. Ideally, the glyphosate should be applied first and the manganese sulfate applied at least three days later. In some cases, the manganese sulfate may need to be applied before the glyphosate. In this case, the two applications should be separated by at least seven days. If you must tank-mix a manganese fertilizer with glyphosate, always use an EDTA-chelated manganese fertilizer. It is essential to add the ingredients to the tank in the following order:
Water
Ammonium sulfate at 17 pounds per 100 gallons
Glyphosate
EDTA chelated manganese fertilizer
An on-farm trial conducted at the responsive locations (muck soils) in showed that manganese sulfate monohydrate fertilizer increased soybean yields by 1.9 bushels per acre over an EDTA chelate manganese fertilizer.
