Best Options for Sidedressing Nitrogen
Injecting anhydrous ammonia or UAN solutions is the best option if conventional application equipment can move through the field, says Iowa State University Nutrient Management Specialist John Sawyer. If corn plants are small, applying ammonium sulfate also provides sulfate if there is a sulfur deficiency. If sulfur deficiency is the only problem, then broadcast calcium sulfate.
Sawyer says the best options for sidedressing, in order from most to least preferable, include:
- injected anhydrous ammonia, UAN or urea,
- broadcast dry ammonium nitrate, ammonium sulfate or urease treated urea,
- surface dribbling UAN solution between rows,
- broadcast UAN, and
- broadcast urea.
Sidedress injection can begin immediately after planting if corn rows are visible or GPS guidance positioning equipment is used, but be sure that soil moved during injection does not cover seeded rows or small corn plants. Injecting into the row middle is easier, and corn roots will reach the row middle at a small growth stage. For late sidedress considerations, click here.