Fate of Applied Fertilizer N through Nitrogen Transformation.

Understanding the retention and transformation of ammonium-N following application of anhydrous ammonia fertilizer to soil is critical to predicting nitrate-N formation and thus potential for leaching and denitrification losses. The distribution patterns of fixed and exchangeable ammonium-N after injection of anhydrous ammonia into several important soil types in the Eastern Corn Belt were examined in this study. Anhydrous ammonia was applied at a rate equivalent to 170 kg N/ha on a 76 cm spacing. After N application, soils were incubated at a moisture tension of 0.05 MPa and 20 ^oC. Soils were sampled in concentric rings from the injection point at 1, 7, 14, 28, and 84 days after application. Fixed and exchangeable ammonium and nitrate were determined for each sample date. The results and implications of these experiments will be presented at the meeting.