Effect of Method of UAN Application on Ammonia Losses.

Urea-ammonium nitrate solution (UAN) is typically applied to pastures and no-till fields as surface broadcast or dribbled. Information on the ammonia loss from each of those two methods is not currently available. We conducted a study in April-June to compare urea, UAN broadcast, and UAN dribbled applied to a fescue/bermudagrass pasture in north Georgia. Treatments at 100 kg N/ha were applied in triplicate to 20-m circular plots and ammonia volatilization was measured for 43 days with an integrated horizontal flux method using passive flux samplers. Results showed that UAN broadcast and urea lost similar amounts of N (10 kg N/ha) while UAN dribbled lost a smaller amount (5 kg N/ha).