Ammoia Volatilization from Fertigated N Applications.

Ammonia losses from fertilizer applications by sprinklers have been debated for some time.  Fertigation of UAN solution via sprinklers using a pivot has not been investigated.  We installed six 0.1 ha pivots for the initial purpose of investigating ammonia losses from fertigation practices.  Pivots were installed in pairs across the OSU farm.  The initial study measured volatilization where UAN was fertigated at 67 kg N/ha on 3 pivots with no fertigation to the remaining three. The first study was to measure ammonia loss with a constant rate of UAN of 67 kg N/ha at 6 irrigation rates 0-25.4 mm.  This study was repeated three times. The second study was to fertigate UAN at 67 kg N/ha applied with and without the urease inhibitor NBPT (Agrotain).  Volatilization was measure in three different ways, by laser, by the periphery method and by flux method. A weather station was installed as well as an ultra-sonic anemometer.   An incubation trial was also performed to measure various products and their propensity for volatilization as compared to urea. Data is currently being assessed