Anhydrous ammonia (NH3) is injected below the soil surface during application to limit loss to the atmosphere. Application at a shallower depth may reduce tractor power or allow greater speed which could increase field capacity if NH3 losses are held to acceptable levels. Losses of NH3 during, and for one hour after, field application were measured from a typical knife injector treatment operated at a 15-cm (6-in.) depth and 8 km/h (5 mi/h) travel speed and from a single-disc injector operated at shallower depths (5 and 10 cm (2 and 4 in.) and a range of travel speeds (8, 12, and 16 km/h (5, 7.5, and 10 mi/h). NH3 losses during application as measured with a hood over the single-disc injector were 3 to 7% in clay loam, silty clay loam, and loam soils and 21 to 52% in a coarser-textured fine sandy loam soil. Applying with a knife injector at deeper depth resulted in losses of 1 to 2% across all soil types. NH3 losses measured during an hour after application with stationary collection over the injection trench were 1% or less for all treatments. Losses during application were 5 to 55 times greater than during the first hour after application.
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