Anhydrous ammonia application losses using single-disc and knife fertilizer injector

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Boyd, Paul
Baker, James
Colvin, Thomas
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Hanna, H. Mark
Extension Agricultural Engineer
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Agricultural and Biosystems Engineering

Since 1905, the Department of Agricultural Engineering, now the Department of Agricultural and Biosystems Engineering (ABE), has been a leader in providing engineering solutions to agricultural problems in the United States and the world. The department’s original mission was to mechanize agriculture. That mission has evolved to encompass a global view of the entire food production system–the wise management of natural resources in the production, processing, storage, handling, and use of food fiber and other biological products.

In 1905 Agricultural Engineering was recognized as a subdivision of the Department of Agronomy, and in 1907 it was recognized as a unique department. It was renamed the Department of Agricultural and Biosystems Engineering in 1990. The department merged with the Department of Industrial Education and Technology in 2004.

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  • Department of Agricultural Engineering (1907–1990)

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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 1 h after, field application were measured from a typical knife injector treatment operated at a 15-cm (6-in.) depth and 8-km/h (5-mph) 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 mph)]. 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.


This article is from Applied Engineering in Agriculture 21 (2005): 573–578, doi:10.13031/2013.18564.