A new cost-effective method to mitigate ammonia loss from intensive cattle feedlots: application of lignite

In open beef feedlot systems, more than 50% of dietary nitrogen (N) is lost as ammonia (NH(3)). Here we report an effective and economically-viable method to mitigate NH(3) emissions by the application of lignite. We constructed two cattle pens (20 × 20 m) to determine the effectiveness of lignite in reducing NH(3) emissions. Twenty-four steers were fed identical commercial rations in each pen. The treatment pen surface was dressed with 4.5 kg m(−2) lignite dry mass while no lignite was applied in the control pen. We measured volatilised NH(3) concentrations using Ecotech EC9842 NH(3) analysers in conjunction with a mass balance method to calculate NH(3) fluxes. Application of lignite decreased NH(3) loss from the pen by approximately 66%. The cumulative NH(3) losses were 6.26 and 2.13 kg N head(−1) in the control and lignite treatment, respectively. In addition to the environmental benefits of reduced NH(3) losses, the value of retained N nutrient in the lignite treated manure is more than $37 AUD head(−1) yr(−1), based on the current fertiliser cost and estimated cost of lignite application. We show that lignite application is a cost-effective method to reduce NH(3) loss from cattle feedlots.