Ammonia emissions from land-applied beef cattle manure

Abstract

Ammonia (NH3) is emitted in vast quantities from exposed livestock manure. The volatilisation of NH3 from livestock manure is a loss in valuable nitrogen in land-applied manure that could otherwise be used for crop production. Ammonia loss to air is also affiliated with environmental problems when it is deposited to the surrounding landscape. The goal o f this study was to quantify the effect of managing beef cattle manure on NH3 emissions of land-applied manure. Three trials were conducted where beef feedlot manure was applied. The NH3 losses were measured from field plots (90 or 160 m2) using acid traps (passive flux samplers). Immediately after applying manure, irrigating with 6 mm of water reduced NH3 loss by 21–52% while tillage (to 15 cm depth) reduced the loss by 76–85% compared with leaving the manure spread on the soil surface. Piled manure that was applied to the land lost 27% less NH3 than did manure taken directly from the pen. There was little NH3 lost from compost that was applied to land since the applied available-N was very low relative to the pen and piled manure. Our study shows that management of livestock manure has a direct impact on NH3 loss to air. It follows that significant reduction in NH3 volatilisation can benefit agriculture and reduce agriculture’s impact on the environment. Key words: Ammonia, manure, tillage, irrigation, compost, feedlot