Direct Measurement of Management Strategy Impacts on Ammonia Volatilization from Swine Manure

Abstract

Ammonia emitted from manure can have detrimental affects on health, environmental quality, and fertilizer value. The objective of this study was to measure the potential for reduction in ammonia volatilization from swine manure by temperature control, stirring, addition of nitrogen binder (Yucca) or urease inhibitor (NBPT), segregation of urine from feces, and pH modification. Swine manure (TS 7.6-11.2%, TKN 3.3-6.2 g/L, NH4 +-N 1.0-3.3 g/L) was stored for 24, 48, 72, or 96 h in 2-L polyvinyl chloride vessels. The manure was analyzed to determine pre- and post-storage concentrations of total and volatile solids, total Kjeldahl nitrogen, and ammonium nitrogen. The accumulation of volatilized ammonia in the vessel headspace after storage was measured using Drager grab sample tubes. Headspace ammonia-N concentrations were reduced (P<0.0001) by segregation of urine from feces (99.3%). Stirring and NBPT increased headspace ammonia-N concentration (119% and 50-140%, respectively). Headspace ammonia-N concentration increased by 2.7 mg/m3 for every 1°C increase in temperature over 35°C. The slurry ammonium-N concentrations were reduced by segregation (78.3%) and acidification to pH 5.3 (9.4%), and increased with stirring (4.8%) and increased temperature (0.06 g/L per 1°C increase in temperature over 35°C). Temperature control, urine-feces segregation, and acidification of swine manure are strategies with the potential to reduce or slow ammonium-N production and ammonia volatilization.