Effect of the Interaction between Excreta Type and Nitrogen Fertilizer on Greenhouse Gas and Ammonia Emissions in Pastures.

This study aimed to evaluate the emission factor of N₂O, CH_4, and the volatilization of NH₃ for the combination of feces or urine with increasing doses of ammonium nitrate in tropical palisade grass pastures. The emission of greenhouse gases was assessed in eight treatments combining feces and urine with doses (75 and 150 kg of N ha⁻¹) of ammonium nitrate, (32% N). The emission factor of N₂O was 0.11, 0.19, and 0.17% for feces, urine, and 75 kg N ha⁻¹ year⁻¹ (as ammonium nitrate) and showed an additive linear effect when feces or urine were combined with increasing doses of N fertilizer. The emission factor of CH₄ of feces (0.18 kg CH₄ animal⁻¹ year⁻¹) was similar irrespective of combination with ammonium nitrate. The N loss by volatilized NH₃ has a decreasing linear effect (p < 0.05) for the combination of feces or urine with ammonium nitrate. We concluded that N₂O and CH₄ emission factors of feces and urine in tropical climate conditions are lower than those reported by the IPCC. However, their N₂O emission factors are sharply enhanced when combined with ammonium nitrate. These results may contribute to improvements in national and regional greenhouse gas inventories of livestock production. [ABSTRACT FROM AUTHOR]