Ammonia and greenhouse gas emissions from different types of deep litter used for pig rearing

• Three appropriate materials were selected in the trial for deep litter system.
• More than 23% of N and 40% of C were transformed into gaseous forms.
• The type of bedding material influences the quantities of NH3 and GHG emissions.

Ammonia (NH3) and greenhouse gas (GHG) emission during pig rearing on deep litter has been rarely reported. To evaluate the emission of NH3 and GHGs according to the compositions of the deep-litter systems during pig rearing, we selected three different types of deep-litter systems: (a) RM, composed of 60% mushroom growth media and 40% rice husk; (b) RS, composed of 60% sawdust and 40% rice husk; and (c) RV, composed of 60% vinasse and 40% rice husk. Samples of the gases emitted were collected continuously using the static box method during one production cycle (150 d). The results showed that the patterns of NH3 volatilization and CH4 emission differed across the three deep-litter systems, but no significant differences were found in the pattern of N2O and CO2 emission. Further, the total quantity of NH3 and GHG emission showed significant differences. Material flow analysis indicated that gaseous loss was the main pathway for escape of N or C. Thus, the use of RS could mitigate the emission of NH3, N2O and CH4 (3.82 kg, 1.50 kg and 5.46 kg, respectively) and limit the effect of GHGs in terms of the emission equivalent carbon value (28% and 86% lower than that of RM and RV, respectively). Thus, the RS system was the most suitable with regard to reduction of environmental pollution.