Methane release from enteric fermentation and manure management of domestic water buffalo in Nepal

Abstract

Methane (CH4) emission in livestock arises from enteric fermentation (EnF) and manure management (MM). This study develops the country-specific CH4 emission factors (EFs) in both EnF and MM for domestic water buffalo (Bubalus bubalis) and estimates total CH4 emission in Nepal using Intergovernmental Panel on Climate Change (IPCC) Tier 2 methodology. Seasonal field data were collected on morphological characteristics, feed characteristics, and manure management practices of the buffalo. The buffalo population was divided into five age groups, and at least 35 buffalo individuals were measured from each age group in the Hilly and Plain regions of Nepal in the winter and summer seasons. Buffalo adult male (BAM) had the highest body weight of 530 ± 53kg in the plain region and 514 ± 65kg in the Hill region. Similarly, the weight of buffalo calf (BC) was 91 ± 25kg in the plain region and 77 ± 26kg in the Hill region. For different age groups of buffalo, EnF EFs ranged from 34 ± 8 to 90 ± 10kg CH4 head-1year-1 and MM EFs ranged from 2.5 ± 0.5 to 7.5 ± 0.5kg CH4 head-1year-1. The estimated EnF and MM EFs of buffalo were not statistically different by region (p > 0 .05). The total CH4 flux from buffalo was 347.8 Gg year-1 in Nepal, contributing 322.2 Gg year-1 from EnF and 25.6 Gg year-1 from MM. The country-specific EFs are highly recommended for precise computing of the national emissions and carrying out mitigation action.