Silvopastoral vs. monoculture cattle systems in a humid Mexican Tropical Region: a greenhouse gas assessment

Cattle production is a key activity for both the economy and food security but is also an important driver of climate change. In Mexico, predominant monoculture pasture systems are associated with high rates of deforestation and methane (CH 4 ) emissions from enteric fermentation. Intensive silvopastoral systems (iSPS) emerge as a sustainable alternative, with the potential to reduce the environmental impacts. This study aimed to: (1) calculate local methane emission indicators (methane conversion factor (Ym), methane yield (MY), Emission Factor (EF)) that could contribute to the national inventory, based on chemical analysis of iSPS forages in seven farms in Los Tuxtlas, Veracruz; (2) compare forage nutritional quality in each system; and (3) estimate the total annual carbon dioxide equivalent (CO 2 eq) emissions from grass monocultures and iSPS. To achieve this, the study considered CH 4 emissions from enteric fermentation and manure, as well as direct and indirect nitrous oxide (N 2 O) emissions. We used Tier 2 methodology from the Intergovernmental Panel on Climate Change (IPCC) Guidelines, along with tropical methane emission models. The results showed that global references values overestimated local methane indicators (Ym: 7.0% vs. 5.88%, MY: 23.3 vs. 19.6 g CH 4 /kg DMI, EF: 58 vs. 57.09 kg CH 4 /head/year), highlighting the importance of using region specific methodologies. Compared to monoculture systems, iSPS showed reductions in methane indicators: EF decreased by 0.19%, MY by 0.28%, and daily CH 4 emissions by 0.22%, alongside better nutritional quality, demonstrating their potential for climate change adaptation and mitigation.