Strategies to reducing GHG emissions in semi-arid rangelands of Mexico

Abstract

SESS (Simple Ecological Sustainability Simulator) model was modified to evaluate 3 management strategies that could increase CO2 sequestration and reduce methane emissions in cow-calf production systems in semi-arid rangelands. The management strategies included (1) maintenance of a high and constant stocking rate (CONTROL), which is the most common current practice, (2) maintenance of a low and constant stocking rate (LOW SR) and (3) adjustment of stocking rate before the beginning of each breeding season based on the amount of precipitation during the previous growing season (REPLA-PPT). The model was parameterized to represent a typical extensive (5 000 ha) cow-calf production system in the northeastern portion of the Mexican state of Coahuila under an historical (1950 to 1994) precipitation regime, and compared carbon sequestration, methane emissions, animal performance and net profit resulting from each strategy. Results of the 45-year simulations indicated the REPLA-PPT stocking rate strategy had the greatest improvement of range condition, captured more CO2 in vegetation, had the lowest methane emissions, substantially improved mean body condition score and reduced annual mortality of cattle, compared to the constant stocking rate strategies. REPLA-PPT also showed the highest values for calves weaned, and kg weaned per ton of methane produced and highest long-term net profit. This suggests that adaptive management of extensive cow-calf production systems in semi-arid environments could increase carbon sequestration in soils and reduce methane emissions, while improving range production, maintaining animal production and giving the greatest long-term net profit.

Keywords

• cattle production
• CO2 sequestration
• methane emissions
• simulation model