Carbon balance in dairy cattle silvopastoral production systems in Colombia’s Andean-Amazon region

Abstract

Silvopastoral systems (SPS) are recognized for their potential to sequester carbon (C) and mitigate greenhouse gas (GHG) emissions in livestock production. However, the extent to which small-scale dairy farms in the Andean region can offset emissions through SPS remains unclear. This study assessed the C capture of SPS to mitigate greenhouse gas emissions in small-scale dairy farms in Colombia's Andean-Amazon region. The average annual carbon increment (AACI) in living biomass (above and below ground) was evaluated in woodlots (WL), live fences (LF), and topsoil of pastures (TP) at plot and farm levels. The carbon footprint (CFP) was calculated using a cradle-to-gate approach with biophysical allocation for fat and protein corrected milk (FPCM) and expressed per product (MgCO2-eq MgFPCM⁻1) and area (MgCO2-eq·yr⁻1 ha⁻1) across 30 farms categorized by high, medium, and low SPS coverage. At plot level, AACI values were 4.54 ± 0.57 Mg·C·ha⁻1·yr⁻1 (LF), 3.20 ± 0.61 Mg·C·ha⁻1·yr⁻1 (WL), and 0.24 ± 0.08 Mg·C·ha⁻1·yr⁻1 (TP). At farm-level AACI was 4.43 ± 0.96, 1.28 ± 0.41, and 0.24 ± 0.08 Mg·C·ha⁻1·yr⁻1 for high, medium, and low SPS coverages respectively. Between 78 and 86% of AACI was attributed to Eucalyptusglobulus (LF). CFP per product averaged 1.24 ± 0.16 MgCO2-eq MgFPCM⁻1. Total emissions per farm averaged 28.27 ± 2.58 MgCO2-eq·yr⁻1 and per area 3.35 ± 0.32 MgCO2-eq·yr⁻1 ha⁻1, with no differences across SPS coverages. Carbon balance was negative regardless of SPS coverage. The mitigation potential of SPS were 63%, 26%, and 4% for high, medium, and low SPS coverage. The required area to offset emissions ranged from 11.5 ha⁻1 considering the soil AACI to 1.2–10.2 ha⁻1 based on the AACI of SPS. Small dairy farms (9.11 ± 0.75 ha−1) in the Andean-Amazon region can mitigate total emissions using a SPS coverage over 13% together with optimized feeding practices, lactation and weaning periods.