Carbon contents and fine root production in tropical silvopastoral systems

Owing to the increasing extension of land for livestock production, silvopastoral practices have been among the promising approaches to enhance carbon (C) sequestration. However, the extent of C sequestration in different silvopastoral systems (SPS) and their relationship with fine root production (FRP) is not well understood. The objective of this research was to evaluate the changes in C storage, FRP, and turnover in a part of tropical SPS. We evaluated above- and belowground C storage, FRP and turnover in live fences (LF), dispersed tree (DT) silvopasture, and compared these with open pasturelands (OP) in Southeastern Mexico. We applied the stock change approach to calculate biomass growth rates and the ingrowth monolith method for FRP. Biomass stocks in the same plots are re-measured over time in the stock change approach. Woody biomass stocks differed significantly between SPS (DT: 37.2, LF: 9.8 Mg ha(-1)) and the accumulation rates in both SPS were significantly higher than zero (0.2-2.2 Mg ha(-1)yr(-1)). Soil organic carbon (SOC) contents were significantly higher in SPS (LF: 2.4%, DT: 3.1%) compared to OP (1.6%). FRP significantly differed between SPS (LF: 27.8, DT: 45.4, and OP: 9.4 g m(-2)yr(-1)) and correlated positively with SOC content. Higher SOC reduced soil compaction in silvopastoral lands as indicated by lower soil bulk density. The results on C stocks change and fine root dynamics contribute to understanding C sequestration potential of tropical SPS, identifying ecologically sound strategies to mitigate greenhouse gases from the livestock sector, and aid restoration of ecosystem services for degraded pasturelands.

Automated summary

This study evaluated the changes in carbon storage, fine root production, and turnover in tropical silvopastoral systems and found that tree biomass and soil organic carbon content were significantly higher in silvopastoral systems compared to open pasturelands. Fine root production differed significantly between different silvopastoral systems and was positively correlated with soil organic carbon content.