CARBON STORAGE IN TREE BIOMASS AND SOILS IN SILVOPASTORAL SYSTEMS OF THE HUMID TROPICS †

Abstract

Background: The transformation native of forests into pasturelands for livestock farming, affects ecosystems carbon (C) stores and soil properties. Objective: Estimate the carbon stored in tree biomass (above and below ground) and determine soil organic carbon and some physical and chemical properties in two silvopastoral systems (SPS): scattered trees in paddocks (STP) and living fences (LF), taking grass monoculture (PM) as reference. Methodology: The C content in the above and below-ground biomass of the trees was estimated through allometric models, the C fraction of the soil from 0-100 cm was determined by chemical digestion, and the soil organic carbon (SOC) stock was estimated. The physical and chemical properties of the soil were determined. Results: SSPs with STP and LF stored a greater amount of total C (387.0 and 362.6 Mg ha-1 de C) compared to GM (312.5 Mg ha-1 de C), tree biomass contributed 6.3% and 8.4% for STP and LF respectively. Soils stored 90% of the total C in STP and LF. The tree component favorably modified soil pH, the bulk density, the organic matter, carbon, and nitrogen content. Implications: This study contributes with scientific information useful to develop low-emission livestock systems for transition towards climate-smart farming systems essential to meet the Sustainable Development Goals. Conclusions: Tree diversity and density in STP ADP and LF play an important role in the storage of total C, favor C accumulation in the deeper layers of the soil and improve the physical and chemical properties of the soil.