Abstract

This study was undertaken to quantify the carbon (C) sequestration potentials in three predominant ecosystems on the volcanic soils in Patagonia, Chile. The systems were: Pinus ponderosa Dougl. ex P. Laws. – based silvopastoral systems arranged in strips (silvopasture), 18-year-old managed exotic stands (plantation), and natural prairie (prairie), in Patagonia, Chile. Most of the data used in the construction of C models were derived from experimental plots, where litterfall, decomposition, soil respiration, and soil C were measured. The values for greenhouse gas (GHG) emissions by cattle and fertilizer application were obtained from the literature. In the silvopasture and the plantation, total above- and belowground tree C stock accounted for 69% and 64% of the total system C, respectively. Total above- and belowground C pools were 224, 199, and 177 Mg C ha−1, with the aboveground: belowground C pool ratios of 1:10, 1:5, and 1:177, respectively, for silvopasture, plantation, and prairie. Soil respiration decreased in the order prairie >silvopasture >plantation. The C leached beyond the root zone (in leachate collected at 80 cm soil depth) decreased in the order plantation >prairie >silvopasture. Estimated system net C flux was +1.8, +2.5, and −2.3 Mg C ha−1 year−1 for the silvopasture, plantation, and prairie, respectively. Based on this study it is estimated that establishing silvopastoral systems with cattle over a land area of approximately 481 km2 or 0.33% of the Chilean Patagonia territory would be adequate to offset all C losses from cattle-based livestock systems. KeywordsAndisols-C pools and fluxes-Greenhouse gases- Pinus ponderosa