Abstract

ROJAS, Andrés Sebastián; ANDRADE, Hernán J.  and  SEGURA M., Milena A.. SOILS IN HIGH-LAND LANDSCAPES OF SANTA ISABEL (TOLIMA, COLOMBIA), ARE THEY A CARBON SINK?. rev.udcaactual.divulg.cient. [online]. 2018, vol.21, n.1, pp.51-59. ISSN 0123-4226.  https://doi.org/10.31910/rudca.v21.n1.2018.662.

Global climate change is one of the most serious problems of mankind, caused mainly by the increase of CO2 and other greenhouse gases in the atmosphere. It is recognized that net emissions of these gases can be reduced either by reducing their emission or by increasing their removal by depositing in terrestrial sinks. The soil is the largest carbon I sink and mitigates its increase in atmospheric concentration. The rural landscapes in high-land ndean zones retain significant amounts of organic soil C (SOC), playing a key role in its global cycle. The objective of this study was to estimate the SOC stocks in the main land uses, and the impacts of land use change in high-land ndean landscapes in Santa Isabel, Tolima, Colombia. Three land uses were evaluated: (i) agricultural crops (AC), (ii) silvopastoral systems of pastures with dispersed trees (SPS), and (iii) native forests (NF), estimating bulk density (BD) by cylinder method and the concentration of SOC to a depth of 0-40cm. The BD notably increased by changing from NF to AC and SPS (0.35 to 0.61 and 0.65g/ cm3, respectively). Contrasting, the concentration of SOC was reduced when NF change to agricultural and livestock uses (8.9 to 5.8%). The NF stocked more C than AC and SPS (122.4, 79.6 and 79.8t/ha, respectively), causing a potential emission of 157t CO2/ha in case of deforestation. Opposite processes imply capture of atmospheric carbon. The conservation of NF in high-land Andean zones must be highly considered in national and regional policies.

Keywords : Agroforestry; tropical forests; crops (agriculture); soil density..

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