CARBONO ORGáNICO DEL SUELO EN DIFERENTES USOS DEL TERRENO DE PAISAJES ANDINOS COLOMBIANOS

the relationship between changes in land use and soil carbon and nitrogen was assessed in alcalá (colombian coffee growing region), between 900 and 1600 m. soils are argiudolls and melanudands and sampling units were defined according to the altitudinal gradient. carbon and nitrogen content, c:n ratio, bulk density and 13c and 15n abundances were measured. significant differences (p < 0.05) were found due to altitude effect, differentiating the high zone by high c (37.06 -42.88 t ha-1), n (3.12-3.86 t ha-1) and c: n (11.17-11.97), low bulk density (0.56-0.65 g cm-3) and 15n abundance (4.59-5.15 %o). fallow and monocultures stored more carbon in deeper layers of the soil, while most preserved sites showed low c, n contents. the 13c in land uses ranged between -25.18%o and -21.17 %o, indicating that carbon was fixed mainly by c3 plants. it was concluded that land use changes affect c stocks, due to practices like chemical fertilization; and alcalá soils have high potential for ecosystem services related with edaphic carbon capture.