Quantification of organic carbon stored in the soil in the paramo of Igualata, Chimborazo province-Ecuador

Abstract

Abstract. The soil organic carbon stock of the paramo of Igualata was assessed during three study terms: 2012, 2013-2014, 2015. The soil samples (material) of this study were obtained through a fixed factorial completely balanced random sampling method. To cover the entire location, the soil was sampled thrice at 5 altitudes (4090, 4100, 4110, 4120 and 4130 m.a.s.l.) and two depths as follows: soil sample 1 (0-0.7 m) and soil sample 2 (0.7-1.2 m). The organic content and apparent density of all samples were evaluated by using the colorimetric Walkley-Black method and the cylinder method, respectively. The quantification of organic carbon in tons per hectare (t/ha) showed highly significant differences (p < 0.01) for the following factors: altitude, material, and altitude per material ratio. Regarding altitude, the highest average content of soil organic carbon (SOC) of 302.13 t/ha was found at 4130 m.a.s.l., while the lowest of 98.91 t/ha at 4090 m.a.s.l. Concerning the material, soil sample 1 showed higher average content of organic carbon (306.89 T/ha) than soil sample 2 (161.55 t/ha). The altitude per material ratio showed that the highest average content of soil organic matter (SOM) (377.69 t/ha) was found in the soil sample 1 at the maximum altitude of 4130 m.a.s.l. while the lowest (47.59 t/ha) corresponds to the soil 2 at 4090 m.a.s.l. The results of this study clearly demonstrated that the average content of the organic carbon stock in the paramo of the Igualata increased at high altitude and diminished according to the soil depth.