Estimation of soil organic carbon (SOC) at different soil depths and soil use in the Sumapaz paramo, Cundinamarca - Colombia

Abstract

The vertical distribution of soil organic carbon (SOC), considered to be a key component of the carbon cycle, is still poorly understood in tropical highest mountain ecosystems such as the Andean paramo. The estimation of the SOC in the presence and absence of anthropic intervention, will help to define policies to mitigate CO2 emissions into the atmosphere from this ecosystem. The aim of this research was to determine soil organic carbon sequestration at three soil depths under two types of soil use in the paramo of Sumapaz, Colombia. The soil variations of pH, phosphorus, aluminum, bulk density, carbon sequestration, cation exchange capacity, texture and to estimate the vertical distribution of soil organic carbon SOC, were evaluated, respectively. Two sites were selected to establish the soil estimations according to soil use: natural vegetation cover and potato (Solanum tuberosum L.) crop. Samples were taken from 0-25, 25-50 and > 50 cm soil depths. Consequently, eight physical-chemical variables were analyzed in terms of the SOC sequestration estimated for each soil depth and soil. The averages for SOC under natural vegetation cover were: 188 tC.ha-1 to 25 cm, 183 tC.ha-1 to 50 cm, and 178 tC.ha-1 at soil depths below 50cm. For potato (Solanum tuberosum L.) crops, SOC sequestration were: 119 tC.ha-1 to 25 cm, 83 tC.ha-1 to 50 cm, and 71.8 tC.ha-1 at soil depths below 50cm. These results allow to support the soil management strategies that addressed to preserve SOC and regulate water level within the ecosystem of the Andean paramo.