Few comparable studies have analyzed the reduction of SOC because of erosion, and assessed how this contributes to the loss of soil as vegetation cover decreases. This is particularly the case in semiarid Mediterranean environments, where erosion is one of the main causes of soil degradation.
This study presents the results of an experiment carried out along a pluviometric gradient from humid to semiarid Mediterranean conditions, in southern Spain. The study involved two soil depths at five field sites having similar lithology, slope and aspect, but differ in vegetation cover and composition related to their location along the gradient. We used soil cation exchange capacity (CEC) as an indicator of soil degradation.
The results showed that: a) SOC decreased with decreasing rainfall; b) SOC is greater at the soil surface than at depth; c) CEC is a good indicator of the degradation of soil surface formations, as it is directly related to the SOC storage capacity; and d) the so-called 鈥淢editerranean mountain鈥?landscape, with sparse and mixed vegetation composed of scrubland and woodland species, is a good organic carbon sink with direct implications in relation to climate change.