Changes in soil properties and soil organic carbon stocks along an elevation gradient at Mount Bambouto, Central Africa

Abstract

The study was designed to investigate the influence of elevation gradient on soil properties and soil organic carbon (SOC) in the Bambouto Mountain in Western Cameroon and the subsequent consequences of human activities on these SOC contents. Five sites, Bawa, Zavion, Totap, Camp Bororo and Meletan, were selected between 1400 m and 2740 m altitude to conduct the study. Three sampling points per site were allocated and each selected point was sampled using depth increments of 25 cm from the soil surface. The studied soils are characterized by low gravel contents. SOC contents and stock (SOCS) decrease with depth at all sites and increase along the elevation gradient, reaching the highest content (123.67 ± 30.44 g kg−1) at 2100 m a.s.l. Higher SOCS (157.14 ± 23.75 Mg ha−1) were found in 0–25 cm depth at Meletan at 2740 m a.s.l. while the lowest SOCS (86.04 ± 3.19 Mg ha−1) in the same depth was found in Bawa at 1500 m a.s.l. It increased and was significantly correlated with elevation (r = 0.86; p < 0.05), reaching a total of 302.15 ± 34.55 Mg ha−1 at 2740 m a.s.l. The difference might be attributed to longer vegetative growing periods at the high altitude without human interference in comparison with the lower altitude. Amorphous Fe and Al exhibited weak correlations with total SOCS along the altitudinal gradient, implying that their role on the stabilization of SOC might be little. The accumulation and stabilization of SOC is ascribed to clay content, parent material, climate and vegetation, which are controlled by the elevation gradient.