Disentangling the pedogenic factors controlling active Al and Fe concentrations in soils of the Cameroon volcanic line

•Active Al/Fe in soils of the Cameroon volcanic line was investigated.•Soils showed an Andisol → Inceptisol → Ultisol → Oxisol developmental sequence.•Temperature was the primary control of organo-Al/Fe complexes.•Soil age and weathering degree regulated short-range-order minerals.•Greater weathering and drier climate favored crystalline clay mineral formation.