Africa's soils are highly diverse, largely defined by the continent's varied climate zones, ancient geology, and parent material. The dominant soil types are characterized by low natural fertility, high weathering, and susceptibility to degradation, posing significant challenges for agriculture. Major soil types are Ferralsols and Acrisols in the wet equatorial tropics and the wet-dry tropical climate of West Africa, Arenosols feature the dry tropical and subtropical regions. Typically reddish-brown soils as Lixisols or Vertisols are found in the Savanna Zones and in the winter-wet subtropics of the Maghreb and the Cape region Chromic Cambisols and Chromic Luvisols are widespread. Key challenges are low fertility and nutrient depletion, acidity and toxicity, water scarcity and erosion and degradation. In particular desertification together with its economic and social impacts and side effects, is a major problem in large parts of the continent. In Africa these landscapes cover an area of about 5.3 million square kilometers and thus around 30 per cent of Africa's area outside the natural deserts with about 65 per cent of the total population of the continent.