Agricultural suitability of dune system and Limpopo Basin soils near Xai-Xai, Mozambique

Abstract

Quaternary dune systems, as well as the Limpopo Basin near the rural city of Xai-Xai in southern Mozambique were studied concerning their soil fertility and sustainability for crop cultivation. Due to population growth, most sites, which are not overbuilt, are used for crop production. The Arenosols and Regosols of the dune area have slope of 20° and sandy textures. A poor water-holding capacity and a low capability of bonding nutrients are the consequence. A lack of food prevents a disciplined crop rotation including longer fallow periods. Despite persistent cultivation for decades, the soils have a high base saturation, but already a slight decline in the base saturation has considerable effects on crop quality. Shifting cultivation along the coastal dunes leads to a massive clearing of woodlands which destabilises the sensitive dune systems and exposes them to erosion. The Fluvisols of the Limpopo River valley on the other hand cannot be used without restrictions either. High salt contents influence plant growth and the clayey soils constrain root penetration, water availability, drainage and cultivation. Nevertheless, the soils are rich in nutrients and organic matter, and there is no water stress, even during the dry season. The valley soils appear to be a reasonable platform for agriculture.

Keywords:

• Arenosol
• dune soils
• Fluvisol
• South-East Africa
• tropical soils