Characteristics and management options of crusting soils in a smallholder farming area of the Zambezi metamorphic belt in northern Zimbabwe

Abstract

Crusting and surface-sealing soils present productivity challenges to smallholder farmers despite their high inherent fertility. Crop production on crusting soils is costly due to unfavourable conditions such as surface capping and compaction, which hinder crop emergence. A study was conducted at Bruton farm in Zimbabwe to characterise crusting soils and assess options for their management. Soil crusting was characterised using crust thickness, crusting susceptibility index, bulk density, infiltration rates, soil aggregate stability and clay mineralogy. Structured and semi-structured interviews were also conducted to capture methods used by farmers to control the crusting. The relationship between crust thickness and soil physical and chemical properties and management practices were assessed using stepwise regression analysis. Soil crusting was largely related to soil aggregation, infiltration, fine sand fraction, cotton monocropping and crop residue incorporation. Crop residue incorporation and crop rotation could be adopted to mitigate soil crusting at the scheme.

Keywords: bulk density, infiltration, metamorphic belt, particle size