Variability of aggregate stability and surface crusting in Zimbabwe

Soil surface samples were collected from several transects in intensively cultivated 'crusting soil' (chromic luvisol) areas in Zimbabwe. The aggregate stability was assessed by measuring particle size distribution after various breakdown treatments and the infiltration during crust formation under simulated rainfall was measured. Almost all cultivated Ap horizons had very weak stability, whereas B horizons of cultivated field and A horizons of virgin soils were very stable. Aggregate stability was mainly influenced by organic carbon and clay content. Infiltration measurements were in good agreement with aggregate stability.