Characterisation of soil physical properties and resistance to erosion in different areas of soil associations

Abstract

Understanding the effects of soil physical properties on resistance to erosion is important for land use planning and soil erosion management. The objective of this study was to characterise the physical soil properties of areas of soil associations and determine the influence of litter source on aggregate stability and rates of soil loss in areas of soil association in the Ntabelanga area, Eastern Cape Province, South Africa. Soil was sampled from 21 randomly selected points in the areas of soil associations. Soil was incubated for 30 weeks after increasing the SOC to > 2% by adding Vachellia karroo leaves (low C/N) and Zea mays stover (high C/N) and rate of soil loss (t ha-1) determined at 1, 3, 8, 14, 23 and 30 weeks of incubation. The soil physical properties, resistance to dispersion and aggregates distribution varied significantly (P < 0.05) across soils. All soils had significantly (P < 0.05) low (< 2%) SOC (%) and high (> 0.02)[(t ha h)·(ha MJ mm)-1] K-factors indicating high erodibility. Vachellia karroo and Z. may organic matter significantly (P < 0.05) reduced soil loss from 1 to 8 weeks after incubation thereafter lost its effectiveness. Organic matter stabilised the soils, but only for a short period (8 weeks). It is recommended to minimise soil disturbance in the Ntabelanga area as this will exacerbates the problem of erosion.