Effects of an Agroforestry System on Wind Speed and Particle Mass Flux on a Farm in Semi-Arid South Africa

Abstract

Soil degradation due to wind erosion is a major concern in semi-arid agricultural regions, particularly in South Africa’s Overberg area. This study evaluates the effectiveness of an agroforestry windbreak composed of Eucalyptus cladocalyx F. Muell. in reducing wind speed and horizontal dust flux on a wheat farm during the fallow period. Aeolian transport was quantified by using meteorological data, dust collection with MWAC samplers, and remote sensing via aerosol optical depth. Results showed that the windbreak reduced wind speeds by up to 24%, with higher effectiveness under moderate wind conditions (<8 m·s−1) and in areas of denser vegetation. Dust transport was significantly lower on the leeward side, confirming the barrier’s mitigating influence. However, gaps within the windbreak channelled wind and elevated dust transport locally. The findings highlight agroforestry’s potential for soil protection and initiation of dust depositions in erosion-prone drylands, emphasizing the need for design optimization and broader implementation to enhance agricultural resilience under climate variability.