The role of cultivation and abandonment in shaping soil erosion in the San Blas-Binġemma valley system on the island of Gozo, Malta

Abstract

Soil erosion is a growing environmental issue around the world, including in Malta. This study focused on estimating soil loss in the San Blas and Binġemma valleys on the island of Gozo, the second largest in the Maltese archipelago. To do this, we used the RUSLE model combined with GIS tools, supported by fieldwork and lab testing of soil properties like texture and organic matter to ensure accurate, ground-based data. A key part of the research was also to understand how much the C-factor in RUSLE, which relates to crop cover, affects erosion in the area. We compared present-day erosion patterns with those from 1957 by analyzing old aerial photos and reconstructing land use back then. The findings show that in 1957, soil erosion was more widespread but generally milder, with most areas losing less than 2.0 t ha⁻¹ yr⁻¹. In contrast, in 2021, erosion tends to be more intense but limited to specific areas, especially along the valley floor, where losses reached up to 13.0 t ha⁻¹ yr⁻¹ compared to 5.5 t ha⁻¹ yr⁻¹ in 1957. The results also suggest that fields under cultivation are more prone to erosion compared to areas that have been abandoned. Based on these trends, this study recommends maintaining traditional erosion control methods like terraces and dry stone-walls, and encouraging farmers to adopt practices such as crop rotation, conservation tillage, contour planting, and strip cropping. It also suggests carrying out similar assessments in other valleys to guide valley-specific actions