Tillage, Mulch, Fire and Cover: Soil Management Impacts on Degraded Terraces in Mediterranean Olive Groves

ABSTRACT Soil degradation on abandoned or poorly managed terraces in the Mediterranean region poses a significant threat to the resilience of agroecosystems, particularly in hillside olive groves where erosion and nutrient depletion accelerate land abandonment. The aim of this study was to evaluate the short‐term effects of five different soil management practices (grass cover, organic mulch, herbicide application, pile burning and tillage) on soil physical and chemical properties, hydrological responses and nutrient and pollutant losses. A field trial with replicated microplots (five per treatment, 25 in total) on a Rendzic Leptosol was conducted on degraded terraces in southern Croatia. Natural rainfall events were monitored in 2024 (spring to autumn) to quantify runoff and sediment yield. Results showed that mulch and grass treatments significantly improved bulk density, water‐holding capacity and aggregate size while reducing runoff, sediment loss and nutrient export. In contrast, herbicide and fire treatments resulted in pronounced compaction, increased runoff and up to nine times higher losses of C, N, P, K and Cu compared to covered plots. Sediment was consistently enriched in nutrients and contaminants compared to soil, with element concentrations up to three times higher, especially under herbicide, fire and tillage. The study provides new insights into erosion‐induced chemical enrichment and degradation processes on Mediterranean terraces and emphasises the effectiveness of protective measures based on soil cover. The results highlight the disproportionate importance of exposed soils for the transport of fine, chemically enriched sediments and confirm that soil cover, particularly mulch or vegetation, provides substantial protection against both on‐site degradation and nutrient export from the site.