Spatial Variability and Magnitude of Soil Erosion in Vineyards Across Spain: Insights from Standardized ISUM Measurements

Soil erosion and sediment redistribution in vineyards often exceed tolerable thresholds, but comparative field measurements across regions remain limited because studies use different methods and sampling designs. This study assesses soil redistribution in vineyards using a common field-based approach. Thirteen vineyard sites across Spain, covering contrasting climates, parent materials, soil types, management conditions, and vineyard ages (2–40 years), were surveyed using the Improved Stock Unearthing Method (ISUM). Soil surface changes were measured along systematic transects and combined with site-specific bulk density and vineyard age to estimate soil mobilization rates in t ha−1 yr−1. Measured surface changes ranged from −28 to +19 cm, while soil mobilization rates varied considerably among sites. The highest net soil losses were recorded in a young vineyard developed on limestone (−103.3 t ha−1 yr−1) and in a vineyard on marls (−87.7 t ha−1 yr−1). Other sites showed moderate net erosion (−3.9 to −15.4 t ha−1 yr−1), whereas positive balances (+7.2 to +17.9 t ha−1 yr−1) were observed in some older or more stable vineyards. Differences among sites suggest that vineyard age and parent material are relevant factors when interpreting erosion magnitude, while management conditions may contribute to the spatial variability of soil redistribution. Spatial maps based directly on ISUM measurements showed marked differences between erosion and deposition areas within individual vineyards, without the use of spatial interpolation. Applying the same ISUM protocol across contrasting vineyard conditions allowed soil redistribution patterns to be compared using a consistent field procedure. The results also showed the large variability that can occur among vineyard systems.