Effects of parent material on soil erosion within Mediterranean new vineyard plantations

Parent material can determine specific physical and chemical soil properties and, therefore, soil erosion rates. However, for new vine plantations, there is not enough research on soil erosion assessment on different parent materials which could be helpful for agricultural management plans. The main aim of this research was to quantify soil erosion rates of two recent vineyard plantations under similar climate and land use management conditions, but on different parent materials, namely colluvium (2 years old) and marls (8 years old), located within the Les Alcusses valley vineyards in Eastern Spain. To achieve this goal, the ISUM (improved stock unearthing method) was applied. ISUM involves measurements of vertical distances from a horizontally stretched meter band attached to opposite pair vine plants to the topsoil surface at 5 sampling points along the cross sections of the pair vine rows. The original surface level was determined from the fixed distance of 2 cm of the graft unions from the soil surface. Digital elevation modelling of the vertical measurements was used to infer the erosion rates. Annual total soil erosion rates were 87.7 Mg ha−1 year−1 and 4.35 Mg ha−1 year−1 in the marls and colluvium plots, respectively. For the marls plot, 67% of the depletion occurred in the inter-row areas, whereas for the colluvium plot the inter-row areas registered 4.78 Mg ha−1 year−1 depletion and the row areas showed only a deposition of 0.44 Mg ha−1 year−1. We hypothesised that the inter-row areas registered the highest erosion rates due to the tillage practices. In the row areas, the cover of the vines possibly reduced soil erosion rates and acted as sinks for sediments. This behaviour of the inter-row areas acting as sources and the row areas as sinks for sediments was more evident on the colluvium plot, while most sections on the marls plot showed intense erosion features. It is suggested that more attention should be paid by policymakers and stakeholders to these differences when new plantations are introduced on marls and colluvium vineyards. We claim that initial soil erosion control measures should be applied during the first few years of plantations instead of when the vineyards are much older and soil has already been mobilised.