Soil and water conservation in terraced and non‐terraced cultivations: an extensive comparison of 50 vineyards

Abstract

Understanding the soil and water conservation (SWC) impact of steep-slope agricultural practices (e.g. terraces) has arguably never been more relevant than today, in the face of widespread intensifying rainfall conditions. In Italy, a diverse mosaic of terraced and non-terraced cultivation systems have historically developed from local traditions and more recently from the introduction of machinery. Previous studies suggested that each type of vineyard configuration is characterised by a specific set of soil degradation patterns. However, an extensive analysis of SWC impacts by different vineyard configurations is missing, while this is crucial for providing robust guidelines for future-proof viticulture. Here, we provide a unique extensive comparison of SWC in 50 vineyards, consisting of 10 sites of 5 distinct practices: slope-wise cultivation (SC), contour cultivation (CC), contour terracing (CT), broad-base terracing (BT) and oblique terracing (OT). A big-data analysis approach of physical erosion modelling based on high-resolution LiDAR data is performed, while four predefined SWC indicators are systematically analysed and statistically quantified. Regular contour terracing (CT) ranked best across all indicators, reflecting a good combination of flow interception and homogeneous distribution of runoff and sediment under intense rainfall conditions. The least SWC-effective practices (SC, CC, and OT) were related to vineyards optimised for trafficability by access roads or uninterrupted inter-row paths, which created high upstream-downstream connectivity and are thus prone to flow accumulation. The novel large-scale approach of this study offers a robust comparison of SWC impacts under intense rainstorms, which is becoming increasingly relevant for the sustainable future management of such landscapes.

Soil erosion on arable land: An unresolved global environmental threat

“…However, it is important to note that especially in semi-arid regions, where vineyards or olive plantations are typically found, cover crops compete with the orchard crops for water and in a best case the prevention of surface runoff should offset additional transpiration losses (Ruiz-Colmenero et al, 2011). As this is difficult to achieve, best soil conservation effects, especially in steep vineyards, are often reached with measures as contour terracing (Pijl et al, 2022).…”

Sustainability by Function (SbF): A Case Study in a Rainfed Vineyard to Reduce the Loss of Soil Nutrients

“…The survey of vineyards' soil erosion has been receiving more attention since the beginning of the 21st century based on different methodologies: rainfall simulations [45], runoff and sediment plots [46], topographical measurements [47] and modelling [48]. Within that research perspective, the study of the connectivity of water and sediments in vineyards has been a key topic to understand the mechanism of sediment transport [29,49]. Measurements of the solutes have been rare in vineyards and our research is pioneering.…”

Coevolution between Terraced Landscapes and Rural Communities: An Integrated Approach Using Expert-Based Assessment and Evaluation of Winegrowers’ Perceptions (Northwest Piedmont, Italy)

“…Most of the respondents (79.6%) reported problems with management of terraced vineyards (question 20). As shown in Table 6, the main problems in the management of terraced vineyards reported by winegrowers were terraces management and accessibility (cited 12 and 11 times, respectively), followed by poor mechanization (7), difficulty with management (5), and water availability (5). Problems cited less frequently were proximity to uncultivated lands (2), too much time for cultivation (2), land pulverization (2), management costs (2), too much time for pergola vine-breeding technique management (1), and pilun management (1).…”

“…These anthropogenic soils were classified by Freppaz et al [6] as Technic Cambisols (Escalic). Pijl et al [7] observed the responses of different practices on steep slopes in Italy to extreme rainfall events and found that terracing practices were characterized by better mitigation of sediment flux than nonterracing practices. Along the same lines, recent research conducted in Morocco showed the important capability of agricultural terraces of increasing water infiltration and their important role in flood protection and runoff mitigation [8].…”