Estimation of potential soil erosion in the Prosecco DOCG area (NE Italy), toward a soil footprint of bottled sparkling wine production in different land-management scenarios.

Abstract

Agricultural lands are the widest Human-modified ecosystems, making crop production the most extensive form of land use on Earth. However, in conventional agricultural land management, soil erosion may be boosted up to 1-2 orders of magnitude higher than the natural rates of soil production, making unproductive about the 30% of the world's arable. Nowadays in Europe, vineyards represent the most erosion-prone agricultural lands, especially in Mediterranean countries, showing the highest erosion rates in comparison to other type of land uses. Prosecco wine is produced in NE Italy by a rate of 400 M bottles per year, with the fastest growing demand in the global market at present. A production of 90 M bottles year-1 is currently running in the historical Prosecco DOCG (215 km2), in a steep hilly landscape of Veneto Region (Conegliano-Valdobbiadene). To sustain wine production, agricultural intensification is at present increasing, by re-setting of hillslopes and land use changes towards new vineyard plantations. The aim of this study is to estimate and to map potential soil erosion rate, calculating a sort of "soil footprint" for wine production in different agricultural land-management scenarios. RUSLE model was adopted to estimate potential soil erosion in Mg ha-1 year-1, by using high resolution topographic data (LiDAR), 10 years rainfall data analysis, detailed land use and local soil characteristics. For a conventional land-management scenario the estimated that total potential soil erosion in the Prosecco DOCG area is 411,266 Mg year-1, with an erosion rate of 19.5 Mg ha year-1. Modelled soil erosion is mainly clustered on steep slopes, with rates higher than 40 Mg ha-1 year-1. In Prosecco vineyards potential soil erosion could reach 300,180 Mg year-1, by a mean rate of 43.7 Mg ha-1 year-1, which is 31 times higher than the upper limit of tolerable soil erosion threshold defined for Europe. In contrast, simulation of different nature-based scenarios (hedgerows, buffer strips, and grass cover) showed soil erosion could be effectively reduced: a 100% inter-row grass cover showed a reduction of almost 3 times in vineyards (from 43.7 to 14.6 Mg ha-1 year-1), saving about 50% of soil in the whole Prosecco DOCG. The soil footprint modelled for a conventional land-management scenario is about 3.3 kg every bottle produced; in contrast it would be reduced to 1.1 kg/bottle in the completely green land-management scenario. This study, as the first estimation of potential soil erosion at Prosecco DOCG scale, suggests that an integrated and public soil erosion monitoring system is strongly needed in viticultural area, by implementing direct/indirect field measures with spatial analyses at agricultural landscape scale.