Drinking earth for wine. Estimation of soil erosion in the Prosecco DOCG area (NE Italy), toward a soil footprint of bottled sparkling wine production

Abstract

Prosecco, one of the most widespread sparkling wine in the world, is produced in Northeast 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 sector (215 km²), defined as the Controlled and Guaranteed Designation of Origin (DOCG) area, in a steep hilly landscape of Veneto Region (Conegliano-Valdobbiadene) registered in 2017 for the UNESCO World Heritage tentative list. To sustain wine production agricultural intensification boosted to re-setting of hillslopes and land use changes toward new vineyard plantations. The aim of this study is to assess soil erosion rate, calculating a sort of “soil footprint” for wine production by i) estimation of the total soil erosion, ii) identification of the most critical areas, iii) simulation of different nature-based mitigation scenarios. RUSLE model was adopted to estimate soil erosion in Mg ha⁻¹ year⁻¹, using high resolution topographic data (LiDAR), 10 years rainfall data analysis, detailed land use and local soil characteristics.

We found that the total soil erosion estimation for the Prosecco DOCG area is 546,263 Mg year⁻¹, with an erosion rate of 25.4 t ha year⁻¹, which is 11 times higher than the Italian average. Prosecco vineyards contributes to 400,000 Mg year⁻¹, by a mean rate of 59.8 Mg ha⁻¹ year⁻¹, and encompass 74% of all the erosion in the whole DOCG area. Soil erosion modelled is mainly concentrated in cultivated hillslopes, highlighting critical areas with more than 40 Mg ha⁻¹ year⁻¹), mainly clustered on steep slopes.

The modelled soil loss of a single bottle of Prosecco is, therefore, about 4.4 kg year⁻¹. In contrast, alternative scenarios of different nature-based mitigation measures (hedgerows, buffer strips, and grass cover) showed that total erosion in the Prosecco DOCG area would be reduced to 275,140 Mg year⁻¹, saving about the 50% of soil. In vineyards a general decrease of almost 3 times (from 400,000 to 135,161 Mg year⁻¹) is also demonstrated, reducing on average the erosion rate from 59.8 to 19.2 Mg ha⁻¹ year⁻¹. This study highlights, thus, that an integrated soil erosion monitor system is needed in the DOCG area as well as the implementation of nature-based mitigation measures as sustainable agricultural layout for modern agroecosystems.