Soil Carbon Budget Account for the Sustainability Improvement of a Mediterranean Vineyard Area

Sustainable viticulture is suggested as an interesting strategy for achieving the objectives of global greenhouse gas (GHG) emission reduction in terms of mitigation and adaptation. However, knowledge and quantification of the contribution of sustainable vineyard management on climate change impact are needed. Although it is widely assessed by several authors that the agricultural stage has a great impact in the wine chain, very few studies have evaluated the greenhouse gas emission in this phase including the ability of soil to sequester carbon (C) or the off-farm C loss by erosion. This work aimed to provide a vineyard carbon budget (vCB) tool to quantify the impact of grape production on GHG emission including the effects of environmental characteristics and agricultural practices. The vCB was estimated considering four different soil management scenarios: conventional tillage (CT), temporary cover crop with a leguminous species in alternate inter-rows (ACC), temporary cover crop with a leguminous species (CC), permanent cover crop (PCC). The estimation of vCB was applied at territory level in a viticulture area in Sicily (2468 ha of vineyard) using empirical data. Results of the present study showed that the environmental characteristics strongly affect the sustainability of vineyard management; the highest contribution to total CO₂ emission is, in fact, given by the C losses by erosion in sloping vineyards. Soils of studied vineyards are a source of CO₂ due to the low C inputs and high mineralization rate, except for soil managed by CC which can sequester soil C, contributing positively to vCB. The highest total CO₂ emission was estimated in vineyards under CT management (2.31 t ha⁻¹y⁻¹), followed by CC (1.27 t ha⁻¹y⁻¹), ACC (0.69 t ha⁻¹y⁻¹) and PCC (0.64 t ha⁻¹y⁻¹). Findings of vCB applied at territory level highlighted the key role of the evaluation of carbon budget (CB) on a larger scale to identify the CO₂ emission in relation to climatic and environmental factors. The present study could contribute to provide suggestions to policymakers and farmers for reducing GHG emissions and promote more sustainable grape production practices.