Soil organic carbon stocks under recommended management practices in different soils of semiarid vineyards

Abstract

The Intergovernmental Panel on Climate Change (IPCC) approach is widely used to estimate the C account through the use of standardized coefficients that are not site specific. For these reasons, the aim of the work was to define specific IPCC coefficient taking into account differences in pedological characteristics that affect soil C steady state. In a vineyard area of Sicily, the effectiveness of 5 years of recommended management practice (RMP) adoption on soil organic carbon (SOC) stock increases was evaluated by considering 100 paired sites distributed over four functional soil groups. Each site consisted of two neighbouring plots. The soil of one plot was managed with cover crops according to RMP, and the other plot was managed with conventional tillage practices. IPCC coefficients were also derived and specifically adjusted for semiarid environments. SOC changes following RMP adoption and SOC steady-state levels were correlated with functional soil groupings. SOC increased from 24.8 to 28.3 t ha−1 in conventional and RMP vineyards, respectively, with the highest increases being observed in vertic and the lowest in calcic soils. The management factor (Fmg) ranged from 1.11 for calcaric to 1.44 for vertic functional soil groups. C maintenance requirement (C input) should be estimated in relation to soil functional groups. Findings of this study highlighted how the fine tuning of C steady state in relation to specific environmental characteristics is necessary to avoid overestimation of soil C sequestration. Awareness of correct soil C sequestration potential is useful for policymakers and stakeholders for future C account and land degradation control planning.