*2.4. Soil Carbon Stock Calculation*

Soil organic carbon stock computation was based on soil bulk-density, the thickness of the soil layer and the proportion of fine soil. The C stock was computed using Equation (1) [42]. Carbon stock was estimated for the four soil layers 0–10, 10–20, 20–30 and 30–40 cm. C stock was considered for each layer, for 0–30 cm and for 0–40 cm.

$$\text{C stock} = \sum\_{\text{Depth}=1}^{\text{Depth}=\text{n}} \text{C stock}\_{\text{Depth}} = \sum\_{\text{Depth}=1}^{\text{Depth}=\text{n}} \left( \text{SOC} \times \text{BD} \times P \times (1 - \text{frog}) \times 10 \right) \tag{1}$$

where C stock (Mg C·ha−<sup>1</sup> ) is the sum of soil organic carbon stock for the different layers considered, C stockDepth (Mg C·ha−<sup>1</sup> ) is the stock of organic carbon at a specific soil depth, SOC (g·C kg−<sup>1</sup> ) is the concentration of soil total organic carbon, BD (g·cm−<sup>3</sup> ) is soil bulkdensity, P (m) is the thickness of the soil layer, frag is the percentage volume of coarse fragments/100 and n is the number of layer considered.
