Abstract. Few studies have focused on arenosols with regard to soil carbon dynamics despite the fact that they represent 8 % of the world's soils and are present in key areas where food security is a major issue (e.g. in Sahelian regions). As for other soil types, land use changes (from forest or grassland to cropland) lead to a loss of substantial soil organic carbon (SOC) stocks and have a lasting impact on the SOC turnover. Here we quantified long-term variations in carbon stocks and their dynamics in a 80 cm deep Mediterranean Arenosol that had undergone a land use change from forest to vineyard over more than 100 years ago. Paired-sites of adjacent plots combined with carbon and nitrogen quantification and natural radiocarbon (¹⁴C) abundance analyses revealed a stock of 50 GtC ha⁻¹ in the 0–30 cm forest soil horizon, which was reduced to 3 GtC ha⁻¹ after long-term grape cultivation. TOC in vineyard was dramatically low, with around 1 gC kg⁻¹ and no vertical gradient as a function of depth. ¹⁴C showed that deep ploughing (50 cm) in vineyard plot redistributed the remaining carbon both vertically and horizontally. This remaining carbon was old carbon (compared to that of the forest), which had a C : N ratio characteristic of microbial OM and was probably stabilized within organomineral associations. Despite the drastic degradation of the OM pool in this Arenosol, this soil would have a high carbon storage potential if agricultural practices, such as grassing or organic amendment applications, were to be implemented within the framework of the 4 per 1000 Initiative.

中文翻译：

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百年规模的森林/葡萄园土地利用变化引起的沙粒碳损失动态

摘要。尽管它们占世界土壤的 8% 并且存在于粮食安全是主要问题的关键地区（例如在萨赫勒地区），但很少有研究关注土壤碳动态方面的沙土溶胶。至于其他土壤类型，土地利用变化（从森林或草地到农田）导致大量土壤有机碳 (SOC) 储量的损失，并对 SOC 周转产生持久影响。在这里，我们量化了 80 厘米深的地中海 Arenosol 中碳储量的长期变化及其动态，该地区在 100 多年前经历了从森林到葡萄园的土地利用变化。相邻地块的配对位点结合碳和氮定量和天然放射性碳 ( ¹⁴ C) 丰度分析显示，存量为 50 GtC 公顷^-1在 0-30 cm 森林土壤层中，在长期葡萄种植后减少到 3 GtC ha ^-1。葡萄园中的 TOC 非常低，约为 1 gC kg ^-1并且没有作为深度函数的垂直梯度。¹⁴C 表明，在葡萄园地块中深耕（50 厘米）在垂直和水平方向上重新分配了剩余的碳。剩余的碳是旧碳（与森林的碳相比），它具有微生物 OM 的 C:N 比特征，并且可能在有机矿物组合中稳定下来。尽管此 Arenosol 中的 OM 池急剧退化，但如果要在 4 per 1000 倡议的框架内实施农业实践，例如植草或有机改良剂应用，则该土壤将具有很高的碳储存潜力。