Abstract

Our knowledge about soil properties and soil organic carbon stock under arid ecosystems is crucial if we are to optimize soil organic carbon sequestration to mitigate climate changes. This study aims at investigating soil properties, soil organic carbon (SOC) pools, and stocks in soil under arid ecosystem oasis. Soil samples were randomly collected from 0–5 and 0–30 cm depths in 17 sites (34 samples). The bulk density, pH, electrical conductivity EC, calcium carbonate and gypsum were measured in soil samples. Total SOC, particulate organic carbon (POC), SOC associated with the fine mineral fraction concentrations and stocks were also determined. Results showed that soils under oasis are characterized by high pH and EC values. Similarly we recorded great amount of CaCO₃ and gypsum among sites and depths. However bulk density values ranged from 1.23 to 1.30 and 1.18 to 1.35 g cm^–3 respectively in 0–5 and 0–30 cm layer depths. The total SOC concentrations range on average between 8.47 to 13.25 g kg^–1 and between 9.27 to 11.06 g kg^–1 in 0–5 and in 0–30 cm layers respectively. In all samples the SOCff represents the major organic pools of SOC (>60%). Among sites the SOCs in 0–5 cm layer depth were between 0.4 and 0.8 kg C m^–2 and reach 4 kg C m^–2 (40 t ha^–1) in 0–30 cm. The POCs constitute only between 21 and 34%. The correlation matrix established between soil properties shows significant negative correlation (p = 0.05) between POC and EC. However, SOCs are largely positively correlated (p = 0.01) with different SOC pools. It can be said that soils under oasis store relatively high amount of organic carbon. Therefore, this study confirms that arid soils can be considered as a potential sink in North Africa to sequester SOC.

中文翻译：

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突尼斯东部干旱沿海生态系统绿洲土壤性质和有机碳储量

摘要

如果我们要优化土壤有机碳封存以缓解气候变化，我们对干旱生态系统下土壤特性和土壤有机碳储量的了解至关重要。本研究旨在调查干旱生态系统绿洲下的土壤特性、土壤有机碳 (SOC) 库和土壤储量。从 17 个地点（34 个样本）的 0-5 和 0-30 厘米深度随机采集土壤样本。在土壤样品中测量容重、pH、电导率EC、碳酸钙和石膏。还确定了总 SOC、颗粒有机碳 (POC)、与细小矿物组分浓度和储量相关的 SOC。结果表明，绿洲下的土壤具有高 pH 值和 EC 值的特点。同样，我们记录了大量的 CaCO ₃和石膏之间的网站和深度。然而，在 0–5 和 0–30 cm 层深度，体积密度值的范围分别为 1.23 至 1.30 和 1.18 至 1.35 g cm ^{–3 。}在 0-5 和 0-30 厘米层中，总 SOC 浓度的平均范围分别为 8.47 至 13.25 g kg ^–1和 9.27 至 11.06 g kg ^{–1 。}在所有样本中，SOCff 代表 SOC 的主要有机池 (>60%)。在站点中，0–5 cm 层深度的 SOC 在 0.4 和 0.8 kg C m ^–2之间，在 0–30 cm 中达到 4 kg C m ^–2 (40 t ha ^{–1 )。}POC 仅占 21% 到 34%。土壤性质之间建立的相关矩阵呈显着负相关（p= 0.05) POC 和 EC 之间。然而，SOC 与不同的 SOC 池在很大程度上呈正相关 ( p = 0.01)。可以说，绿洲下的土壤储存了较高量的有机碳。因此，这项研究证实，干旱土壤可被视为北非封存 SOC 的潜在汇。