Osman Hanan E M, Elaidarous Abeer A, El-Morsy Mohamed H, Eid Ebrahem M, Keshta Amr E
Biology Department, Faculty of Science, Umm-Al-Qura University, Makkah 24243, Saudi Arabia.
Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo 11651, Egypt.
Heliyon. 2023 Jan 16;9(1):e12988. doi: 10.1016/j.heliyon.2023.e12988. eCollection 2023 Jan.
In arid ecosystems, lack of vegetation and nutrients can negatively impact soil carbon (C) content. In the current study, our goals were to assess soil C stocks to a depth of 50 cm in an arid ecosystem (Wadi Al-Sharaea, Saudi Arabia) and determine their relation to different vegetation cover. To address our research objective, a total of 102 quadrate (randomly selected) were established along the desert wadi. Soil samples were collected to a depth of 50 cm with 5 cm interval, then Soil Bulk Density (SBD, g/cm), Soil Organic C Content (SOC, g C/kg), and stocks (kg C/m) were estimated. Both soil mechanical and chemical analyses were conducted for a composite soil sample. Study sites were categorized based on their visual vegetation cover (VC) percentage (%) into three major groups: 1) scarce vegetation cover (VC less than 25%); 2) medium vegetation cover (VC is higher than 25% and less than 75%); and lastly 3) dense vegetation cover (VC is higher than 75%). Soils were characterized by higher sand content (48.2%, both fine and coarse compiled) than silt (36.7 ± 1.64%) or clay (10.1 ± 1.28%). There were significant differences among soil Calcium (Ca) and Potassium (K) content ( < 0.05), while those plant communities with medium vegetation cover showed the highest soil content of Ca and K (1.7 ± 0.24 and 0.2 ± 0.03 meq/l, respectively). Plant communities with dense vegetation cover had the lowest SBD (1.96 ± 0.03 g/cm) and the highest SOC stocks (14.9 ± 2.1 kg C/m). Moreover, our data analyses indicated that SBD and SOC content had strong and negative correlation, where soils with dense vegetation cover had the most significant correlation (R = 0.95). Our results recommend that soil carbon stocks to a depth of 50 cm based on different vegetation cover of arid ecosystems should be implemented on global soil carbon budget to better elucidate factors controlling SOC content at the regional and global scales.
在干旱生态系统中，植被和养分的缺乏会对土壤碳（C）含量产生负面影响。在当前的研究中，我们的目标是评估一个干旱生态系统（沙特阿拉伯的瓦迪·沙拉埃亚）中深度达50厘米的土壤碳储量，并确定它们与不同植被覆盖度的关系。为了实现我们的研究目标，沿着沙漠干河共设立了102个样方（随机选取）。以5厘米的间隔采集深度达50厘米的土壤样本，然后估算土壤容重（SBD，克/立方厘米）、土壤有机碳含量（SOC，克碳/千克）和储量（千克碳/平方米）。对一个复合土壤样本进行了土壤机械和化学分析。研究地点根据其可视植被覆盖度（VC）百分比（%）分为三大类：1）植被覆盖稀少（VC小于25%）；2）中等植被覆盖（VC高于25%且小于75%）；最后3）密集植被覆盖（VC高于75%）。土壤的特点是砂含量较高（细砂和粗砂合计为48.2%），高于粉砂（36.7±1.64%）或黏土（10.1±1.28%）。土壤钙（Ca）和钾（K）含量之间存在显著差异（P<0.05），而中等植被覆盖的植物群落土壤中Ca和K含量最高（分别为1.7±0.24和0.2±0.03毫克当量/升）。密集植被覆盖的植物群落土壤容重最低（1.96±0.03克/立方厘米），土壤有机碳储量最高（14.9±2.1千克碳/平方米）。此外，我们的数据分析表明，土壤容重和土壤有机碳含量呈强负相关，其中密集植被覆盖的土壤相关性最为显著（R=0.95）。我们的研究结果建议，基于干旱生态系统不同植被覆盖度的深度达50厘米的土壤碳储量应纳入全球土壤碳预算，以更好地阐明区域和全球尺度上控制土壤有机碳含量的因素。
