Dong Xinping, Tariq Akash, Graciano Corina, Zhang Zhihao, Gao Yanju, Keyimu Maierdang, Cong Mengfei, Zhao Guangxing, Yan Jingming, Wang Weiqi, Sardans Jordi, Peñuelas Josep, Zeng Fanjiang
Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China; State Key Laboratory of Ecological Safety and Sustainable Development in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; University of Chinese Academy of Sciences, Beijin, 100049, China.
Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China; State Key Laboratory of Ecological Safety and Sustainable Development in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China.
Environ Res. 2025 Oct 1;282:121989. doi: 10.1016/j.envres.2025.121989. Epub 2025 May 28.
Desertification and soil carbon loss threaten arid ecosystem sustainability, yet the long-term stability of soil organic carbon (SOC) following afforestation in hyperarid regions remains poorly understood. Here, we investigated SOC dynamics across a 22-year Populus alba chronosequence at the Taklimakan Desert edge, combining physical fractionation particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) with microbial phospholipid fatty acid (PLFAs) and enzymatic analyses. Afforestation significantly increased SOC content by 50.97 %-108.05 %, with MAOC surging 100.94 %-160.59 % after 22 years (P < 0.01). SOC stability (MAOC/POC ratio) peaked at 12 years before declining. Random forest modeling identified total nitrogen (TN) and available phosphorus (AP) as key drivers. Meanwhile, microbial metabolic limitations, assessing by the stoichiometric of soil extracellular enzymes, shifted from phosphorus (P) limitation to carbon-phosphorus (C-P) colimitation suppressed decomposition activity, enhancing SOC stability. This study provides the quantification of nonlinear SOC stability trajectories in hyperarid plantations, offering critical insights for optimizing afforestation age to enhance the stability of SOC. Our findings advance mechanistic understanding of SOC persistence in water-limited ecosystems and directly inform desertification control policies under climate change scenarios.
荒漠化和土壤碳流失威胁着干旱生态系统的可持续性，但在极端干旱地区造林后土壤有机碳（SOC）的长期稳定性仍知之甚少。在此，我们研究了塔克拉玛干沙漠边缘一个22年的银白杨时间序列中的SOC动态，将物理分级的颗粒有机碳（POC）和矿物结合有机碳（MAOC）与微生物磷脂脂肪酸（PLFAs）及酶分析相结合。造林使SOC含量显著增加了50.97%-108.05%，22年后MAOC激增了100.94%-160.59%（P<0.01）。SOC稳定性（MAOC/POC比率）在下降前的12年达到峰值。随机森林模型确定总氮（TN）和有效磷（AP）为关键驱动因素。同时，通过土壤胞外酶的化学计量评估的微生物代谢限制从磷（P）限制转变为碳-磷（C-P）共同限制，抑制了分解活性，增强了SOC稳定性。本研究量化了极端干旱人工林中非线性的SOC稳定性轨迹，为优化造林年龄以增强SOC稳定性提供了关键见解。我们的研究结果推进了对水分受限生态系统中SOC持久性的机理理解，并直接为气候变化情景下的荒漠化控制政策提供了依据。
