摘要
植被恢复作为退化生态系统修复和重建的重要措施,对土壤碳氮循环和水分平衡起着关键作用。本研究以青藏高原高寒沙区不同恢复年限(5、10、15、20、25年)的青杨人工林为对象,研究0~200cm土层土壤碳、氮、水的分布特征,分析其对不同恢复年限的响应。结果表明:随着恢复年限的增加,青杨人工林土壤有机碳和全氮含量及储量显著增加,无机碳含量及储量显著下降。不同恢复年限青杨人工林0~200cm土层土壤有机碳、无机碳和全氮含量分别为0.41~1.24g C·kg^(-1)、4.53~8.07g C·kg^(-1)和0.12~0.22g N·kg^(-1),储量分别为16.08~33.51t C·hm^(-2)、187.12~241.02t C·hm^(-2)和4.27~6.66t N·hm^(-2)。恢复25年林地0~200cm土层土壤有机碳和全氮储量较恢复5年林地分别显著增加68.1%和39.6%,无机碳储量显著下降9.5%。100~200cm土层土壤有机碳、无机碳和全氮储量是0~100cm土层的1.3~1.4倍。0~200cm土层土壤无机碳储量为有机碳储量的8.2倍。恢复10、15、20、25年林地0~200cm土层土壤有机碳储量较恢复5年林地的增幅为13.3%~68.1%,是同期全氮储量增幅的1.0~2.1倍,存在土壤碳氮累积的脱耦现象。恢复15年后,土壤平均含水量和储水量达到最大,分别为7.4%和274.17mm。恢复年限与土壤有机碳、全氮含量呈显著正相关,与土壤含水量无显著相关关系;土壤有机碳储量、全氮储量和储水量之间呈显著正相关,两两间存在正向促进效应。无机碳库是青藏高原高寒沙区碳库重要的组成部分,植被恢复年限是促进土壤碳氮水固持的主要因素,深层土壤碳氮水对区域碳氮水储量的贡献不可忽视,区域植被恢复早期应采取提高土壤氮固持能力的生态恢复措施。
As the most effective way to remedy and reconstruct the degraded ecosystems,vegetation restoration could affect soil carbon and nitrogen cycles and water balance.We examined the responses of carbon,nitrogen,and water in 0-200 cm soil layer to vegetation restoration years by analyzing their distribution characteristics across a restoration chronosequence of Populus cathayana plantation(5,10,15,20,and 25 years)in alpine sandy region of the Qinghai-Tibetan Plateau.The results showed that the content and storage of soil organic carbon(SOC)and soil total nitrogen(STN)increased significantly,while that of soil inorganic carbon(SIC)decreased significantly with restoration years.SOC,SIC and STN content for the entire 200 cm soil layer were 0.41-1.24 g C·kg^(-1),4.53-8.07 g C·kg^(-1),and 0.12-0.22 g N·kg^(-1),respectively.S0C,SIC,and STN storage for the entire 200 cm were 16.08-33.51 t C·hm^(-2),187.12-241.02 t C·hm^(-2),and 4.27-6.66 t N·hm^(-2),respectively.After 25 years vegetation restoration,the storage of SOC and STN for the entire 200 cm soil layer were significantly increased by 68.1%and 39.6%,while the SIC storage was significantly decreased by 9.5%compared with the 5 years vegetation restoration.The storage of SOC,SIC and STN in the 100-200 cm soil layer were 1.3-1.4 times higher than those in the 0-100 cm layer.The storage of SIC within the 0-200 cm layer was 8.2 times of the SOC storage over the same layer.Compared with the 5 years restoration,S0C storage in the 0-200 cm soil layer of 10,15,20,and 25 restoration years increased by 13.3%-68.1%,which were 1.0-2.1 times of the STN storage,suggesting a decoupling of SOC and STN accumulation during restoration.After 15 years vegetation restoration,soil water content and storage peaked at 7.4%and 274.17 mm,respectively.Restoration years were significantly positively correlated with SOC and STN contents,but not related to water content.SOC,STN,and water storage were significantly and positively correlated with each other,resulting in a positive promoting effect between each pair.In conclusion,the inorganic carbon pool was a significant contributor to the total carbon pool in alpine sandy region of the Qinghai-Tibetan Plateau.Vegetation restoration year is a primary determinant of soil carbon,nitrogen,and water sequestration,with the contributions of deeper soil layers to regional levels being equally important and can not be ignored.This finding suggested that alpine sandy ecosystems required soil nitrogen input in the early vegetation restoration stages.
作者
徐仁飞
王璐
邓磊
王文颖
杜盛
关晋宏
XU Renfei;WANC Lu;DENG Lei;WANC Wenying;DU Sheng;GUAN Jinhong(School of Life Science,Qinghai Normal University/Academy of Plateau Science and Sustainability,Xining 810008,China;Key Laboratory of Biodiversity Formation Mechanism and Comprehensive Utilization of the Qinghai-Tibetan Plateau in Qinghai Province,Xining 810008,China;College of Coastal Agricultural Sciences,Guangdong Ocean University,Zhanjiang 524088,Guangdong,China;State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau,Northwest A&F University,Yangling 712100,Shaanxi,China)
出处
《应用生态学报》
CAS
CSCD
北大核心
2024年第10期2657-2666,共10页
Chinese Journal of Applied Ecology
基金
国家自然科学基金项目(42267072)
中央财政林业科技推广示范项目([2021]TG02)资助。
关键词
高寒沙区
植被恢复
土壤有机碳
土壤无机碳
碳氮储量
alpine sandy region
vegetation restoration
soil organic carbon
soil inorganic carbon
carbon and nitrogen storage