欢迎访问《应用生态学报》官方网站,今天是 分享到:

应用生态学报 ›› 2020, Vol. 31 ›› Issue (3): 814-820.doi: 10.13287/j.1001-9332.202003.005

• • 上一篇    下一篇

草甸草原土壤碳/氮矿化潜力及土壤微生物水分敏感性对极端干旱的响应

李磊1,2, 王岩1,3, 胡姝娅1,2, 李阳1,2, 申颜1, 庾强4, 黄建辉1,2, 王常慧1*   

  1. 1中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093;
    2中国科学院大学资源环境学院, 北京 100049;
    3河南科技大学, 河南洛阳 471000;
    4中国农业科学院农业资源与农业区划研究所, 北京 100081
  • 收稿日期:2019-10-11 出版日期:2020-03-15 发布日期:2020-03-15
  • 通讯作者: E-mail: wangch@ibcas.ac.cn
  • 作者简介:李磊, 男, 1989年生, 博士研究生。主要从事草地土壤氮转化研究。E-mail: zhiwuLL@ibcas.ac.cn
  • 基金资助:
    本文由国家自然科学基金项目(31572452,41573063)和国家重点研发计划项目(2017YFA0604802)资助

Responses of soil potential carbon/nitrogen mineralization and microbial activities to extreme droughts in a meadow steppe

LI Lei1,2, WANG Yan1,3, HU Shu-ya1,2, LI Yang1,2, SHEN Yan1, YU qiang4, HUANG Jian-hui1,2, WANG Chang-hui1*   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;
    2College of Environmental Resources, University of Chinese Academy of Sciences, Beijing 100049, China;
    3Henan University of Science and Technology, Luoyang 471000, Henan, China;
    4Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
  • Received:2019-10-11 Online:2020-03-15 Published:2020-03-15
  • Contact: E-mail: wangch@ibcas.ac.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (31572452, 41573063) and the National Key R&D Program of China (2017YFA0604802)

摘要: 土壤碳、氮矿化是生态系统养分循环的关键过程,受到水分供给的强烈影响。本研究对极端干旱处理(连续3年生长季减少66%降水)的内蒙古草甸草原野外取土,采用超低温冻干后再调节土壤水分至3%、8%、13%、18%、25%和35% 6个水平进行室内培养,研究极端干旱处理后土壤碳/氮矿化潜力以及土壤微生物对水分变化的敏感性。结果表明: 与对照(自然降雨)相比,极端干旱处理后,6个培养水平的平均土壤氮矿化潜力显著提高14.2%,但未显著影响土壤碳矿化潜力。极端干旱显著提高土壤微生物生物量氮和土壤可溶性有机碳26.8%和26.9%。无论是对照还是极端干旱处理,土壤氮矿化潜力、碳矿化潜力和微生物生物量碳和氮均随着土壤含水量增加而增加,而可溶性有机碳从较低水分的培养水平(3%和8%)到较高水分的培养水平(>13%)显著降低,表明底物的扩散起到重要作用。极端干旱处理显著提高了碳矿化初始脉冲强度,表明极端干旱提高了土壤微生物对水分的敏感性。极端干旱显著降低了土壤碳矿化潜力/氮矿化潜力的比值,表明长期干旱可能会降低土壤碳、氮循环过程的耦合作用。极端干旱对土壤碳矿化和氮矿化过程的影响存在差异,激发了土壤微生物对水分的敏感性,弱化了碳、氮循环过程的耦合关系,并进一步影响中国北方草甸草原生态系统的生物地球化学循环过程及草地生产力。

Abstract: The mineralization of soil carbon (C) and nitrogen (N) is a critical process in the cycling of C and N in terrestrial ecosystems, which is strongly controlled by water availability. In this study, we collected soil samples in a 3-year extreme drought experiment in a meadow steppe in Inner Mongolia, freeze-dried these samples, and measured the potential C and N mineralization rates and water sensitivity of soil microorganism by incubating soils under soil water contents (SWC) of 3%, 8%, 13%, 18%, 25% and 35%. The results showed that averaged across different SWC, the extreme drought treatment of reducing 66% precipitation in growing season significantly increased potential N mineralization rate by 14.2%, but did not affect the potential C mineralization. Extreme drought significantly increased soil microbial biomass N and soil dissolved organic C by 26.8% and 26.9%, respectively. In both the control (natural rainfall) and extreme drought treatment, the potential C and N mineralization and microbial biomass C and N increased with SWC in the incubation, which was possibly caused by the enhanced substrate diffusion. Extreme drought also promoted the initial pulse response of C mineralization, implying the enhanced microbial response to water availability. Extreme drought significantly reduced the ratio of the potential soil C mineralization to the potential N mineralization, suggesting that extreme drought might weak the coupling of soil C and N. Extreme drought could cause different responses to soil water availability between soil C and N cycling. Extreme drought could enhance microbial response to increasing water availability, weak coupling between soil C and N, with consequences on nutrient cycling and primary productivity in the meadow steppe of northern China.