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草业学报 ›› 2021, Vol. 30 ›› Issue (4): 24-33.DOI: 10.11686/cyxb2020276

• 研究论文 • 上一篇    下一篇

不同时期干旱对青藏高原高寒草甸生态系统碳交换的影响

王子欣1,2(), 胡国铮1,2(), 水宏伟1,2, 葛怡情1,2, 韩玲1,2, 高清竹1,2, 干珠扎布1,2, 旦久罗布3   

  1. 1.中国农业科学院农业环境与可持续发展研究所,北京 100081
    2.农业农村部农业环境重点实验室,北京 100081
    3.那曲市草原站,西藏 那曲 852000
  • 收稿日期:2020-06-16 修回日期:2020-10-10 出版日期:2021-04-20 发布日期:2021-03-16
  • 通讯作者: 胡国铮
  • 作者简介:Corresponding author. E-mail: huguozheng@caas.cn
    王子欣(1996-),女,山东潍坊人,在读硕士。E-mail: wangzixinzixin@163.com
  • 基金资助:
    第二次青藏高原综合考察研究(2019QZKK0307);国家重点研发计划课题(2016YFC0502003);国家自然科学基金项目(31800383);中央级公益性科研院所基本科研业务费专项资金(20290-2017);西藏那曲地区与中国农业科学院合作项目资助

Effect of seasonal timing of drought on carbon exchange in the alpine meadow ecosystem of the Qinghai-Tibetan Plateau

Zi-xin WANG1,2(), Guo-zheng HU1,2(), Hong-wei SHUI1,2, Yi-qing GE1,2, Ling HAN1,2, Qing-zhu GAO1,2, Ganjurjav HASBAGAN1,2, Luo-bu DANJIU3   

  1. 1.Institute of Environment and Sustainable Development in Agriculture,Chinese Academy of Agricultural Sciences,Beijing 100081,China
    2.Key Laboratory of Agro-Environment,Ministry of Agriculture and Rural Affairs,Beijing 100081,China
    3.Naqu Grassland Station,Naqu 852000,China
  • Received:2020-06-16 Revised:2020-10-10 Online:2021-04-20 Published:2021-03-16
  • Contact: Guo-zheng HU

摘要:

极端干旱事件能够显著地改变土壤水热条件和群落特征,进而影响生态系统碳交换。以青藏高原高寒草甸为研究对象,通过设置截雨棚,模拟发生在生长季前期(返青期,5-6月)和中期(快速生长期,7-8月)的极端干旱事件,研究不同时期干旱对群落特征和生态系统碳交换的影响。结果发现:不同时期干旱事件对高寒草甸生态系统的影响均表现在生长季中期,生长季前期干旱处理(ED)下,群落植被高度、盖度和地上生物量均显著降低于对照(CK) (P<0.05);此外,ED和生长季中期干旱处理(MD)均显著抑制了总生态系统生产力(GEP)和生态系统呼吸(ER) (P<0.05),且MD显著降低了净生态系统碳交换(NEE)(P<0.05)。相关分析结果表明,ED处理下,生长季中期的土壤体积含水量与ER显著正相关(P<0.05);MD处理下,在生长季前期的土壤体积含水量、群落地上生物量均与ER显著正相关(P<0.05)。表明生长季不同时期干旱对生态系统碳交换的影响机理不同,生长季前期干旱主要通过抑制植物生长过程影响碳交换,而生长季中期干旱则主要通过抑制植物生理活动影响碳交换。研究结果加深了高寒草甸生态系统对不同时期干旱响应的认识,为气候变化预测研究提供了数据支撑。

关键词: 生长季, 干旱事件, 碳交换, 土壤体积含水量, 生物量

Abstract:

Extreme drought events can significantly change soil hydrothermal conditions and plant community characteristics, and then affect the ecosystem carbon exchange. In this study, we used rain shelters to artificially produce early season growing drough (ED, greening up stage, May-June) and middle growing season drought (MD, rapid growing stage, July-August), to study the responses of plant community responses and ecosystem carbon exchange. It was found that vegetation height, cover and aboveground biomass were significantly lower in ED than in control (P<0.05) during the middle of the growing season. ED and MD depressed the total ecosystem productivity (GEP) and ecosystem respiration (ER) significantly (P<0.05) in the middle of the growing season. Moreover, net ecosystem carbon exchange significantly decreased (P<0.05) under the MD treatment. Regression analysis showed that there was a significant positive correlation between the soil moisture and ER (P<0.05) under ED in the middle of growing season. Also, ER was significantly positively correlated with soil moisture and community biomass (P<0.05) in the MD treatment during the early growing season. The mechanisms of drought impact differed with different seasonal timing of imposed drought. The ED mainly affected carbon exchange by inhibiting plant growth processes, while the MD primarily affected carbon exchange by inhibiting plant physiological activity. This study expands knowledge of how this alpine meadow ecosystem responds to drought at different times within the growing season, and provides data supporting climate change projection research.

Key words: growing season, drought events, carbon exchange, soil volume water content, biomass