植物生态学报 ›› 2018, Vol. 42 ›› Issue (1): 86-94.doi: 10.17521/cjpe.2017.0086

• 研究论文 • 上一篇    下一篇

青藏高原东缘窄叶鲜卑花灌丛生长季土壤无机氮对增温和植物去除的响应

马志良1,2,赵文强1,赵春章1,刘美1,2,朱攀1,刘庆1,*()   

  1. 1 中国科学院山地生态恢复与生物资源利用重点实验室, 生态恢复与生物多样性保育四川省重点实验室, 中国科学院成都生物研究所, 成都 610041
    2 中国科学院大学, 北京 100049
  • 出版日期:2018-01-20 发布日期:2017-06-22
  • 通讯作者: 刘庆 ORCID:0000-0002-7046-0307 E-mail:liuqing@cib.ac.cn
  • 基金资助:
    国家自然科学基金(31570476);国家科技基础性工作专项(2015FY110300)

Responses of soil inorganic nitrogen to increased temperature and plant removal during the growing season in a Sibiraea angustata scrub ecosystem of eastern Qinghai-Xizang Plateau

MA Zhi-Liang1,2,ZHAO Wen-Qiang1,ZHAO Chun-Zhang1,LIU Mei1,2,ZHU Pan1,LIU Qing1,*()   

  1. 1 Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, China;

    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Online:2018-01-20 Published:2017-06-22
  • Contact: LIU Qing ORCID:0000-0002-7046-0307 E-mail:liuqing@cib.ac.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(31570476);the National Science and Technology Basic Work Project(2015FY110300)

摘要:

为了揭示气候变暖背景下高寒灌丛土壤氮转化过程, 该文研究了青藏高原东缘窄叶鲜卑花(Sibiraea angustata)灌丛生长季节土壤硝态氮和铵态氮含量对增温和去除植物的响应。结果表明: 窄叶鲜卑花灌丛土壤硝态氮和铵态氮含量具有明显的季节动态。整个生长季节, 土壤硝态氮含量呈先增加后降低的趋势, 而铵态氮含量均表现为一直增加的趋势。在生长季初期和中期, 各处理土壤硝态氮含量均显著高于铵态氮含量, 而在生长季末期土壤硝态氮含量均显著低于铵态氮含量, 说明该区域土壤氮转化过程在生长季初期和中期以硝化作用为主, 而在生长季末期以氨化作用为主。不同时期土壤硝态氮和铵态氮含量对增温和去除植物的响应不同: 增温对硝态氮的影响主要发生在生长季中期和末期, 且因植物处理的不同而有显著差异, 增温仅在生长季中期使不去除植物样方铵态氮含量显著升高。去除植物对土壤硝态氮的影响仅表现在对照样方(不增温), 去除植物显著提高了生长季初期和中期土壤硝态氮含量, 显著降低了生长季末期土壤硝态氮含量; 同时去除植物显著降低了增温样方生长季中期土壤铵态氮含量。灌丛植被在生长季初期和中期可能主要吸收土壤硝态氮, 其吸收过程不受土壤增温的影响。

关键词: 高寒灌丛, 增温, 植物去除, 土壤氮转化, 硝态氮, 铵态氮

Abstract:
Aims Little information has been available on the soil nitrogen transformation process of alpine scrubland under global warming and changing climate. This study aimed at clarifying seasonal dynamics of the soil nitrate and ammonium contents and their responses to increased temperature under different plant treatments. Methods We conducted a field experiment including two plant treatments (removal- or unremoval-plant) subjected to two temperature conditions (increased temperature or control) in Sibiraea angustata scrub ecosystem on the eastern Qinghai-Xizang Plateau. The contents of soil nitrate and ammonium were measured at the early, middle and late growing seasons. Important findings The results showed that soil nitrate and ammonium contents exhibited obvious seasonal dynamics. Throughout the entire growing season, the soil nitrate contents increased firstly and then decreased, while the soil ammonium contents increased continually. Particularly, in the early and middle growing season, the soil nitrate contents were significantly higher than those of ammonium, regardless of increased temperature and plant treatments; however, in the late growing season, the soil nitrate contents were significantly lower than those of ammonium. These results implied that soil nitrification was the major process of soil nitrogen transformation in the early and middle growing season; soil ammonification contributed mostly to soil nitrogen transformation in the late growing season. Furthermore, different responses of soil nitrate and ammonium contents to increased temperature and plant removal treatments were observed at the different stages in the growing season. The effects of increased temperature on soil nitrate contents mainly occurred in the middle and late growing season, but the effects varied with plant treatments. Increased temperature only significantly increased soil ammonium contents in the unremoval-plant plots during the middle growing season. The effects of plant treatments on soil nitrate contents only occurred in the control plots (controlled temperature). Plant removal only increased soil nitrate contents in the early and middle growing season, but significantly decreased soil nitrate contents in the late growing season. Plant removal significantly decreased soil ammonium contents in the increased temperature plots during the middle growing season. Probably, in the early and middle growing season, scrub vegetation mainly absorbed soil nitrate and the absorption process was not affected by increased temperature. These results would increase our understanding of the soil nitrogen cycling process in these alpine scrub ecosystems under global warming and changing climate.

Key words: alpine scrub, warming, plant removal, soil nitrogen transformation, nitrate, ammonium