植物生态学报 ›› 2018, Vol. 42 ›› Issue (1): 38-49.DOI: 10.17521/cjpe.2017.0255

• 研究论文 • 上一篇    下一篇

氮肥添加对川西北高寒草甸植物群落根系动态的影响

字洪标,陈焱,胡雷,王长庭()   

  1. 西南民族大学青藏高原研究院, 四川成都 610041
  • 出版日期:2018-01-20 发布日期:2018-03-08
  • 通讯作者: 王长庭
  • 基金资助:
    国家自然科学基金(31370542);国家重大科学研究计划(973计划)(2013CBA01807)(2013CBA01807);四川省教育厅创新团队项目(14TD0049);中央高校基本科研业务费专项资金(2018NZD13)

Effects of nitrogen addition on root dynamics in an alpine meadow, Northwestern Sichuan

ZI Hong-Biao,CHEN Yan,HU Lei,WANG Chang-Ting()   

  1. Institute of Qinghai-Tibetan Plateau Research, Southwest Minzu University, Chengdu 610041, China
  • Online:2018-01-20 Published:2018-03-08
  • Contact: Chang-Ting WANG
  • Supported by:
    Supported by the National Natural Science Foundation of China(31370542);the National Basic Research Program (973 Program)(2013CBA01807);the Innovation Team Project of Education Office of Sichuan Province(14TD0049);the Fundamental Research Funds for the Central Universities(2018NZD13)

摘要:

该文以川西北高寒草甸为研究对象, 采用微根管法研究了不同施氮(N)水平下高寒草甸植物群落根系现存量、生产量、死亡量和周转率的变化及其与土壤理化性质的相互关系。结果表明: N添加显著增加了土壤速效氮(AN)含量, 降低了土壤pH值, 但是对土壤有机质(SOM)和全氮(TN)含量无显著影响。在0-10 cm土层, 平均根系现存量和累积根系生产量无显著变化, 累积根系死亡量在N10处理下显著降低了206.1 g·m -2, 根系周转率在N30处理下显著提高了17%; 在10-20 cm土层, N添加处理的平均根系现存量和累积根系生产量分别显著降低了195.3和142.3 g·m -2 (N10)、235.8和212.1 g·m -2 (N20)、198.0和204.4 g·m -2 (N30), 累积根系死亡量和周转率无显著变化。此外, 累积根系生产量、死亡量和周转率与AN含量相关性较大, 而平均根系现存量与SOM、AN和TN含量相关性较大。综上所述, N添加对高寒草甸的影响主要通过改变土壤可利用N含量, 进而影响根系的动态特征、空间分布格局和周转以及碳分配特征。

关键词: 高寒草甸, 氮肥添加, 植物根系, 微根管法

Abstract:

Aims Our aim was to characterize the effects of nitrogen (N) addition on plant root standing crop, production, mortality and turnover in an alpine meadow on the Northwestern plateau of Sichuan Province, China.

Methods A N addition experiment was conducted in an alpine meadow on the Northwestern plateau of Sichuan Province since 2012. Urea was applied at four levels: 0, 10, 20 and 30 g·m -2·a -1, referred to as CK, N10, N20 and N30. Root samples in surface (0-10 cm) and subsurface layers (10-20 cm) were observed using Minirhizotron from May 10th to Sept. 27th in 2015. The root standing crop, production, mortality and turnover rate were estimated using WinRHZIO Tron MF software. Repeated-measure ANOVA, one-way ANOVA and Pearson correlation were performed to analyze the effect of N addition on soil and root characteristics.

Important findings N addition significantly increased soil available N content and decreased soil pH value, but did not alter soil total N and SOM contents under all treatments. N addition did not exhibit any significant effects on the mean root standing crop and cumulative root production in the 0-10 cm, but significantly reduced mean root standing crop and cumulative root production in 10-20 cm soil layer by 195.3 and 142.3 g·m -2 (N10), 235.8 and 212.1 g·m -2 (N20) and 198.0 and 204.4 g·m -2(N30), respectively. The cumulative root mortality was significantly decreased by 206.1 g·m -2in N10 treatment and root turnover rate was significantly increased with 17% for N30 treatment at the 0-10 cm soil depth, but the cumulative root mortality and root turnover rate was not significantly different at 10-20 cm soil depth. In addition, cumulative root production, mortality and turnover rate in 0-10 cm soil layer were significantly correlated with the soil available N content, whereas no significant associations were observed in 10-20 cm soil. Taken together, these results demonstrate that N addition alters the soil N availability and thus induces the root dynamics and changes in root distribution as well as C allocation in alpine meadow.

Key words: alpine meadow, nitrogen addition, plant roots, minirhizotron