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南亚热带不同演替阶段森林土壤呼吸对模拟酸雨的响应

梁国华1,吴建平2,3,熊鑫2,3,吴小映1,褚国伟2,周国逸2,曾任森1,张德强2*   

  1. (1华南农业大学, 广州 510642; 2中国科学院华南植物园, 广州 510650; 3中国科学院大学, 北京 100049)
  • 出版日期:2016-01-10 发布日期:2016-01-10

Response of soil respiration to simulated acid rain in three successional subtropical forests in southern China.

LIANG Guo-hua1, WU Jian-ping2,3, XIONG Xin2,3, WU Xiao-ying1, CHU Guo-wei2, ZHOU Guo-yi2, ZENG Ren-sen1, ZHANG De-qiang2*   

  1. (1 South China Agricultural University, Guangzhou 510642, China; 2 South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China; 3 University of Chinese Academy of Sciences, Beijing 100049, China)
  • Online:2016-01-10 Published:2016-01-10

摘要: 以鼎湖山不同演替阶段的3种森林类型(马尾松针叶林、针阔叶混交林和季风常绿阔叶林)为研究对象,2009年6月开始,在森林里喷施不同处理水平的模拟酸雨(对照(pH 4.5的天然湖水)、T1(pH 4.0)、T2(pH 3.5)和T3(pH 3.0)),2012年4月—2013年3月对模拟酸雨下土壤呼吸速率及其相关影响因子进行观测,试图揭示南亚热带不同演替阶段森林土壤呼吸对酸雨的响应规律及机制。结果表明:模拟酸雨抑制了森林土壤呼吸,但抑制作用随森林演替阶段、观测季节和处理水平的不同而不同;模拟酸雨没有显著影响松林的土壤呼吸,但却显著地抑制了阔叶林土壤呼吸(P<0.05),同时在一定程度上抑制了混交林土壤呼吸(P=0.10);与对照相比,阔叶林T1、T2和T3处理的年平均土壤呼吸速率分别下降了0.1%、10.5%和17.1%,混交林为-1.7%、8.1%和13.9%,而松林则为1.1%、1.9%和8.1%;3个林型土壤呼吸对模拟酸雨的响应敏感性随森林的顺行演替而增强。但模拟酸雨对土壤呼吸的抑制作用具有季节差异性,抑制作用只在湿季达到显著差异,且只有强酸处理T3显著抑制了土壤呼吸。模拟酸雨对土壤呼吸的抑制作用与其胁迫下土壤酸化而导致土壤微生物活性下降有关,这种下降程度也大体上随森林的顺行演替而增强。

关键词: 澜沧江, 跳跃变异, 统计试验, 水文时间序列, 气候变化

Abstract: Soil respiration in forest is a key process that underlies our understanding of the terrestrial carbon cycle, and therefore, its response to acid rain is an increasing concern. Here, we investigated this issue in three subtropical forests of different successional stages \[i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an oldgrowth broadleaved forest (BF)\] at the Dinghushan Nature Reserve in southern China. Simulated acid rain was applied semimonthly from June 2009. Soil respiration was measured under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, pH 4.0; T2, pH 3.5; and T3, pH 3.0) from April 2012 to March 2013. Generally, SAR reduced soil respiration in the forests, but this reduction varied with forest type, SAR application level, and measurement season. The repeated measures ANOVA showed that SAR did not affect soil respiration in the PF (P>0.05), but it significantly reduced soil respiration in the BF (P<0.05) and the reduction was marginally significant in the MF (P=0.10). Compared with the CK, mean annual soil respiration in treatments T1, T2, and T3 was reduced by 0.1%, 10.5%, and 17.1% in the BF, -1.7%, 8.1%, and 13.9% in the MF, and 1.1%, 1.9%, and 8.1% in the PF, respectively. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive succession of forests. In the BF, there were no significant differences among the CK, T1, and T2 treatments, while the T3 treatment was significantly lower than the CK and T1 treatments (P<0.05). These negative effects were evident in the warmwet season (P<0.05), but not in the cooldry one. The depression of soil respiration in the MF and the BF was related to the reduction of microbial activity caused by soil acidification under the SAR. Moreover, consistent with the situation of soil respiration, the response sensitivity of soil acidification and the reduction of microbial activity showed an increasing trend with the progressive succession of forests.

Key words: climate change., statistical experiment, Lancang River, abrupt change, hydrological time series