广西植物Issue(1)：61-68,8.DOI:10.11931/guihaia.gxzw201308024
南亚热带森林土壤有机碳组分对模拟酸雨的早期响应
Effects of simulated acid rain on soil organic carbon fractions in southern subtropical forests
摘要
Abstract
Soil carbon cycling is one of the important links in soil ecosystem,while the soil ecosystem is the final ac-ceptor of the acid rain.Thus,the acid rain will have dramatic impacts on the stability of soil organic carbon and even the forest soil carbon cycling.Soil is also the largest carbon pool in terrestrial ecosystem,and stores approximately 1 500 Pg of C in the upper meter of soil.Even a small change of the contents can result in a significant consequence on carbon cycling in forest.The readily oxidation organic carbon (ROC),as one of the liable soil organic carbon frac-tions,is more sensitive to environmental changes and its turnover rate is faster than other stable soil organic carbon. Consequently,ROC is considered as an early indicator of changes in total soil organic carbon (TOC).However,there have been very few studies on the fractions of soil organic carbon (liable and stable organic carbon)in response to the acid rain at home and abroad,despite the fact that acid rain has recently become a serious environmental threat in this region.In this paper,four gradients of simulated acid rain (SAR)treatments were designed[control (natural lake wa-ter,pH4.5±0.3),pH4.0,pH3.5,pH3.0]to investigate the effects of simulated acid rain on soil organic carbon frac-tions,including total soil organic carbon,readily oxidation organic carbon and non-readily oxidation organic carbon (NROC),in three forests[i.e.a pine forest (PF),a mixed conifer and broadleaf forest (MF)and broadleaved forest (BF)]of Dinghushan Biosphere Reserve in southern China.The acidic solutions were used a mixture of H2 SO4 and HNO3 in a 1∶1 mole ratio to the natural lake water.Results showed that ROC,NROC and TOC in the topsoil (0-20 cm)varied with types of forest:MF >BF>PF.After 25 months’SAR treatments,the pH values in the forest topsoil reduced gradually with the increase of acidity,and presented a trend toward increasing soil acidification with SAR.This phenomenon was in consistent with results from other researchers at Dinghushan Nature Reserve.Mean-while,the concentrations of ROC in BF (7.14 g·kg-1 for CK,8.29 g·kg-1 for pH4.0,8.74 g·kg-1 for pH 3.5,9.84 g ·kg-1 for pH3.0),MF (8.58 g·kg-1 for CK,8.53 g·kg-1 for pH4.0,10.28 g·kg-1 for 3.5,10.36 g·kg-1 for pH3.0) and PF (3.90 g·kg-1 for CK,4.49 g·kg-1 for pH4.0,4.74 g·kg-1 for pH3.5,5.48 g·kg-1 for pH3.0),which indica-ted ROC increased gradually with the decrease of treatment pH value in all forests.Meanwhile,the percentage of ROC to total soil organic carbon was also increased.However,due to the relative stability of soil total organic carbon, the concentrations of TOC and NROC were not significantly different among the four treatments in all forests (P>0.05).The results indicated that the ROC was more sensitive to long-term acid rain treatment,and would have nega-tive effects on the accumulation of soil organic carbon.However,more long-term investigations are needed in order to validate the role of acid rain on soil organic carbon storage.关键词
南亚热带森林/模拟酸雨/有机碳组分/土壤酸化Key words
southern subtropical forests/simulated acid rain (SAR)/soil organic carbon fractions/soil acidification分类
农业科技引用本文复制引用
吴建平,陈小梅,褚国伟,熊鑫,周国逸,张德强..南亚热带森林土壤有机碳组分对模拟酸雨的早期响应[J].广西植物,2015,(1):61-68,8.基金项目
国家重点基础研究发展计划(973)项目(2009CB421101) （973）
中国科学院战略性先导科技专项(XDA05050205) （XDA05050205）
