鼎湖山季风常绿阔叶林土壤微生物量碳和有机碳对模拟酸雨的响应  

Effects of simulated acid rain on soil microbial biomass carbon and total organic carbon in a monsoon evergreen broadleaved forest at the Dinghushan Nature Reserve

作　　者：吴建平[1,2] 梁国华[1,2,3] 熊鑫[1,2] 褚国伟[1] 周国逸[1] 张德强[1] 

机构地区：[1]中国科学院华南植物园,广州510650 [2]中国科学院大学,北京100049 [3]华南农业大学,广州510642

出　　处：《生态学报》2015年第20期6686-6693,共8页Acta Ecologica Sinica

基　　金：中国科学院战略性先导科技专项(XDA05050205)

摘　　要：在鼎湖山季风常绿阔叶林设置人工模拟酸雨实验,研究土壤总有机碳含量、微生物量碳含量、土壤p H值和土壤呼吸速率几个指标对不同酸处理梯度(CK:p H值4.5的天然湖水;T1:p H值4.0;T2:p H值3.5;T3:p H值3.0)的响应。结果表明,在模拟酸雨的持续作用下,样地土壤酸化有加剧趋势。2011年的6月(CK:(603.76±46.18)mg/kg,T1:(565.41±44.48)mg/kg,T2:(521.58±30.92)mg/kg,T3:(509.49±19.40)mg/kg)、12月(CK:(488.92±22.71)mg/kg,T1:(379.65±49.46)mg/kg,T2:(346.08±33.81)mg/kg,T3:(318.00±52.35)mg/kg)和2012年6月(CK:(540.48±39.11)mg/kg,T1:(492.30±43.15)mg/kg,T2:(489.65±51.39)mg/kg,T3:(428.53±49.66)mg/kg)3次测定的土壤微生物量碳含量有随模拟酸雨强度增加而显著降低的趋势,高强度的酸处理T3显著低于CK值(P<0.05);土壤呼吸速率在各处理中的响应与土壤微生物量碳含量变化一致。由于旱季和湿季的土壤温湿度相差较大,以上各指标在旱湿两季的差异明显,表现为湿季大于旱季。由于土壤总有机碳含量变化缓慢,其在各酸梯度处理下无显著差异(P>0.05)。以上结果显示,长期酸雨作用使土壤酸化不断加剧,并降低了土壤微生物量碳的含量,抑制了土壤的呼吸速率,有利于土壤碳的累积,但对土壤总有机碳的影响仍需长期实验研究。Soil is not only a pivotal link connecting the atmosphere,hydrosphere,biosphere,and lithosphere,but also an important component of carbon cycling. Meanwhile, soil is the largest carbon pool in terrestrial ecosystems, with approximately 1500 Pg of C stored in the upper meter of soil. Even small changes in forest soil composition can result in significant consequences for carbon cycling. Soil organic carbon is easily affected by environmental conditions and its stability plays an important role in forest soil. Although soil microbial biomass carbon（ SMBC）,one of the soil organiccarbon fractions,accounts for only a small fraction of soil total organic carbon（ TOC）,it is more sensitive to environmental change and its turnover rate is faster than that of TOC. Consequently,SMBC is considered an early indicator of changes to TOC. Many studies of SMBC and TOC responses to acid rain have been carried out in temperate forests in developed countries such as Europe and the United States. However,very few such studies have been carried out in the subtropical forests of southern China,despite the fact that acid rain is a serious environmental threat in this region. We conducted a field experiment to simulate acid rain（ SAR） in a monsoon evergreen broadleaved forest（ BF） in the Dinghushan Nature Reserve of southern China. We investigated the responses of SMBC,TOC,soil p H,and soil respiration rate to SAR. The SAR treatments included control（ CK,p H ≈ 4. 5; natural lake water）,T1（ p H = 4. 0）,T2（ p H = 3. 5）,and T3（ p H =3. 0）. The acidic solutions consisted of H2SO4 and HNO3（ 1∶ 1 mole ratio） in natural lake water. Results showed that p H values of forest topsoil decreased gradually with the increase of acidity,indicating increased soil acidification due to SAR.This phenomenon was consistent with results from other studies conducted at the Dinghushan Nature Reserve. Concentrations of SMBC in June 2011（（ 603. 76 ± 46. 18） mg / kg for CK,（ 565. 41 ± 44. 48） mg / kg for T1,（ 52

关 键 词：模拟酸雨 土壤酸化 土壤微生物量碳 土壤有机碳 

分 类 号：S714.3[农业科学—林学] X517[环境科学与工程—环境工程]