摘要:酸沉降造成的土壤持续酸化对毛竹林生态系统碳循环具有重要的影响，为量化酸沉降我国亚热带毛竹林土壤的影响，于2016年在浙江省杭州临安天目山国家级自然保护区毛竹林持续开展了2年野外模拟酸雨淋溶土壤实验，设置pH 4.0（T1）和pH 2.0（T2）两个模拟酸雨处理，以pH 5.8天然湖水为对照（CK），分析酸雨作用下土壤CO₂排放及土壤微生物多样性的变化趋势，并明确毛竹林土壤呼吸、土壤微生物及土壤理化性质三者之间的关系。结果表明：土壤呼吸速率在酸雨作用下经过缓冲期后呈现先促进后抑制的变化，作用强度表现为：T2>T1。不同处理的土壤呼吸对温度的敏感性由高到低依次是：T2、CK、T1。PCR-DGGE分析表明，模拟酸雨改变了土壤微生物菌群结构，T2处理抑制了土壤细菌的多样性和丰富度，而T1处理对土壤真菌多样性和丰富度具有促进作用。土壤pH值、有效钾、可溶有机碳、微生物量碳、碱解氮和有效磷对土壤微生物群落结构及土壤呼吸具有显著的影响（P<0.05）。综上所述，模拟酸雨能够显著抑制毛竹林的土壤呼吸，并改变土壤微生物群落结构及多样性，这些结果为进一步研究毛竹林土壤生态系统对环境问题响应机制提供理论基础。



Abstract:Acid rain is an important phenomena in global climate change and it can strongly influence forest ecology. Many studies have shown the impacts of acid rain on soil respiration, but the results are very different due to the different species and environmental conditions. The persistent acidification of soil caused by acid rain has an important impact on the carbon cycle of the Moso bamboo forest ecosystem. To quantify the effect of acid rain on the soil ecosystem of Moso bamboo forest in subtropical China, the experiment of soil by simulated acid rain in the field was carried out for two years of 2016-2018. Two treatments of the simulated acid rain with pH value of 4.0 (T1) and 2.0 (T2) were set, at the same time taking pH value of 5.8 (CK) as control. The relationship between soil CO₂ emission and soil microbial diversity in the Moso bamboo forest of Tianmu Mountain National Nature Reserve under the simulated acid rain was analyzed, and the relationship between soil respiration, soil microbial and soil physical and chemical properties in subtropical Moso bamboo forest was determined. The results showed that soil respiration rate increased firstly and then decreased after the buffer period under the action of acid rain, and the intensity of the action was T2>T1. The sensitivity of soil respiration to temperature in different treatments from high to low was T2, CK, T1, and increased seasonally with increasing temperature. PCR-DGGE analysis showed that strong acid rain treatment inhibited the growth of soil bacterial community and the order of soil bacteria diversity and richness from high to low was CK, T1, and T2. The weak acid rain had a positive effect on the diversity and abundance of soil fungi, and the opposite was strong acid rain. The effects of acid rain resulted in the decrease or disappearance of Bacillus, Caulobacter, Cystobacteraceae, Bradyrhizobium and Candida, as well as inhibiting soil respiration, while Carnobacterium, Propionibacterium, and Clostridium played greater roles in soil respiration under the simulated acid rain. Soil pH, available potassium, soluble organic carbon and microbial biomass carbon were closely and positively correlated with the soil microbial community structure under simulated acid rain treatment, while alkali nitrogen and available phosphorus were negatively correlated with the soil microbial community structure. In general, simulated acid rain can significantly inhibit soil respiration in Moso bamboo forests, and change soil microbial community structure and diversity. These results provide theoretical basis for further study on the response mechanism of soil ecosystem of Moso bamboo forest to environmental problems.





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