• 论文与研究报告 •

### 湿地松人工林土壤呼吸及其组分对模拟酸雨的响应

1. 1. 江西农业大学林学院 南昌 330045
2. 江西省水土保持科学研究院 南昌 330029
3. 江西省土壤侵蚀与防治重点实验室 南昌 330029
4. 江西师范大学 南昌 330022
5. 江西省水利规划设计研究院 南昌 330029
• 收稿日期:2020-04-10 出版日期:2021-07-25 发布日期:2021-09-02
• 通讯作者: 欧阳勋志
• 基金资助:
国家自然科学基金项目(41303064);国家自然科学基金项目(41761063);江西省水利科技重大研究项目(KT201716)

### Responses of Soil Respiration and Its Components to Simulated Acid Rain in Pinus elliottii Plantation

Huanying Fang1,2,Shengsheng Xiao2,3,Xiaofang Yu4,Yong Xiong5,Xunzhi Ouyang1,*,Xiaolei Qin2

1. 1. College of Forestry, Jiangxi Agricultural University Nanchang 330045
2. Jiangxi Institute of Soil and Water Conservation Nanchang 330029
3. Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention Nanchang 330029
4. Jiangxi Normal University Nanchang 330022
5. Jiangxi Provincial Water Conservancy Planning Design and Research Institute Nanchang 330029
• Received:2020-04-10 Online:2021-07-25 Published:2021-09-02
• Contact: Xunzhi Ouyang

Abstract:

Objective: The study was aimed to investigate the patterns of impacts of acid rain at different intensities on total soil respiration rate(Rs) and its components of soil heterotrophic respiration rate(Rh) and soil autotrophic respiration rate(Ra) in Pinus elliottii plantation, in order to improve our understandings of the process of soil respiration and further to provide a scientific basis for forest management under environmental stresses such as acid deposition. Method: We conducted a one-way factorial acid rain addition(CK: pH 6.5; low acid addition level(LA): pH 4.5; high acid addition(HA): pH 2.5, with 3 replicates) field experiment in a subtropical P. elliottii plantation in China. The trenching method was used to separate the heterotrophic and autotrophic soil respiration. From January to December of 2015, the Rs, Ra, Rh effluxes were measured twice a month using a LI-8100A automated soil CO2 flux system. Soil temperatures and soil volumetric water content and soil biochemical properties adjacent to each soil respiration points were simultaneously detected. Result: Rs, Ra, Rh showed clear seasonal dynamics with similar single peak curves in all treatments, and were mainly driven by the surface soil temperature. Compared to the Rs under CK, the Rs under LA and HA were significantly reduced by 25.83% and 30.95%(P < 0.05). Also, LA and HA treatments inhibited the Rh effluxes by 29.60% and 35.20%(P < 0.05), reduced the Ra effluxes by 19.15% and 23.40%(P < 0.05). The inhibitory effect of simulated acid addition on soil respiration rates only showed in the growing season. Ra even being promoted in non-growth season(P < 0.05). In the CK plots, Rh accounted for 63.94% in Rs, and the proportion was significantly reduced(P < 0.05) in the LA and HA treatments. The intensity of Ra increased with the enhancement of acid rain. There were significant exponential correlations between Rs, Rh, Ra and soil temperature(P < 0.01), and both addition levels of the simulated acid rain could reduce the temperature sensitivity coefficient of soil respiration. Surface soil moisture was significantly related to the total soil respiration rates and the two main components under HA treatments(P < 0.01). The combined action of soil temperature and soil moisture also had a significant impact on soi respiration(P < 0.01). The variation of Rh was mainly controlled by the activity of soil urease and soil sucrase, topsoil organic carbon(TOC) and soil pH, while the Ra rates were mainly influenced by the soil urease activity, soil temperature and TOC, and the these factors jointly contributed 83.9% to the variation of Rs. Conclusion: The seasonal characteristics of soil respiration and its main components were similar and mainly controlled by surface soil temperature. Simulated acid rain exacerbated soil acidification, and significantly changed soil enzymes and soil organic carbon, which caused the inhibitory effects of Rs mainly due to Rh and Ra, and the changes of soil hydrothermal status induced the inhibition effects more obvious in the growing season. The proportion of Rh in the total soil respiration decreased with the increase of simulated acid rain intensities, but in the short term, the Rs variation was mainly controlled by the change of Rh.