植物生态学报 ›› 2022, Vol. 46 ›› Issue (8): 855-870.DOI: 10.17521/cjpe.2021.0358

所属专题: 全球变化与生态系统

• 综述 •    下一篇

氮磷添加对土壤有机碳的影响: 进展与展望

冯继广1, 张秋芳1, 袁霞2, 朱彪1,*()   

  1. 1北京大学城市与环境学院, 生态研究中心, 地表过程分析与模拟教育部重点实验室, 北京 100871
    2杭州师范大学生命与环境科学学院, 杭州 311121
  • 收稿日期:2021-10-11 接受日期:2022-01-08 出版日期:2022-08-20 发布日期:2022-06-09
  • 通讯作者: *朱彪 ORCID:0000-0001-9858-7943 (biaozhu@pku.edu.cn)
  • 作者简介:冯继广 ORCID:0000-0002-7342-9313
  • 基金资助:
    国家自然科学基金(31988102);国家自然科学基金(31800437)

Effects of nitrogen and phosphorus addition on soil organic carbon: review and prospects

FENG Ji-Guang1, ZHANG Qiu-Fang1, YUAN Xia2, ZHU Biao1,*()   

  1. 1College of Urban and Environmental Sciences, Institute of Ecology, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
    2College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 311121, China
  • Received:2021-10-11 Accepted:2022-01-08 Online:2022-08-20 Published:2022-06-09
  • Contact: *ZHU Biao ORCID:0000-0001-9858-7943 (biaozhu@pku.edu.cn)
  • Supported by:
    National Natural Science Foundation of China(31988102);National Natural Science Foundation of China(31800437)

摘要:

土壤有机碳库是陆地生态系统最大的碳库, 在调控全球碳循环和气候变化中起着重要的作用。人为活动所导致的氮、磷输入和大气氮、磷沉降提高了陆地生态系统的氮、磷可利用性, 进而会通过调控植物生长和微生物活性对土壤有机碳动态产生重要影响。目前, 在全球范围内已经开展了很多氮磷添加调控土壤有机碳动态的野外控制实验, 并取得了一些突破和进展, 但还缺乏较为系统全面的梳理与总结。该文以氮磷添加对土壤碳输入和输出的影响为切入点, 从土壤有机碳的碳库大小、组分和分子组成3个方面系统阐述了氮磷添加对土壤有机碳的影响及其潜在机制。根据以往的研究结果, 氮添加、磷添加和氮磷共同添加对土壤有机碳库的影响总体上表现为促进作用。其中, 氮添加引起的促进作用是微生物对土壤有机碳的分解输出降低和/或植物碳输入增加所致, 而磷添加引起的促进作用可能主要是由于植物碳输入的增加。对于土壤有机碳组分(粒径分组或密度分组)而言, 氮添加虽然同时促进了活性有机碳组分(颗粒态有机碳或轻组分有机碳)和稳定性有机碳组分(矿物结合态有机碳或重组分有机碳), 但降低了稳定性碳组分占土壤总有机碳的比例。此外, 氮添加对土壤有机碳分子组成的影响较为复杂, 受到土壤氮有效性、氮添加量和氮形态等因素的调节。与氮添加相比, 磷添加和氮磷共同添加对土壤有机碳组分和分子组成影响的研究十分有限, 其影响机制尚不清楚。基于已有研究中存在的不足, 该文提出了未来需要加强的4个方面的研究内容: 磷添加对不同类型生态系统尤其是热带森林土壤有机碳的影响, 氮磷添加下植物和微生物在调控土壤有机碳及其组分变化中的作用与相对贡献, 长期氮磷添加及其交互作用对土壤有机碳的影响, 氮磷添加对深层土壤有机碳的影响。

关键词: 土壤有机碳, 矿物结合态有机碳, 颗粒态有机碳, 分子组成, 微生物群落结构, 密度分组, 氮沉降, 磷沉降

Abstract:

Soil organic carbon (SOC) pool is the largest carbon pool in terrestrial ecosystems and plays an important role in regulating the global carbon cycle and climate change. The inputs of nitrogen (N) and phosphorus (P) induced by anthropogenic activities and atmospheric deposition of N and P increase the availabilities of N and P in terrestrial ecosystems, which in turn will have important impacts on SOC dynamics via regulating plant growth and microbial activity. At present, many field-manipulation experiments regarding the effects of N addition and/or P addition on the dynamics of SOC have been conducted worldwide, and some breakthroughs and progress have been made, but a systematic and comprehensive review and summary of them is still lacking. By taking the effects of N addition and/or P addition on the inputs and outputs of soil carbon as the starting point, we systematically reviewed the effects of N addition and/or P addition on SOC and the potential mechanisms from three aspects: the size, fraction and molecular composition of SOC. According to the results of previous studies, N addition, P addition, and combined N and P (N + P) addition generally stimulate the size of SOC pool. The stimulation effect of N is caused by the decreased carbon outputs from microbial decomposition and/or the enhanced carbon inputs of plant above- and/or below-ground under N addition. However, the stimulation effect of P may be dominated by the enhanced carbon inputs of plant above- and/or below-ground under P addition. As for the fractions of SOC separated by particle-size or density fractionation, N addition promotes both labile fractions (particulate organic carbon or light fraction carbon) and stable fractions (mineral-associated organic carbon or heavy fraction carbon) of SOC, but reduces the proportion of stable carbon fractions to total SOC. In addition, the effects of N addition on the molecular composition of SOC are complex and diverse, and are regulated by environmental and experimental factors such as soil N availability, N addition rate, and N fertilizer form. Compared with N addition, studies on the effects of P addition and N + P addition on the fraction and molecular composition of SOC are very limited, and the associated mechanisms for the effects of P addition and N + P addition on these variables are still unclear. To improve our understanding, we propose four aspects of studies that need to be strengthened in the future, including the effects of P addition on SOC in different types of ecosystems (especially tropical forests), the role and relative contribution of plants and microorganisms in regulating the changes of SOC and its fractions under N addition and/or P addition, the effects of long-term N addition and/or P addition and their interactions on SOC, and the effects of N addition and/or P addition on SOC in deep soils (below 20 cm).

Key words: soil organic carbon, mineral-associated organic carbon, particulate organic carbon, molecular composition, microbial community structure, density fractionation, nitrogen deposition, phosphorus deposition