植物生态学报 ›› 2024, Vol. 48 ›› Issue (9): 1232-1242.DOI: 10.17521/cjpe.2023.0272  cstr: 32100.14.cjpe.2023.0272

• 研究论文 • 上一篇    

增温和氮磷添加对亚热带森林凋落物溶解有机碳生物可降解性的影响

冉佳鑫1,2, 张宇辉1,2, 王云1,2, 杨智杰1,2, 毛超1,2,*()()   

  1. 1福建师范大学地理科学学院, 福州 350117
    2福建三明森林生态系统国家野外科学观测研究站, 福建三明 365002
  • 收稿日期:2023-09-22 接受日期:2024-02-07 出版日期:2024-09-20 发布日期:2024-02-18
  • 通讯作者: 毛超(maochao@fjnu.edu.cn)
  • 基金资助:
    国家自然科学基金(31930071);国家自然科学基金(32201354)

Effects of warming and nitrogen and phosphorus addition on dissolved organic carbon biodegradability of litter in a subtropical forest

RAN Jia-Xin1,2, ZHANG Yu-Hui1,2, WANG Yun1,2, YANG Zhi-Jie1,2, MAO Chao1,2,*()()   

  1. 1School of Geographical Science, Fujian Normal University, Fuzhou 350117, China
    2Sanming Forest Ecosystem National Observation and Research Station, Sanming, Fujian 365002, China
  • Received:2023-09-22 Accepted:2024-02-07 Online:2024-09-20 Published:2024-02-18
  • Contact: MAO Chao (maochao@fjnu.edu.cn)
  • Supported by:
    National Natural Science Foundation of China(31930071);National Natural Science Foundation of China(32201354)

摘要:

凋落物源溶解有机碳(DOC)是森林土壤DOC的重要来源, 其生物降解性的大小会影响土壤有机碳的固定和损失。关注气候变暖、氮磷养分输入量增加等因子对DOC生物降解性的影响, 有助于深入理解全球变化背景下森林土壤有机碳的形成和稳定。该研究依托亚热带常绿阔叶林野外增温实验平台, 以分解0天(未分解)和180天(分解中后期)的格氏栲(Castanopsis kawakamii)的叶片凋落物为研究对象, 探究增温和氮磷添加及其交互作用对不同分解阶段的凋落物源DOC生物可降解性(BDOC)及相应的光谱指标变化量(ΔDOC光谱指标)的影响。结果表明: (1)凋落物BDOC随凋落物分解逐渐降低, 分解中后期较未分解阶段减少了22.6%。(2)增温显著提高未分解凋落物的BDOC, 但未显著影响分解中后期的BDOC。同时, 增温也显著增加了未分解阶段的ΔDOC光谱指标, 且未显著影响分解中后期的ΔDOC光谱指标。(3)氮添加显著降低了未分解阶段的BDOC, 但提高了分解中后期的BDOC。与BDOC不同, 氮添加均未显著影响两个分解阶段的ΔDOC光谱指标。(4)磷添加不仅显著提高未分解和分解中后期凋落物BDOC, 也显著增加了两个阶段的ΔDOC光谱指标。(5)增温和氮磷添加对凋落物BDOC和ΔDOC光谱指标均存在显著交互作用。总之, 增温和磷添加均会加速未分解凋落物源DOC的降解, 而分解中后期凋落物源DOC的降解主要受氮磷养分含量的影响。

关键词: 增温, 氮添加, 磷添加, 亚热带森林, 凋落物, 溶解有机碳生物可降解性, 格氏栲

Abstract:

Aims The biodegradability of dissolved organic carbon (DOC) is crucial to affect the amount of soil organic carbon in forest ecosystems as litter-derived DOC is one of the important sources of soil DOC. To further understand the formation and stability of forest soil organic carbon under climate change scenarios, it is essential to focus on the effects of climate warming and nutrient addition on the biodegradability of DOC (BDOC).

Methods Based on a manipulative soil warming experiment in a subtropical evergreen broadleaf forest, we took leaf litter of Castanopsis kawakamii with 0-day decomposition (undecomposed stage) and 180-day decomposition (middle-late stage of decomposition) as research materials. We experimentally quantified the effects of warming and nitrogen and phosphorus addition and their interactions on the BDOC of litter and the corresponding variation in ultraviolet-visible spectral index (ΔDOC spectral index) at different decomposition stages.

Important findings The results showed that: (1) the BDOC decreased gradually with litter decomposition, with a 22.6% reduction at the middle-late stage of decomposition compared to the undecomposed stage. (2) Warming significantly enhanced the BDOC at undecomposed stage while had no significant effects at the middle-late stage. Similarly, warming significantly increased the ΔDOC spectral index of undecomposed litter, but not at the milled-late stage. (3) Nitrogen addition significantly decreased BDOC at undecomposed stage but increased it at the middle-late stage. However, nitrogen addition did not change ΔDOC spectrum index at both decomposition stages. (4) Phosphorus addition significantly enhanced BDOC and ΔDOC spectrum index at both decomposition stages. (5) The interaction between warming and nutrient addition also had significant effects on increasing BDOC and ΔDOC spectrum index. Overall, both warming and phosphorus addition accelerated the degradation of DOC derived from undecomposed litter, while the degradation of DOC derived from middle-late decomposed litter was mainly regulated by nutrient contents.

Key words: warming, nitrogen addition, phosphorus addition, subtropical forest, litter, dissolved organic carbon biodegradability, Castanopsis kawakamii