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应用生态学报 ›› 2022, Vol. 33 ›› Issue (10): 2611-2618.doi: 10.13287/j.1001-9332.202210.013

• 陆地生态系统固碳与增汇专栏 • 上一篇    下一篇

罗浮栲林土壤微生物碳利用效率对短期氮添加的响应

戴辉1,2, 曾泉鑫1,2, 周嘉聪1,2, 彭园珍1,2, 孙雪琦1,2, 陈静琪1,2, 陈文伟3, 陈岳民1,2*   

  1. 1福建师范大学地理科学学院, 福州 350007;
    2福建师范大学湿润亚热带生态地理过程教育部重点实验室, 福州 350007;
    3福建戴云山国家级自然保护区管理局, 福建泉州 362500
  • 收稿日期:2022-02-23 修回日期:2022-07-25 出版日期:2022-10-15 发布日期:2023-04-15
  • 通讯作者: * E-mail: ymchen@fjnu.edu.cn
  • 作者简介:戴辉, 男, 1997年生, 硕士研究生。主要从事全球变化背景下森林生态系统碳循环和土壤微生物研究。E-mail: 1807315761@qq.com
  • 基金资助:
    福建省自然科学基金项目(2020J01142,2020J01397)

Responses of soil microbial carbon use efficiency to short-term nitrogen addition in Castanopsis fabri forest

DAI Hui1,2, ZENG Quan-xin1,2, ZHOU Jia-cong1,2, PENG Yuan-zhen1,2, SUN Xue-qi1,2, CHEN Jing-qi1,2, CHEN Wen-wei3, CHEN Yueh-min1,2*   

  1. 1School of Geographical Science, Fujian Normal University, Fuzhou 350007, China;
    2Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education, Fujian Normal University, Fuzhou 350007, China;
    3Daiyun Mountain National Nature Reserve Administration Bureau, Quanzhou 362500, Fujian, China
  • Received:2022-02-23 Revised:2022-07-25 Online:2022-10-15 Published:2023-04-15

摘要: 作为调节土壤碳矿化过程的重要参数,微生物碳利用效率(CUE)对理解陆地生态系统中的碳循环至关重要。本研究在戴云山罗浮栲林设置对照(0 kg N·hm-2·a-1)、低氮(40 kg N·hm-2·a-1)和高氮(80 kg N·hm-2·a-1) 3个氮添加水平以模拟氮沉降,测定了表层(0~10 cm)土壤基本理化性质、有机碳组分、微生物生物量和酶活性;并利用18O标记水方法测定土壤微生物CUE,以更好地理解氮沉降加剧对微生物CUE的影响及其影响因素。结果表明: 短期氮添加显著降低了土壤微生物的呼吸速率、碳和氮获取酶活性,但显著增加了土壤微生物CUE。β-N-乙酰氨基酸葡糖苷酶(NAG)/微生物生物量碳(MBC)、微生物呼吸速率、β-葡萄糖苷酶(BG)/MBC、纤维素水解酶(CBH)/MBC和土壤有机碳含量是影响CUE的主要因素,且CUE与NAG/MBC、微生物呼吸速率、BG/MBC和CBH/MBC呈显著负相关,与土壤有机碳呈显著正相关。综上,短期氮添加导致土壤微生物获取碳和氮的成本降低,减少微生物呼吸,从而提高了土壤微生物CUE,这将有助于提高罗浮栲林土壤碳固存潜力。

关键词: 氮添加, 微生物碳利用效率, 土壤胞外酶, 微生物呼吸速率

Abstract: As an important parameter regulating soil carbon mineralization, microbial carbon use efficiency (CUE) is essential for the understanding of carbon (C) cycle in terrestrial ecosystems. Three nitrogen supplemental levels, including control (0 kg N·hm-2·a-1), low nitrogen (40 kg N·hm-2·a-1), and high nitrogen (80 kg N·hm-2·a-1), were set up in a Castanopsis fabri forest in the Daiyun Mountain. The basic physical and chemical properties, organic carbon fractions, microbial biomass, and enzyme activities of the soil surface layer (0-10 cm) were measured. To examine the effects of increasing N deposition on microbial CUE and its influencing factors, soil microbial CUE was measured by the 18O-labelled-water approach. The results showed that short-term N addition significantly reduced microbial respiration rate and the activities of C and N acquisition enzymes, but significantly increased soil microbial CUE. β-N-acetyl amino acid glucosidase (NAG)/microbial biomass carbon (MBC), microbial respiration rate, β-glucosidase (BG)/MBC, cellulose hydrolase (CBH)/MBC, and soil organic carbon content were the main factors affecting CUE. Moreover, CUE significantly and negatively correlated with NAG/MBC, microbial respiration rate, BG/MBC, and CBH/MBC, but significantly and positively correlated with soil organic carbon. In summary, short-term N addition reduced the cost of soil microbial acquisition of C and N and microbial respiration, and thus increased soil microbial CUE, which would increase soil carbon sequestration potential of the C. fabri forest.

Key words: nitrogen addition, microbial carbon use efficiency, soil extracellular enzyme, microbial respiration rate