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应用生态学报 ›› 2019, Vol. 30 ›› Issue (9): 2923-2932.doi: 10.13287/j.1001-9332.201909.011

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凋落物去除和氮添加对亚热带阔叶林土壤不同组分碳、氮的影响

吴越, 马红亮*, 尹云锋, 高人, 王梦思, 杨柳明   

  1. 福建师范大学湿润亚热带山地生态国家重点实验室培育基地/福建师范大学地理科学学院, 福州 350007
  • 收稿日期:2019-04-22 出版日期:2019-09-15 发布日期:2019-09-15
  • 通讯作者: * E-mail: mhl936@163. com
  • 作者简介:吴越,男,1993年生,硕士研究生.主要从事土壤碳氮和森林生态研究.E-mail:877179760@qq.com
  • 基金资助:
    国家自然科学基金项目(31770659,31570607)和福建省自然科学基金项目(2018J01716)资助

Effects of litter removal and nitrogen addition on carbon and nitrogen in different soil fractions in a subtropical broad-leaved forest.

WU Yue, MA Hong-liang*, YIN Yun-feng, GAO ren, WANG Meng-si, YANG Liu-ming   

  1. Cultivation Base of State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, Fujian Normal University/School of Geographical Science, Fujian Normal University, Fuzhou 350007, China
  • Received:2019-04-22 Online:2019-09-15 Published:2019-09-15
  • Contact: * E-mail: mhl936@163. com
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (31770659, 31570607) and the Natural Science Foundation Project of Fujian Province (2018J01716)

摘要: 人类活动显著增加了氮沉降,对森林生态系统产生了不同程度的影响;凋落物在其分解过程中输入的大量有机碳、氮也会影响土壤碳氮的形成、稳定及转化.本研究选择亚热带常绿阔叶林,对样地进行8年氮添加[对照(0)、低氮(75 kg·hm-2·a-1)、高氮(150 kg·hm-2·a-1)]和控制凋落物处理(保留凋落物、去除凋落物),之后采集土壤样品,通过K2SO4、Na2B4O7、Na4P2O7、NaOH、H2SO4、Na2S2O4、HF等化学试剂逐级浸提土壤,测定各浸提液和残渣中的碳、氮含量,研究凋落物及氮添加对土壤矿物结合态碳、氮的影响.结果表明: 整体上,胡敏素(humin,H)组分的土壤碳、氮含量均为最高,分别占土壤全量的33.5%和33.3%.Na2B4O7溶液提取的土壤可溶性碳、氮含量最高,其次是NaOH和Na4P2O7溶液,3种试剂提取的土壤可溶性总碳、可溶性总氮以及可溶性有机氮分别占提取总量的46.2%、47.9%和76.5%.与对照相比,氮添加增加了Na2S2O4和H组分碳、氮含量;与保留凋落物比较,去除凋落物降低了Na2B4O7、H2SO4、Na2S2O4和H组分的碳含量,以及NaOH、HF和H组分的氮含量.保留凋落物和氮添加显著增加了K2SO4组分氮含量.可见,保留凋落物和外源氮通过影响化学稳定性不同的土壤组分的碳氮变化来改变土壤碳氮过程.

Abstract: The increasing nitrogen deposition due to human activities has impacted forest ecosystems to a large extent. The organic carbon and nitrogen released from decomposing litters play an important role in the formation, stability and transformation of soil organic carbon and nitrogen. We collected soil samples from a subtropical evergreen broadleaved forest experiment with nitrogen deposition [control (0), LN (75 kg·hm-2·a-1), HN (150 kg·hm-2·a-1)] and litter control (litter retained and litter removal) for eight years. After extracted by solution of K2SO4, Na2B4O7, Na4P2O7, NaOH, H2SO4, Na2S2O4 and HF step by step, carbon and nitrogen in each extraction was analyzed. The results showed that overall most of soil carbon and nitrogen existed in the Humin fraction, accounting for 33.5% of the total carbon and 33.3% of the total nitrogen. The soluble total carbon and nitrogen extracted by Na2B4O7 solution was the highest, followed by NaOH and Na4P2O7 solution. The soluble total carbon, soluble total nitrogen and soluble organic nitrogen of soil extracted by three reagents accounted for 46.2%, 47.9%, and 76.5% of the total extractions, respectively. In addition, nitrogen addition significantly increased carbon and nitrogen content in Na2S2O4 and Humin fractions. Litter removal reduced carbon content in Na2B4O7, H2SO4, Na2S2O4 and Humin fractions, and nitrogen content in NaOH, HF and Humin fractions. The nitrogen content in the K2SO4 extraction was significantly increased by both litter remained and nitrogen addition. Our results demonstrated that litter and nitrogen added could mutually affect carbon and nitrogen concentration of soil fractions with different chemical stability, with consequences on the process of soil carbon and nitrogen.