亚热带四种类型森林凋落叶分解过程中土壤氮淋溶与N?O排放动态特征
Soil nitrogen turnover controlled by litter input in four subtropical forests
张名凤 1李安迪1
作者信息
- 1. 福建师范大学地理科学学院，湿润亚热带生态-地理过程教育部重点实验室，福州 350117
- 折叠
摘要
凋落物分解是森林氮循环的核心环节，但复杂林分转换及凋落物输入如何调控土壤氮的流失路径（淋溶与气态排放）仍缺乏系统认知。本研究依托原位凋落物输入微宇宙实验，以亚热带4种典型森林（45年生和9年生常绿阔叶次生林、9年生米槠人工林、9年生杉木人工林）为对象，探究了凋落叶分解一年内土壤氮淋溶（总氮、铵态氮、硝态氮）与N?O排放通量的动态特征。结果表明：短期的凋落叶输入处理对四种林型土壤的氮淋溶和N?O排放通量均无显著的直接影响，但森林类型转换从根本上重塑了土壤氮的流失格局。在水文淋失方面，天然次生林表现出更高的淋溶潜力，45年生与9年生次生林的年总氮淋溶通量（分别为12.71和13.14 g/(m2 yr)）显著高于9年生米槠人工林（7.00 g/(m2 yr)）。在气态排放方面，树种更替产生了显著差异，9年生米槠人工林土壤的N?O平均排放通量（0.15 mg/(m2 d)）显著高于9年生杉木人工林（0.04 mg/(m2 d)）。综上所述，亚热带森林土壤氮的流失特征更多受控于长期林分发育塑造的微生态环境与树种特性，而非短期的凋落物输入。天然次生林具有更为活跃的水文氮循环，而转换为人工林后，阔叶林（米槠）倾向于加剧气态氮（N?O）的排放，针叶林（杉木）则表现出极度保守的氮流失特征。本研究揭示了亚热带森林集约化经营与演替过程中的氮素周转权衡机制。
Abstract
Litter decomposition is a core link in the forest nitrogen cycle, but there is still a lack of systematic understanding of how complex stand conversion and litter input regulate the pathways of soil nitrogen loss (leaching and gaseous emissions). Based on an in-situ litter input microcosm experiment, this study took four typical subtropical forests (45-year-old and 9-year-old evergreen broad-leaved secondary forests, 9-year-old Castanopsis carlesii plantation, and 9-year-old Cunninghamia lanceolata plantation) as research objects, and explored the dynamic characteristics of soil nitrogen leaching (total nitrogen, ammonium nitrogen, nitrate nitrogen) and N?O emission flux during one year of leaf litter decomposition. The results showed that short-term leaf litter input treatment had no significant direct effect on soil nitrogen leaching and N?O emission flux in the four forest types, but forest type conversion fundamentally reshaped the pattern of soil nitrogen loss. In terms of hydrological leaching loss, natural secondary forests showed higher leaching potential; the annual total nitrogen leaching fluxes of the 45-year-old and 9-year-old secondary forests (12.71 and 13.14 g/(m2 yr), respectively) were significantly higher than that of the 9-year-old Castanopsis carlesii plantation (7.00 g/(m2 yr)). In terms of gaseous emissions, tree species replacement caused significant differences: the average soil N?O emission flux of the 9-year-old Castanopsis carlesii plantation (0.15 mg/(m2 d)) was significantly higher than that of the 9-year-old Cunninghamia lanceolata plantation (0.04 mg/(m2 d)). In summary, the characteristics of soil nitrogen loss in subtropical forests are more controlled by the microecological environment and tree species characteristics shaped by long-term stand development, rather than short-term litter input. Natural secondary forests have a more active hydrological nitrogen cycle; after conversion to plantations, broad-leaved forests (Castanopsis carlesii) tend to intensify the emission of gaseous nitrogen (N?O), while coniferous forests (Cunninghamia lanceolata) show extremely conservative nitrogen loss characteristics. This study reveals the trade-off mechanism of nitrogen turnover during the intensive management and succession of subtropical forests.关键词
土壤氮淋溶/N2O排放/凋落物分解/亚热带森林/杉木人工林Key words
soil nitrogen leaching/N?O emission/litter decomposition/subtropical forest/Cunninghamia lanceolata plantation引用本文复制引用
张名凤,李安迪.亚热带四种类型森林凋落叶分解过程中土壤氮淋溶与N?O排放动态特征[EB/OL].(2026-05-26)[2026-05-28].http://www.paper.edu.cn/releasepaper/content/202605-118.学科分类
环境科学技术现状/环境保护宣传、环境保护教育/环境管理
