植物生态学报

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温带过渡区4种典型天然林林型土壤有机碳组分与碳库管理指数变化特征

胡璟1,吕世琪2,李 冰1,马志波3,符利勇4,殷建章1,肖玖金1,闫佳源1,胡宗达5   

  1. 1. 四川农业大学
    2. 山西文峪河国家级湿地公园管理局
    3. 中国林业科学研究院资源信息研究所, 森林生态环境与保护研究所
    4. 中国林业科学研究院
    5. 四川农业大学资源学院
  • 收稿日期:2024-09-20 修回日期:2024-12-20 发布日期:2025-01-20
  • 通讯作者: 胡宗达

Variation characteristics of soil organic carbon components and soil carbon pool management index in the top-soil from four typical natural forest types in a temperature-transition area in Western of Taiyuan City, China

Jing HU1,Shiqi LV2,Bing LI3,Zhi-bo Ma4,Liyong FU5,Jianzhang YIN3,Jiujin XIAO3,Jiayuan YAN3,Hu Zongda6   

  1. 1.
    2. National Wetland Park Management Bureau of Shanxi Wenyuhe
    3. Sichuan Agricultural University
    4. Research Institute of Forest Resource Information Techniques, Research Institute of Forest Ecology Environment and Protection, Chinese Academy of Forestry
    5. Chinese Academy of Forestry
    6. College of resources, Sichuan Agricultural University
  • Received:2024-09-20 Revised:2024-12-20
  • Contact: Hu Zongda

摘要: 探究温带过渡区典型天然林土壤有机碳组分与碳(C)库管理指数变化特征及其影响因素,对提升土壤C储量和林地质量并制定合理有效的营林管护措施具有十分重要的现实意义。以山西庞泉沟国家级自然保护区境内的白桦林(BP)、青扦+华北落叶松+桦木针阔混交林(PLB)、白扦+青扦针叶混交林(PP)和华北落叶松林(LP)等4种林型为对象,以灌草地为对照(CK),采集0–20cm土层土壤样品,分析了土壤有机碳(SOC)、可溶性有机碳(DOC)、易氧化有机碳(EOC)、微生物量碳(MBC)和惰性有机碳(ROC)以及C库管理指数(CPMI)对林型变化的响应及其影响因素。发现:(1) SOC含量为PP ? PLB ? BP ? LP,较CK分别增加了74.22%、41.62%、39.05%和3.01%;4种天然林林型的DOC、EOC、MBC和ROC变化趋势与SOC相似,但DOC和MBC含量变化不显著。(2) DOC/SOC和ROC/SOC受林型显著影响,LP的DOC/SOC和BP的ROC/SOC分别显著高于和低于其他3种天然林;其余C组分对SOC的贡献未见显著变化,均表现为PP中最低和LP中最高。(3) CPMI受林型显著影响,其变化趋势与SOC相似。冗余分析(RDA)和随机森林分析显示:全氮和硝态氮是影响C组分和CPMI的主导因素,其次是土壤含水量、有效钾和pH值。总体上,混交林尤其是针叶混交林提高了土壤C组分含量和CPMI,改善了土壤质量,有助于土壤C储存;土壤氮素、水分及土壤酸碱度在预测温带过渡区森林生态系统土壤C库变化中起着关键的作用。因此,适当增加土壤氮素和改善物种多样性可能是提高温带过渡区天然林土壤C固存的有效手段。

关键词: 林型, 土壤有机碳, 有机碳组分, 土壤碳库管理指数, 温带气候过渡带

Abstract: Aims The present study was to quantify the variation characteristics of soil organic carbon (SOC) fractions and the carbon (C) pool management index (CPMI) in the top-soil (0 ? 20cm) from the four different natural forest types in the temperate climate?transition area in Pangquangou National Nature Reserve in Shanxi Province. The study results may provide an interesting reference and valuable information for increasing soil C storage and for-estland quality, and sustainable forest management for the native forestry sectors in the future. Methods Four forest types with similar site conditions were used to study the variations and influencing factors of soil C fractions and CPMI in the top-soil layer. Here, the soil samples were collected from representative for-estlands, including Betula platyphylla forest (BP), Picea wilsonii + Larix principis-rupprechtii + Betula coni-fer-broadleaf mixed forests (PLB), P. meyeri + P.wilsonii conifer mixed forest (PP), L. principis?rupprechtii forest (LP) and scrub-grass land (CK), respectively. SOC and its fractions contents were measured, and CPMI was cal-culated. Pearson correlation and redundancy analysis (RDA) were used to examine the relationships between soil environmental factors and carbon pool characteristics. Random forest analysis (RFA) to identify the soil proper-ties significantly affecting the soil C fractions and CPMI. Important findings Different forest types associated with distinct species composition and forest structure may have varying effects on the buildup of SOC and its fractions, as well as soil C pool index (CPI) and CPMI. First, the contents of SOC were as follows: PP ? PLB ? BP ? LP, which increased by 74.22%、41.62%、39.05% and 3.01% in the top-soil layer respectively compared to CK. For soil C components, dissolved organic carbon (DOC), easily oxidizable organic carbon (EOC), microbial biomass carbon (MBC) and recalcitrant organic car-bon (ROC) contents from the different forest types followed similar trends as the concentration of SOC at the surface layer where PP recorded the maximum concentration. Here we show, MBC and DOC contents did not vary significantly among different forest types. Second, our data clearly evidenced that DOC/SOC and ROC/SOC was significantly greater and lower in LP and BP respectively than other three forest types, while EOC/SOC, MBC/SOC and AOC/SOC were stable and no significant differences were observed among four forest types where PP recorded the lowest values. Third, the variation tendency of CPMI in line with SOC, while the CPMI in LP was significantly lower than that of the other three forest types. RDA revealed that TN and NO3--N may play prominent role in the variation characteristics of soil C pools in the natural forests in the temperate climate?transition zone. Furthermore, we observed that soil water content and available potassium had a significant im-pact on soil C fractions, while the CPMI was significantly affected by soil water, pH and TP. Taken together, our findings demonstrate that both temperate mixed forests especially coniferous mixed forests promoted SOC stock by increasing C pool fractions contents, which promoted soil fertility and quality of the forest land in a temperate transition zone, and emphasize the key role of the interplay between soil nitrogen, soil water and soil pH in pre-dicting soil C pool in temperate forests. Consequently, these results should be considered by the forestry sectors, and suggest that the forest ecological restoration should promote biodiversity especially conifer species in the context of improving C stock and soil quality in temperate forests. Thus, it is predicted that increasing soil nitro-gen and species diversity may be an effective measure for improving soil C sequestration in natural forest ecosys-tem in the temperate climate?transition zone.

Key words: forest types, soil organic carbon, soil organic carbon fractions, soil carbon pool management index, temperate climate-transition zone