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林业科学 ›› 2026, Vol. 62 ›› Issue (3): 61-73.doi: 10.11707/j.1001-7488.LYKX20250050

• 研究论文 • 上一篇    下一篇

杉木纯林林下补植模式对土壤质量和微生物群落的影响

胡宇欣1,2,江怡航1,刘振华3,朱光玉4,张建国1,张雄清1,2,*()   

  1. 1. 中国林业科学研究院林业研究所 林木资源高效生产全国重点实验室 国家林业和草原局林木培育重点实验室 北京 100091
    2. 南京林业大学南方现代林业协同创新中心 南京 210037
    3. 湖南省林业科学院 长沙 410004
    4. 中南林业科技大学 长沙 410004
  • 收稿日期:2025-02-02 修回日期:2025-10-28 出版日期:2026-03-15 发布日期:2026-03-12
  • 通讯作者: 张雄清 E-mail:xqzhang85@caf.ac.cn
  • 基金资助:
    国家“十四五”重点研发计划项目(2021YFD2201304)。

Effects of Understory Enrichment Planting Modes in Pure Chinese fir Forests on Soil Quality and Microbial Communities

Yuxin Hu1,2,Yihang Jiang1,Zhenhua Liu3,Guangyu Zhu4,Jianguo Zhang1,Xiongqing Zhang1,2,*()   

  1. 1. State Key Laboratory of Efficient Production of Forest Resources Key Laboratory of Tree Breeding and Cultivation of the National Forestry and Grassland Administration Research Institute of Forestry, Chinese Academy of Forestry Beijing 100091
    2. Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University Nanjing 210037
    3. Hunan Academy of Forestry Changsha 410004
    4. Central South University of Forestry and Technology Changsha 410004
  • Received:2025-02-02 Revised:2025-10-28 Online:2026-03-15 Published:2026-03-12
  • Contact: Xiongqing Zhang E-mail:xqzhang85@caf.ac.cn

摘要:

目的: 构建杉阔复层异龄混交林,评估不同林下补植模式的土壤质量变化,筛选适宜的林下补植模式,为杉木人工林土壤健康维护和可持续经营提供科学依据。方法: 在1998年营建的杉木人工林中,2014年进行第3次间伐(平均保留密度225株·hm–2),2015年设置杉木纯林对照(M0)、仅补植闽楠(M1)、补植闽楠和红豆杉(M2)、补植闽楠和红豆杉及木荷(M3)4种林下补植模式,杉木与补植树种的株数比例均为3∶7;在补植7年后的2022年,采集0~60 cm土层深度的土样,测定化学性质、胞外酶活性和细菌群落特征(16S rRNA)。选取最小数据集建立土壤质量指数(SQI)模型,采用方差分解量化生物因素(酶活性、微生物代谢限制和群落结构)和非生物因素(化学性质及其计量比)对土壤质量的贡献率,并通过结构方程模型解析“林下补植模式?土壤质量指数”之间的关系。结果: 与纯林M0相比,经林下补植形成的杉阔复层异龄混交林(M1、M2、M3)可显著改善土壤质量和微生物群落生态功能,0~20 cm土层的全氮、全磷、碱解氮、有效钾、土壤有机碳等关键养分含量提升29.87%~72.62%,其中M2的0~20 cm土层各指标增幅最大。林下补植通过优化土壤酶活性驱动碳氮磷循环,M1的土壤蔗糖酶活性、葡萄糖苷酶活性和M3的脲酶活性在0~20 cm土层达到峰值,而纯林的酸性磷酸酶活性、过氧化氢酶活性较高,反映出分解代谢路径的差异。M2的微生物磷限制平均值较纯林下降12.05%,并通过提升0~20 cm土层的氮水解酶相对活性和缓解40~60 cm土层的微生物碳限制优化养分利用策略。微生物群落分析显示,营建的复层异龄混交林可显著提高土壤微生物的Shannon多样性指数,改变酸杆菌门、变形菌门等功能菌群丰度。林下补植模式通过调控全磷(路径系数0.68)、氮磷比(0.71)及SOC(0.33)、pH值(0.34)、氮水解酶活性(0.17)和土壤微生物Shannon多样性(0.60)间接影响土壤质量。3种林下补植模式的土壤质量指数均优于纯林,其中M2的0~20 cm土层的土壤质量最高,纯林的40~60 cm土层的土壤质量最低。结论: 通过在杉木人工纯林林下补植乡土树种形成的杉阔复层异龄混交林,能够提升土壤养分水平、平衡化学计量限制、优化酶活性和微生物群落多样性,改善土壤质量,其中林下补植闽楠和红豆杉改造模式的土壤改良作用最为突出。

关键词: 杉木人工林, 杉阔混交林, 土壤质量, 土壤酶活性, 土壤微生物群落

Abstract:

Objective: To address ecological issues such as soil degradation caused by long-term continuous monoculture of Cunninghamia lanceolata (Chinese fir), it is necessary to establish and transform plantations into multi-layered, uneven-aged mixed forests of Chinese fir and broadleaved species to enhance the sustainability of forest ecosystems. This study evaluated changes in soil quality under different understory enrichment planting modes of native tree species, aiming to identify suitable understory enrichment planting modes and provide a scientific basis for maintaining soil health and sustainable management of Chinese fir plantations. Method: In a Chinese fir plantation established in 1998, the third thinning was conducted in 2014 (retaining an average density of 225 tree·hm–2). In 2015, four understory enrichment planting modes were conducted: a pure plantation served as the control without thinning or planting (M0), understory replanting of Phoebe bournei only (M1), understory replanting of Phoebe bournei and Taxus wallichiana var. chinensis (M2), and understory replanting of P. bournei, T. wallichiana var. chinensis, and Schima superba (M3). The proportion of Chinese fir to understory planted species was 3∶7 in all modes. In 2022, seven years after understory replanting, soil samples were collected from 0–60 cm depth to determine chemical properties, extracellular enzyme activities, and bacterial community characteristics (16S rRNA). A minimum data set (MDS) was selected to establish a soil quality index (SQI) model. Variance partitioning analysis (VPA) was used to quantify the contributions of biotic factors (enzyme activities, microbial metabolic limitations, and community structure) and abiotic factors (chemical properties and stoichiometric ratios) to soil quality. Structural equation model (SEM) was applied to analyze the relationships among “understory replanting mode–soil quality index”. Result: Compared with the pure plantation (M0), the multi-layered uneven-aged Chinese fir and broad-leaved species mixed forests (M1, M2, M3) formed by understory replanting significantly improved soil quality and microbial ecological functions. The content of key nutrients in the 0–20 cm soil layer, including total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available potassium (AK), and soil organic carbon (SOC), increased by 29.87%–72.62%, with the greatest improvements observed in M2. Understory enrichment planting drove carbon, nitrogen, and phosphorus cycling by optimizing soil enzyme activities. The soil sucrase (SUC) activity and glucosidase (GLU) activity of M1, and urease (URE) activity of M3 reached their peak in the 0–20 cm layer. In contrast, the pure plantation had higher acid phosphatase (ACP) and catalase (CAT) activities, reflecting differences in catabolic pathways. The average microbial phosphorus limitation in M2 decreased by 12.05% compared with the pure plantation. Additionally, M2 optimized nutrient utilization strategies by enhancing the relative activity of nitrogen hydrolase (RAN) in the 0–20 cm layer and alleviating microbial carbon limitation in the 40–60 cm layer. Microbial community analysis revealed that the established multi-layered uneven-aged mixed forests significantly increased the Shannon diversity index of soil microorganisms and altered the abundance of functional bacterial phyla such as Acidobacteriota and Proteobacteria. Understory enrichment planting modes indirectly affected soil quality by regulating total phosphorus (path coefficient: 0.68), nitrogen-to-phosphorus ratio (0.71), SOC (0.33), pH (0.34), nitrogen hydrolase activity (0.17), and soil microbial Shannon diversity (0.60). The SQI values of the three understory enrichment planting modes were higher than that of the pure plantation, with M2 exhibiting the highest soil quality in the 0–20 cm layer and the pure plantation showing the lowest soil quality in the 40–60 cm layer. Conclusion: Transforming pure Chinese fir plantations into multi-layered uneven-aged mixed forests by understory replanting native broadleaved species can enhance soil nutrient levels, balance stoichiometric limitations, optimize enzyme activities and microbial diversity, and improve overall soil quality. Among them, understory replanting of P. bournei and T. wallichiana var. chinensis (M2) demonstrates the most significant soil improvement effects. These findings provide a theoretical basis for the sustainable management of Chinese fir plantations.

Key words: Chinese fir plantation, Chinese fir-broadleaf mixed forest, soil quality, soil enzyme activity, soil microbial community

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