植物生态学报 ›› 2021, Vol. 45 ›› Issue (8): 903-917.DOI: 10.17521/cjpe.2020.0421

• 研究论文 • 上一篇    下一篇

油松人工林火烧迹地早期土壤入渗动态

秦倩倩1, 邱聪1, 郑大柽3, 刘艳红2,*()   

  1. 1北京林业大学生态与自然保护学院, 北京 100083
    2北京林业大学森林资源生态系统过程北京市重点实验室, 北京 100083
    3北京林业大学林学院, 北京 100083
  • 收稿日期:2020-12-17 修回日期:2021-04-13 出版日期:2021-08-20 发布日期:2021-04-25
  • 通讯作者: 刘艳红
  • 作者简介:* liuyh@bjfu.edu.cn
  • 基金资助:
    国家重点研发计划(2017YFC0504004)

Soil infiltration dynamics in early period of a post-fire Pinus tabulaeformis plantation

QIN Qian-Qian1, QIU Cong1, ZHENG Da-Cheng3, LIU Yan-Hong2,*()   

  1. 1School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
    2Beijing Key Laboratory of Forest Resources and Ecosystem Process, Beijing Forestry University, Beijing 100083, China
    3College of Forestry, Beijing Forestry University, Beijing 100083, China
  • Received:2020-12-17 Revised:2021-04-13 Online:2021-08-20 Published:2021-04-25
  • Contact: LIU Yan-Hong
  • Supported by:
    National Key R&D Program of China(2017YFC0504004)

摘要:

土壤入渗是决定雨水或融水通过地表再分配给土壤的关键, 影响着森林生态水文过程。为研究北京油松(Pinus tabulaeformis)人工林火烧迹地早期土壤入渗特征及其结构性控制因素, 在火灾发生(2019年3月)的当年对火烧和对照样地的0-20 cm土壤进行为期8个月(5-12月)的采集, 测定分析土壤结构和入渗对火烧干扰的响应及随土壤深度和时间的变化, 并通过路径分析探讨火烧和土壤结构性质对土壤入渗的作用机制。结果表明: 1)土壤各结构指标(除小团聚体外)随土壤深度和时间变化总体具有浅层>深层和6-8月>其他月份的趋势。火烧改变了土壤结构原有的垂直分布特征和季节动态规律, 火烧后2个月土壤>5、2-5和1-2 mm团聚体含量和容重显著增加, 其余指标均显著减少。随土层加深和时间推移, 火烧的作用减弱, 但与土壤深度和时间变化具有明显的交互效应。2)土壤入渗特征随土壤深度变化缓慢, 但随时间变化显著, 表现为雨水较多且出现强降雨事件的8月土壤初渗速率、稳渗速率、入渗总量和饱和导水率最大。火烧后0-5 cm和6-9月的土壤入渗过程与对照相比差异较大, 各月土壤入渗特征均下降, 出现峰值时间提前1-2个月。3)火烧显著影响土壤结构性质, 而土壤入渗性主要受土壤结构性质的直接影响。在未受火烧干扰的情况下, 土壤的入渗性受到土壤团聚体、容重和持水量的正效应以及孔隙度的负效应, 有机质含量和初始含水率对入渗性的直接影响均不显著, 但有机质含量可以通过影响孔隙度或持水量间接影响入渗性。火烧后土壤初始含水率是唯一显著且直接影响入渗性的因素, 且初始含水率越高, 土壤入渗越慢。综上所述, 火烧会改变或解耦火烧迹地早期土壤结构对土壤入渗及其内部的作用程度及途径而间接影响土壤入渗。

关键词: 火烧干扰, 入渗过程, 土壤深度, 土壤结构, 时间变化

Abstract:

Aims As a key factor for the redistribution of rainwater or meltwater, soil infiltration has a substantial effect on forest eco-hydrological processes. This study aims to investigate the characteristics of soil infiltration and its structural controlling factors in the early stage of a post-fire Pinus tabulaeformis plantation in Beijing.
Methods After a fire occurred in March of 2019, the 0-20 cm soils in both post-fire and control plots were monthly collected from May to December 2019. Soil structure and infiltration were determined to analyze their response to fire disturbance and explore how they changed with soil depth and time. Path analysis was employed to discuss the effects of fire and soil structural properties on infiltration.
Important findings The results showed that: 1) In general, the surface soil had higher values of structural indexes (except small aggregates) than subsoils, and values of structural indexes recorded from June to August were higher than those recorded in other months. The vertical distribution characteristics and seasonal dynamics of soil structure were changed by fire. The content of soil aggregates >5, 2-5 and 1-2 mm and bulk density increased significantly two months after fire, while other indicators decreased significantly after fire. The effect of fire was weakened as soil layers deepened and time went by. Also, we observed distinct interactions among fire, soil depth and time. 2) Soil infiltration characteristics changed slowly with soil depth, but changed significantly with time. In addition, soil initial infiltration rate, steady infiltration rate, cumulative-infiltration volume and saturated hydraulic conductivity were largest in August (with higher rainwater and heavy rainfall events). After the fire, soil infiltration in 0-5 cm and that from June to September considerably varied. Soil infiltration characteristics generally decreased, and the peak value in post-fire plots occurred one or two months ahead of that in control plots. 3) Fire significantly affected soil structural properties, while soil infiltration was mainly and directly affected by soil structural properties. Excluding the impact of fire disturbance, the infiltrability of soil had a significant positive correlation with soil aggregate, bulk density and water holding capacity, and a negative correlation with porosity. Although organic matter content and initial water content had no significant effect on infiltrability, organic matter content could indirectly affect infiltrability by affecting porosity or water holding capacity. However, only initial water content had a significant and direct effect on infiltrability at the early stage of a post-fire forest, and the higher the initial moisture content was, the slower the soil infiltration was. Taken together, fire could change or decouple the way soil structure affected soil infiltration and its internal part, and indirectly affected soil infiltration in the early period of post-fire.

Key words: fire disturbance, infiltration process, soil depth, soil structure, time variation