黄土高原地区林地枯枝落叶层水土保持效应研究进展

枯枝落叶层是林地垂直结构中参与水文循环过程的重要作用层,在涵养水源和保持水土中发挥着重要作用。黄土高原经过20年植被快速恢复,枯落物覆盖使近地表植被特征和生态过程变化明显,这必将影响地表土壤水分入渗、产汇流等水文和土壤侵蚀过程。为全面掌握黄土高原地区林地枯枝落叶层的水土保持效应研究动态,系统回顾了林地枯枝落叶层在凋落动态、蓄积量变化、截留降雨、阻延地表径流、提高土壤抗蚀抗冲能力和增加土壤入渗等方面的研究历史。分析了目前林地枯枝落叶层研究中存在的若干问题,提出未来黄土高原地区应加强野外坡面枯落物原位长期监测和降雨试验研究,开展多地貌、多尺度研究,关注天然林和人工林枯枝落叶层水土保持功能的对比研究,以及水文物理过程模型建立和参数确定,并重视林地枯枝落叶层的保护和监管。

Research Advances on Water and Soil Conservation Effects of Forest Litter Layer on the Loess Plateau

Litter is an important layer involved in the hydrological cycle process in the vertical structure of forestlands, and plays an indispensable role in water retention and soil conservation. After 20 years of rapid vegetation restoration on the Chinese Loess Plateau, litter coverage in forestlands has caused significant changes in vegetation characteristics and ecological processes on the near surface, which will certainly affect the hydrological and soil erosion processes such as soil infiltration, surface runoff and confluence. In order to comprehensively grasp the dynamics of soil and water conservation effects of litter layer in forestlands on the Loess Plateau, we systematically reviewed the research progress of litter layer in forestlands in terms of the litter dynamics, accumulation changes, rainfall interception, surface runoff interception, soil erosion resistance and soil infiltration. Some existing problems in the current studies on litter layer in forestlands on the Loess Plateau were analyzed objectively. In the future, the long-term in-situ monitoring and rainfall experiments on field slopes should be strengthened, and multi-landform as well as multi-scale dynamic studies should be carried out. In addition, we are supposed to pay attention to the comparative studies on the eco-hydrological functions of litter layer in natural forests and artificial forests, and establish hydro-physical process models and determine the relevant key parameters, as well as enhance the protection and supervision of litter layer in forestlands.