土壤冻融交替生态效应研究进展

土壤冻融作用是高纬度和高海拔地带性土壤热量动态的一种表现形式.国际上关于冻融的研究多集中在北方高纬度地带,特别是苔原、泰加林和北极生态系统,越来越集中在全球变化对冻融生态系统土壤过程的效应方面.已有研究表明冻融作用会引起土壤团聚结构破坏并导致冻融侵蚀、土壤溶液中养分浓度升高而导致土壤养分流失、土壤解冻后还可能导致土壤呼吸和N素矿化以及一些痕量气体短时间释放增加等,这些研究表明了冻融过程对土壤物理、化学、生物等各方面的效应.我国有大面积北方季节性地带冻土和青藏高原高海拔冻土,而在土壤冻融作用及生态效应方面的工作较少,值得关注和深入研究.

Freeze-Thaw Cycles and Their Impacts on Ecological Process:A Review

Freeze-thaw cycles are very common in temperate, high latitude and high altitude soils. Freeze-thaw cycles have been considered as one of the important factors contributing to increasing physical disruption of soil aggregates, and enhancing soil erosion and nutrients loss. Moreover, freezing and subsequently thawing of soil often results in an increase in soil solution nutrients, a flush of soil nitrogen release, and an initial flush of microbial respiration and some trace gases emission. However, so far most of studies on freeze-thaw cycles and their effects on soil ecosystem functioning have been conducted in the northern sub-polar ecosystem. Although subalpine and alpine forests distributed in the Qinghai-Tibet Plateau have been thought as an important ecosystem in the research of regional impacts and responses of global changes, few works on the influences of soil freeze-thaw cycles have been reported. Some recommendations for further research on ecological effects of soil freeze-thaw cycles in the subalpine and alpine ecosystems of the western China, especially in Qinghai-Tibetan Plateau, the vastest expanse of highest altitude freezing soil of the world, were also presented in this paper.