季节性冻融作用对土壤理化与微生物特征的影响研究

Seasonal Freezing-thawing Influences on Soil Physicochemical and Microbial Characteristics

季节性冻融是主要出现在高纬度与高海拔地区的引起土壤内部热量与水分随着时间变化而动态波动的过程。季节性冻融通过反复的冻结——融冻改变了土壤物理结构,降低了土壤团聚体稳定性;通过了土壤的淋溶作用和硝化作用,促进了溶解性有机酸的释放,改变土壤中有机质的含量,从而导致土壤中酸碱度的增减以及碳氮磷与重金属含量的变化;受到温度、水分的影响,使得土壤中微生物的数量与结构趋于动态过程。在综述季节性冻融作用对土壤理化与生物学性质影响研究的基础上,提出了应加强对青藏高原冻土区特别是藏东南高山林线地带冻土的研究与野外监测力度、原位研究以及在更大尺度土壤生态位下对冻融土壤的研究,这对于践行“两山”理论与开展生态安全屏障建设有着重要的意义。

Seasonal freeze-thaw is a process that mainly occurs in high latitudes and high altitudes,causing the internal heat and moisture of the soil to fluctuate dynamically with time.Seasonal freezing and thawing changes the physical structure of the soil and reduces the stability of soil aggregates through repeated freezing and thawing;through the leaching and nitrification of the soil,it promotes the release of dissolved organic acids and changes the organic matter in the soil.The content of soil leads to the increase and decrease of soil p H values and the changes of carbon,nitrogen,phosphorus and heavy metal content;the influence of temperature and moisture makes the number and structure of microorganisms in the soil tend to be a dynamic process.Based on the review of the effects of seasonal freezing and thawing on the physical,chemical and biological properties of the soil,it is proposed to strengthen the study of frozen soil in the permafrost regions of the Qinghai-Tibet Plateau,especially the alpine forest line in southeastern Tibet,as well as field monitoring and in-situ research.As well as the study of freeze-thaw soils in a larger-scale soil niche,this is of great significance for the practice of the"two mountains"theory and the construction of ecological security barriers.