关键词: 亚高山森林土壤, 颗粒态有机碳(POC), 低温季节, 全球变暖

Abstract: [Objective] The aim of the study was to determine seasonal dynamics of soil particulate organic carbon (POC)in the subalpine forest under different surface cover treatments. [Method] Repacked homogenized soil columns were incubated in situ under different surface cover treatments (bare soil without snowcover in winter,BNS;bare soil with snow in winter,BS;littercovered soil without snowcover in winter,LNS;and litter-covered soil with snowcover in winter, LS) and soil columns were sampled in September,November,March,May,and July,respectively,to investigate the temporal dynamics of POC contents in both soil layers (0-10 cm and 10-20 cm). [Results] The contents of POC were relatively stable in the short term but significant differences were detected between cold season and growth season in both soil layers.POC content was higher mid in the cold season than early and later in the cold season regardless of soil layer and treatment.Repeated measures ANOVA analysis showed that soil POC content was impacted significantly by sampling date (temperature)other than soil surface cover conditions (litter or snowcover).However,the interactions of sampling time,surface cover and soil depth had significant effects on soil POC contents. [Conclusion] Soil POC was primarily impacted by soil sampling date (soil temperature)other than surface cover conditions in the short term.Soil POC was accumulated early and middle in the cold season but depleted in the growing season.Therefore,warminginduced shrinkage in cold season may stimulate depletion of soil POC in subalpine forests,which could lead to a new potential carbon source.

Key words: subalpine forest soil, particulate organic carbon(POC), cold season, global warming