土地利用方式对高寒草甸土壤有机碳及其组分的影响

目的]探讨土壤碳库的变化规律。方法]以原生高寒草甸、人工草地和农田(油菜地)作为研究对象,利用土壤有机碳密度分组法,研究3种土地利用方式对高寒草甸土壤有机碳(SOC)及轻组有机碳(LFOC)含量变化的影响。结果]3种土壤0～40 cm土体内,SOC含量依次为人工草地>高寒草甸>油菜地,分别为113.13、111.61和93.54 t/hm2;LFOC含量依次为人工草地>高寒草甸>油菜地,分别为10.36、8.93和5.83 t/hm2。人工草地与高寒草甸相比,0～40 cm土壤SOC含量间差异不明显,但LFOC高16.01%;耕作20年的农田中,SOC和LFOC分别较高寒草甸低16.19%、34.71%。结论]人工草地土壤中总SOC和LFOC则略高于高寒草甸,明显高于农田,人工草地和高寒草甸的植物-土壤系统的总固碳量明显高于农田。

Effects of Different Land Use Modes on Organic Carbon and Its Component in Alpine Meadow Soil

Objective]This study aimed to explore the law of variation of soil carbon pool.Method]With the land types of alpine meadow,artificial grassland and farmland(rapeseed field) as research objects,the effet of 3 kinds of soil land using modes on the change of soil organic carbon(SOC) and light fraction organic carbon(LFOC) contents were studied.Results] In 0-40 cm soil body of 3 kinds of lands,the contents of SOC in order were: artificial grassland>alpine meadow> rapeseed field,with the amount of 113.13,111.61 and 93.54 t /hm2 resp.;the contents of LFOC in order were artificial grassland > alpine meadow >rapeseed field,with the amount of 10.36,8.93 and 5.83 t /hm2 resp.Compared with alpine meadow,the content of SOC in 0-40 cm soil body in artificial grasslands had not changed obviously,but the content of LFOC was increased by 16.01%.The contents of SOC and LFOC in farmland cultivated for 20 years were decreased by 16.19%,34.71% resp.than that in alpine meadow.Conclusion] The content of SOC and LFOC in artificial grasslands were slightly higher than that in alpine meadow and significantly higher than in farmlands.The total carbon-fixed amounts in plant-soil system in artificial grassland and alpine meadow were significantly higher than that in farmland.