黄河源高寒草甸退化过程中CO_(2)通量的变化  

Variation of CO_(2)Flux in Process of Alpine Meadow Degradation in Zone of Yellow River Source

作　　者：孙华方 李希来[1] 苏晓雪 金立群[1,2] 张静 阿卓毛世吉[1] 刘凯 SUN Huafang;LI Xilai;SU Xiaoxue;JIN Liqun;ZHANG Jing;Azhuomaoshiji;LIU Kai(College of Agriculture and Animal Husbandry,Qinghai University,Xining 810016,China;Grassland Station of Huangyuan County,Huangyuan Qinghai 812100,China;Qinghai Provincial Grassland Station,Xining 810008,China)

机构地区：[1]青海大学农牧学院,西宁810016 [2]湟源县草原站,青海湟源812100 [3]青海省草原总站,西宁810008

出　　处：《西北农业学报》2022年第12期1544-1552,共9页Acta Agriculturae Boreali-occidentalis Sinica

基　　金：青海省科技厅项目(2020-ZJ-904);国家自然科学基金(31872999);三江源国家公园联合研究专项(LHZX-2020-08);高等学校学科创新引智计划(D18013)。

摘　　要：为研究草地退化对高寒草甸碳排放的影响,选取青海省黄南州河南县的未退化(No degraded,ND)、中度退化(Moderate degraded,MD)和重度退化(Serious degraded,SD)高寒草甸,利用LI-8100A红外气体分析仪测定CO_(2)通量。结果表明:草地退化能够显著降低高寒草甸CO_(2)通量。未退化高寒草甸CO_(2)通量为12.44μmol/(m^(2)·s),显著高于重度退化高寒草甸4.64μmol/(m^(2)·s),中度与重度退化草甸差异不显著。全氮含量在重度退化区最高,全磷含量表现出相反趋势;速效养分随着退化的加剧逐渐减少。随机森林模型分析发现,植被特征中杂类草盖度和地上生物量是降低CO_(2)通量的关键因子,各土层中土壤pH,0~2、2~5 cm土壤细砂粒比例和5~10 cm土壤全磷含量为关键因子,均与CO_(2)通量呈显著正相关。说明高寒草甸的退化引起植被类型和土壤特征发生变化,进而导致CO_(2)通量发生变化,且不同土层关键因子具有差异,因此,研究黄河源高寒草甸碳排放的过程中需要密切关注植被类型和土壤变化。The CO_(2)flux in the process of alpine meadow degradation was measured by portable CO_(2)measuring system(LI-8100A),so as to quantify the effect of degradation on carbon emission in Henan county of Qinghai province.The results showed that the CO_(2)flux of alpine meadow was significantly reduced alone with the severity of degradation.The CO_(2)emission of non-degraded alpine meadow[12.44μmol/(m^(2)·s)]was significantly higher than that of the severely degraded alpine meadow[4.64μmol/(m^(2)·s)],and there was no significant difference between moderate and severely degraded alpine meadows.The content of total nitrogen(TN)and the available nutrients increased with theseverity of the degradation,but the content of total phosphorus(TP)presented an inverse trend.Random forest analysis showed that the coverage and biomass of forbs were the key factors to reduce CO_(2)flux.Soil characteristics,such as soil pH,fine sand content(0-2 cm and 2-5 cm soil layers)and TP of 5-10 cm soil layer,played significant role in promoting CO_(2)flux.Thus,vegetation and soil conditions altered by degradation were the vital process of carbon emission in alpine grassland.Therefore,it is necessary to pay attention to the changes of vegetation and soil for studying carbon emission of alpine meadow in the zone of the Yellow River source.

关 键 词：CO_(2)通量 退化高寒草甸 植被特征 土壤特征 随机森林 

分 类 号：S812[农业科学—草业科学]