Nutrient Enrichment Mediates the Relationships of Soil Microbial Respiration with Climatic Factors in an Alpine Meadow.
Quantifying the effects of nutrient additions on soil microbial respiration (R m) and its contribution to soil respiration (R s) are of great importance for accurate assessment ecosystem carbon (C) flux. Nitrogen (N) addition either alone (coded as LN and HN) or in combination with phosphorus (P) (coded as LN + P and HN + P) were manipulated in a semiarid alpine meadow on the Tibetan Plateau since 2008. Either LN or HN did not affect R m, while LN + P enhanced R m during peak growing periods, but HN + P did not affect R m. Nutrient addition also significantly affected R m /R s, and the correlations of R m /R s with climatic factors varied with years. Soil water content (Sw) was the main factor controlling the variations of R m /R s. During the years with large rainfall variations, R m /R s was negatively correlated with Sw, while, in years with even rainfall, R m/R s was positively correlated with Sw. Meanwhile, in N + P treatments the controlling effects of climatic factors on R m /R s were more significant than those in CK. Our results indicate that the sensitivity of soil microbes to climatic factors is regulated by nutrient enrichment. The divergent effects of Sw on R m /R s suggest that precipitation distribution patterns are key factors controlling soil microbial activities and ecosystem C fluxes in semiarid alpine meadow ecosystems.
Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Road, Chaoyang District, Beijing 100101, China ; University of Chinese Academy of Sciences, No. 19A Yuquan Road, Shijingshan District, Beijing 100049, China.
Ning
N
Zong
Nanjing Agricultural Institute of Jiangsu Hilly Region, Nanjing, Jiangsu 210046, China.
Jing
J
Jiang
Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Road, Chaoyang District, Beijing 100101, China.
Peili
P
Shi
Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Road, Chaoyang District, Beijing 100101, China.
Minghua
M
Song
Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Road, Chaoyang District, Beijing 100101, China.
Zhenxi
Z
Shen
Lhasa National Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modelling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, A11 Datun Road, Chaoyang District, Beijing 100101, China.
Xianzhou
X
Zhang
D000531:Altitude; D057919:Biological Oxygen Demand Analysis; D002244:Carbon / Q000737:chemistry* / Q000378:metabolism; D057486:Carbon Cycle / Q000502:physiology; D003889:Desert Climate; D005308:Fertilizers / Q000032:analysis; D065948:Grassland; D059013:Microbial Consortia / Q000502:physiology*; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism; D010758:Phosphorus / Q000737:chemistry* / Q000378:metabolism; D006109:Poaceae / Q000502:physiology; D011891:Rain; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D018609:Tibet
D005308:Fertilizers; D012987:Soil; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen