C:N:P stoichiometry of plants, soils, and microorganisms: Response to altered precipitation
AbstractPrecipitation changes modify C, N, and P cycles, which regulate the functions and structure of terrestrial ecosystems. Although altered precipitation affects above- and belowground C:N:P stoichiometry, considerable uncertainties remain regarding plant–microbial nutrient allocation strategies under increased (IPPT) and decreased (DPPT) precipitation. We meta-analyzed 827 observations from 235 field studies to investigate the effects of IPPT and DPPT on the C:N:P stoichiometry of plants, soils, and microorganisms. DPPT reduced leaf C:N ratio, but increased the leaf and root N:P ratios reflecting stronger decrease of P compared with N mobility in soil under drought. IPPT increased microbial biomass C (+13%), N (+15%), P (26%), and the C:N ratio, whereas DPPT decreased microbial biomass N (−12%) and the N:P ratio. The C:N and N:P ratios of plant leaves were more sensitive to medium DPPT than to IPPT because drought increased plant N content, particularly in humid areas. The responses of plant and soil C:N:P stoichiometry to altered precipitation did not fit the double asymmetry model with a positive asymmetry under IPPT and a negative asymmetry under extreme DPPT. Soil microorganisms were more sensitive to IPPT than to DPPT, but they were more sensitive to extreme DPPT than extreme IPPT, consistent with the double asymmetry model. Soil microorganisms maintained stoichiometric homeostasis, whereas N:P ratios of plants follow that of the soils under altered precipitation. In conclusion, specific N allocation strategies of plants and microbial communities as well as N and P availability in soil critically mediate C:N:P stoichiometry by altered precipitation that need to be considered by prediction of ecosystem functions and C cycling under future climate change scenarios.
1 State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, College of Soil and Water Conservation Science and Engineering (Institute of Soil and Water Conservation) Northwest A&F University Yangling China
2 Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources Yangling China
3 College of Forestry Northwest A&F University Yangling China
4 CREAF, Cerdanyola del Vallès Barcelona Spain
5 CSIC, Global Ecology Unit CREAF-CSIC-UAB Barcelona Spain
6 Center of CEF/ESCER, Department of Biological Science University of Quebec at Montreal Montreal Quebec Canada
7 Department of Soil Science of Temperate Ecosystems University of Goettingen Göttingen Germany
8 Department of Agricultural Soil Science University of Goettingen Göttingen Germany
9 Peoples Friendship University of Russia (RUDN University) Moscow Russia