Nitrogen addition increases biomass but reduces nitrogen use efficiency of terrestrial plants in China
Aims Studies on the adaptation of plant biomass and nitrogen use efficiency(NUE)to atmospheric nitrogen(N)deposition were helpful to understand the changes of carbon(C)and N cycling in terrestrial ecosystems under the background of global N deposition.However,the effects of N addition on plant biomass and NUE and the main factors affecting these responses remained unclear.Our objective was to explore the responses of biomass and NUE in the whole and different components of plants to N addition.Methods We conducted a meta-analysis by collecting data from 94 publications focusing on N addition in China,to quantitatively assess the effects of N addition on biomass allocation and NUE of plants,as well as the main influencing factors.Important findings The results showed that:(1)N addition significantly increased total,aboveground,and belowground biomass while significantly decreased the NUE of different components.Plant aboveground biomass(34.0％)increased more than that of belowground biomass(5.3％),and the decreased belowground NUE(29.9％)was higher than that of aboveground(15.4％).(2)The responses of plant biomass and NUE to N addition varied across ecosystem types,N forms,N addition levels,duration,and water conditions.The responses of plant in grassland and desert to N addition were significantly higher than that in other ecosystems.(3)Soil total N content was the most important factor affecting the responses of plant total,aboveground,and belowground biomass.The responses of plant and aboveground NUE were mainly modulated by N addition rate,and the form of N fertilizer mainly influenced the responses of belowground NUE.In conclusion,the effects of N addition on plant biomass and NUE were opposite,and they were mainly affected by soil total N content and N addition rate,respectively.These findings may provide reference for further research and practice on the distribution and utilization of C and N in plants under the background of N deposition.
meta-analysissoil total nitrogennitrogen additionbiomass allocationnitrogen use efficiencyecosystem type
NETL
NSTL
万方数据
