AUTHOR=Li Chunli , Li Yonghui , Li Xinwei , Ma Li , Xiao Yuanming , Zhang Chunhui 

TITLE=Differential Responses of Plant Primary Productivity to Nutrient Addition in Natural and Restored Alpine Grasslands in the Qinghai Lake Basin

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 12 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.792123

DOI=10.3389/fpls.2021.792123

ISSN=1664-462X

ABSTRACT=As two aspects of global change, climate and land-use changes strongly impact plant primary productivity, particularly in the alpine grassland ecosystem. In this study, the differential responses of plant community primary productivity to nitrogen (N) and phosphorus (P) nutrient application were investigated in the natural (NG) and “Grain for Green” restored (RG) alpine grasslands by a continuous three-year experiment around the Qinghai Lake Basin. N addition only significantly promoted plant aboveground biomass (AGB) by 42%, and had no significant effect on belowground biomass (BGB) and total biomass (TB) in NG. In comparison with NG, N addition elevated AGB and BGB concurrently in RG, by 138% and 24%, respectively, which further significantly increased TB by 41% in RG. Meanwhile, N addition significantly decreased BGB and AGB ratio (R/S) both in the NG and RG. Compared with N addition, P addition nearly did not perform an evident effect on plant biomass parameters in this study. Additionally, AGB were merely negatively influenced by growing season temperature (GST) under N addition treatment in NG. AGB were negatively associated with GST but positively related to growing season precipitation (GSP) in RG. In contrast, the changes of R/S ratio in RG were positively correlated with GST and negatively related to GSP. In sum, the results revealed that plant community biomass exhibited convergent and divergent responses to N addition between NG and RG. In addition, the outcomes suggested that climate warming would enhance plant biomass allocation to belowground under ongoing N deposition, and imply the significance of precipitation for plant growth and AGB accumulation in the restored alpine grassland ecosystem.