科研进展

【论文题目】Nutrient budgets drive the changes in shoot N and P concentrations of plants in Inner Mongolia's grasslands over the past 40 years

【论文题目】近40年养分平衡驱动了内蒙古草原植物地上部氮磷浓度的变化

【作者】Qian Liu, Weiwei Chen, Hui Gao, Zhi Sun, Yalan Wang, Haigang Li*

【作者】刘茜，陈薇薇，高卉，孙智，王雅兰，李海港

【期刊名称和年（卷、期）】Science of the Total Environment 2022, 838: 156374

【Abstract】The nutrient budgets of grassland ecosystems have been extensively disturbed by human activity. The aims of this study were to quantify nitrogen (N) and phosphorus (P) budgets, and evaluate their contributions to changes in shoot nutrient concentrations of dominant plants in Inner Mongolia's grasslands over the past 40 years. N and P bud- gets were assessed using a nutrient budget model based on flowing intensity of nutrients in and out of the grassland. Meta-analysis was then conducted to quantify changes in shoot nutrient concentrations. The N budget remained pos- itive and continued to increase throughout the study period, while enhanced N deposition and increased supplemen- tary feeding dominated N input (76% of the total in 2017). In contrast, the P budget was negative until 2003, and became positive thereafter. The P input was mainly attributed to supplementary feeding (88% of the total in 2017). The mean shoot N concentration in 1979–1986 was 2.25%, while an increase to 2.53% was observed in 2006–2016. In contrast, the mean shoot P concentration was 0.17% in 1979–1991, subsequently leveling off at 0.17% in 2006–2016. The mean shoot N: P ratio basically remain unchanged over time from 16.72 to 15.85. The N surplus caused major increases in the shoot N concentration of the grassland plants; also, the increased P budget to compensate for past P deficiency resulted in no significant change of shoot P concentrations. Consequently, the grass- land system had been in the joint N and P co-limitation over the past 40 years.

【Keywords】Grassland ecosystem; Nitrogen concentration; Phosphorus concentration; N: P ratio; Nutrient budget; Inner Mongolia