Changes in soil nutrient availability attributed to climate change and associated permafrost degradation have been reported in several ecosystems. However, little is known about the changes of soil nutrient availability in alpine grassland ecosystems. Based on a comprehensive dataset and random forest models, we investigated soil available nutrients changes and their relationships with environmental factors for the top 10 cm soils across Tibetan grassland between the 1980s and 2010s. During this period, topsoil available nitrogen stocks increased significantly by 24%, while available phosphorus and potassium stocks decreased significantly by 3% and 23%, respectively. Topsoil nutrient availability dynamics varied substantially among vegetation types. Initial nutrient stocks explained the largest proportions of available nutrients changes, though climate, permafrost, vegetation, soil properties, and their interactions also had significant contributions. The increasing rate of active layer thickness was negatively related to soil available nitrogen dynamics but did not significantly change available phosphorus and potassium, indicating that the increase in the annual depth of surface thaw of the permafrost was associated with an increase in soil nitrogen availability but no significant changes in available phosphorus and potassium. These results suggest that the Tibetan alpine grassland ecosystems may shift from nitrogen limited to phosphorus or potassium-limited in the future.
1.Nanjing Univ Informat Sci & Technol, Sch Geog Sci, Nanjing 210044, Jiangsu, Peoples R China 2.Chinese Acad Sci, Northwest Inst Ecoenvironm & Resources, State Key Lab Cryospher Sci, Cryosphere Res Stn Qinghai Tibetan Plateau, Lanzhou 730000, Gansu, Peoples R China 3.Sichuan Univ, Coll Life Sci, Key Lab Bioresource & Ecoenvironm, Minist Educ, Chengdu 610064, Sichuan, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 5.Lanzhou Jiaotong Univ, Sch Environm & Municipal Engn, Lanzhou 730070, Gansu, Peoples R China 6.Chinese Acad Sci, State Key Lab Frozen Soil Engn, Northwest Inst Ecoenvironm & Resources, Lanzhou 730000, Gansu, Peoples R China 7.Lanzhou Univ Technol, Sch Civil Engn, Lanzhou 730050, Gansu, Peoples R China 8.Univ Alaska Fairbanks, Palmer Res Ctr, Agr & Forestry Expt Stn, Palmer, AK 99645 USA
Recommended Citation:
Tian, Liming,Zhao, Lin,Wu, Xiaodong,et al. Variations in soil nutrient availability across Tibetan grassland from the 1980s to 2010s[J]. GEODERMA,2019-01-01,338:197-205