J Plant Ecol ›› 2023, Vol. 16 ›› Issue (5): rtad005.DOI: 10.1093/jpe/rtad005

• Research Articles •    

Altitudinal variations of the rate and temperature sensitivity of soil nitrogen mineralization on the Qinghai-Tibetan Plateau

Xikang Hou1, Dan Kou2, Mitsuru Hirota3, Tong Guo4,*, Tao Lang5,*   

  1. 1State Key Laboratory of Environment Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China;
    2Biogeochemistry Research Group, Department of Biological and Environmental Sciences, University of Eastern Finland, Kuopio 70210, Finland;
    3Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan;
    4Institute of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of Ministry of Education, Peking University, Beijing 100871, China;
    5MNR Key Laboratory for Geo-Environmental Monitoring of Great Bay Area & Shenzhen Key Laboratory of Marine Bio-resource and Eco-environmental Science, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518071, China
  • Received:2021-12-29 Revised:2022-03-26 Accepted:2023-02-03 Online:2023-02-09 Published:2023-10-01
  • Contact: E-mail: tongg@pku.edu.cn (T.G.); langt@szu.edu.cn (T.L.)


Abstract: Changes in soil nitrogen mineralization can impact nutrient availability, and further affect plant growth. It is unclear, however, how temperature elevation in alpine grassland will affect soil net N mineralization rate (Nmin) across altitudes. At six altitudes (3200-4200 m with an interval of 200 m) along a slope in Lenglong mountain in the northern Qinghai-Tibetan Plateau, we performed an in situ soil incubation experiment by using the resin-core method to assess altitudinal variations of Nmin. Meanwhile, we evaluated the effects of temperature elevation on Nmin and its temperature sensitivity (Q10) through a soil downward transplantation experiment based on three reference baseline altitudes (3800, 4000 and 4200 m). The results showed that high altitudes generally led to low values of Nmin. Structural equation modeling analysis revealed that Nmin along the altitude was mainly controlled by soil temperature. Increased temperature caused by the altitude transplantation significantly elevated Nmin for all of the three reference altitudes. The value of Q10 was 3.4 for soil samples transplanted from the reference altitude of 4200 m, which was about twice that of the lower reference altitudes of 4000 and 3800 m.

Key words: alpine ecosystems, soil transplantation, warming, nitrogen mineralization rate, Q10

土壤氮矿化速率的变化会影响营养物质的可利用性,进而影响植物生长。然而,温度升高如何影响不同海拔高山草地土壤净氮矿化速率仍不清楚。在青藏高原北部的祁连山脉一处坡地上,我们从海拔3200至4200 m每隔200 m设立一观测样地,用树脂芯法开展了沿海拔梯度土壤净氮矿化速率的原位观测实验。同时我们以海拔3800、4000和4200 m的样地作为基准,通过分别向低海拔移栽土壤样方的实验方法评估土壤净氮矿化速率及其温度敏感性(Q10)受升温的影响。研究结果表明,土壤净氮矿化速率随海拔升高而降低;结构方程模型分析结果显示沿海拔梯度土壤净氮矿化速率主要受土壤温度的影响;海拔间移植实验导致的温度增加显著提高了土壤净氮矿化速率;基于海拔4200 m开展的移植实验表明土壤净氮矿化速率的Q10值达到3.4,这大约是基于海拔4000和3800 m的Q10值的两倍。

关键词: 高山生态系统, 土壤样方移栽, 增温, 氮矿化速率, 温度敏感性