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Lv P, Sun S, Li Y, Zhao S, Zhang J, Hu Y, Yue P, Zuo X. Plant composition change mediates climate drought, nitrogen addition, and grazing effects on soil net nitrogen mineralization in a semi-arid grassland in North China. Sci Total Environ 2024; 908:168282. [PMID: 37923269 DOI: 10.1016/j.scitotenv.2023.168282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 10/18/2023] [Accepted: 10/31/2023] [Indexed: 11/07/2023]
Abstract
Human activities induce alterations of the nitrogen (N) cycle, climate drought, and disturbance (e.g., livestock grazing) regimes at the global scale. Their individual, interactive, and combined effects on soil N cycling in grasslands are unclear. We investigated the N addition, drought, and grazing effects on the N mineralization, as well as their correlations with N-related variables, including the C4 species, shoot biomass (SB), root biomass (RB), plant total nitrogen (PTN), plant total carbon (PTC), soil total nitrogen (STN), soil total carbon (STC), and soil microbial N and C, during a three-year field experiment conducted in a semi-arid grassland in North China. The results showed that N addition increased the nitrate N (NO3--N) and ammonium N (NH4+-N) concentrations, whereas drought decreased the NO3--N concentration because of strengthened N limitation. Pronounced temporal variation in the N mineralization occurred under seasonal drought (maxima in August and September) and under its combination with N addition and grazing (minima in August). RB and the C4 species were positively correlated, whereas STC and the NO3--N concentration were negatively correlated with the N mineralization under the combined influence of the three factors. The structural equation model showed that at the site affected by all three factors, drought indirectly increased the N mineralization by reducing the NO3--N concentration, whereas N addition and grazing did not alter the N mineralization. N addition directly increased while indirectly reduced N mineralization by increasing the NO3--N concentration. Additionally, N addition and grazing increased the C4 species and decreased the STC, consequently enhanced N mineralization. These results highlight the predominant role of drought, when combined with N addition and grazing, in controlling the N mineralization. The N supply balance in semi-arid grasslands could be stabilized in response to increased N addition, climate drought, and grazing.
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Affiliation(s)
- Peng Lv
- Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China
| | - Shanshan Sun
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuqiang Li
- Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China
| | - Shenglong Zhao
- College of Resources and Environmental Engineering, Tianshui Normal University, Tianshui 741000, China
| | - Jing Zhang
- Information Center, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Ya Hu
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China
| | - Ping Yue
- Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China
| | - Xiaoan Zuo
- Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Urat Desert-Grassland Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Key Laboratory of Stress Physiology and Ecology in Cold and Arid Regions, Gansu Province, Lanzhou 730000, China.
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