1. Phosphorus addition promotes Nitrogen retention in alpine grassland plants while increasing N deposition.
- Author
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Xiao, Jiannan, Dong, Shikui, Shen, Hao, Li, Shuai, Zhi, Yangliu, Mu, Zhiyuan, and Ding, Chengxiang
- Subjects
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GRASSLAND plants , *MOUNTAIN plants , *GRASSLAND soils , *MOUNTAIN ecology , *MOUNTAIN meadows , *PHOSPHORUS - Abstract
• P addition increased N retention mainly by promoting plant N uptake. • N addition without P showed neutral effects of N retention. • N addition showed positive effects on gaseous losses of N. • N loss through NH 3 and N 2 O emissions was quite low. Nitrogen (N) and phosphorus (P) are common limiting nutrients affecting plant growth in alpine ecosystems. Anthropogenic activities significantly increase N input in ecosystems, thereby increasing P limitation when in excess. The increase of N input and P limitation may affect N retention, which is a critical ecosystem function. To understand how ecosystem N retention and N loss respond to N and P addition, this study investigated the effects of N and P addition on NH 3 volatilization, N 2 O emissions, and N pools of plants and soil in two alpine grasslands (alpine meadow and alpine steppe). The results showed that P addition (with or without N) increased N retention, mainly by promoting plant N uptake, underlining the importance of P availability in N retention in the QTP alpine grassland ecosystems while increasing N deposition. N addition without P showed neutral effects of N retention of plant, soil and microbes, and N addition (with or without P) showed positive effects on gaseous losses of N. N loss through NH 3 volatilization and N 2 O emissions was quite low (less than 1%), suggesting that N gaseous loss was not a significant pathway of N loss from the alpine grassland ecosystems. These results were meaningful for estimating the impacts of N retention and N loss under future N deposition scenarios in alpine grassland ecosystems in the QTP. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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