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Journal of Arid Land

Article Title

Contrasting effects of nitrogen addition on litter decomposition in forests and grasslands in China

Authors

SU Yuan, 1 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 2 Bayanbulak Grassland Ecosystem Research Station, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Bayanbulak 841314, China; 3 University of Chinese Academy of Sciences, Beijing 100049, China
MA Xiaofei, 1 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 3 University of Chinese Academy of Sciences, Beijing 100049, China
GONG Yanming, 1 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 2 Bayanbulak Grassland Ecosystem Research Station, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Bayanbulak 841314, China
LI Kaihui, 1 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 2 Bayanbulak Grassland Ecosystem Research Station, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Bayanbulak 841314, China; 4 Chinese Academy of Sciences Research Center for Ecology and Environment of Central Asia, Urumqi 830011, ChinaFollow
HAN Wenxuan, 1 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 5 Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
LIU Xuejun, 1 State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; 5 Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, ChinaFollow

Abstract

Nitrogen (N) addition has profound impacts on litter-mediated nutrient cycling. Numerous studies have reported different effects of N addition on litter decomposition, exhibiting positive, negative, or neutral effects. Previous meta-analysis of litter decomposition under N addition was mainly based on a small number of samples to allow comparisons among ecosystem types. This study presents the results of a meta-analysis incorporating data from 53 published studies (including 617 observations) across forests, grasslands, wetlands, and croplands in China, to investigate how environmental and experimental factors impact the effects of N addition on litter decomposition. Averaged across all of the studies, N addition significantly slows litter decomposition by 7.02%. Considering ecosystem types, N addition significantly accelerates litter decomposition by 3.70% and 11.22% in grasslands and wetlands, respectively, clearly inhibits litter decomposition by 14.53% in forests, and has no significant effects on litter decomposition in croplands. Regarding the accelerated litter decomposition rate in grasslands due to N addition, litter decomposition rate increases slightly with increasing rates of N addition. However, N addition slows litter decomposition in forests, but litter decomposition is at a significantly increasing rate with increasing amounts of N addition. The responses of litter decomposition to N addition are also influenced by the forms of N addition, experiential duration of N addition, humidity index, litter quality, and soil pH. In summary, N addition alters litter decomposition rate, but the direction and magnitude of the response are affected by the forms of N addition, the rate of N addition, ambient N deposition, experimental duration, and climate factors. Our study highlights the contrasting effects of N addition on litter decomposition in forests and grasslands. This finding could be used in biogeochemical models to better evaluate ecosystem carbon cycling under increasing N deposition due to the differential responses of litter decomposition to N addition rates and ecosystem types.

Keywords

litter decomposition rate, N addition, ambient N deposition, litter quality, meta-analysis, forests, grasslands

First Page

717

Last Page

729

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