AUTHOR=Su Yuan , Ma Xiaofei , Gong Yanming , Ahmed Zeeshan , Han Wenxuan , Li Kaihui , Liu Xuejun 

TITLE=Global Patterns and Drivers of Litter Decomposition Under Nitrogen Enrichment: A Meta-Analysis

JOURNAL=Frontiers in Forests and Global Change

VOLUME=Volume 5 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/forests-and-global-change/articles/10.3389/ffgc.2022.895774

DOI=10.3389/ffgc.2022.895774

ISSN=2624-893X

ABSTRACT=Nitrogen (N) enrichment has substantially altered terrestrial litter decomposition, with positive, neutral and negative effects. However, general pattern and drivers of how global litter decomposition responds to N enrichment rates remain limited and how litter decomposition, especially in different ecosystems, changed with differential N
enrichment rates still need to be answered. Here, this study reviewed 118 published papers of litter mass remaining after N enrichment to assess the influences of relevant environmental and experimental factors on the relationships between N enrichment and litter decomposition in grassland, forest, and wetland ecosystems. Results indicated that N enrichment had non-significant effect on global litter decomposition. However, the effects were greatly variable among ecosystem type, with an increase in litter decomposition by 3.91% in grassland and by 1.82% in wetland and a decrease in litter decomposition by 1.23% in forest. When forest was further grouped into plantation, primary and secondary forest, results showed that N enrichment significantly slowed litter decomposition rate by 2.96% in plantation and did not significantly influence litter decomposition in primary and secondary forest. The effect magnitude and direction of N enrichment are regulated by experimental and environmental factors. Specially, mixed N enrichment (for example, urea and glycine) exhibited stronger effects on litter decomposition relative to single N fertilizer. Our findings indicated that the divergent responses of litter decomposition in forest and grassland, which will greatly advance our ability to accurately evaluate and predict global C cycling under increased N enrichment, and should be considered and applied in global biogeochemical models.