Nitrogen Deposition Weakens Soil Carbon Control of Nitrogen Dynamics Across the Contiguous United States

作者：Matthew A. Nieland, Piper Lacy, Steven Allison, Jennifer Bhatnagar, Danica A. Doroski, Serita D. Frey, Kristen Greaney, Sarah E. Hobbie, Sara E. Kuebbing, David B. Lewis, Marshall D. McDaniel, Steven S. Perakis, Steve M. Raciti, Alanna N. Shaw, Christine D. Sprunger, Michael S. Strickland, Pamela H. Templer, Corinne Vietorisz, Elisabeth B. Ward, Ashley D. Keiser · 发表于：Global Change Biology · 年份：2024 · DOI：10.1111/gcb.70016 · 被引用次数：8 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Groundwater and Isotope Geochemistry

ABSTRACT Anthropogenic nitrogen (N) deposition is unequally distributed across space and time, with inputs to terrestrial ecosystems impacted by industry regulations and variations in human activity. Soil carbon (C) content normally controls the fraction of mineralized N that is nitrified ( ƒ nitrified ), affecting N bioavailability for plants and microbes. However, it is unknown whether N deposition has modified the relationships among soil C, net N mineralization, and net nitrification. To test whether N deposition alters the relationship between soil C and net N transformations, we collected soils from coniferous and deciduous forests, grasslands, and residential yards in 14 regions across the contiguous United States that vary in N deposition rates. We quantified rates of net nitrification and N mineralization, soil chemistry (soil C, N, and pH), and microbial biomass and function (as beta‐glucosidase (BG) and N ‐acetylglucosaminidase (NAG) activity) across these regions. Following expectations, soil C was a driver of ƒ nitrified across regions, whereby increasing soil C resulted in a decline in net nitrification and ƒ nitrified . The ƒ nitrified value increased with lower microbial enzymatic investment in N acquisition (increasing BG:NAG ratio) and lower active microbial biomass, providing some evidence that heterotrophic microbial N demand controls the ammonium pool for nitrifiers. However, higher total N deposition increased ƒ nitrified , including for high soil C site...