Nitrogen (N) cycling has been poorly characterized in urban ecosystems. Processes involving N are of specific concern due to increasing anthropogenic inputs from fertilizer uses and fossil fuel combustion in cities. Here we report on a study of N biogeochemistry in city green retention basins and city parks in the Phoenix metropolitan area, Arizona, USA. City retention basins receive N inputs from street runoff, and along with city parks, fertilizer input from management, making these urban patches potential hot spots for biogeochemical cycling. We sampled soils from six retention basins and two nonretention city parks and measured soil organic matter (SOM) content, net N mineralization, net nitrification, denitrification potential, and intact core denitrification flux and nitrate retention. Our results showed significantly higher SOM, extractable nitrate, nitrification rates and potential denitrification rates in surface soils (0-7.5 cm; soil that is directly affected by fertilizer N input, irrigation, and storm runoff) than in deeper soils. We also observed a distinct horizontal trend of decreasing SOM and denitrification potentials from inlet to outlet (dry well) in the retention basins. Denitrification rates, measured both as potential rates with substrate amendment (390-1151 ng N 2 O-N g À1 soil h À1 ), and as intact core fluxes (3.3-57.6 mg N m À2 d À1 ), were comparable to the highest rates reported in literature for other ecosystems. Management practices that affect biogeochemical processes in urban retention basins thus could affect the whole-city N cycling.
Nitrogen (N) cycling has been poorly characterized in urban ecosystems. Processes involving N are of specific concern due to increasing anthropogenic inputs from fertilizer uses and fossil fuel combustion in cities. Here we report on a study of N biogeochemistry in city green retention basins and city parks in the Phoenix metropolitan area, Arizona, USA. City retention basins receive N inputs from street runoff, and along with city parks, fertilizer input from management, making these urban patches potential hot spots for biogeochemical cycling. We sampled soils from six retention basins and two nonretention city parks and measured soil organic matter (SOM) content, net N mineralization, net nitrification, denitrification potential, and intact core denitrification flux and nitrate retention. Our results showed significantly higher SOM, extractable nitrate, nitrification rates and potential denitrification rates in surface soils (0-7.5 cm; soil that is directly affected by fertilizer N input, irrigation, and storm runoff) than in deeper soils. We also observed a distinct horizontal trend of decreasing SOM and denitrification potentials from inlet to outlet (dry well) in the retention basins. Denitrification rates, measured both as potential rates with substrate amendment (390-1151 ng N 2 O-N g À1 soil h À1 ), and as intact core fluxes (3.3-57.6 mg N m À2 d À1 ), were comparable to the highest rates reported in literature for other ecosystems. Management practices that affect biogeochemical processes in urban retention basins thus could affect the whole-city N cycling.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.