Quantifying Urban Bioswale Nitrogen Cycling in the Soil, Gas, and Plant Phases

Water

Krista McGuire¹  Nandan Shetty²  Patricia Culligan²  Ranran Hu³  Jessica Hoch⁴  Matthew Palmer⁴  DuncanN. L. Menge⁴  Brian Mailloux⁵  Wade McGillis⁶ 

[1] Department of Biology, University of Oregon, 1210 University of Oregon, 77 Klamath Hall, Eugene, OR 97403, USA;Department of Civil Engineering and Engineering Mechanics, Columbia University, 500 West 120th Street, 610 Mudd, New York, NY 10027, USA;Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, 918 Mudd, New York, NY 10027, USA;Department of Ecology, Evolution, and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, 10th Floor Schermerhorn Ext, New York, NY 10027, USA;Department of Environmental Science, Barnard College, 3009 Broadway, 404 Altschul Hall, New York, NY 10027, USA;Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY 10964, USA;

关键词: nitrogen cycle;    mineralization;    nitrification;    nitrous oxide;    plant uptake;    bioswale;   

DOI  :  10.3390/w10111627

来源: DOAJ

【 摘 要 】

Bioswales are a common feature of urban green infrastructure plans for stormwater management. Despite this fact, the nitrogen (N) cycle in bioswales remains poorly quantified, especially during dry weather in the soil, gas, and plant phases. To quantify the nitrogen cycle across seven bioswale sites located in the Bronx, New York City, we measured rates of ammonium and nitrate production in bioswale soils. We also measured soil nitrous oxide gas emissions and plant foliar nitrogen. We found that all mineralized nitrogen underwent nitrification, indicating that the soils were nitrogen-rich, particularly during summer months when nitrogen cycling rates increase, as indicated by higher levels of ammonium in the soil. In comparison to mineralization (0 to 110 g N m⁻² y⁻¹), the amounts of nitrogen uptake by the plants (0 to 5 g N m⁻² y⁻¹) and of nitrogen in gas emissions from the soils (1 to 10 g N m⁻² y⁻¹) were low, although nitrous oxide gas emissions increased in the summer. The bioswales’ greatest influx of nitrogen was via stormwater (84 to 591 g N m⁻² y⁻¹). These findings indicate that bioswale plants receive overabundant nitrogen from stormwater runoff. However, soils currently used for bioswales contain organic matter contributing to the urban nitrogen load. Thus, bioswale designs should use less nitrogen rich soils and minimize fertilization for lower nitrogen runoff.

【 授权许可】

Unknown