Characterization of dissolved organic nitrogen in leachate from a newly established and fertilized turfgrass

WATER RESEARCH

卷:131

Article

Lusk, Mary G.¹  Toor, Gurpal S.²  Inglett, Patrick W.³ 

[1] Univ Florida, Gulf Coast Res & Educ Ctr, Inst Food & Agr Sci Extens, 1200 N Pk Rd, Plant City, FL 33563 USA

[2] Univ Maryland, Dept Environm Sci & Technol, College Pk, MD 20742 USA

[3] Univ Florida, Soil & Water Sci Dept, Gainesville, FL 32611 USA

关键词: Nitrogen;    Dissolved organic nitrogen;    Leaching;    Turfgrass;    Groundwater quality;   

DOI  :  10.1016/j.watres.2017.11.040

来源: Elsevier

【 摘 要 】

Understanding the mechanisms of nitrogen (N) retention and loss from fertilized urban turfgrass is critical to develop practices that mitigate N transport and protect water quality in urban ecosystems. We investigated the fate of N in lysimeters sodded with St. Augustine turfgrass and amended with labeled N-15 from either ammonium sulfate or urea. Fourier transform ion cyclotron resonance mass spectroscopy (FTICR-MS) was employed to identify various biomolecular classes in the leached dissolved organic N (DON) from one lysimeter for each treatment and the control. Mean DON concentrations, over 92 days, were 88, 94, and 94% of total N in the leachate from the control, urea, and ammonium sulfate treatments, respectively. Isotopic analysis showed that <3% of N in the leachate originated from newly applied N fertilizer, suggesting that the remainder of the N in the leachate was derived from the lysimeter soil or sod biomass pools. The N-15 fertilizer recovery was greatest in soil (44-48%), followed by sod+thatch (18-33%), grass clippings (10-13%), and leachate (<3%). Despite isotopic evidence of little contribution of N from fertilizers in the leachate, a fraction of ammonium sulfate fertilizer was recovered as DON in the leachate, likely after uptake and conversion of inorganic fertilizer to organic plant exudates and/or microbial byproducts. FTICR-MS identified N-bearing organic molecular formulas in the leachate from urea and ammonium sulfate treatments, providing evidence of N leaching from newly established turfgrass of DON compounds in a range of biomolecular compositions such as lipid-, protein-, carbohydrate-, and lignin-like molecules. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

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