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Direct Measurement of Denitrification Using 15 N‐labeled Fertilizer Applied to Turfgrass
Author(s) -
Horgan B. P.,
Branham B. E.,
Mulvaney R. L.
Publication year - 2002
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2002.1602
Subject(s) - loam , poa pratensis , agronomy , denitrification , nitrous oxide , fertilizer , agrostis , nitrogen , nitrification , urea , poaceae , festuca pratensis , biology , soil water , chemistry , lolium perenne , ecology , biochemistry , organic chemistry
Denitrification losses are a possibility from turfgrass because of frequent irrigation, multiple applications of N fertilizers, and an abundance of readily decomposable organic C in thatch and verdure. Field experiments were conducted to directly measure N 2 and N 2 O evolved from a Flanagan silt loam soil under Kentucky bluegrass ( Poa pratensis L.) or creeping bentgrass ( Agrostis palustris Huds.). Mass spectrometric procedures were used to analyze atmospheric samples collected from replicated 15 N fertilized turf (49 kg ha −1 ). Data showed that labeled fertilizer N (LFN) losses ranged from 2.1 to 7.3% for N 2 and from 0.4 to 3.9% for N 2 O; that large N 2 and N 2 O fluxes occurred after heavy rainfall events; and that more N 2 was evolved than N 2 O. Emission of gas was detected while standing water was visible within cylinders, suggesting the transfer of gases from the flooded soil to the atmosphere through the turfgrass plants. Evolution of N 2 and N 2 O was greater from creeping bentgrass treated with KNO 3 than urea through the first 3 wk of the experiment, whereas N 2 emission was greater for urea during the last 2 wk of the experiment, presumably because of NO 3 production through nitrification. Nitrous oxide was detected on the day of fertilization with the KNO 3 treatment, and the mole fraction of N 2 O decreased from 0.44 to 0.11 with each weekly application of N.