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Wheat Volatilized Ammonia and Resulting Nitrogen Isotopic Fractionation
Author(s) -
O'Deen W. A.
Publication year - 1989
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1989.00021962008100060027x
Subject(s) - fractionation , volatilisation , nitrogen , chemistry , ammonia , agronomy , isotopes of nitrogen , chromatography , biology , organic chemistry
Many agricultural crops show significant losses of N from flowering to maturity (during senescence). This research employs 15 N fertilization to measure volatilization of NH 3 directly from plants. A Plexiglas chamber was designed to isolate the aerial part of winter wheat ( Triticum aestivum L. cv. Vona) from its growth medium following anthesis. The system was a continuous free‐flow, open design. Volatilized ammonia was trapped in surfaces of 0.1 M HCl continuously for three separate 90 d runs conducted in 1983, 1984, and 1985. The potted wheat yielded sensitive double‐peaked senescent N bands representing 3 to 4% of the N within the in‐chamber crop. The NH 15 ‐N emission was from the internal N pool of the plant. Wheat tissue total N was determined by gravimetric Kjeldahl procedures employing tube diffusion. Fractionation of 14 N and 15 N isotopes, previously observed with tube diffusion and steam distillation, provided a basic model for similar fractionation caused by wheat volatilization of NH 3 . The varying atom percent 15 N trends fit a model of continuously increasing wheat 15 N content due to volatilization of NH 3 with lower 15 N content.