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Ammonia Volatilization from Spring Wheat Plants
Author(s) -
Parton W. J.,
Morgan J. A.,
Altenhofen J. M.,
Harper L. A.
Publication year - 1988
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/agronj1988.00021962008000030008x
Subject(s) - loam , shoot , volatilisation , nitrogen , chemistry , agronomy , ammonia , poaceae , horticulture , ammonia volatilization from urea , soil water , biology , ecology , organic chemistry
Plant shoots may be a significant source of N loss in crops. Ammonia volatilization and CO 2 exchange rates from ‘Olaf’ spring wheat ( Triticum aestivum L.) plants exposed to low‐ and high‐N treatments were observed from heading through the hard kernel phenological stages. The plants were grown in growth chambers (Nunn clay loam soil [Aridic Argiustoll]) where whole‐plant gas‐exchange measurements were made using a plexiglass cuvette. Plants lost NH 3 at fairly constant rates (60–120 ng NH 3 –N m −2 s −1 ) during the pre‐senescence time period (before milk ripe stage), but the loss rate increased to 200 to 300 ng NH 3 m −2 s −1 during final plant senescence. A reverse pattern was observed in CO 2 exchange rates. Rates of CO 2 exchange ranged from 0.13 to 0.42 mg CO 2 s −1 during heading, but dropped off (gradually in the high‐N treatment, abruptly in the low‐N treatment) as the plants began to senesce. The NH 3 loss rates on a leaf‐area basis were similar for the low‐ and high‐N plants despite significantly higher N concentrations in high‐N plants. Twice the leaf area was attained by the high‐N plants, resulting in NH 3 volatilization rates per plant roughly twice those observed in the low‐N plants. The results suggest that significant amounts of NH 3 can be lost from wheat shoots.