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Gaseous N Losses from Winter Wheat 1
Author(s) -
Hooker M. L.,
Sander D. H.,
Peterson G. A.,
Daigger L. A.
Publication year - 1980
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/agronj1980.00021962007200050024x
Subject(s) - volatilisation , reagent , nitrogen , chemistry , ammonia , elongation , agronomy , horticulture , environmental science , zoology , biology , materials science , organic chemistry , metallurgy , ultimate tensile strength
Research monitoring N uptake by various agricultural crops has shown total N accumulations in the plant to increase prior to the growth stages around heading to flowering with a subsequent decrease in total N occurring after flowering. Volatilization of N from the plant may account for much of this loss as well as account for some of the deficits exhibited in N balance studies. Experiments were conducted in a gas‐tight growth chamber to determine what role plants alone may play in the overall loss of N from the soil‐plant system. Winter wheat ( Triticum aestivum L.) was established, vernalized, and grown to maturity in the growth chamber. At first internode elongation, the chamber was closed and sealed for the duration of the experiment. Air supplied to the chamber during this period was bubbled through 1 N H 2 SO 4 to remove ambient NH 3 and through a reagent specific to NO and NO 2 to remove these gases. Air samples were continuously drawn from the chamber and bubbled through 0.2 N H 2 SO 4 to trap evolved NH 3 . These samples were collected weekly and analyzed using steam distillation. A second portion of the air sample was washed through the NO‐NO 2 specific reagent and analyzed colorimetrically. Only trace amounts of NO and NO 2 could be found at any time during the experiment leading to the conclusion that volatilization of these gases does not contribute significantly to the loss of N from the plant. Ammonia volatilized from the system at the rate of 0.34 to 0.89 ✕ 10 −1 mg NH 3 ‐N/m 2 /day prior to flowering. After flowering the rate of NH 3 ‐N evolution increased to 1.03 to 1.32 ✕ 10 −1 mg/m 2 /day. This dramatic increase in the rate of NH 3 ‐N evolution at flowering coincides with the plant growth stage that researchers have begun to observe deficits in total N accumulations in the above ground portion of the plants. This data supports the hypothesis forwarded here, that volatilization of NH 3 from plant tissue can partially account for the deficits in total N accumulation observed in plant tissue following flowering.