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Gaseous Ammonia Losses from Urea Solutions Applied as a Foliar Spray to Various Grass Sods
Author(s) -
Simpson D. M. H.,
Melsted S. W.
Publication year - 1962
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1962.03615995002600020026x
Subject(s) - urea , ammonia , ammonia volatilization from urea , acre , zoology , volatilisation , chemistry , hydrolysis , agronomy , horticulture , biology , biochemistry , organic chemistry
The gaseous loss of NH 3 from urea applied to plant sods was studied under laboratory conditions, using various grasses which had been grown in pots under greenhouse conditions. Spray applications of N 15 ‐ and C 14 ‐labeled urea solutions equivalent to 50, 100, and 150 pounds of N per acre were made to the potted plant samples which had been transferred to a bell‐jar apparatus. Care was taken to spray as much of the solution as possible directly on the plant foliage. The total amount of NH 3 lost through volatilization, as measured over a period of 8 to 10 days, increased with increasing rates of application. Losses ranged from about 0.5 pounds per acre with a 50‐pound application to about 45 pounds with the 150‐pound application. A lag period of 2 to 3 days occurred before any measurable quantity of NH 3 was lost from any of the plants, with the exception of bluegrass. The greatest amount of urea hydrolysis, as measured by C 14 O 2 evolution, occurred during this 2‐ to 3‐day period. The amount of NH 3 lost and the rate of urea hydrolysis were influenced somewhat by the type of sod to which urea was applied. In most cases, there apparently was little or no direct relationship between C 14 O 2 evolution and the NH 3 lost.