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A model of ammonia volatilization from applied urea. III. Sensitivity analysis, mechanisms, and applications
Author(s) -
NYE P. H.
Publication year - 1986
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1986.tb00004.x
Subject(s) - ammonia volatilization from urea , urease , ammonia , volatilisation , chemistry , urea , environmental chemistry , adsorption , bicarbonate , inorganic chemistry , ammoniacal nitrogen , nitrogen , organic chemistry
SUMMARY A sensitivity analysis of the model described in Part I showed that the proportion of N lost as ammonia from surface applied urea is very sensitive to the initial pH of the soil, its pH buffer capacity, the rate of urea application, and the soil urease activity. Under the conditions tested, the diffusion of bicarbonate ion to the soil surface, to neutralize the acid generated when NH 4 + is volatilized as NH 3 , appeared to be the main process controlling the rate of ammonia volatilization. The amount of ammonia volatilized was not very sensitive to the value of the transfer coefficient between the soil surface and the atmosphere, nor to the soil moisture status if this was around field capacity. Adsorption of ammoniacal‐nitrogen was less important than the soil pH buffer capacity in influencing the ammonia volatilization. Further applications and extensions of the model are discussed.