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Ammonia Volatilization from Urea as Influenced by Soil Temperature, Soil Water Content, and Nitrification and Hydrolysis Inhibitors
Author(s) -
Clay D. E.,
Malzer G. L.,
Anderson J. L.
Publication year - 1990
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/sssaj1990.03615995005400010042x
Subject(s) - ammonia volatilization from urea , urea , chemistry , urease , volatilisation , fertilizer , nitrification , environmental chemistry , ammonia , incubation , nitrogen , zoology , agronomy , biochemistry , organic chemistry , biology
Residue cover influences temperature and water gradients in the soil profile. Changes in the physical environment of the soil influence NH 3 volatilization from urea‐containing fertilizers. Field and laboratory experiments were conducted to investigate the influence of residue‐cover‐induced changes in soil water and temperature on NH 3 volatilization as impacted by urea treatment with a nitrification and urease inhibitor. Fertilizer treatments were urea, urea plus dicyandiamide (DCD), urea plus N‐(n‐butyl)thiophosphoric triamide (NBPT), and urea plus NBPT and DCD. Following fertilizer application, the soil was either left bare or covered with corn ( Zea mays L.) residue. Every 3 h over a 4‐d period, water potential, soil temperature, CO 2 production, and NH 3 volatilization were measured. The influence of fertilizer treatments on soil pH was determined in a laboratory incubation experiment conducted over 8 d under controlled environmental conditions. Treatments were similar to the field experiment, with NH 3 volatilization, pH, and CO 2 production measured daily. The NH 3 ‐volatilization rate in the field was highest 2 d after urea application at a time that corresponded with daily maximum soil temperature and decreasing soil water content. Residue cover reduced NH 3 volatilization. Volatilization of NH 3 as a result of urea application was not increased when urea was treated with DCD. Ammonia volatilization as a result of urea treatment with NBPT was reduced by 100 times over untreated urea. During an incubation experiment, soil pH increased from 6.5 to 7.2 in the urea‐NBPT, and from 6.5 to 9.0 in the urea and urea‐DCD treatments. Associated with the pH increase in the urea‐NBPT treatment was a reduction in CO 2 production when compared with the untreated soil.