2013/04/25 by Philippe Rochette, Denis A. Angers, Martin H. Chantigny +5
Agricultural and Biological Sciences · Engineering · Environmental Science · #Soil Carbon and Nitrogen Dynamics #Soil and Unsaturated Flow #Soil and Water Nutrient Dynamics
paper · pdf · doi:10.4141/cjss2012-095
Rochette, P., Angers, D. A., Chantigny, M. H., Gasser, M.-O., MacDonald, J. D., Pelster, D. E. and Bertrand, N. 2013. NH 3 volatilization, soil [Formula: see text] concentration and soil pH following subsurface banding of urea at increasing rates. Can. J. Soil Sci. 93: 261–268. Subsurface banding of urea can result in large ammonia (NH 3 ) emissions following a local increase in soil ammonium ([Formula: see text]) concentration and pH. We conducted a field experiment to determine how application rates of subsurface banded urea impact NH 3 volatilization. Urea was banded at a 5 cm depth to a silty loam soil (pH=5.5) at rates of 0, 6.1, 9.2, 13.3 and 15.3 g N m −1 . Ammonia volatilization (wind tunnels), and soil [Formula: see text] concentration and pH (0–10 cm) were monitored for 25 d following urea application. Volatilization losses increased exponentially with urea application rate to 11.6% of applied N for the highest urea rate, indicating that as more urea N was added to the soil a larger fraction was lost as NH 3 . Cumulative NH 3 -N emissions were closely related (R 2 ≥0.85) to maximum increases in soil [Formula: see text] concentration and pH, and their combined influence likely contributed to the nonlinearity of the volatilization response to urea application rate. However, the rapid increase in NH 3 losses when soil pH rose above 7 suggests that soil pH was the main factor explaining the nonlinear response of NH 3 volatilization. When compared with previous studies, our results suggest that the response of NH 3 volatilization losses to urea application rate in acidic soils are controlled by similar factors whether urea is broadcasted at the soil surface or subsurface banded.