Emissions of Nitrous Oxide, Ammonia, and Carbon Dioxide from a Cambisol at Two Contrasting Soil Water Regimes and Urea Granular Sizes

Comparative Efficacy of Urea Fertilization via Supergranules Versus Prills on Nitrogen Distribution, Yield Response and Nitrogen Use Efficiency of Spring Wheat

“…By contrast, USGs placed at depths of either 5.0 or 7.5 cm reduced 15 N losses to 2.6 -4.8%, a finding signifying that gaseous N losses (and NH 3 in particular) could be minimized by deeper USG placement as compared to prills. This is in conformity with the findings of Khalil et al (2006Khalil et al ( , 2009aKhalil et al ( , 2009b) who reported small gaseous losses of USG-N, particularly in the form of NH 3 , NO x , and N 2 O. This also appears to be true with split application of the prills, given that top or side dressing is highly prone to volatilization loss.…”

“…Given the significant improvement in crop production they can be achieved with the banding or nesting of urea prills (Malhi and Nyborg, 1991), we further hypothesize that a shallow (Singh and Beauchamp, 1988) and narrow placement of a relatively small supergranule (<1 g) should be highly effective for achieving the desired crop output levels while simultaneously lessening the risk of added N losses. In particular, the use of USGs could have a large potential for reducing the loss of reactive gaseous N species, especially NH 3 , nitrogen oxides (NO x ) and nitrous oxide (N 2 O) (Khalil et al, 2005(Khalil et al, , 20062009a;2009b).…”

Emission of CO₂, CH₄ and N₂O and dynamics of mineral N in soils amended with castor bean (Ricinus communis L.) and piñón (Jatropha curcas L.) seed cake

“…Zou et al (2005) also reported an increase in N 2 O emissions (17%) when rapeseed cake was added to rice paddies. The amount of N mineral-ized was larger in the RSC-amended soil than in JSC-amended soil so more nitrification occurred in the first than in the latter and N 2 O is emitted when NH 4 + is oxidized to NO 2 -and then to NO 3 - (Khalil et al 2009). Agricultural soils that are a sink for CH 4 can become a source when organic material is applied.…”

Physical and Chemical Manipulation of Urea Fertilizer To Limit the Emission of Reactive Nitrogen Species

“…In another laboratory study, Khalil et al (3) found highest N losses from the PU-treated treatment (1.73%) and regardless of soil type, the larger urea granules did not emit more than 0.27% of the added N over 22 days. This signifies that NH 3 volatilization decreases with increasing granule size and the mixing of PU deeper into the soil reduces NH 3 volatilization greatly as compared to USG point-placed and/or banding of urea (3,4,6,11).…”