Ammonia volatilisation from urea fertiliser products applied to an alkaline soil

摘要

A static chamber system was used to measure the levels of ammonia volatilisation from 7 urea-based fertiliser products and one non-urea based nitrogen fertiliser, applied to the surface of a Calcixerollic xerochrept. Ammonium sulfate, urea, urea coated with sulfur (2 levels), urea coated with polymer (2 levels) and zinc-coated urea (2 levels) were applied to the surface of the alkaline soil and incubated in sealed jars for 4 and 7 days. Ammonia volatilisation levels varied from 4.9% for ammonium sulfate to 7.9% for one of the zinc-coated urea products, after 7 days of incubation. There was no significant difference between urea and any of the urea-coated fertilisers. Significantly higher levels of ammonia were volatilised after 7 days compared to 4days. The levels of volatilisation were low compared with other studies, possibly caused by low levels of urease activity in the soil used. In addition, the lack of inhibition of volatilisation by the surface-coated fertilisers was in contrast to previous findings.