Mitigation of ammonia volatilisation from urea with micronised sulfur applied to common bean

Urea with micronised sulfur (S) in granules may result in lower nitrogen (N) depletion through ammoniacal N (NH3-N) loss than conventional urea due to the acidification reaction of S near urea granules in soil, and the addition of S to the urea may provide a limiting nutrient in tropical soils. The research objectives were to (1) verify whether urea containing micronised S (urea+S) can mitigate NH3-N volatilisation in comparison to conventional urea, ammonium nitrate, and ammonium sulfate; and (2) evaluate the efficiency of N and S sources for common bean (Phaseolus vulgaris L.) grown on coarse-, medium-, and fine-textured soil. The results showed that 90% of NH3-N volatilisation occurred during the first 14 days after application. The blend of elemental sulfur and sulfate in urea reduces the loss of N by NH3-N volatilisation compared with regular urea but not enough to achieve the low volatilisation as observed for ammonium nitrate and ammonium sulfate application. Despite the differences in the leaf N and S concentration and bean yield components, no differences were observed among N sources in grain yield in general.