Comparison of sulphur-coated urea and ammonium sulphate amended with N-Serve as sources of nitrogen for sugarcane

Abstract

SUMMARYA comparison of ammonium sulphate (AS) with and without N-Serve and sulphurcoated urea (SCU) as N sources for sugarcane, studied in a pot experiment, showed that although the tillering, the leaf N concentration and cane yield were increased by adding fertilizer N there were no significant differences between N sources. However, AS and AS + N-Serve depressed the soil pH, especially that of acidic soils, much more than SCU. In a field experiment where AS, urea and SCU were compared on a calcareous soil, it was observed that urea gave significantly lower cane and sucrose yields than AS and SCU when N was applied on the surface, possibly due to greater volatiliization losses from urea. Subsurface application increased the efficiency of urea, although the method of placement had no significant effect on the N efficiency of AS and SCU. AS was as effective as SCU. Thus the coating of urea by sulphur increased its efficiency for sugarcane only when applied on the surface of a calcareous soil.