Nitrogen losses can be high from irrigated cropping soils, but these losses can be minimised with careful attention to N fertiliser management. N is lost principally where nitrate is converted to N gases (denitrification), but also with nitrate leaching. These losses account for 30% of the N fertiliser applied to irrigated cotton on average; these losses can be doubled in extreme cases where poorly-structured soils become waterlogged. Because some fertiliser N is lost as nitrous oxide (N2O), an extremely potent greenhouse gas, inefficient N fertiliser use has become an environmental issue that the cotton industry is addressing with research and improved N fertiliser management practices.