The global distribution of nitrogten input via application of chemical nitrogenous fertilizers to agricultural ecosystems is presented. The suite of 1¿ (latitude/longitude) resolution data bases includes primary data on fertilizer consumption, as well as supporting data sets defining the distribution and intensity of agriculture associated with fertilizer use. The data were developed from a variety of sources and reflect conditions for the mid-1980s. East Asia, where fertilizer use is increasing at ~10%/year, accounted for ~37% of the total, while North America and western Europe, where fertilizer use is leveling off, accounted for 17% and 14% of global use, respectively. Former centrally planned economies of Europe consumed one fifth of the 1984 total, but rapid increases in the 1980s are slowing, and consumption trends are variable. The most widely used chemical nitrogenous fertilizer is urea which accounted for 40% of the world's total in the mid-1980s. While almost every country consumes urea, ~75% of the large East Asian fertilizer use is supplied by this one fertilizer. Ammonium nitrate, used primarily in the former centrally planned economies of Europe, in West Asia, and in Africa, accounted for about one quarter of global consumption. These data were used to estimate distributions of the annual emission of nitrous oxide (N2O) and of ammonia (NH3) associated with the use of fertilizers. Applying published ranges of emission coefficients for fertilizer types in the data base yields a median emission of 0.1 Tg N2O-N, with lower and upper values of 0.03 and 2.0 Tg N2O-N in 1984.

This equals <1% to ~3% of the total nitrogen applied via commercial fertilizers and represents <1% to 15% of the annual emission of N2O from terrestrial sources. Assuming that the ~4% annual increase in consumption of nitrogenous fertilizers during the 1980s corresponds to a ~4% rise in the release of N2O-N, yearly increases in emissions from fertilizer use are <0.01 to 0.08 Tg N2O-N equal to <1% to 3% of the current growth of atmospheric nitrous oxide. However, since no measurements of fertilizer-derived nitrous oxide emissions are available for agricultural consumption is increasing rapidly, relative contributions of climatic regions to current and future emissions remain uncertain. Ammonia emission coefficients for simple groups of fertilizer types were applied to derive the global distribution of ammonia volatilization associated with nitrogenous fertilizer consumption. The 1984 total of ~5-7 Tg NH3-N, about 10--15% of the annual ammonia source, is concentrated overwhelmingly in subtropical Asia owing to the dominant use of urea with high rates of volatilization. However, the paucity of measurements in representative ecological and management environments suggests that the magnitude and distribution of current and future ammonia emission from fertilizers is still poorly known. ¿ American Geophysical Union 1994