Fertilizer-induced nitric oxide emissions from agricultural soils

We summarize and evaluate 23 studies of the effect of fertilizer use on nitric oxide (NO) emission from agricultural soils. To quantify this effect we selected only field-scale studies with duration of at least one complete growing season and excluded studies with a legume as the principle crop. Only 6 studies met the established criteria, resulting in a total of 12 observations of soil/crop/fertilizer combinations, all in temperate areas. For these studies, the amount of NO emitted was linearly related to the amount of fertilizer applied (R2 = 0.64) and about 0.5% of applied nitrogen was emitted as NO during the crop growing season. The available data are too limited to separate the effects of fertilizer type, soil type, or crop management.