There is growing concern regarding the prospect for global climate change and potential health and environmental effects of increasing atmospheric concentrations of trace gases. Nitrous oxide (N20) and nitric oxide (NO) are among the trace gases of greatest concern. N2O plays two important roles in global change processes. First, it contributes to the depletion of stratospheric ozone [Cicerone, 1987] which protects the biosphere from the harmful effects of solar ultraviolet radiation [Crutzen, 1981]. Second, relative to other greenhouse gases the radiative forcing by N2O is increasing [Shine et al., 1990] and is calculated to currently contribute about 5% of the anthropogenic greenhouse effect. N20 emissions from humid tropical forests account for 20- 50% of all global sources of atmospheric N20 [Davidson, 1991 ]. Because the atmospheric lifetime of N2O is 110-170 years [Ko et at., 1991], current emissions will affect the atmosphere for a long time to come. The global budget of N2O shows a significant imbalance between the known rate of destruction in the stratosphere and the estimated rates of natural and anthropogenic production in soils and the ocean.