Abstract: Amethod for measuring NOand NO₂ exchanges between cultivated lands and the atmosphere in a FACE (free-air CO₂ enrichment) study is described. With this method, gas is sampled with a technique of static-opaque-chamber and the fluxes of NOand NO₂ exchanges are determined by analyzing the NOand NO₂ concentrations with a chemiluminescent NOx analyzer. Application of this method in the FACEstudy of a rice-wheat ecosystem has indicated that reliable data on the exchange fluxes could be obtained. Over the non-waterlogged period of a rice-wheat rotation, net emission of NOfrom the fields was observed, while net uptake of NO₂ occurred. The daily net emission of NOdid not correlated with the soil temperature, but negatively depended upon soil moisture (R²=0.82,P<0.001). Asignificant seasonal variation in the net uptake of NO₂ was observed, which was regulated by wheat growth status. The daily uptake of NO₂ depended upon both soil temperature and soil moisture. The dependence for each could be described with a parabola function (for soil temperature:R²=0.74,P<0.001;for soil moisture:R²=0.69,P<0.001). An elevation of atmospheric CO₂ by 200±40μmol·mol^-1 mitigated the net emission of NOby 19% (t-test P=0.096) and might be possible to reduce the net uptake of NO₂ by 10% (t-test P=0.26), which was likely due to the stimulated wheat growth.