Abstract:Nitrous oxide (N2O) plays an important role in global warming. N2O is long-lived and cause harm to the stratospheric ozone. The concentration of N2O has increased from 270 ppbv during the preindustrial period to 319 ppbv in 2005. The greenhouse effect of N2O is 296 to 310-fold higher than that of carbon dioxide, although its contribution is only 5% (2.6 Tg) of the total annual man-made greenhouse gas emissions in 2010. Use of fertilizer is a major factor in the increase in N2O levels in agricultural systems. The wheat-maize rotation system is one of the most popular cultivating systems in the North China Plain. In recent years, a new method of fertilization (controlled-release fertilization) has been introduced in this region to reduce N fertilizer losses and to save labor inputs; this has mainly been used in crop lands, such as paddy fields, wheat and maize growing systems, but also in vegetable fields, such as tomato fields. The reported results mostly focus on crop growing and nitrogen leaching, but rarely on the N2O emissions characteristics related to controlled-release fertilizers in wheat-maize rotation systems, and even more rarely on exact quantities of various controlled-release fertilizers being applied in the North China Plain. This study was conducted from October 2013 to October 2014, with the major focus on the effects of application of controlled-release fertilizers on nitrous oxide and crop yields. The N2O emission driving factors, such as the soil temperature, soil moisture, and the content of soil NO3--N, were also analyzed together with N2O fluxes. Five treatments were included in this study:control treatment (CK), controlled-release fertilization treatment 1 (CRF1), optimized controlled-release fertilization treatment 1 (80%CRF1), optimized controlled-release fertilization treatment 2 (80%CRF2), and controlled-release fertilization treatment 3 (CRF3+Urea). The results show that the high N2O peaks usually following the basal fertilization can be attributed to irrigation or precipitation. Irrigation during the period of wheat seeding establishment, and precipitation during the later period of maize cultivation may also result in weak N2O peaks. The N2O fluxes changed from -235.61 μg N2O m-2 h-1 to 2625.01 μg N2O m-2 h-1, and daily mean N2O fluxes ranged from 23.88 μg N2O m-2 h-1 to 51.39 μg N2O m-2 h-1. N2O fluxes were positively correlated to soil temperature at a depth of 5 cm for CK and CRF3+Urea; the correlation coefficient (r2) was 0.38 and 0.30, respectively. N2O fluxes were positively correlated to soil water filled pore space (WFPS) during wheat and whole rotation system for CRF1 and 80%CRF1 (for wheat:r2=0.50, P < 0.01; r2=0.39, P < 0.05; for whole system:r2=0.39, P < 0.05; r2=0.43, P < 0.05). For the same fertilizer type, compared to CRF1 treatment, 80%CRF1 reduced the annual N2O emission by 14.23%. For the same fertilizer rate, there was no significant difference between CRF1 and CRF3+Urea, but 80%CRF1 significantly reduced the annual N2O emission by 16.16% compared to 80%CRF2 (P < 0.05). There was no significant difference in crop yields between these treatments and the treatments practiced by farmers. In conclusion, controlled-release fertilizer management could reduce N2O emission from the wheat-maize rotation system while maintaining cropping yields.