[Effects of applying controlled-release fertilizer and its combination with urea on nitrous oxide emission during rice growth period].

By the method of static chamber, a field experiment was conducted to study the effects of applying controlled-release fertilizer (CRF) and its combination with urea on the N2O emission during rice growth period. Four treatments, i.e., no fertilization (CK), urea (U), urea and CRF with a ratio of 3:7 (U+C), and CRF (C) were installed, and the N application rate in treatments U, U+C, and C was the same. Compared with treatment U, treatments U+C and C decreased the N2O emission during rice growth season by 40.4% and 59.6%, and decreased the emission at midseason aeration stage by 65.1% and 83.9%, respectively (P < 0.05). Compared with that in treatment C, the N2O emission in treatment U+C had a slight decrease, and decreased by 53.9% at midseason aeration stage. Applying CRF increased rice yield, and the increment in treatments C and U+C was 7.8% and 9.8%, respectively, as compared to treatment U. Applying CRF delayed the peak time of soil inorganic nitrogen concentration, resulting in the reduction of N2O emission at midseason aeration stage. During rice growth season, no significant correlation was observed between N2O flux and soil Eh or soil temperature.