Influences of tillage methods on N2O emission from winter wheat field in North China Plain

To determine the effects of tillage practice on N2O emission from winter wheat field and the cause of seasonal emission variation in the emission, a field experiment was carried out at Luancheng Agroecosystem Experiment Station, Chinese Academy of Sciences, in Hebei province. The experimental design consisted of conventional tillage (CT), rotary tillage (RT) and no tillage (NT) treatments. The N2O emissions were measured in the winter wheat growing season with the static close chamber method. The results showed that, during 72 hours after seeding, the N2O cumulative emission of CT, RT and NT were 3.83, 10.27 and 10.55 mg/m2, respectively. Under the condition of straw returning, the seasonal cumulative N2O emission of winter wheat field demonstrated as CT>RT>NT. The N2O emission significantly positively correlated with soil temperature at 0–20 cm soil layer under CT and NT treatment, while negative correlation was found between the N2O emission and soil air-filled porosity at 0–5 cm soil layer. With a higher C/N ratio in soil treatment, NT was more likely to reduce the emission of N2O. Generally, NT would be a better choice to reduce the N2O emission effectively in the Northeast Plain.