Annual dynamics of N<sub>2</sub>O emissions from a tea field in southern subtropical China

Abstract

The annual dynamics of N<sub>2</sub>O emissions from a tea field in southern subtropical China was observed in situ weekly in 2010 using a static closed chamber – gas chromatography (GC) method for three treatments: non-fertilised (CK), conventional (CON) and rice straw mulching (SM). The annual N<sub>2</sub>O emissions for CK, CON and SM were 7.1, 17.2 and 16.7 kg N/ha/year, respectively. The N<sub>2</sub>O emission factors for the CON and SM treatments were estimated as 2.23% and 1.91% of the total fertiliser N applied, respectively. Rice straw mulching exhibited a potential to reduce the N<sub>2</sub>O emissions from the tea field, but not statistically significant (P = 0.82). The daily N<sub>2</sub>O fluxes were positively correlated with the air temperature. The cumulative precipitation of the previous five days was significantly correlated with the daily N<sub>2</sub>O fluxes of CON. The soil water contents were significantly correlated with the daily N<sub>2</sub>O fluxes in the three treatments. The N<sub>2</sub>O fluxes from CON had a more significant correlation with the soil NH<sub>4</sub><sup>+</sup>-N contents than with the soil NO<sub>3</sub><sup>–</sup>-N contents, while the N<sub>2</sub>O fluxes from SM showed an inverse pattern. The N<sub>2</sub>O fluxes from CK did not show any significant relationship with the soil mineral N content.