Annual dynamics of N2O emissions from a tea field in southern subtropical China

Abstract

The annual dynamics of N2O 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 N2O emissions for CK, CON and SM were 7.1, 17.2 and 16.7 kg N/ha/year, respectively. The N2O 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 N2O emissions from the tea field, but not statistically significant (P = 0.82). The daily N2O fluxes were positively correlated with the air temperature. The cumulative precipitation of the previous five days was significantly correlated with the daily N2O fluxes of CON. The soil water contents were significantly correlated with the daily N2O fluxes in the three treatments. The N2O fluxes from CON had a more significant correlation with the soil NH4+-N contents than with the soil NO3--N contents, while the N2O fluxes from SM showed an inverse pattern. The N2O fluxes from CK did not show any significant relationship with the soil mineral N content.

Keywords

• fertilised tea field
• nitrous oxide
• straw mulching
• environmental factors