Abstract:

Nitrous oxide (N₂O) emissions from the Pinus massoniana woodland were continuously measured using a static closed-chamber method for a year of 2010 and gas chromatography in the southern subtropical in China, and the relationship between N₂O fluxes and main environmental factors were analyzed. The observation result showed that the mean daily N₂O flux during the period was 3.89 g N·hm^-2d^-1. The N₂O fluxes had seasonal variation with the higher fluxes occurring in summer and early autumn, and the lower fluxes in late autumn, winter and spring. The negative fluxes were also observed in winter. The Pearson's correlation analysis indicated that daily N₂O fluxes showed positive and significant correlations with daily minimum air temperature, soil temperature at 5 cm depth and soil volumetric water content of the 0~20 cm soil layer, and highly significant correlation with the cumulative precipitation over previous four days and soil mineral nitrogen content of the 0~20 cm soil layer. In addition, a model for predicting N₂O emissions from the Pinus massoniana woodland was established using multiple linear regression analysis.

Key words: N₂O emissions, Pinus massoniana, subtropical region, environmental factor, forest soil