[Soil N2O flux and its affecting factors under different land use patterns in Three Gorges Reservoir Area of China].

By using static chamber techniques, the N2O emission from soils under different land use patterns was measured. The results showed that the N2O flux ranged from -21 to 435 microg x m(-2) h(-1), and the annual N2O flux was decreased in the order of vegetable field > orchard > upland > upland transferred from paddy field > woodland, being 447.14, 313.

[Variations and influencing factors of nitrate nitrogen concentration in water in a small watershed of Three Gorges area].

In order to study the water quality and response to influencing factors in typical watersheds of Three Gorges area between 2004 and 2005, the variation characteristics of nitrate nitrogen concentration were analyzed under heterogeneous landscape condition through continuous observation with method of dividing into sub-watersheds in Quxi watershed (the first-grade branch, located in Three Gorges). The results suggested that nitrate nitrogen concentration fluctuated between 0.4 and 14.

[CO2 fluxes from red soil under four land use types in mid-subtropical, China].

CO2 fluxes from red soil under different land use (paddy, upland, woodland and orchard) were measured at Xianning city, Hubei province with closed chamber method. The results showed that the annual CO2 emission were 1129, 632, 533, and 828 g/(m2 a) for paddy, upland, woodland, and orchard respectively. Soil CO2 fluxes revealed seasonal fluctuations, with the tendency that maximum value was in summer, minimum was in winter and intermediate in spring and autumn except for paddy soil.