长白山北坡不同土壤N_2O和CH_4排放的初步研究

A preliminary study on N_2O and CH_4 emissions from differentsoils on northern slope of Changbai Mountain

用箱法技术原位测定了长白山北坡不同土壤（苔原土、生草森林土、棕色针叶林土和暗棕色森林土）６—８月间的Ｎ２Ｏ和ＣＨ４排放．结果表明，这些土壤既是Ｎ２Ｏ的源，又同时是ＣＨ４的汇．Ｎ２Ｏ通量变化于６．１７—１２．３３μｇ·ｍ－２·ｈ－３之间（平均９．３７μｇ·ｍ－２·ｈ－１），ＣＨ４通量为－８５．６３—－７．５８μｇ·ｍ－２·ｈ－１（平均－４１．４５μｇ·ｍ－３·ｈ－１），并观察到在Ｎ２Ｏ排放和ＣＨ４吸收之间有着相互消长关系．实验室培养实验表明，最大反硝化作用活性存在于土壤上层（０—６ｃｍ）；不同土壤的反硝化作用活性明显不同．山地暗棕色森林土的ＣＨ４吸收作用也主要发生在土壤的上层（０—１２ｃｍ）．

The fluxes of N2O and CH4 from tundra soil, soddy forest soil, brown coniferous forest soil and dark brown forest soil on northern slope of Changbai Mountain are measured in situ by chamber technique from June and August, 1994. The results show that all of the soils studied are the source of N2O, and the sink of CH4. The N2O flux is in the range of 6. 17 and 12. 33 μg·m-2· h-1, while the CH4 flux is between -85. 63 and -7. 58μg·m-2·h-1. There is a trade-off between N2O emission and CH4 uptake. Laboratory experiments show that upper soil layer(0-6cm) has the highest denitrification activity, which has a significant difference among different soils. The uptake of CH4 by dark brown forest soil mainly occurs in upper soil layer (0-12cm).