氮和磷增加对华南两种人工林土壤甲烷通量的影响

以含氮和磷的养分溶液(NH4NO3和KH2PO4)模拟大气氮和磷沉降,对华南地区两种人工林马占相思(Acacia mangium)和尾叶桉(Eucalyptus urophylla)林下群落进行处理,通过静态气箱法色谱法测定土壤CH4通量,以研究外源氮和磷对华南地区人工林土壤CH4通量的影响.结果 表明,两种人工林的对照样方下CH4通量均为负值,这说明土壤从大气中吸收CH4,也表明鹤山人工林是大气CH4的汇.增氮和增磷处理都增加了马占相思林的CH4排放通量,即促进了马占相思林CH4的排放过程;在旱季,增氮和增磷处理促进了尾叶桉林土壤CH4的排放,但是,从整个实验期间的观测来看,氮和磷处理对尾叶桉林土壤CH4通量没有显著的影响.

EFFECTS OF NITROGEN AND PHOSPHORUS ADDITION ON SOIL CH4 FLUXES IN TWO PLANTATIONS IN SOUTHERN CHINA

To study the effects of nitrogen and phosphorus addition on CH4 fluxes in subtropical zone, a simulated field experiment was carried out in two plantations. Atmospheric N and P deposition were simulated by spraying N and P solution continuously on community in the understorey. The fluxes of CH4 in the plantations soil were measured using static chamber-gas chromatograph technique. The results showed that the fluxes of CH4 under control treatments both in Acacia mangium and Eucalyptus urophylla were negative, which indicated that CH4 were absorbed from the atmosphere, and the plantations in Heshan station were the sink of CH4. N and P addition treatments both increased efflux of CH4 in Acacia mangium. Although N and P treatments had totally no significant effects to the efflux of CH4 in Eucalyptus urophylla, the oxidation of CH4 had been promoted in the dry season.