珠江三角洲四种森林类型土壤CO_2通量特征研究

采用开路式土壤CO2通量测量系统Li-8100＆Li-8150对珠江三角洲地区尾叶桉（Eucalyptus urophylla）人工林、乡土树种恢复林、针阔叶混交林和常绿阔叶林4种林型的土壤CO2通量进行了观测。结果表明：4种森林类型年均土壤CO2通量为尾叶桉人工林（3.35μmol.m-2.s-1）〉针阔叶混交林（2.66μmol.m-2.s-1）〉乡土树种恢复林（2.09μmol.m-2.s-1）〉常绿阔叶林（1.86μmol.m-2.s-1）;旱季土壤CO2通量明显小于雨季。前3种森林类型凋落物呼吸处理表明,旱季对照组土壤CO2通量均小于相应的去除凋落物组、雨季则相反,全年的对比结果显示,3种森林类型的凋落物呼吸贡献分别达到1.3%、7.1%和10.8%。土壤CO2通量与10 cm土壤温度呈显著指数相关,且土壤CO2通量温度敏感指数表现为针阔叶混交林Q10最大（3.49）,尾叶桉人工林Q10最小（1.95）。

The study of soil CO_2 flux of four forest types in Pearl River Delta

Li-8100＆Li-8150 was used to observe soil CO2 fluxes of Eucalyptus urophylla forest （EUF）, native tree forest （NTF）, coniferous and broad-leaved mixed forest （CBMF） and evergreen broad-leaved forest （EBF） in Pearl River Delta. Results showed that annual soil CO2 fluxes of four forest types can be represented by the following order： EUF （3.35 μmol·m^-2·s^-1） 〉 CBMF （2.66 μmol·m^-2·s^-1） 〉 NTF （2.09 μmol·m^-2·s^-1） 〉 EBF （1.86 μmol·m^-2·s^-1）. Soil CO2 fluxes of 4 forest types were lower in the dry season than that in the rainy season. In the former three forest types （EUF, NTF, CBMF）, we found that soil CO2 fluxes of contrast groups were lower than that of litter exclusion groups in the dry season, correspondingly, and that showed opposite patterns in the rainy season. The respiration contribution percentages of the former three forest types （EUF, NTF, CBMF） were 1.3%, 7.1% and 10.8%, respectively. Soil CO2 flux had a significantly exponential correlation with soil temperature at 10 cm depth. The Qi0 value was highest in CBMF （3.49） and lowest in EUF （1.95）.