吊罗山低地森林不同地形土壤的呼吸变化

以地处热带北缘的吊罗山低地森林为研究区，选择在景观结构上具有显著差异的3种地形（分别为平地、坡地和洼地)为研究对象，利用LGR便携式温室气体分析仪及土壤气体通量监测系统，测定吊罗山热带低地森林不同地形土壤呼吸速率和土壤温湿度，研究不同森林地形土壤呼吸的季节变化规律及其差异，并探讨土壤呼吸与水热因子的关系。结果表明:（1）平地和坡地的土壤呼吸速率均表现出“雨季高、旱季低”的动态变化，雨季6～8月出现排放峰值；洼地则出现“雨季低、旱季高”的动态变化，进入旱季土壤呼吸速率升高，3～5月出现排放峰值，雨季开始降低；（2）不同地形的土壤呼吸年积累量大小具有明显差异，表现为洼地(986.37 ± 46.91) g C·m?2·a?1]> 坡地(901.46 ± 47.00) g C·m?2·a?1] > 平地796.85 ± 36.86) g C·m?2·a?1]；（3）不同地形土壤呼吸与土壤温湿度的关系并不一致，其中坡地的相关关系最显著(P< 0.01)，Q₁₀值为3.19。综上所述，吊罗山低地森林中不同地形土壤呼吸存在显著差异，当把土壤二氧化碳通量外推到更大尺度时，必须要考虑地形的复杂性。

Soil Respiration of Different Terrains in a Tropical Lowland Rainforest in Diaoluoshan,Hainan, China

Soil respiration is a frontier topic in the carbon cycle of terrestrial ecosystems. The seasonal variations and differences of soil respiration in different terrains were analyzed by measuring the soil respiration rate and soil temperature and moisture in a tropical lowland forest in Diaoluoshan, Hainan, China, and the relationship between the soil respiration and the hydrothermal factors was also analyzed. The results showed that the soil respiration rate in the flat terrain and sloping terrain had a dynamic change of "higher in rainy season and lower in dry season", with peak emissions from June to August. On the contrary, the soil respiration rate in the low-lying terrain had a dynamic change of "lower in rainy season and higher in dry season", with the peak emissions from March to May. The annual accumulation of soil respiration in different terrains varied significantly, which was in the order of the low-lying terrain (986.37 ± 46.91) g C· m?2·a?1 > the sloping terrain (901.46 ± 47.00) g C·m?2·a?1 > the flat terrain (796.85 ± 36.86) g C·m?2·a?1. The soil respiration in different terrains was not consistently correlated with the soil temperature and moisture, but the soil respiration in the sloping terrain was most significantly correlated with the soil temperature and moisture (P< 0.01), with a Q₁₀ value of 3.19. These results indicated that there were significant differences in soil respiration in different terrains in a tropical lowland forest in Diaoluoshan, Hainan. When the soil CO₂ flux is extrapolated to a larger scale, the complexity of the terrain should be taken into account.