海南儋州地区橡胶林碳通量特征研究

以位于海南省西北部儋州地区的橡胶林为研究对象，采用涡度相关技术进行长期CO₂通量观测。结果表明:1）橡胶林净生态系统碳交换（NEE）日动态为“U”型曲线，白天NEE为负值，是碳吸收，夜间NEE为正值，是碳排放；全年除2月份为较弱的碳排放外，其余月份均为碳吸收，雨季各月NEE值较大，旱季各月NEE值较小，橡胶林碳吸收最强月份为6月，碳排放最强（吸收最弱）的月份为2月；因研究样地橡胶林树正处于生长旺盛期，固碳能力强大，橡胶林年NEE总量超过11.0 t·hm^-2·a^-1，碳汇能力高于其他亚热带和热带人工林，也高于纬度接近的海南岛尖峰岭热带山地雨林。2）橡胶林生态系统呼吸（R_e）日动态为单峰型曲线，全年R_e均为正值，即为碳排放，白天R_e量及变动幅度均明显大于夜间；全年R_e日变化呈不规则曲线，全年雨季各月R_e值均较大，旱季各月R_e值相对较小，橡胶林生态系统呼吸最强月份为8月，呼吸最弱的月份为12月；海南岛橡胶林生态系统年呼吸总量巨大，年总量超过20.0 t·hm^-2·a^-1，与同纬度的热带雨林接近。

Characteristics of Carbon Fluxes in a Rubber Plantation Ecosystem in Danzhou Area,Hainan Province

In order to obtain the characteristics of carbon fluxes in rubber plantation ecosystem, the rubber plantations in Danzhou, which is located in northwest of Hainan Province was selected as research object, and CO₂, temperature, moisture, photosynthetically active radiation (PAR), and were monitored by eddy covariance. The following results were obtained: 1) The daily net ecosystem exchange (NEE) dynamic of rubber plantation ecosystem showed a "U" shape curve. The daytime NEE was negative, representing carbon absorbing, while positive NEE at nighttime representing carbon releasing. In all the months of a year, except for February (which demonstrated a weak carbon relasing), carbon absorption was observed. NEE values were higher in rainy season than in dry season. The strongest carbon absorption was found in June, while the strongest carbon releasing was in February. Because the rubber plantations selected were in their vigorous growth periods, they demonstrated the strongest carbon fixation capacity. The total annual NEE of the rubber plantation was more than 11.0 t·hm^-2·a^-1 which was larger than the subtropical and tropical plantations, higher than the tropical mountaineous rainforest in Jianfengling with similar latitude. 2) The daily ecosystem respiration (R_e) dynamic of rubber plantation ecosystem showed a single peak curve. The R_e of the whole year was positive which meant carbon releasing. The R_e amount and the change amplitude of daytime were obviously larger than those in nighttime. The diurnal R_e changes of the year showed irregular curve. Monthly R_e value in rainy season was larger than in dry season. The strongest month of respiration in rubber plantation ecosystem was August, and the weakest was December. The annual total R_e of rubber plantation ecosystem in Hainan Island was very large, more than 20.0 t·hm^-2·a^-1, and the value was nearly closer with the same latitude tropical rainforest.