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温室气体大量排放使得全球变暖已成为世界公认的热点问题之一。农田生态系统在全球碳循环与碳平衡中扮演着重要的角色。文中运用开路式涡度相关测量系统进行定点定位观测,研究干旱区农田生态系统/大气间净交换量(Net Ecosystem Exchange),分析农田生态系统中碳源/汇功能的关系。结果表明:新疆棉田生态系统在现蕾期、开花期与铃期CO_2通量日变化呈现出单峰型的“U”型曲线,现蕾期、开花期和铃期CO_2通量最高点在凌晨3:00、4:00和1:00,分别为9.45、8.78和7.68umol·m~(-2)·s~(-1),CO_2通量最低点在正午14:00、15:00和15:00,依次为-19.35、-21.73和-20.51umol·m~(-2)·s~(-1)。不同生育期夜晚NEE值均负值,表明棉田生态系统夜间处于碳排放过程;白天正值,棉田生态系统为碳吸收过程。棉花不同生育期均为碳储存,且开花期碳储量最大,平均值为-7.26g·m~(-2)·d~(-1),其次是现蕾期,平均值为-6.31g·m~(-2)·d~(-1),铃期平均值为-5.37g·m~(-2)·d~(-1)。温度和降雨对棉田生态系统碳储量影响显著。研究结果表明干旱区高产棉田生态系统有着较好的碳储量,是一个碳汇过程。
The massive emission of greenhouse gases makes global warming has become one of the hot issues recognized by the world. Farmland ecosystems play an important role in the global carbon cycle and carbon balance. The article uses the open-path vorticity-related measurement system to carry out fixed-point positioning observation to study Net Ecosystem Exchange in arid area, and to analyze the relationship between carbon source / sink function in farmland ecosystem. The results showed that the diurnal variation of CO_2 flux in the cotton ecosystem in Xinjiang showed a unimodal curve of “U” shape, the highest CO 2 flux in budding, flowering and boll stage At 9.45, 8.78 and 7.68umol · m -2 s -1, respectively, at 3:00, 4:00 and 1:00, the lowest CO 2 flux was at 14:00 noon and 15: 00 and 15:00, followed by -19.35, -21.73 and -20.51umol · m -2 · s -1, respectively. The values of NEE at different growth stages were negative, indicating that the cotton ecosystem was carbonated at night and the daytime was positive and the cotton ecosystem was carbon absorption. Cotton had carbon storage at different growth stages and had the largest carbon storage at flowering stage with an average of -7.26g · m -2 · d -1, followed by budding stage with an average of -6.31g · m ~ (-2) · d ~ (-1), and the average of boll stage was -5.37g · m ~ (-2) · d ~ (-1). Temperature and rainfall have a significant impact on ecosystem carbon storage in cotton fields. The result shows that the high yield cotton ecosystem in arid area has a good carbon storage and is a carbon sink.