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土壤异养呼吸是土壤碳库净输出的主要途径,其对气候变暖的响应已引起国内外学者的广泛关注。对森林生态系统来说,林龄是影响生态系统碳平衡的一个重要因素。柑橘作为三峡库区第一大支柱产业,种植面积极广,对维持该区域的生态平衡起着巨大的调节作用。该文以三峡库区宜昌市郊区种植年限不同的3个橘林土壤为研究对象,采用室内培养法,研究在不同温度条件下,不同林龄土壤的异养呼吸及其温度敏感系数的差异,探讨该区域生态系统对未来气候变化的潜在响应。结果显示,随着种植年限的增加,橘林土壤pH值减小,有机质和全氮含量显著增加,土壤微生物生物量碳呈下降趋势。无论在低温、常温还是高温条件下,林龄较小的橘树土壤异养呼吸及其累积释放量较低。与其他研究相比,该区域人工橘林土壤异养呼吸的温度敏感系数Q10值相对较低(1.45–1.69),且随着培养时间的变化而变化。随着种植年限的增加,人工橘林土壤异养呼吸的温度敏感性逐渐降低,表明在未来全球气候变暖条件下,幼龄人工橘林要比成熟林对温度的反应敏感。
Heterotrophic respiration of soil is the main way of net output of soil carbon pool, and its response to climate warming has drawn wide attention of domestic and foreign scholars. For forest ecosystems, stand age is an important factor affecting the carbon balance of ecosystems. Citrus, as the first pillar industry in the Three Gorges Reservoir Area, has a very large planting area and plays a huge regulatory role in maintaining the ecological balance in the region. In this paper, three orange plantations with different planting years in the suburbs of Yichang in the Three Gorges Reservoir Area were selected as research objects. The indoor culture method was used to study the heterotrophic respiration and temperature sensitivity of different age soils under different temperature conditions. Explore the potential response of the region’s ecosystems to future climate change. The results showed that with the increase of planting years, soil pH decreased, the contents of organic matter and total nitrogen increased significantly, and the soil microbial biomass carbon decreased. No matter under the condition of low temperature, normal temperature or high temperature, the heterotrophic respiration and the cumulative release amount of soil of the younger orange tree are lower. Compared with other studies, the Q10 value of soil heterotrophic respiration in this region was relatively low (1.45-1.69), and varied with the incubation time. With the increase of planting years, the temperature sensitivity of soil heterotrophic respiration decreased gradually in artificial orange plantation, which indicated that the young artificial orange plantation was more sensitive to temperature than the mature plantation under the global warming condition in the future.