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[目的]了解柑橘果园土壤有机碳矿化在不同温度下对不同氮肥施用量的影响关系,为构建果园生态系统的碳循环模型提供参数。[方法]采用室内模拟试验,在10、20、30℃3个温度条件下,研究施肥施用对柑橘果园土壤有机碳矿化的影响。[结果]3种温度处理下,各施氮处理土壤有机碳矿化速率都表现为培养前期快速下降,培养后期保持相对稳定的趋势。在整个培养过程中,3种温度条件下各施氮处理的土壤CO2累积排放量为1328.25~2219.42mg/kg,100mg/kg(N4)处理土壤有机碳矿化量最大,CK处理最低,100mg/kg(N4)和80mg/kg(N3)2个高氮处理显著高于低氮50mg/kg(N2)、30mg/kg(N1)处理。土壤有机碳矿化速率随温度升高而增长,不同的土壤施氮条件下土壤有机碳矿化的温度敏感性不同,N2处理土壤有机碳矿化的温度敏感性最低,N4处理最高。柑橘果园土壤有机碳矿化受高施氮量影响较大,低施氮影响不明显。[结论]随着施氮量的增加土壤有机碳矿化的温度敏感性增加,氮肥施用和温度的共同作用可能使柑橘林向大气中排放的CO2增加。
[Objective] The research aimed to understand the relationship between soil organic carbon mineralization and nitrogen fertilizer application rates in citrus orchards and provide parameters for constructing carbon cycle model of orchard ecosystem. [Method] The effects of fertilization on the mineralization of organic carbon in citrus orchard were studied by indoor simulation experiment under the conditions of 10, 20 and 30 ℃. [Result] Under the three treatments, the mineralization rates of soil organic C showed the rapid decline in the early stage of culture and the relatively stable trend in the late stage of culture. During the whole incubation process, the accumulated CO2 emission of soil under nitrogen application was 1328.25-2219.42mg / kg under the three temperature conditions. Soil organic carbon mineralization was the highest at 100mg / kg (N4) The two high nitrogen treatments of kg (N4) and 80mg / kg (N3) were significantly higher than those of low nitrogen 50mg / kg (N2) and 30mg / kg (N1). Soil organic carbon mineralization rate increased with increasing temperature. Soil organic carbon mineralization under different nitrogen application conditions had different temperature sensitivity. Soil organic carbon mineralization under N2 treatment had the lowest temperature sensitivity and highest N4 treatment. Soil organic carbon mineralization in citrus orchards was greatly affected by high amount of nitrogen application, but the effect of low amount of nitrogen application was not obvious. [Conclusion] The temperature sensitivity of soil organic carbon mineralization increased with the increase of nitrogen application rate. The combination of nitrogen application and temperature may increase the CO2 emission from the citrus forest to the atmosphere.