氮肥施用对柑橘果园土壤有机碳矿化的影响(英文)

Effects of Nitrogen Treatments on Organic Carbon Mineralization of Citrus Orchard Soil

[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CO：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（N1）、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] This study aimed to investigate the effect of soil organic carbon mineralization at different temperature on the amount of nitrogen application, in order to provide references for the establishment of carbon circulation model for orchard eco-system. [Method] The effects of nitrogen treatments on soil organic carbon mineralization of citrus orchard soil were investigated under 10, 20, 30 ℃ by laboratory simulated experiment. [Result] The mineralization rate decreased quickly at the be- ginning of the experiment but remained stable at the late period under three temper- ature treatments. The amounts of CO2 ranged from 1 328.25-2 219.42 mg/kg under three temperature condition, and the amount of soil organic carbon mineralization of 100 mg/kg （N4） treatment was the greatest, while that of CK was the lowest. High level nitrogen treatment （N4 and N3） were significant higher than the lower level nitro- gen treatment （N2 and N1）. The soil organic carbon mineralization rate increased with the temperature from 10 to 30℃. The dependence of soil carbon mineralization to temperature （Q10） was different under different nitrogen treatments that the Qlo value of N2 treatment was the lowest while that of the N4 treatment was the greatest. The soil organic carbon mineralization in Citrus orange orchard soil was affected significantly by high level nitrogen treatment, but with no significance under lower nitrogen treatment. [Conclusion] The dependence of soil carbon mineralization to temperature （Q10） increased with the increasing nitrogen input. The combination of nitrogen with temperature may increase the CO2 emission from Citrus orchard soil.