增温对秦岭温带森林土壤N2O通量的影响

Effects of Warming on Soil N2O Flux in Qingling Temperate Forest

  • 摘要: 为探讨气候变暖对温带森林土壤N2O通量的影响,在秦岭火地塘林区锐齿栎林内利用开顶式增温装置对土壤进行2 a的增温模拟试验,分析增温条件下土壤N2O通量的变化规律和土壤特性对N2O通量的影响。结果表明:增温处理使锐齿栎林土壤N2O通量增加了13.9%,年排放量(1.88±0.57) kg/(hm2·a),其中显著增加了春季和夏季土壤N2O通量。增温处理对土壤碳氮含量影响显著,与对照相比,土壤硝态氮含量平均增加8.4%,土壤有机碳和全氮含量分别下降了30.1%、34.9%,C/N提高了7.5%。土壤N2O通量与土壤温度、含水量、硝态氮含量,呈显著的正相关(P<0.05),与土壤有机碳含量呈显著负相关(P<0.05)。土壤温度和硝态氮含量可以解释土壤N2O通量变异的70%以上,土壤含水量可以解释变异的39.5%。因此,土壤温度和硝态氮含量是影响土壤N2O通量的关键因子,未来气候变暖会增加秦岭锐齿栎林土壤N2O的排放。

     

    Abstract: In order to investigate the effect of global warming on soil N2O flux from temperate forest, we conducted warming experiment using open top chambers(OTC) for 2 years in the Quercus aliena var. acutiserrata forest in Huoditang forest Station, Qinling Mountains. In this study, we explored the emission pattern of N2O and the effect of edaphic factors after soil warming. The results showed that the annual N2O flux increased by 13.9% with an average of (1.88±0.57) kg/(hm2·a) after soil warming, and N2O flux was significantly increased in spring and summer. Soil warming significantly increased soil NO3−N content by 8.4% and decreased soil organic carbon and total N contents by 30.1% and 34.9%, respectively, and consequently increased C/N ration by 7.5%. The N2O flux had a significantly positive correlation with soil temperature, water filled pore space and NO3−N content(P<0.05). There was a significantly negative correlation between soil SOC content and N2O flux(P<0.05). The soil temperature, NO3−N content and WFPS accounted for 70% and 39.5% of the variation in N2O flux, respectively. Therefore, soil temperature and NO3−N content were the key factors affecting N2O emission. The projected climate warming would increase the N2O flux in in the Q. aliena var. acutiserrata forest of Qinling Mountains.

     

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