碳源与底物对不同层次土壤产生N2O能力的影响

底层土壤的反硝化作用是土壤排放N_2O的重要来源,同时也是影响浅层地下水硝酸盐含量的重要因素.通过一系列室内培养试验.研究了一种农用土壤不同土层在碳源和NO_3含量不同情况下产生N_2O的能力。结果表明,试验用土壤的不同土层均具有进行反硝化作用产生N_2O的能力.底层土壤产生N_2O的能力大于根区土壤:单独添加葡萄糖、NO_3或同时添加葡萄糖和NO_3.对土壤N_2O和CO_2释放的影响与土壤层次和观测时间有关;向土壤添加葡萄糖和NO_3,各个土层释放N_2O的能力均显著提高;从产生N_2O和CO_2能力的角度而言,不同层次土壤的微生物区系间存在较大差异。采用短期(24h之内)饱和泥浆好气培养法,可以区分土壤微生物区系在产生N_2O方面的差异。

Effects of carbon and substrate on the N2O productivity of different soil layers

Denitrification in subsurface is the important source of N2O emission from soil. It is also a key factor of affecting NO3 content of shallow groundwater. In the present study, a series laboratory incubation experiment was carried out to investigate the productivity of N2O from the different layers of an agro-soil. The result showed that all the layers of the soil used in experiment had the ability to produce N2O under the laboratory conditions. The ability to produce N2O was greater in subsurface soil than root zone soil. The effect of adding glucose, NO3 and glucose + NO3 on the emission of N2O and CO2 was dependent on the layer of soil and the observing time. The ability to form N2O of each layer would be significantly improved when adding labile carbon and NO3 to soil. Based on the ability to form N2O and CO2, there was great difference in microflora between each soil layer, and this difference could be measured by the short-term slurry aerobic incubation method.