Department of Plant Sciences, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
Environ Pollut. 2011 Feb;159(2):401-7. doi: 10.1016/j.envpol.2010.10.033. Epub 2010 Nov 27.
We investigated the influence of elevated CO(2) and O(3) on soil N cycling within the soybean growing season and across soil environments (i.e., rhizosphere and bulk soil) at the Soybean Free Air Concentration Enrichment (SoyFACE) experiment in Illinois, USA. Elevated O(3) decreased soil mineral N likely through a reduction in plant material input and increased denitrification, which was evidenced by the greater abundance of the denitrifier gene nosZ. Elevated CO(2) did not alter the parameters evaluated and both elevated CO(2) and O(3) showed no interactive effects on nitrifier and denitrifier abundance, nor on total and mineral N concentrations. These results indicate that elevated CO(2) may have limited effects on N transformations in soybean agroecosystems. However, elevated O(3) can lead to a decrease in soil N availability in both bulk and rhizosphere soils, and this likely also affects ecosystem productivity by reducing the mineralization rates of plant-derived residues.
我们在美国伊利诺伊州的大豆自由空气浓度富集（SoyFACE）实验中，研究了在大豆生长季节内以及在不同土壤环境（即根际和非根际土壤）中，升高的 CO(2) 和 O(3) 对土壤氮循环的影响。升高的 O(3) 可能通过减少植物物质输入和增加反硝化作用来降低土壤矿质氮，这一点可以通过硝化基因 nosZ 的丰度增加来证明。升高的 CO(2) 没有改变评估的参数，而且 CO(2) 和 O(3) 升高对硝化和反硝化生物丰度以及总氮和矿质氮浓度均没有交互作用。这些结果表明，升高的 CO(2) 可能对大豆农业生态系统中的氮转化作用影响有限。然而，升高的 O(3) 可能导致非根际和根际土壤中氮的有效性降低，这可能通过降低植物衍生残体的矿化速率来影响生态系统生产力。
