Disentangling gross N2O production and consumption in soil

作者：Wen Yuan; Chen Zhe; Dannenmann Michael; Carminati Andrea; Willibald Georg; Kiese Ralf; Wolf Benjamin; Veldkamp Edzo; Butterbach Bahl Klaus; Corre Marife D^*

来源：Scientific Reports, 2016, 6(1): 36517.

DOI：10.1038/srep36517

The difficulty of measuring gross N2O production and consumption in soil impedes our ability to predict N2O dynamics across the soil-atmosphere interface. Our study aimed to disentangle these processes by comparing measurements from gas-flow soil core (GFSC) and (N2O)-N-15 pool dilution ((N2OPD)-N-15) methods. GFSC directly measures soil N2O and N-2 fluxes, with their sum as the gross N2O production, whereas (N2OPD)-N-15 involves addition of (N2O)-N-15 into a chamber headspace and measuring its isotopic dilution over time. Measurements were conducted on intact soil cores from grassland, cropland, beech and pine forests. Across sites, gross N2O production and consumption measured by (N2OPD)-N-15 were only 10% and 6%, respectively, of those measured by GFSC. However, (N2OPD)-N-15 remains the only method that can be used under field conditions to measure atmospheric N2O uptake in soil. We propose to use different terminologies for the gross N2O fluxes that these two methods quantified. For (N2OPD)-N-15, we suggest using 'gross N2O emission and uptake', which encompass gas exchange within the (N2O)-N-15-labelled, soil air-filled pores. For GFSC, 'gross N2O production and consumption' can be used, which includes both N2O emitted into the soil air-filled pores and N2O directly consumed, forming N-2, in soil anaerobic microsites.

• 出版日期2016-11-4