Soil Water Content and the Ratio of Nitrous Oxide to Nitric Oxide Emitted from Soil

摘要: Nitrification and denitrification are oxidative reductive microbial processes, respectively, that occur simultaneously at different microsites within the soil, each process produces both nitric oxide (NO) nitrous (N2O). Although much is known about regulation of these processes in laboratory, salient factors appropriate for use regional global models N trace gas emissions have not been identified. However, trends exist growing database N2O NO consistent with soil water content functioning as an important controller ratio to emitted from soils. Below 60% water-filled pore space (WFPS), often limited by diffusion organic-C inorganic-N substrates films, whereas O2 atmosphere limits aerobic when WFPS > (60% roughly equivalent field capacity many soils). In laboratory studies nitrification inhibitors, process, chemoautotrophic nitrification, was dominant source 60%, anaerobic denitrification, source, were 10 or more times greater than emissions. Emission ratios 1 60%. Few report WFPS, but even gravimetric content, which does account textural differences among soils, crudely predicted emission NO. Prediction based on (or a related parameter content) would be most useful combined ecosystem cycling dynamics predict total indices availability site fertility.