Effect of silicon on barley growth and N₂O emission under flooding

The global climate change is related with greenhouse gas emission from cultivated soils - carbon dioxide, methane and nitrous oxide. The emissions of N₂O also have negative influence on ozone layer of our planet. The major source of the nitrous oxide is denitrification process in soil, which controlled by specific soil microbe society. The pot experiment with flooding to accelerate the denitrification process and the application of the monosilicic acid as a source of soluble form of Si was carried out with barley. Several forms of nitrous oxide emission (unlimited carbon denitrification and potential denitrification with or without ethylene application) were measured. The obtained data showed that the application of monosilicic acid to brown soil when growing barley under conditions of soil flooding has a significant effect on nitrogen emission and can change the N₂O:N₂ ratio. The application of the monosilicic acid reduced the uC-D N₂O emission, while increased the PD N emission. Generally the application of the water soluble Si decreased the N₂O:N₂ ratio. We suggested that the presence of monosilicic acid in the system provides a more complete denitrification process with the formation of N₂ in the NO₃^- → NO₂^- → NO→N₂O → N₂ reaction sequence, while the deficiency of bioactive Si mainly provides the formation and emission of N₂O. Considering that N₂ is not a greenhouse gas, we can conclude that application of monosilicic acid to the soil can reduce greenhouse gas emissions and reduce the impact of global climate change on agricultural activity.