Soil NO3− level and O2 availability are key factors in controlling N2O reduction to N2 following long-term liming of an acidic sandy soil

Publication date: Available online 19 February 2019Source: Soil Biology and BiochemistryAuthor(s): Mehmet Senbayram, Alice Budai, Roland Bol, David Chadwick, Laszlo Marton, Recep Gündogan, Di WuAbstractLiming of acidic soils has been suggested as a strategy to enhance N2O reduction to N2 during heterotrophic denitrification, and mitigate N2O emission from N fertilised soils. However, the mechanisms involved and possible interactions of key soil parameters (NO3− and O2) still need to be clarified. To explore to what extent soil pH controls N2O emissions and the associated N2O/(N2O + N2) product ratio in an acidic sandy soil, we set-up three sequential incubation experiments using an unlimed control (pH 4.1) and a limed soil (pH 6.9) collected from a 50-year liming experiment. Interactions between different NO3− concentrations, N forms (ammonium- and nitrate) and oxygen levels (oxic and anoxic) on the liming effect of N2O emission and reduction were tested in these two sandy soils via direct N2 and N2O measurements.Our results showed 50-year liming caused a significant increase in denitrification and soil respiration rate of the acidic sandy soil. High concentrations of NO3− in soil (>10 mM N in soil solution, equivalent to 44.9 mg N kg−1 soil) almost completely inhibited N2O reduction to N2 (>90%) regardless of the soil pH value. With decreasing NO3− application rate, N2O reduction rate increased in both soils with the effect being more pronounced in the l...

Source: Soil Biology and Biochemistry - February 20, 2019 Category: Biology Source Type: research