Interaction of straw amendment and soil NO3− content controls fungal denitrification and denitrification product stoichiometry in a sandy soil

Publication date: November 2018Source: Soil Biology and Biochemistry, Volume 126Author(s): Mehmet Senbayram, Reinhard Well, Roland Bol, David R. Chadwick, David L. Jones, Di WuAbstractThe return of agricultural crop residues are vital to maintain or even enhance soil fertility. However, the influence of application rate of crop residues on denitrification and its related gaseous N emissions is not fully understood. We conducted a fully robotized continuous flow incubation experiment using a Helium/Oxygen atmosphere over 30 days to examine the effect of maize straw application rate on: i) the rate of denitrification, ii) denitrification product stoichiometry N2O/(N2O+N2), and iii) the contribution of fungal denitrification to N2O fluxes. Five treatments were established using sieved, repacked sandy textured soil; i) non-amended control, ii) nitrate only, iii) low rate of straw + nitrate, iv) medium rate of straw + nitrate, and iv) high rate of straw + nitrate (n = 3). We simultaneously measured NO, N2O as well as direct N2 emissions and used the N2O 15N site preference signatures of soil-emitted N2O to distinguish N2O production from fungal and bacterial denitrification. Uniquely, soil NO3− measurements were also made throughout the incubation. Emissions of N2O during the initial phase of the experiment (0–13 days) increased almost linearly with increasing rate of straw incorporation and with (almost) no N2 production. However, the rate of straw amendment was negat...
Source: Soil Biology and Biochemistry - Category: Biology Source Type: research