Fig. 4: Gross cyanate production and consumption in soil solution of a urea-amended arable soil (“urea addition experiment”).
From: Cyanate is a low abundance but actively cycled nitrogen compound in soil
a Schematic representation of pools and fluxes used to model rates of abiotic cyanate formation from urea and microbial consumption of soil cyanate. Urea, ammonium and cyanate, which are involved in the chemical equilibrium reaction, are highlighted as grey boxes. Rate constants of abiotic reactions are depicted in orange and were used to model cyanate fluxes based on observed pool sizes. We included abiotic hydrolysis of cyanate to ammonium, as the rate constants for the reaction are well established. b–d show urea, ammonium and cyanate concentrations in soil solution, respectively. Filled circles are observed data (average ± 1SE) at 0, 6, 12, 24 and 30 h after urea addition. Model fits are described in detail in Material and Methods. e Modeled rates of gross cyanate production from urea (orange line; “Formed from urea”) are shown as cyanate accumulation over time and gross cyanate consumption (blue line; “Consumed”) calculated as the difference between cyanate production and the observed net change in concentration.
