| Abstract: | Abstract Two experiments were conducted to evaluate the inhibitory effects of 2-chloro-6 (trichloromethyl) pyridine (nitrapyrin) and dicyandiamide on nitrous oxide (N2O), a greenhouse gas, emission from soils amended with ammonium sulfate. In the two experiments, samples of an Andosol and a Gray Lowland soil were kept in glass vessels sealed with a butyl rubber cap and incubated at 25°C. In the first experiment, nitrapyrin (1 µg g?1 dry soil) and dicyandiamide (10 µg g?1 dry soil) were applied to samples of a water-saturated Andosol and a Gray Lowland soil to which ammonium sulfate had been applied at a rate of 0.1 mg N g?1 dry soil. Nitrapyrin decreased N2O emissions from the Andosol and the Gray Lowland soil by 71% and 24%, respectively. Dicyandiamide decreased N2O emissions from the Andosol and Gray Lowland soil by 31% and 18%, respectively. In the second experiment, nitrapyrin (1 µg g?1 dry soil) was applied to samples of an Andosol at 51% water-filled pore space to which ammonium sulfate had been applied at rates of 0.01, 0.1 and 0.5 mg N g?1 dry soil. Nitrapyrin decreased N2O emissions by 62%, 83% and 74%, respectively. Changes in the NH+ 4 and NO? 2 + NO? 3 concentrations in soil showed that nitrapyrin and dicyandiamide slowed down the nitrification process, but did not completely stop the process at any time. The results reveal the potential of nitrification inhibitors to decrease N2O emission from fertilized soil in a wide range of moisture conditions and nitrogen levels. |
