Soil, slurry and application effects on greenhouse gas emissions

In conjunction with soil type and climate, the use of nitrogen fertilizers is a major factor affecting nitrous oxide emissions. This study compares injection of pig slurry and pig slurry digestate at 15 or 20 cm depths with trailing-hose application followed by immediate incorporation. The work was based on a laboratory microcosm experiment with undisturbed soil cylinders (0-30 cm depth) from three arable soils (Histosol, Gleysol and Plaggic Anthrosol). Soil cylinders were fertilized with pig slurry and pig slurry digestate (150 kg N/ha) and emissions of N2O, CH4 and CO2 were monitored. The comparison of application techniques over a 37-day period show that soil type and application technique, had a strong (P < 0.001) impact on N2O emissions. Fertilization with pig slurry showed no significantly higher N2O emissions than pig slurry digestate. Fertilizer injection significantly increased N2O emissions compared to fertilization with a trailing-hose with incorporation.