Increased N-2 emissions from an arable soil four years after biochar application

Four years after a single biochar (BC) application of 72 t ha(-1), significantly higher N-2 fluxes were measured from BC-treated soil using the helium gas flow soil core method compared with the control. Nitrous oxide was below the detection limit. Soil moisture and temperature significantly affected N-2 fluxes, which were highest at 70% water-filled pore space and 5 degrees C. The BC-treated soil was characterized by higher organic C and NO3-N concentrations and a wider C/N ratio of the microbial biomass.