N2O emission and governing factors on arable fields

This study focuses on the soil N₂O emission of arable fields. We initially set up several soil column experiments in laboratory and based on these findings we started field measurements in a long term tillage experiment at Józsefmajor Experimental and Training Farm, Hungary. For the column experiments we collected undisturbed soil columns (d=10 cm, h=10 cm) from mouldboard ploughing (P) and no-till (NT) treatments.  We investigated the effect of different fertilizer doses (40, 80, 160, 240 kg h^-1 N), soil water content (SWC) and different tillage methods on soil N₂O emission.

We found a nonlinear response of N₂O emission on the applied fertilizer doses. The moderately fertilized (80-160 kg ha^-1 N) samples had the highest N₂O emissions. Samples from NT had higher N₂O emission than samples from P. We found better correlation between N₂O emission and SWC in NT (R² is between 0.47 and 0.62) than in the P (R² is between 0.01 and 0.35).  The N₂O emission values showed high spatial variability. The field measurements showed similar findings of N₂O emission compared to the column experiments. In 2020 we intend to continue the field measurements and include further investigations of governing factors of soil N₂O emission.