Nitrous oxide mitigation potential of reduced tillage and N input in durum wheat in the Mediterranean

In Italy, managed soils account for about 50% of annual national emissions of nitrous oxide (N₂O), thus the effect of agricultural practices on N₂O emissions must be studied in order to develop mitigation strategies. Soil N₂O emissions were measured in two field campaigns (2013–2014 and 2014–2015) on durum wheat in a Mediterranean environment to test the mitigation potential of reduced tillage and nitrogen (N) fertilization rate. N₂O emissions were measured with a fully-transportable instrument developed during the project LIFE?+?IPNOA “Improved flux Prototypes for N₂O emission reduction from Agriculture” and equipped with an infrared laser detector. Reducing tillage from ploughing to minimum tillage had no effect on average daily N₂O flux, while decreasing the N rate from 170 to 110 kg N ha^?1 reduced the average daily N₂O flux, without negatively affecting the grain yield. Furthermore, N₂O daily flux were positively correlated with soil water filled pore space, NO₃-N, and NH₄-N concentrations, and they were largely variable between the two field campaigns as a result of different environmental and management conditions (i.e.: rainfall, different amount of crop residues incorporated in soil). Overall, the innovative fully-transportable instrument performed well in the field and allowed us to conclude that decreasing the N fertilizer rate was a valuable option to mitigate N₂O emissions without negative effects on wheat productivity.