Influence of a nitrification inhibitor and of placed N-fertilization on N2O fluxes from a vegetable cropped loamy soil

Arable soils are a major source of the climate relevant trace gas nitrous oxide (N2O). Although N2O emissions from soils increase with the amount of N-fertilizer, there is still a lack of data for intensively fertilized systems, such as vegetable production. We investigated the effect of an ammonium sulfate nitrate (ASN) fertilization either placed or broadcast applied combined with a nitrification inhibitor (3,4-dimethylepyrazole phosphate (DMPP)) on soil surface N2O fluxes as compared to conventional broadcast ASN fertilization in a lettuce–cauliflower rotation over two years of measurement. Except for a lower cauliflower yield in the second experimental year with placed fertilization, no differences in yields between the fertilized treatments were observed. Annual cumulative N2O emissions of the conventionally fertilized treatment were 8.8 and 4.7 kg N2O-N ha−1 yr−1 for the first and second experimental year, respectively, indicating a high inter-annual variability.