Fertilizer type influences tomato yield and soil N<sub>2</sub>O emissions  

Improvements in crop management for a more sustainable agriculture are fundamental to reduce environmental impacts of cropland and to mitigate effects on global climate change. In this study three fertilization types – ammonium nitrate (control); mineral fertilizer added with a nitrification inhibitor (3,4-dimethylpyrazole phosphate (DMPP)), and an organo-mineral fertilizer (OM) – were tested on a tomato crop in order to evaluate effects both on crop production and soil N₂O emissions. Plants grown under OM fertilization had a greater relative growth rate compared to mineral fertilization, due to a higher net assimilation rate, which was related to a greater light interception rather than to a higher photosynthetic efficiency. OM fertilization determined the highest fruit production and lower soil N₂O fluxes compared to NH₄NO₃, although the lowest soil N₂O fluxes were found in response to mineral fertilizer added with a nitrification inhibitor. It can be concluded that organo-mineral fertilizer is a better nutrient source compared to mineral fertilizers able to improve crop yield and to mitigate soil N₂O emission.