Environmentally Sustainable Nitrogen Nutrition Management in Processing Tomato

The availability of nitrogen (N) is a key factor for ensuring optimum crop growth, high yield and a good quality of the marketable product in processing tomato. A well-balanced N fertilization rate should cover the gap between the crop N requirement for maximum yield and the soil N availability, while should avoid overfeeding. On the contrary, processing tomato is often over-fertilized because fertilizer costs are relatively low and the side effects of a too high N rate are often not visible. This implies well-known nitrate pollution risks. Developing integrated N management is crucial to optimize N fertilization and to protect the environment. This keynote is focused on results of several researches that have been carrying since 1996 at the University of Perugia, Italy. These researches provided useful information to develop an environmentally sustainable N management in processing tomato. In detail, our studies allowed to define: the crop N demand and partitioning throughout the growth cycle; the assessment of crop N status; the apparent recovery of broadcast and localised N-fertilizer application; the effect of the irrigation and/or fertigation frequency on the fate of N in the “soil-plant” system; the effect of mineral and organic fertilization on crop N nutrition, crop yield and N fate in the environment; the effect of cover crops and green manuring (with legumes and non legumes, as pure crops or mixtures) on soil N fertility and N leaching control; the effect of crop rotation and cropping system (i.e., conventional or organic) on efficacy and efficiency of N management.