RESUMEN
Processing tomato (Lycopersicon esculentum Mill.) is regarded amongst the most dominant horticultural crops globally. Yet, due to its elevated water and fertilization needs, its environmental footprint is significantly high. The recent efforts to reduce the footprint of agriculture have rekindled the search for optimized fertilization regimes in tomato. The aim of the present study was to assess the effect of different urea fertilizers and tomato pomace-based composts on the performance and quality traits of processing tomato. A two-year field experiment was conducted in the Larissa region, Central Greece, during 2018-2019. The experiment was set up in a randomized complete block design (RCBD), with five treatments: control, urea (Urea), urea with nitrification and urease inhibitors (Urea + NI + UI), processing tomato pomace with farmyard manure (TP + FM), and processing tomato pomace with compost from plant residues (TP + CM). Measurements included soil total nitrogen (STN), soil organic matter (SOM), root length density (RLD), arbuscular mycorrhiza fungi (AMF) colonization, dry weight per plant, fruit yield (number per plant, total yield, weight, diameter), fruit firmness, total soluble solids (TSS), titratable acidity (TA), lycopene content and yield, and fruit surface color (L*, a*, b*, CI). Overall, the best results in soil properties and quality traits were reported in the organic fertilization treatments (STN, SOM, AMF, TSS, TA, lycopene content, L*, a*, b*) and the differences among TP + FM and TP + CM were insignificant in their majority. On the contrary, fruit yield and its components were significantly improved in Urea + NI + UI.