Quality of tomato (Solanum lycopersicum l.) changes under different cover crops, soil tillage and nitrogen fertilization management

The purpose of this study was to evaluate the interaction effects of winter cover crops (hairy vetch, subclover and black oat) and a bare soil, cover crop biomass management (incorporated into the soil or left on the soil surface as death mulch), and nitrogen (N) fertilization level (0, 75 and 150 kg ha−1 of N) on fruit yield and fruit quality parameters of processing tomato. Hairy vetch residues increased the yield (+57%), color index (+8%) and sugar/acidity ratio (+7%) of marketable tomato fruits compared to bare soil regardless of cover crop biomass management. Black oat residues determined a poor marketable yield, especially in tilled soil (on average, −26%, compared to bare soil) and they had a tendentially negative effect on some parameters of tomato quality (high firmness and titratable acidity, low color index and pH). Subclover residues, when incorporated into the soil, determined similar marketable fruit yield to bare soil, although they had a more favorable effect on the color parameters of tomato fruits. The increasing of the N fertilization level from 0 kg ha−1 of N to 150 kg ha−1 of N always positively influenced the tomato yield and fruit characteristics. The results suggest that hairy vetch, compared to other cover crops, had a positive influence on tomatoes and it could be part of an environmentally friendly management package for sustainable tomato cultivation in Mediterranean conditions.