Compost da pastazzo fresco di agrumi: confronto con altre tipologie di compost per un utilizzo nel vivaismo orticolo

In Southern Italy, the increasing amount of by-products generated from citrus processing plants has greatly encouraged the process of composting of citrus wastes for its potential use as a component of growing media in nursery crop production. The aim of the present work was to compare the growth responses induced by orange waste compost on tomato and zucchini seedlings with those by three commercial composts (Aimag, Berco, Sienambiente). Perlite was chosen as a complementary mixing medium. Tomato and zucchini seedlings were grown in potting mixtures amended with two dosages (7.5 or 15%, by volume) for 21 and 42 days or 12 and 20 days, respectively. The results indicated that plant growth responses were species-specific and dose-dependent. In tomato, both plant fresh and dry weight were selectively affected by the compost type and application dose, being higher at the lowest application dose (7.5%). Whereas, in zucchini there were no significant differences in response to compost dose and type. The influence of compost chemical properties was also discussed. The results showed that orange waste compost could represent an efficient complementary substrate for growing containerized horticultural crops, provided the amendment rate never exceeds a 7.5% dosage.