The effect of soil solarization and protection techniques on yield traits of melon in unheated greenhouse

The results of a trial conducted in spring 1999 on melon (Cucumis melo L. var. reticulatus Naud., cv Baggio) grown in unheated greenhouse in Southern Italy to evaluate the effect of 3 different mulching films, combined with a small tunnel protection on solarized and not-solarized soil are reported. The 3 mulching films used were a traditional one (black LDPE), a biodegradable and a photo-degradable one; the melon plant protection was obtained by superimposing small tunnels on some mulched rows for the first 60 days of the growing cycle. A part of the soil inside the greenhouse had also been previously solarized during summer 1998. The obtained results showed that, among the mulching films, the photo-degradable one increased yield and also gave a shorter and intensive harvest time. Biodegradable film gave good result only when applied on the solarized soil. Small tunnels improved the fruit number, especially when associated with photodegradable mulching. Moreover, soil solarization, as expected, produced an increase of 86.2% and 155.5%, respectively in number and weight, as well as in soluble solids content and several other parameters of marketable fruits. Finally, also the thermal behaviour of the mulched soil was different in the examined cases: under photo- and biodegradable mulching films temperatures were quite higher (2-3°C) at 10-30 cm depth with respect to the black LDPE. Spectroradiometric properties of transparent films played a notable role in increasing solar radiation use efficiency; its photo- and biodegradable characteristics may be usefully employed in protected cultivation in Mediterranean climates in order to reduce the total amount of agricultural plastic wastes.