EFFECTS OF SOIL SOLARIZATION WITH DIFFERENT PLASTIC FILMS ON YIELD PERFORMANCE OF STRAWBERRY PROTECTED PLANTATIONS IN SICILY

Two main alternatives to replace methyl-bromide soil fumigation are soil solarization, which is feasible in geographical areas with high solar radiation, and the combination of the nematocide 1,3-dichloropropene (1,3-D) and the fungicide chloropicrin (Pic) applied through drip irrigation lines. The objective of this two-year study was to evaluate solarization and fumigation with 1,3-D + Pic as preplant soil treatments for plasticulture strawberry production in the northern coast of Sicily. Plots to be solarized were covered with transparent polyethylene (PE) or with green ethylene-vinylacetate (EVA) film mulches and left undisturbed for 69 and 77 days in 2009 and 2010, respectively. Freshly bare rooted plants and containerized plants were transplanted in the first and second year, respectively. Cultivars ‘Candonga’ and ‘Nora’ were tested using standard plasticulture practices. Soil temperatures recorded in PE solarized plots were higher than 37°C for 792 and 750 hours, in 2009 and 2010 respectively, whereas cumulative exposure above 37°C in green-EVA film solarized soil was 615 and 592 hours in the first and second year, respectively. These temperature are considered lethal for several soil pathogens. In both years, regardless of the cultivars tested, total marketable fruit yields in fumigated and solarised plots were significantly higher than in the untreated plots. Our results demonstrated the efficiency of solarization with either transparent-PE or green-EVA mulching films as alternative to 1,3-D + Pic soil preplant treatment. The green-EVA plastic mulch, was designed to be kept on soil after the end of soil solarization during the cropping season because it prevents infestation with weeds and therefore may need not to be replaced by traditional black plastic mulch. The green-EVA film induced both thermal regimes and fruit yields comparable to those obtained under conventional PE film. Therefore, it was concluded that its use would be a feasible option and a considerable reduction of plastic waste.