Soil solarization as an alternative to methyl bromide fumigation for annual strawberry production in a Mediterranean area

This study compares the effects of soil solarization and methyl bromide fumigation on the growth and yield of strawberry plants (Fragatia xananassa Duch.) cultivated under plastic tunnel conditions. The study was conducted in a Mediterranean coastal area, in four consecutive annual production cycles in a field with no history of methyl bromide fumigation and 2-year history of strawberry production. In all 4 years, solarization was conducted for 7- to 9-week intervals from late June to early September. Cultivar Tudla frigo-plants were planted through mulch in the first week of September of each year. Average daily soil temperatures in solarized plots measured at 15 cm depth were 6.0, 8.1, 7.8, and 8.4 degrees C higher than the control, during Summer 2001, 2002, 2003 and 2004, respectively. Solarization produced 781, 610, 630, and 525 hours above 37 degrees C at 15 cm depth during the first, second, third, and fourth year, respectively. In the first year, solarization significantly increased both early and total marketable yields by 15% compared with the fumigated plots, whereas in the successive years, solarization and fumigation were equally effective in increasing yields when compared to untreated plots. No significant differences in average fruit weight were observed between solarized and fumigated plots in individual years. The study demonstrated that the Mediterranean coastal areas have appropriate environmental conditions to apply soil solarization in strawberry planting as a viable substitute to methyl bromide fumigation.