A Field experiment was conducted at the Technical Centre for Organic Agriculture in Sousse, Tunisia, during 2006-07 to study the effect of three soil building crops on potato (cv.spp) in the Mediterranean organic farming system. Faba bean, peas, and fennel were grown as soil building crops while natural weeds were used as control. Potato was grown as main crop after incorporation of soil building crops. Compost tea and a commercial fertilizer (Molex) were applied to potato plots as fertigation. Results showed that the effect of soil building crops and fertigation on potato yield and yield contributing characters were not significant. However, striking effects of compost tea on the potato tuber number were recorded. Higher late blight attacks were reported in compost tea applied plots, which limited the yield.
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A significant correlation between infection and tuber quantity and compost tea application were also observed. Higher gross margins were obtained with commercial fertilizer application.
