The present study is the third of a series of Master’s Theses started up in 2006 and aimed at developing a suitable cropping system for organic vegetables under Mediterranean climatic conditions. A split plot design was adopted for testing the effect of three pre-crops (beans, peas and zucchini) and two types of feeding programs (compost and compost tea + organic fertilizer) on the main crop (cucumber) and on soil fertility. Zucchini, beans and peas yielded 44, 11.3 and 10 tons/ha respectively accounting for 80, 102, and 90% of the average yield obtained in conventional production under Agadir conditions. The main crop (cucumber) yielded 92 tons/ha while, under conventional conditions, the yield is about 110 tons/ha. A feeding program based on compost tea and organic fertilizer induced a significantly higher cucumber yield.
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N, P, K and OM of the soil were improved after two years of crop rotation. Zucchini provides the highest amount of biomass (35.9 tons/ha) and has induced a strong competition with weeds. The weakest crop-weed competition was observed with peas. The highest total gross margin was gained from zucchini-compost (389.79€/100m²), and the lowest from fallow-compost tea + organic fertilizer (203.89€/100m²).