Evaluation of pre-crops and fertilization on organic zucchini under Mediterranean conditions: case of Turkey

Summary in the original language of the document

Soil fertility is fundamental in determining the productivity of all farming systems. Major tools utilized in organic farming to increase the fertility of the soil can be expressed as rotation, green manuring and allowed organic fertilizers and soil amendments. A field experiment was conducted at Ege University in Izmir, Turkey, to study the effects of pre-crops used as green manure - including vetch, faba bean, broccoli and spontaneous weeds - and fertilization (compost tea, commercial fertilizer) on zucchini (the main crop in the rotation program) and on soil fertility. The main aim of the experiment was to identify the most suitable rotation program in organic farming for Turkey under prevailing conditions. Tested treatments had no marked effect on yield or quality of zucchini except inorganic matter content of the fruits. There were significant differences among tested pre-crops for N, P, K, OM and C values of the soil. Zucchini after broccoli fertilized with compost tea gave the highest gross margin due to the higher income derived from two different crops complemented with lower production costs compared to the commercial fertilizer.