Artichoke (Cynara scolymus L.) as cash-cover crop in an organic vegetable system

In organic vegetable systems green manure crops play an important role as a nitrogen source, but they cover the soil for several months without producing a direct income. Globe artichoke (Cynara scolymus L.) provides both heads to be harvested and particularly abundant plant residues to be possibly incorporated into the soil, so it may play a double role of cash and cover crop. This paper describes an on-farm study in which seed-propagated artichoke, cultivated as an annual crop, preceded zucchini squash and lettuce cultivated in sequence within a vegetable organic system. Artichoke produced about 7 t ha^-1 of saleable heads and left, after harvest, 50.3 t ha^-1 of fresh biomass usable as green manure. Zucchini squash and lettuce following artichoke showed a significant increase in yield when artichoke residues were incorporated into the soil. Furthermore, a residual positive effect of green manure on soil fertility was detected after lettuce harvest.