Influence of biostimulating products on irrigated artichoke crop in Southern Italy

In a context of eco-compatible agriculture, the objective of modern fertilization techniques is to compensate specific shortage or unbalanced plant nutrition. Several experiments have underlined the complex problem of artichoke manuring in early irrigation, in southern Italy (Caruso, 1965). The results obtained have not always furnished reasonable explanations for some biological phenomena and for the probable biochemical processes that the plant puts into effect as an answer to fertilizing elements. However, the effects of artichoke manuring should not exhaust in to exalt plant productivity and earliness, but should also concern the qualitative improvement of the inflorescences, increase of fruit size, content of sugars, fibres, proteins, amino acids, and so on. The bio-stimulating involves products are extremely specific. It turned out last years, they interact with plant biochemical processes and therefore are good to improve fruit production and quality. Several firms of the sector have put highly effective products on the market, in many cases represented by plant natural extracts, which also suit well for biological agricultural practice. With the purpose to improve our knowledge on this complex problem and to acquire new information on the action of these products, an active experimentation has been started to test also their effectiveness in combination with the action of plant regulators, whose purpose is to accelerate the mechanisms of differentiation of the vegetative apex and therefore to induce a greater earliness of heads maturation (Marzi, Dellacecca, 1969). The employment of gibberellic acid in artichoke production is almost always justified by the favourable effects of this plant regulator on earliness of heads maturation, as demonstrated by the abundant literature. This is an essential condition to attain satisfactory economic results, since in southern Italy, the global production of irrigated artichoke fields is not as important as earliness. In fact, when prices are not profitable anymore, artichoke plants are abandoned, even if their heads are still good for heating (Mangano and Signorelli, 1979). Unfortunately, the effects of gibberellic acid on the total head production, head shape, head size and plant habitus are not as clear as for the earliness trait.