Response of seed-grown globe artichoke to different levels of nitrogen fertilization and water supplies

Direct-seeded plants of seed-grown varieties of globe articboke, compared to vegetatively propagated plants of traditional clones, may utilize soil moisture and fertilizer more efficiently because tbey develop long vertical tap-roots, wbicb penetrate deeper into tbe soil. Tbe aim of tbis work was to measure ecopbysiological and crop yield responses to different levels of nitrogen fertilization and water supplies, in order to evaluate the possibility of reducing tbe external crop inputs. Tbe field experiment was conducted at Siracusa-south Italy (360 58' N,ISo 11' E, 15 m above sea level). Using tbe seed-grown variety 'Orlando' Fh two water supplies (50 or 100% of maximum evapotranspiration - ETM) and tbree rates of nitrogen fertilization (O,200 or 400 Kg ba-l of N, as NH4N03) were studied. Tbe reduction in N-rate caused a significant increase in earliness but was not significant on yield and head cbaracteristics. The supply of 50% ETM, compared to 100% ETM, determined a significative decrease in head yields, whicb was more evident during tbe first two months of harvest tban at tbe end of the cycle. These results indicate tbe possibility of reducing tbe amounts of nitrogen usually applied by farmers, witbout a significant loss in total yield, while tbe reduction of water supply may cause a negative effect on yield, especially in tbe early stages.