Effects of nitrogen fertilization and watering on grain yield, dry matter accumulation and nitrogen uptake in durum wheat

Three water levels (A = non-irrigated; B = 350 m(3) ha(-1) of water applica tion in wilting point soil condition; C = 350 m(3) ha(-1) of water applicat ion at 35% of available water) and five nitrogen fertilizer doses (1 = 40 k g N ha(-1); 2 = 80 kg; 3 = 120; 4 = 160; 5 = 200 kg) were compared in South ern Italy on a continuous cropping of durum wheat. The results were strongly influenced by seasonal climatic trends; in the dr ougthy years the effects of waterings on grain yields, dry maner accumulati on, total N plant content and N uptake were very evident and positive. The weather also affected the behavoiur of nitrogen fertilizer: in the rainy ye ars the variations depending from N doses were small. Among the experimental treatments, the best results were obtained, on the w hole, with "B" water level and 120 kg ha(-1) of nitrogen.