Effetti di diversi concimi azotati e di alcuni fattori dell'agrosistema sulla nutrizione e sulla qualità dell'uva (Cabernet Sauvignon in Oltrepò Pavese)

According to the importance of nitrogen nutrition and the enviroment on the quantitative and qualitative grapevine production, an experiment was conduced, from 2008 to 2011, in a Cabernet Sauvignon vinyard in Oltrepò Pavese (north-west Italy), to check the nutritional effect of different nitrogen formulations in reference to the quality of grapes produced (used products: calcium cyanamide, ammonium nitrate and Nitrophoska gold was tested for 60 kg/ha of N, in comparison with a control). The application of fertilizer was divided in randomized block design and it was used the multifactorial ANOVA (with sources of variation: fertilization, different position in the field and year, and their interactions) to measure also the importance (sum of squares) of each source of variation. The main variables measured: leaf mineral composition (limbe and petioles), presence of chlorophill (SPAD) weight of berry and grapes per vine, sugars, acids and anthocyanins in the must. The main factors that have affected the vegetation and the production of the vines are estimated in the climate (by the year factor) and in soil (by the block factor). The fertilizers, that among them have not shown any substantial difference, has showed a significant increase of nitrogen concentrationi in leaves (veraison) and a significant reduction of sugar, anthocyanins and tartaric acid/malic acid.