Grapes yield, composition and nitrogen content in leaf and leaf petioles in grapevine with nitrogen fertilization

The vine has art economic importance in the South of Brazil, but its productivity is associated with the utilization of fertilizers, especially nitrogen (N) ones, which affects the productivity and the composition of the grapes Its nutritional state can be evaluated by the N content in the foliar lamina and petiole. Two experiments were carried out in 2006/07 to evaluate the effect of the N fertilization in the N content of the foliar lamina and petiole, which is used for the N recommendation, yield and grape composition of vine, at Haplumbrept soil in Southern Brazil, Planalto city. Bordo vines of the experiment I and Couderc 13 ones of the experiment 2 were submitted to applications of 0. 30, 60 and 90kg ha(-1) of N as follow: 50% was applied after the beginning of bud burst, 25% during bud burst and 25% during the flowering Samples of the foliar lamina and petiole were collected in the flowering and verasion. The samples were dried, grinded and prepared to the total N analysis. By the time of the grape maturation, five bunches were collected randomly in the center and in the external part of the plant, which were weighted and submitted to length and wide measurements. Sequentially, 100 grapes were taken from these bunches, weighted and reserved. Following, the other bunches were collected and weighted, in order to determine the yield per plain and per hectare. Berries reserved were triturated and N-total, P and K were evaluated. The results clearly showed that the samples of foliar lamina collected in the flowering of the 'Bordo' and 'Courdec 13' cultivars were suitable to evaluate the availability of N in the plant. The N fertilization had increased the Yield of grape in the Bordo cultivar and the total N in the grapes of both cultivars.