Cobertura do solo e níveis de nitrogênio no desenvolvimento, na produção e na qualidade de frutos de mirtileiros

Abstract

The Blueberry is a temperate fruit tree traditionally grown in the North hemisphere, which has great economic importance. In Brazil the blueberry tree culture is still in development phase being necessary to develop an efficient and competitive production system that ensures the entrance on the world market. This work aimed to evaluate the growth, yield and fruits quality of blueberry trees using different types of mulching and nitrogen doses. The experiments were carried out at commercial orchard, located at Morro Redondo-RS from March 2007 at March 2009. Blueberry plants cultivars Climax and Bluegem were used for two experiments with mulching and Powderblue for that with nitrogen. In the beginning of the first year, the plants were 4 years old and with space of 1m among plants and 3m among rows. For those with mulching, the experimental design was a randomized blocks with 4 repetitions, three plants per plot and five treatments: T1: plot without mulching (control); T2: natural mulching (native and exotic species commonly found in areas of fruit cultivation); T3: eucalyptus sawdust; T4: pinus needle and T5: rice hull. For the experiment with nitrogen, the experimental design was that of randomized blocks with three repetitions and three plants per plot. Different nitrogen doses using ammonium sulfate (NH4)2SO4 with 21% of N as source were adopted, applying 5, 10, 15 e 20 grams plant-1 (16,66; 33,33; 49,99 e 66,66kg ha-1), divided in monthly doses of 5g per plant and the control constituted that without nitrogen. The different treatments with mulching did not present difference on the fruit yield and growth of branches in the two years for the two experiments. The physico-chemical characteristics were not affected with the mulching used, however the fruit phenols content was higher in plants that did not receive mulching. The N different doses only presented crescent and linear growth of branches in the first year. The yield fruits were not influenced by N different doses in the two years, as well as, the physico-chemical characteristics and nutraceutical quality did not differ for N treatments.