Validation of Non-destructive Methodology of Grapevine Leaf Area Estimation on cv. Blaufränkisch (Vitis vinifera L.)

This paper evaluates the application of a statistical model to estimate leaf surface area in grapevines, expressed asleaf area of an individual leaf as well as total leaf area per shoot, including any lateral shoots. Estimating the area ofan individual leaf was based on a formula obtained by regression analysis that uses the sum of length of two inferiorleaf veins as an independent variable. To estimate the leaf area per main shoot and per lateral shoot we used themodel derived from multiple regression analysis that has the following independent variables: the number of leaves,and surface area of the largest and of the smallest leaf on the shoot. High values of the coefficient of determination(r2), as well as satisfactory levels of mean absolute error (MAE), suggest that the applied models appear valid. Theseresults have shown a good fit of observed and predicted values of shoot and lateral leaf areas

PRODUCTIVE AND TECHNOLOGICAL CHARACTERISTICS OF TABLE VARIETIES GROWE IN THE CONDITIONS OF OPLENAC VINEYARDS

Investigations were carried out in vineyard of King Petar I Karadjordjevic Foundation of at Oplenac. In experiment were tested four table grapes varieties: Black Magic, Victoria, Michel palieri and Muscat Hamburg. Training system is characterized with height of 90 cm on which Guyot pruning is used. In research is studied vegetative potential, fertility, mechanical composition of grape and berries and sugar content and acidity. In red varieties is determined anthocyanins concentration. Michel palieri was with the largest vegetative potential expressed through shoot mass (0,590 kg/vine). The highest values of fertility parameters (number productive shoots, number of inflorescences on spur and arc, coefficients of fertility) had a variety Muscat Hamburg. The highest sugar content was determined in Muscat Hamburg must, a total acid in Victoria variety must. According to anthocyanins Mikele palieri content variety is dissociate (0.179 mg/g fresh weight)

EFFECT OF BACTERIAL FERTILIZER ON GROWTH, YIELD AND GRAPE QUALITY OF POTTED CABERNET SAUVIGNON (VITIS VINIFERA L.)

In these studies, one commercial bacterial fertilizer - BactoFil B10 was used during the first and second growing seasons of the potted vines. The influence of the fertilization was investigated on the vine growth – total leaf area, shoot diameter, dormant pruning weight and fresh root weight. The most expressed effect of Bactofil application was in the first vegetation with increases of the total leaf area of 9%, shoot length of 6% and shoot pruning weight of 14.6%, in comparison to the control. At the end of the second vegetation, plants were removed from the pots and the fresh root weight was measured. It was found that applied treatment was not influenced on the variations of the average root weight. The first grapes were obtained in the second vegetation, and treatment with BactoFil was not influenced on the differences in the yield, grape and berry weight. Also, treatment was not influenced on the must quality which was expressed over the dry matter content and total acid content

INFLUENCE OF VANADIUM CONTENT ON THE TRIBOLOGICAL BEHAVIOUR OF X140CrMol2-l AIR-HARDENING STEEL

The paper presents experimental testing of wear resistance of steel samples from the same groups of steel. Test results were recorded and presented in the form of diagrams showing the wear resistance of the tested materials in different sliding conditions. The tested steels have high carbon content; the addition of chromium and molybdenum results in the high hardness and low impact toughness of the steels. The addition of vanadium changes the microstructure when the metal grain becomes smaller and the whole structure is martensitic, with chromium and vanadium carbides in the metal matrix. A change in the microstructure causes a change in mechanical properties. The obtained results showed that the addition of vanadium increases impact toughness. However, it is not known how it affects wear resistance and hardness. This type of steel belongs to a new group of steels resistant to wear. A change in the vanadium content causes a decrease in the hardness and wear resistance of the steel and an increase in its impact toughness