THE Ca, K and Mg RATIO IN SOIL AND VINES UNDER EFECTS OF FERTILIZATION WITH DIFFERENT POTASSIUM FERTILIZER DOSES

The investigation was carried out in the vineyards of “Radmilovac” on the Faculty of Agriculture experimental station, with cv. Sauvignon blanc grafted to the rootstock Berlandieri x Riparia Kober 5BB. The aim of this research was to determine the effects of potassium fertilizer application on the Ca:Mg and K:Mg ratio in soil and vines organs. In this experiment the following treatments were used: control (without fertilization) and treatments with 50, 100 and 150 kg K2O/ha 50% KCl potassium fertilizer. The soil type was eutric cambisol. Treated soil was subjected to the detail agrochemical soil analysis, while the soil samples was collected from the depth of 0-30, 30-60, 60-90 and 90-120 cm. Leaves for analysis were collected in august and shoots after pruning. Potassium and magnesium analysis has been by AAS. The level of available potassium was (11,95-14,15 mg/100g of soil), magnesium (20,2-23,7 mg/100 g of soil) and calcium (354-464 mg/100 g of soil). During the first year, Ca:Mg ratio was 5,8-14,4:1, in the second year 5,4-18,5:1 and at third year 4,9-25,2:1. The K:Mg ratio ranged from 0,08-0,21:1 in the first, 0,13-0,29:1 in the second and 0,11-0,21:1 in the third year of study. The Ca:Mg and K:Mg ratio were mostly influenced by 100 and 150 kg K2O/ha potassium doses. The K:Mg ratio in the leaves and shoots did not change under influence of different potassium fertilizer doses, so that the antagonism between these two elements was not manifested

On the optimal shape of a compressed column

A new numerical solution to the Lagrange problem is presented. The solution is compared with a priori estimates obtained recently. Also we derive a new relation that shows that the cross-sectional area at the middle of the optimally shaped column is larger than the cross-sectional area at the ends. Our numerical experiments confirm that conclusion

An approach to optimal architectural and urban design from the energy efficiency point of view

This paper presents a new approach to architecture and urban design that results in an increase of the energy efficiency of buildings set close to each other, which is set as the optimization problem. The main goal is to maximize the sunlight impact on objects, in a way to minimize inter-object shading on each building. The problem is solved by the PSO (Particle Swarm Optimization) algorithm and its modifications, as well as the application of PSO algorithm with niches, which makes it possible to find a large number of local optima. It turned out that the PSO algorithm with niches is especially suitable for solving the described problems. The proposed methodology is illustrated by a few examples