ENERGY BUDGET AT THE EXPERIMENTAL VINEYARD IN ZAGREB

Within the collaboration of VITiculture and CLImate Change in Croatia (VITCLIC) project and Croatian-Hungarian bilateral scientific program, micrometeorological measurements are performed at the Faculty of Agriculture experimental vineyard near Zagreb in the hilly experimental field during the vegetation periods of 2017/2018 and 2018/2019. The microclimate of two places of cordon cultivated grape has been studied for the investigation of the effect of cultivation method. In one row, the grapes were left to be naturally covered by leaves, while in the other row the leaves were being thinned corresponding to the cultivation method. For characterizing the microclimate, the relative humidity and air temperature, wind speed and direction, UV radiation, leaf wetness and leaf temperature were measured inside the cordon rows among the leaves. Air temperature, relative humidity and wind speed gradient have also been measured above the plants. Radiation budget components were detected with CNR1 net radiometer. Heat flux into the soil and the soil temperature and moisture profiles from the surface to a depth of 1 m were also determined. Two soil heat flux plates were set at 8 cm deep. Measurement frequency was 5 sec and the average time was 1 min using Campbell data collecting systems. Our goal, besides the agroclimatological investigations, is the estimation of soil and surface energy budget components (using Bowen-ratio and gradient methods) and the determination of the optimum roughness length and displacement height as a function of the wind velocity. Daily variation of meteorological elements and energy budget components are demonstrated with case studies.