This article deals with energetic evaluation and potential of pomace – a waste product originating during production of grape wine. Calorimetric analysis of 19 grapevine varieties was performed in 2013 and 2014. The aim was to specify their combustible limit and the gross calorific value. The evaluations were performed on pristine pomace, pomace without seeds, and only on seeds themselves. The results obtained imply that pomace is an interesting energetic resource with a gross calorific value of 16.07-18.97 MJ kg⁻¹. Lower calorific values were detected in pomace after seed separationie14.60-17.75 MJ kg⁻¹; on the contrary, seeds alone had the highest calorific values of 19.78-21.13 MJ kg⁻¹. It can be assumed from the results of energetic evaluation of pomace in Czech Republic conditions that, by purposeful and efficient usage of pomace, 6.4 GWh of electric energy and 28 GWh of thermal energy can be generated.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

Poplars and willows have been cultivated for their environmental benefits for millennia. In the present study, physiological responses were examined in three poplar and three willow clones grown in soil from the landfills near Novi Sad and Belgrade, Serbia. The experiment, conducted under controlled conditions in pots with soil directly from the landfill sites, aimed to identify the most suitable clones based on their physiological performance on examined substrates. Within the process of phyto-recurrent selection, six clones were selected for this experiment: Populus deltoides cl. PE 19/6, PE 4/68, S 1-8, and Salix alba cl. 107/65-9, 79/64-2, 380. Four physiological parameters (net photosynthesis [A], transpiration [E], water use efficiency [WUE], and stomatal conductance [gs]) were measured throughout the research. Analysis of variance revealed that certain clones exhibited superior physiological responses compared to others. The superior performance of poplar clones PE 4/68 and S 1-8 in key physiological parameters underscores their potential for improving growth, resilience, carbon sequestration, and overall ecological and economic benefits, making them valuable candidates for forestry and environmental management programs.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic

This study deals with the rheological properties of wine lees. Samples of wine lees of the Saint Laurent variety were used in this experiment. The investigated wine lees arose in the process of production red grape wine in 2013 (Czech Republic). At first, the chemical background was determined. The chemical background includes the following chemical parameters: total acidity, pH, alcohol content, reduced sugars, free SO₂, total SO₂, and volatile acid. In the second phase of the study, physical properties were determined. Specifically, a sample of wine lees was subjected to rheological tests. These tests consisted in determination of dependence of dynamic viscosity on the temperature, hysteresis loop tests, dependence of dynamic viscosity on the time and step-down in the shear rate test. The experiment demonstrated that the dynamic viscosity increased with increased temperature – this phenomenon is caused by thermolabile proteins – and the wine lees has rheopectic behaviour; the degree of rheopexy was found to rise with the increasing temperature.