This article focuses on an examination of the possibility of using potatoes as a binder in the production of heating pellets from flax stalks. This research was carried out in the form of an experimental production, laboratory analyses, and combustion tests of pellets with the Biltstar variety of flax stalks. The production was carried out using an MGL 200 pelletizing line. Adéla potatoes were used as a binder at a dose of 10%. The results were compared to the control variant without the addition of potatoes. Potatoes had a positive effect on the mechanical properties of the pellets as well as on carbon monoxide emissions. A positive effect of the addition of potatoes was recorded by an increase in specific weight (599.2 kg/m³ for the potato-free variant and 1092.3 kg/m³ for the variant with potatoes) and a significant increase in mechanical durability (4.39% for the potato-free variant and 0.71% for the variant with potatoes). The biggest difference was measured in carbon monoxide emissions (13,082 mg/m³_N for the potato-free mg/m³_N ariant and 5186 mg/m³_N for the variant with potatoes). The values were converted to a reference oxygen content of 10%.

The results of this study provide overall information on the verification of the effect of applying two different mulching materials of an organic origin to the soil surface in the area between rows of grape vines in vineyards on selected physical and chemical properties of the soil and, at the same time, on the yield and quality parameters of the grape vines (Vitis vinifera L.). During the period under study, 2018–2020, the effect of shredded cereal straw (CS) and compost from garden waste (CO) was investigated. The control variant (CWC) was left without any cover and was regularly cultivated with a coulter cultivator to a depth of 60 mm. During the experiments, meteorological data were monitored and recorded along with soil temperature and soil moisture for each variant. The results show that the lowest temperature was measured for the straw cover variant (11.10–11.87 °C), while the highest soil temperature was measured for compost (11.93–13.16 °C). Under the straw, the moisture level in the soil was higher compared to the other variants, and there was a gradual increase (of 3%) in soil bulk density values compared to the baseline. By contrast, the compost variant showed a decrease (of 1%) in bulk density values. The differences in nutrient content were slight among the variants. The only statistically significant difference was identified for the compost variant with respect to the content of total nitrogen and phosphorus. Further results demonstrated a positive effect of both mulch material variants on grape yield, which was 6–19% higher in the variants with a cover layer. In addition, the use of mulch also had a positive effect on grape quality. For example, the sugar content—one of the main quality parameters—increased by 1–7% due to the mulch layer. Based on these results, the use of mulching materials can be recommended for areas with low total rainfall during the growing season, as well as when growing varieties with irregular yields and uneven grape quality.

The present article focuses on pressed biofuel preparation from invasive herbaceous plants, and the quality indicators and properties were analyzed and determined. Two invasive herbaceous plants were chosen for this research: giant knotweed (Fallopia sachalinensis) and Sosnowsky’s hogweed (Heracleum sosnowskyi). For a control, pine wood biomass was utilized. After harvesting and drying, plant biomass was chopped and milled and later pressed into cylindrical pellets and briquettes. The research results for the pellets’ and briquettes’ physical and elemental properties showed that the density of the pellets (moisture 5–8%) reached 1145.60–1227.47 kg m⁻³, and the average density of the briquettes reached 615.60–867.31 kg m⁻³. The determined critical compressive strength of the pellets ranged from 420 N to 676 N, and the briquettes disintegrated under a significantly greater critical force of 783 N to 1219 N. The variation in pellet compressive strength with changes in their moisture content was also investigated. The determined lower caloric value of the pellets varied from 15.9 MJ kg⁻¹ to 18.6 MJ kg⁻¹. Harmful gas emissions during burning of the tested biofuel pellets were also evaluated and determined, and they were sufficiently low and did not exceed the permissible values. Finally, it can be stated that all of the pressed biofuels produced from invasive herbaceous plants met the most important requirements for the quality of pressed solid biofuel and can be used for burning in special boilers.

Due to ongoing changes in the European energy market, there is currently a need to find new and additional uses for waste materials. Horticultural waste, which has not yet been fully recognized, offers a relatively wide potential in this area. Although the properties of these wastes are not ideal for combustion, they can be used as a solid biofuel. The pellets that are produced, however, may have useful properties, either energetic or environmental, and are valuable when utilized in boilers. In this study, six examples of typical input raw materials were selected, analysed, and subsequently pelletized. The experimental results provided an overview of the physio-chemical properties of the evaluated samples. Specifically, the moisture content (9.2–27.8%), bulk density (131.4–242.8 kg·m⁻³ wt), ash content (3.0–28.0%), lower calorific value (11.3–16.2 MJ·kg⁻¹), and major and minor elements, were evaluated. The pelletization process and resultant pellet characteristics, such as durability (96.3–98.8%), moisture content (7.5–11.5%), and dimensions, were also evaluated. In the statistical evaluation, significant differences were found between individual samples. In particular, both the branches and the mixture of perennial plants met the industry standard limits, showing that they are of sufficient quality. On the contrary, the sample of fallen leaves was particularly problematic with regard to a number of parameters (moisture, ash content, and calorific value). The overview of the analyses performed expands the current state of knowledge on the potential to use selected types of horticultural waste in the field of energy and for the production of shaped biofuels.

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

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