An Assessment of the Effects of Applying Ash from the Thermal Disposal of Sewage Sludge for Fertilizing Energy Plants Using the Example of Giant Miscanthus (Miscanthus Sinensis Giganteus)

The aim of the research was to determine the possibility of using ash from the thermal utilization of municipal sewage sludge as a fertilizer in the cultivation of giant miscanthus (miscanthus sinensis giganteus) for energy purposes. An attempt was also made to determine the optimal level of fertilization with ash from the thermal utilization of municipal sewage sludge in the commodity cultivation of miscanthus. It was assumed that the ash produced after thermal utilization of municipal sewage sludge could replace conventional mineral fertilizers. To prove the thesis, laboratory experiments of the miscanthus cultivation miscanthus were carried out. The results allowed to determine the optimal fertilization dose for miscanthus to be used in the next stage of the field research. Miscanthus does not pose a succession threat due to the method of reproduction in central Europe; therefore, its cultivation may remain under control. The research showed that for fertilization of miscanthus × giganteus crops, the ashes from thermal utilization of municipal sewage sludge could be used effectively. In experimental crops, it was shown that the optimal level of miscanthus fertilization in terms of yield was 8.32 g of ash per pot and 0.1 g of nitrogen per pot. As a result of laboratory tests, based on biometric features, the most favorable dose of ash and nitrogen fertilization from thermal utilization of municipal sewage sludge for use in field conditions was selected. The dose amounted to 3.7 t of ash∙ha−1 and 45 kg of nitrogen∙ha−1. In order to reduce the costs of cultivation, it was possible to abandon the use of nitrogen fertilizers since their omission did not cause a significant drop in yield. It is necessary to continue research in the field in order to confirm the correctness of the results obtained from laboratory tests.

Effect of Forecast Climate Changes on Water Needs of Giant Miscanthus Cultivated in the Kuyavia Region in Poland

Giant miscanthus is a vigorously growing energy plant, popularly used for biofuels production. It is a grass with low soil and water requirements, although its productivity largely depends on complementary irrigation, especially in the first year of cultivation. The aim of the study was to assess the impact of the forecast climate changes, mainly air temperature increase, on the water needs of giant miscanthus during the growing season in 2021–2050 in the Kuyavia region (central Poland). The years 1981–2010 as the reference period were applied. The meteorological data was based on the regional climate change model RM5.1 with boundary conditions from the global ARPEGE model for the SRES A1B emission scenario. Crop evapotranspiration, calculated using the Penman-Monteith method and crop coefficients, was assumed as a measure of water needs. The study results showed that in view of the expected temperature changes, in the forecast period 2021–2050, the giant miscanthus water needs will increase by 10%. The highest monthly increase may occur in August (16%) and in September (23%). In the near future, the increase in water needs of giant miscanthus will necessitate the use of supplementary irrigation. Hence the results of this study may contribute to increasing the efficiency of water use, and thus to the rational management of irrigation treatments and plant energy resources in the Kuyavia region.

Ionic liquid pretreatment of stinging nettle stems and giant miscanthus for bioethanol production

Production of ethanol from lignocellulosic biomass is considered the most promising proposition for developing a sustainable and carbon–neutral energy system. The use of renewable raw materials and variability of lignocellulosic feedstock generating hexose and pentose sugars also brings advantages of the most abundant, sustainable and non-food competitive biomass. Great attention is now paid to agricultural wastes and overgrowing plants as an alternative to fast-growing energetic crops. The presented study explores the use of stinging nettle stems, which have not been treated as a source of bioethanol. Apart from being considered a weed, stinging nettle is used in pharmacy or cosmetics, yet its stems are always a non-edible waste. Therefore, the aim was to evaluate the effectiveness of pretreatment using imidazolium- and ammonium-based ionic liquids, enzymatic hydrolysis, fermentation of stinging nettle stems, and comparison of such a process with giant miscanthus. Raw and ionic liquid-pretreated feedstocks of stinging nettle and miscanthus were subjected to compositional analysis and scanning electron microscopy to determine the pretreatment effect. Next, the same conditions of enzymatic hydrolysis and fermentation were applied to both crops to explore the stinging nettle stems potential in the area of bioethanol production. The study showed that the pretreatment of both stinging nettle and miscanthus with imidazolium acetates allowed for increased availability of the critical lignocellulosic fraction. The use of 1-butyl-3-methylimidazolium acetate in the pretreatment of stinging nettle allowed to obtain very high ethanol concentrations of 7.3 g L−1, with 7.0 g L−1 achieved for miscanthus. Results similar for both plants were obtained for 1-ethyl-3-buthylimidazolium acetate. Moreover, in the case of ammonium ionic liquids, even though they have comparable potential to dissolve cellulose, it was impossible to depolymerize lignocellulose and extract lignin. Furthermore, they did not improve the efficiency of the hydrolysis process, which in turn led to low alcohol concentration. Overall, from the presented results, it can be assumed that the stinging nettle stems are a very promising bioenergy crop.

Evaluation of polyploid miscanthus lines usage efficiency as a feedstock for bioethanol production

Aim. Main aim of this research was the evaluation of theoretical bioethanol yield (per ha) from hexaploid giant miscanthus (Miscanthus х giganteus) and further comparison with conventional triploid form as well as with other bioethanol crops. Methods. Several mathematic functions were determined that describe yearly yield dynamics and equations, which were used in calculations of theoretical bioethanol yield. Results. The theoretical bioethanol yield was evaluated for different hexaploid miscanthus lines. The most productive in terms of ethanol yield were lines 108 and 202, from which potential bioethanol yield was found to be higher than in control line (6451 L/ha) by 10.7 % and 14.2% respectively and can reach 7144 L/ha and 7684 L/ha. Conclusions. It was determined that the most productive lines of polyploid miscanthus (lines 108 and 202) are able to compete with other plant cellulosic feedstocks for second-generation bioethanol production in Ukraine. However, these lines show bioethanol productivity than sweet sorghum, in the case when sweet sorghum is processed for obtainment of both first- and second-generation bioethanol. Keywords: bioenergy crops, biofuels, giant miscanthus, Miscanthus, polyploidy, second-generation bioethanol.

Weed Management Practices to Improve Establishment of Selected Lignocellulosic Crops

Lignocellulosic biomass is one of the dominant renewable energy resources suited for the production of sustainable biofuels and other energy purposes. This study was focused on weed management strategies that can improve the establishment of six lignocellulosic crops. The studied crops included: giant miscanthus, switchgrass, giant reed, cardoon, sweet sorghum, and kenaf. Delayed planting, increased planting densities, and mulching techniques can suppress weeds in giant miscanthus. Weed competition is detrimental for switchgrass establishment. Seedbed preparation and cultivar selection can determine its ability to compete with weeds. Giant reed is unlikely to get outcompeted by weeds, and any weed control operation is required only for the first growing season. Competitive cultivars and increased seeding rates maximize the competitiveness of cardoon against weeds. Several cultural practices can be used for non-chemical weed management in sweet sorghum and kenaf. For all crops, pre-emergence herbicides can be applied. The available safe post-emergence herbicides are limited. Mechanical weed control during crucial growth stages can provide solutions for sweet sorghum, kenaf, and perennial grasses. Further research is required to develop effective weed management strategies, with emphasis on cultural practices, that can improve the establishment of these prominent lignocellulosic crops.

Growing giant miscanthus in Polissya on radioactively contaminated soils

Purpose. Investigate the accumulation of 137Cs and 90Sr radionuclides in the biomass of giant miscanthus depending on the agronomic methods of growing it on radioactively contaminated soils in Polissia. Method. Biomorphological, radiometric, lysometric, statistical, comparative and computational. Results. The article presents the results of research to study the accumulation of radionuclides 137Cs and 90Sr in the biomass of giant miscanthus. It was found that in the variants where the bioenergy crop was grown on soils contaminated with radionuclides, the accumulation of 137Cs in the biomass in the range of 14.7–18.6 Bq/kg and 90Sr — 0.46–0.54 Bq/kg was observed. The use of mineral fertilizers together with liming and inoculation with giant miscanthus with the microbial preparation Polymyxobacterin and treatment with organo-mineral fertilizer BioMAG helped to reduce the accumulation of radionuclides in the biomass of giant miscanthus as following: 90Sr — by 15% and 137Cs by 21%. It was investigated that the use of these agronomic techniques contributed to the formation of dry biomass yield at the level of 9.96 t/ha on average over three years of cultivation, which is 28% higher than the control. Conclusion. It is established that the use of mineral fertilization in combination with liming, inoculation of rhizomes of giant miscanthus with the microbial drug Polymyxobacterin and pre-planting treatment with organo-mineral fertilizer BioMAG contributes to a significant increase in dry biomass yield with reducing 90Sr and 137Cs. The accumulation of these radioactive isotopes in the biomass of giant miscanthus when grown on radionuclide-contaminated soils did not exceed the permissible level for cereal grains, and the use of agronomic techniques helped to reduce the content of 90Sr by 9–15% and 137Cs by 12–21% compared to control. The lowest coefficients of radionuclide conversion into biomass of giant miscanthus were obtained for both 90Sr (0.15) and 137Cs (0.24) for the use of mineral fertilizers together with liming and inoculation of giant mismanthus rizomes with Polymyxobacterin and treatment with BioMAG organo-mineral fertilizer.

Formation of Crop Yields of Energy Crops Depending on the Soil and Weather Conditions

The article presented discusses the need to use plant biomass made of energy crops grown in marginal soils as an alternative energy source. Variability of biometric indicators of the plant vegetative parts (productivity elements) was experimentally established: stem quantity per area unit and stem height depending on the soil and weather conditions. Based on the five-year research, there was observed a significant influence of soil and climatic growing conditions (average daily air temperature; rainfall; soil fertility) on formation of crop energy productivity. Results showed that the variability of stem density and height; dry phytomass productivity of millet switchgrass and giant miscanthus during observed years depended on the studied factors. Correlation-regression analysis proved and characterized the influence of soil and climatic conditions during the growing season of energy crops on the yield of dry phytomass of millet switchgrass and giant miscanthus in the central part of the Ukraine forest-steppe. The impact proportion share of weather conditions and plant productivity elements on the level of energy crops yields was calculated.

The influence of perennial bioenergy crops on the soil fertility restoration

It was found that long-term cultivation of perennial cereal bioenergy plants has a positive effect on the fertility of low-yielding soils. Thus, for the cultivation of switchgrass for nine years, the content of organic carbon in the soil increased from 1.87 to 2.40%, and for the cultivation of giant miscanthus for six years from 1.87 to 2.42%. Conclusions. Laying plantations of perennial cereal bioenergy plants on low-yielding and erosion-prone lands helps to restore their fertility and provides a sustainable supply of high quality feedstock for the production of biofuels.

Growing miscanthus on radioactively contaminated soils and regularities of 137 CS redistribution in the system «Soil-Plant-Lysimetric waters»

Purpose. Investigate the patterns of transition of 137 Cs radionuclide from soil to biomass and lysimetric waters depending on the elements of technology for growing giant miscanthus on solid fuel on contaminated soils. Methods. Lysimetric, biomorphological, radiometric, statistical, comparative and computational. Results. The article presents the results of research to study the accumulation of the radioactive isotope 137 Cs in the biomass of giant miscanthus and its transition into lysimetric waters. According to the research results, the level of 137 Cs radionuclide accumulation in miscanthus plants on contaminated soils depends on its concentration in the soil and elements of cultivation technology. It was found that in the variants where the bioenergy crop was grown on soils contaminated with radionuclides, the accumulation of 137 Cs in the biomass in the range of 14.7–18.6 Bq/kg and in the lysimetric waters of 4.36–4.57 Bq/l was observed, respectively. Fertilization with mineral fertilizers together with defecation and treatment with miscanthus rice before planting with the microbial preparation Polymyxobacterin in combination with BioMAG helped to increase the yield of dry biomass by 28% of control. Conclusions. The use of mineral fertilization in combination with liming, inoculation of miscanthus rhizomes with the microbial drug Polymyxobacterin and pre-planting treatment with organo-mineral fertilizer BioMAG significantly increases the yield of dry biomass, reduces the content of 137 Cs in biomass and lysimetric waters. The accumulation of 137 Cs in the biomass of miscanthus when grown on soils contaminated with radionuclides did not exceed the permissible level (DR), and the use of elements of technology helped to reduce the content of 137 Cs by 12–21% compared to control variants. The use of the fertilizer complex «mineral fertilizers + defect + Polymyxobacterin + BioMAG» resulted in the lowest accumulation coefficients of 137Cs, which are 0.07 in the biomass of miscanthus and 0.02 in lysimetric waters, respectively.

Effect of Compaction Pressure and Moisture Content on Post-Agglomeration Elastic Springback of Pellets

Renewable energy sources (RES) represent an increasing share of global energy production. Biomass has the highest potential of all RES. Biomass is used to produce solid biofuels, liquid biofuels, and gaseous biofuels. One of the main directions of research on solid biofuels is to optimize the agglomeration process. The main factors determining the characteristics of the final product in the production of pellets are process and material parameters. Process parameters include compaction pressure, temperature, and geometry of the matrix channel. The parameters of the material are the type of biomass, moisture content, degree of fragmentation, and method of preparation of the material (e.g., drying). The process of pressure compaction is always associated with the negative phenomenon of elastic springback. The aim of this work was to check the influence of compaction pressure and material moisture content on the springback value. The research was conducted on three materials (giant miscanthus, cup plant and Virginia mallow), using four different pressures (131, 196, 262, and 327 MPa) and three different moisture levels (8, 11, and 14%). For all material springback values, the range was 9–16%. Statistical analysis showed that for all plants tested, the effects of compaction pressure and moisture content significantly affected the elastic springback value. Areas of high value springback in the pattern of process parameters were determined.