Miscanthus x giganteus is an energy crop relatively recently introduced into Croatia, that is suitable for cultivation on marginal or abandoned agriculturl land. Energy crops can contribute to ...climate change mitigation both by carbon sequestration into soil/plant pool and by substitution of fossil fuels. Therefore, the aim of this paper is to evaluate the impact of Miscanthus x giganteus cultivation on the environment by determination of soil and soil-plant system's carbon budget, as well as to estimate the sequestration potential of Miscanthus stand on abandoned agricultural land at national level. After the 3 years of Miscanthus cultivation, soil pH and K2O decreased, P2O5 increased and Ntot remained the same. Plant biomass increased from April, peaked in September, and decreased towards the spring harvest with harvested yield of 14.5 t/ha. Average soil respiration amounted 9.1 t/ha/y, and didn't show seasonal trend, or significant correlation to soil temperature and moisture. Estimated sequestration potentials of Miscanthus are 1.3 (soil system) and 2.0 (soil-plant system) t/ha/y. The highest contribution to carbon gains and losses had respectively preharvest losses and soil respiration. Between 704 520-3 251 600 t C could be sequestrated in soil/plant pool in Miscanthus lifespan if 5-15% of abandoned agricultural land would be converted to Miscanthus cultivation. Therefore, Miscanthus represents biological carbon sink due to great sequestration potential and additional fossil fuel replacement benefits.
The application of municipal sewage sludge as fertilizer in the production of non-food energy crops is an environmentally and economically sustainable approach to sewage sludge management. In ...addition, the application of municipal sewage sludge to energy crops such as Miscanthus x giganteus is an alternative form of recycling nutrients and organic material from waste. Municipal sewage sludge is a potential source of heavy metals in the soil, some of which can be removed by growing energy crops that are also remediation agents. Therefore, the objective of the research was to investigate the effect of municipal sewage sludge applied at three different rates of 1.66, 3.22 and 6.44 t/ha on the production of Miscanthus. Based on the analyses conducted on the biomass of Miscanthus fertilized with sludge from the wastewater treatment plant in three fertilization treatments, it can be concluded that the biomass of Miscanthus is a good feedstock for the process of direct combustion. Moreover, the application of the largest amount of municipal sewage sludge during cultivation had no negative effect on the properties of Miscanthus biomass. Moreover, the cellulose and hemicellulose content of Miscanthus is ideal for the production of second-generation liquid biofuels. Fertilizer treatments had no effect on the content of cellulose and lignin, while a significant statistical difference was found for hemicellulose.
Miscanthus and Virginia Mallow are energy crops characterized by high yields, perenniality, and low agrotechnical requirements and have great potential for solid and liquid biofuel production. Later ...harvest dates result in lower yields but better-quality mass for combustion, while on the other hand, when biomass is used for biogas production, harvesting in the autumn gives better results due to lower lignin content and higher moisture content. The aim of this work was to determine not only the influence of the harvest date on the energetic properties but also how accurately artificial neural networks can predict the given parameters. The yield of dry matter in the first year of experimentation for this research was on average twice as high in spring compared to autumn for Miscanthus (40 t/ha to 20 t/ha) and for Virginia Mallow (11 t/ha to 8 t/ha). Miscanthus contained 52.62% carbon in the spring, which is also the highest percentage determined in this study, while Virginia Mallow contained 51.51% carbon. For both crops studied, delaying the harvest date had a positive effect on ash content, such that the ash content of Miscanthus in the spring was about 1.5%, while in the autumn it was 2.2%. Harvest date had a significant effect on the increase of lignin in both plants, while Miscanthus also showed an increase in cellulose from 47.42% in autumn to 53.5% in spring. Artificial neural networks used to predict higher and lower heating values showed good results with lower errors when values obtained from biomass elemental composition were used as input parameters than those obtained from proximity analysis.
Biomass obtained from cultivated energy crops is one of the raw materials with the highest potential in renewable energy production. Although such biomass can be used in production of lignocellulose ...bioethanol, it is currently mostly used as solid fuel for generating heat and/or electric energy via combustion processes. Calorific values, proximate and ultimate analysis, cell structure and micro- and macro-elements data are considered as basic parameters in the valorization of fuel properties during biomass combustion processes. Energy crops are cultivated with the aim to produce the largest possible quantity of biomass with minimal agro-technical inputs. One of these crops is Sida hermaphrodita (L.) Rusby. Given the fact that the chemical composition of biomass is influenced by a number of agro-ecological and agro-technical factors, the aim of this work was to determine the fuel properties of Sida hermaphrodita biomass obtained from three different harvest seasons (autumn, winter and spring) and cultivated in the area of the Republic of Croatia. On the basis of these investigations it was possible to conclude that harvest delaying towards spring season had a positive impact on suitability of using biomass of Sida hermaphrodita in the combustion process, which primarily means significant lowering the contents of moisture (18.64%), ash (1.94%), and nitrogen (0.65%), but also means increasing the contents of fixed carbon (6.21%) and lignin (25.45%).
Straw, the primary agricultural waste, constitutes approximately 20% of the total biomass in the EU. Only a small fraction of the material is applied in various products, e.g., animal bedding, mulch, ...building, and composite materials, while a significantly larger portion is often burned in the field. This practice, while prohibited for several reasons, including the increased risk of fire and the release of carbon dioxide contributing to global warming, is still prevalent. Given the increasingly evident effects of climate change, EU legislation aims to reduce greenhouse gas emissions as much as possible. One of the strategies includes applying the cascade principle in the circular economy. This principle aims to use the entire raw material, in this case, cereal crops, such that the products with the highest added value, like cellulose fibers from cereal straw, are extracted first. The vast potential for utilizing lignocellulosic agro-waste sustainably arises from its status as the most abundant organic compound on Earth. Its significant presence, renewability, and biodegradability make it a desirable source for producing materials in numerous industries. This study examines the potential of wheat fibers, isolated from the straw of two distinct cultivars (Srpanjka represents an old variety, and Kraljica represents the new variety) primarily for application in technical textiles. The following testing methods were applied: determination of wheat fibers and residues yield, fibers tensile properties, length, moisture content/regain, density, morphology, and Fourier transform infrared (FTIR) spectroscopy. The yield of isolated fibers relies on the wheat variety and the climatic conditions affecting plant growth, resulting in fiber yields from 10.91% to 15.34%. Fourier transform infrared (FTIR) analysis indicates reduced peak intensity, which is related to hemicellulose and lignin content, suggesting their improved deposition following the process of chemical maceration. Wheat fiber quality was found to be comparable to cotton fibers regarding its density. However, they showed a significant difference in higher moisture regain (9.72–11.40%). The vast majority of the scientific papers related to wheat fibers did not indicate the length of the individual fibers obtained by chemical maceration nor their strength. Therefore, this paper indicated that both varieties demonstrated sufficient fiber tenacity (greater than 10 cN/tex) and fiber length (2–3 cm), stressing the spinning potential of these fibers into yarns and extending their use to the apparel industry. Moreover, our research underscores the feasibility of adhering to the zero-waste principle. A high percentage of solid waste remaining after fiber extraction (25.3–39.5%) was successfully used for biofuel production, thus closing the loop in the circular economy.
Selecting cultivars with greater biomass results in higher yields and greater carbon sequestration. Storage of atmospheric carbon in the plant/soil pool contributes not only to food security but also ...to mitigating climate change and other agroecological benefits. The objective of this study was to determine: (1) grain, residue, and root biomass yields; (2) harvest indexes; (3) residue-to-product ratio; (4) root-to-shoot ratio; (5) biomass carbon and nitrogen contents; and (6) C:N ratios for two new and two old winter wheat cultivars. The greatest yield difference was found between old Srpanjka (the lowest) and new Kraljica (the highest) cultivar where grain, residue, root, and total biomass yield was higher by 38%, 91%, 71%, and 64%, respectively. Total biomass was composed of 40–47% grain, 10–11% roots, 32–36% stems + leaves, 9–11% chaff, and 1–2% spindle. The range of HI was 0.45–0.53, RPR 0.91–1.25, and R:S ratio 0.12–0.13. For all cultivars, positive carbon and negative nitrogen balance within the plant pool was determined. Still, root biomass and rhizodeposition carbon remain open questions for a better understanding of agroecosystems’ C dynamics.
This research aims to use artificial neural networks (ANNs) to estimate the yield and energy characteristics of Miscanthus x giganteus (MxG), considering factors such as year of cultivation, ...location, and harvest time. In the study, which was conducted over three years in two different geographical areas, ANN regression models were used to estimate the lower heating value (LHV) and yield of MxG. The models showed high predictive accuracy, achieving R2 values of 0.85 for LHV and 0.95 for yield, with corresponding RMSEs of 0.13 and 2.22. A significant correlation affecting yield was found between plant height and number of shoots. In addition, a sensitivity analysis of the ANN models showed the influence of both categorical and continuous input variables on the predictions. These results highlight the role of MxG as a sustainable biomass energy source and provide insights for optimizing biomass production, influencing energy policy, and contributing to advances in renewable energy and global energy sustainability efforts.
Biological carbon sequestration is considered an important strategy to mitigate climate change. The energy crop Miscanthus × giganteus has great sequestration potential. The objective of this study ...was to determine: a) the dry matter yield and carbon content in aboveground and belowground biomass; b) the total carbon balance in the plant and soil pool. The study was conducted in continental Croatia (N 45°51′01.32″; E 16°10′35.85″) by the destructive harvesting of five-year-old Miscanthus × giganteus stands established by rhizomes (MxgR) and seedlings (MxgS) in the spring of 2021. The soil sampling was conducted in 2016 and 2022. The average amount of carbon in the aboveground biomass of MxgR and MxgS is 11.51 t/ha and 9.87 t/ha, respectively, and in the belowground biomass it is 13.18 t/ha and 14.90 t/ha, respectively. The carbon balance in the plant pool of MxgR is three times lower (1.67 t/ha) than that in the plant pool of MxgS (5.03 t/ha). The total soil carbon content increased by 8.7 t/ha under MxgR and by 14.8 t/ha under MxgS during 2016–2022. Therefore, under the studied agroecological conditions, seedlings should be preferred over rhizomes in the selection of planting material. The obtained data represent valuable input data for sequestration modeling.
Agricultural greenhouse gas emissions can be reduced by the cultivation of cultivars with lower carbon footprint. Considering the hypothesis that there are differences in soil respiration, due to ...differences in physiological and morphological characteristics of wheat and barley, the aim of this study is an assessment of soil respiration rates and microclimate under different cover (bare soil, wheat, and barley) and cultivar (four barley and four wheat) types. Soil respiration was determined by in situ closed static-chamber method in continental Croatia, during the 2020/2021 season. The seasonal pattern of the soil respiration was similar for all cultivars, respiration was increasing with crop development stages until maturity, when it decreased until the harvest. Cover type did not have influence on soil microclimate but did have on soil respiration. Bare soil had significantly lower annual respiration rates, compared to the barley/wheat covers. Average annual respiration rates were similar between the barley and wheat covers, as well as between all studied barley cultivars. A significant difference between winter wheat cultivars have only been determined between the Renata (9.78 kg C-CO2 ha−1 day−1) and El Nino (12.67 kg C-CO2 ha−1 day−1) cultivars. However, the determination of the total carbon budget is needed, in order to determine the most suitable cultivar, in the light of climate change.
The aim of this study was to investigate the potential of using structural analysis parameters for estimating the higher heating value (HHV) of biomass by obtaining information on the composition of ...cellulose, lignin, and hemicellulose. To achieve this goal, several nonlinear mathematical models were developed, including polynomials, support vector machines (SVMs), random forest regression (RFR) and artificial neural networks (ANN) for predicting HHV. The performed statistical analysis “goodness of fit” showed that the ANN model has the best performance in terms of coefficient of determination (R2 = 0.90) and the lowest level of model error for the parameters X2 (0.25), RMSE (0.50), and MPE (2.22). Thus, the ANN model was identified as the most appropriate model for determining the HHV of different biomasses based on the specified input parameters. In conclusion, the results of this study demonstrate the potential of using structural analysis parameters as input for HHV modeling, which is a promising approach for the field of biomass energy production. The development of the model ANN and the comparative analysis of the different models provide important insights for future research in this field.
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