No abstract

Six Trifolium pratense L. cultivars, five diploid and one tetraploid, were grown in the lowland region (123 m altitude) and the mountain region (650 m altitude). Dry ma�er (d.m.) and green mass (g.m.) yield, stem height and leaf proportion were assessed from each of the three growing seasons. Chemical composition was assessed from the average samples of all cuts in the second year of the experiment. Greater green mass (54.14 t/ha) and dry ma�er yield (9.86 t/ha), stem height (0.61 m), crude protein (157.6 g/kg), crude fiber (222.9 g/kg), crude ash (100.68 g/kg) and crude fat (30.09 g/kg) content were observed in the mountain region, compared to the lowland region (45.61 t/ha g.m. 8.92 t/ha d.m. 0.59 stem height, 156.38 g/kg crude protein, 216.6 g/kg crude fiber, 94.85 g/kg crude ash, 24.98 g/kg crude fat). The greater leaf proportion (47.2%) and nitrogen free extract content (420.13 g/kg) were observed in the lowland region compared to the mountain region (42.95% and 402.99 g/kg, respectively). A significant location × cultivar interaction was found for all investigated parameters except for leaf proportion.

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.

SummaryAlthough biomass of Miscanthus x giganteus shows a significant potential for production of second-generation biofuels, it is currently mostly used as a combustion fuel. The objective of this paper is to investigate: (I) dry matter yield and yield components; (II) biomass composition; and (III) potential divergences of the investigated parameters from the standard for solid fuels CEN/TS 14961:2005, in relation to two harvest seasons and six fertilizer treatments. The investigation has determined that there is a potential for producing significant quantity of biomass from M x giganteus in the investigated agro-ecological conditions of the mountain areas of Croatia. The laboratory analyses indicated the suitability of using biomass in direct combustion.

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%).