Dobek T.K., Šařec P., Kołosowski P., Šařec O. (2017): Effect of chopped maize straw on the quantity and quality of biogas produced. Res. Agr. Eng., 63 (Special Issue): S8-S12.The increase in production costs of maize silage intended for biogas has led the producers to look for alternative sources of raw material. One of such materials is straw of agricultural crops, including maize. The use of lignin-cellulose materials, such as straw, by bacteria in a biogas fermenter is limited by its polymer structure. Therefore, it is required to process the straw before it is introduced into the biogas fermenter, which may allow to increase the biogas potential of straw. The simplest way of straw processing is its chopping. On the basis of the obtained results, it can be said that cutting the straw did not help increase the amount of biogas produced, but even limited the potential of this raw material.

DOBEK TOMASZ K., RYNKIEWICZ MAREK, ČERVINKA JAN, MAREČEK JAN: Energy and economic eff ectiveness of winter rape and winter wheat cultivation for liquid biofuel production. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 5, pp. 1255-1259 Aim of this study was an analysis and assessment of the economy and energy eff ectiveness of winter wheat and winter rape cultivation for liquid biofuel production. The cost of production and economical eff ect index is more profi table in case of winter rape. Also the fi nal balance of energy eff ectiveness has shown better values if the biodiesel had been produced from winter rape as compared with bioethanol from winter wheat. Calculation of the obtained products and their comparison with an energy unit has shown that the netto energy from biodiesel was positive while that from bioethanol was negative, which means that in the latter case expenditure is greater than that gained in the produced biofuel.biodiesel, bioethanol, production cost, energy input, labour input, energy eff ectiveness, fuel use Study possibility of using agricultural row materials for energy needs has been taken for several years (Mokrzycki, 2005). Processing biomass to energy has got a lot of advantages such as reduction of chemical compound emission, greenhouse eff ect reduction, and biodegradation. An important advantage of this type of fuel is its possibility of continuity of its production (it is possible to renew this type of fuel). The cost of biofuel production is determinated by raw materials price. The price of raw materials depends on technologies and allocation system for agriculture. Costs of production of the most known liquid fuels such as bioethanol, rape's ester are about 2.4-2.6 times higher than costs of production of mineral fuels. However, decreasing of natural energy recourses (gas, oil, coal) causes that people are more interested in this type of energy. An important component of valuation of fuel's production, besides costs, is an energy eff ectiveness calculation. The energy eff ectiveness calculation shows how much energy must be used to get biofuel energy unit (Dobek, 2004). The advantage of energy eff ectiveness calculation is its independence of prices. Independence enables to compare the results.An aim of a study was to evaluate a technology of winter wheat and winter rape production, to evaluate processing agricultural products into biofuels and to count energy and economical eff ectiveness coeffi cients of biodiesel production from winter rape and of bioethanol production from winter wheat. MATERIALS AND METHODSStudies were made in 2010−2012 on agricultural farms placed on the terrain of north-western Poland. In winter rape production traditional technology of cultivation was used (moldboard plough and disc harrows), in secondary tillage compactor was used. Fertilizer application was done three times by using trailed fertilizer distributor. Seeding was done by using multipurpose drill. During a vegetation season spraying was done...