Crop fertilization with sulfur is an important part of agricultural practices, as is the systematic increase in soil organic matter content. Materials of waste origin constitute a source of plant-available sulfur, as well as soil organic matter. The study was to verify the hypothesis assuming that combining waste sulfur pulp and its mixtures with organic materials enables simultaneous soil enrichment with readily available sulfur and organic matter. A 240-day incubation experiment was conducted, on two soils: very light and heavy; with two sulfur doses applied to each soil (20 and 40 mg S/kg d.m. for very light soil, and 30 and 60 mg S/kg d.m. for heavy soil). The sulfate sulfur content in the incubated soil material, treated with the addition of sulfur pulp and its mixtures with organic materials, increased significantly up to day 60 and then decreased. The application of these materials significantly increased the content of available sulfur and decreased the pH value of the incubated material. The effect of the introduced materials on dehydrogenase activity depended on soil granulometric composition (the impact of the applied materials on the activity of these enzymes in very light soil was small, and in heavy soil, their activity was usually limited by the presence of introduced materials). Application of the studied materials had little effect on the total organic carbon content in the incubated soil material (a significant change in the value of this parameter, in relation to the control soil, was recorded in some treatments of heavy soil).

Energy from biogas is widely available, inexpensive, and often contributes to waste management, making it one of the most promising renewable energy sources. The main factors influencing this process’ efficiency include the substrates’ chemical composition, temperature, and digester load. This paper presents the possibilities offered by a biogas plant built at a farm specialising in dairy cows. The dependence of the power generated in the micro biogas plant on its technical parameters was analysed in detail. Studies carried out by the authors in an agricultural microgas plant (with an electrical output of 40 kW) have shown that they are designed to maintain continuous energy production, despite changing process parameters such as digester mass level, biogas height, temperature or slurry flow into the digester. However, from the point of view of the amount of electricity generated, changes would have to be made to the design of the biogas plant. Firstly, a more powerful generator would have to be installed to cover the electricity requirements of the equipment installed in the biogas plant so that power close to the rated capacity of the biogas plant is still sent to the grid. Secondly, replacing the two existing agitators of the digestion mass (9 kW each) with more agitators of lower power (e.g., four agitators of 4.5 kW each) would be necessary. These should be programmed so that one of the agitators operates at any given time (the operating time of a given agitator should depend on the composition of the digestate).

The level of sustainability of agricultural production in the surveyed holdings was assessed both in ecological and in social terms. The balance of reproduction and degradation of organic matter was prepared using the calculation method, with coefficients provided by the Institute of Soil Science and Plant Cultivation (IUNG). The level of sustainability of organic matter in the soil was the most favourable in holdings that were the biggest territorially and economically and with the highest amount of subsidy and business income. They also had the greatest net commodity production. This group of holdings (area of 70 ha UAA) showed the highest level of decomposition of organic matter in crop production, but the overall balance was positive due to large-scale animal production. In contrast, small farms with lower production do not produce a sufficient mass of organic matter. Environmental sustainability was found in holdings using more than 30 ha of arable land that received subsidies in the amount over 100 thousand Polish zlotys and showed a balance of organic matter above 0.26 tons per hectare of arable land. Social sustainability was shown in households using more than 30 ha of arable land, where the level of mechanization reduced the workload (less than 2,000 working hours per employee per year and less than 100 man-hours per ha UAA).

W pracy przedstawiono zróżnicowanie zasobów oraz dynamiki zmian mocy w gospodarstwach rodzinnych w latach 2004–2009. Przeanalizowano 70 gospodarstw rolnych pod względem kwoty pomocy, powierzchni UR, wielkości ekonomicznej i dochodu przedsiębiorstwa. Podstawowym źródłem mocy w badanych gospodarstwach były ciągniki rolnicze. Poziom mocy zainstalowanej dwukrotnie wzrósł w gospodarstwach mniejszych obszarowo, do 10 ha UR i tendencja ta utrzymała się dla gospodarstw o najmniejszej żywotności ekonomicznej oraz niskim poziomie dochodu przedsiębiorstwa. Zasoby mocy malały wraz ze wzrostem powierzchni gospodarstw rolnych, ale najwyższą dynamikę zmian odnotowano w gospodarstwach najmniejszych (< 10 ha UR).