The development of the modern economic system is becoming increasingly dependent on the sufficient provision of quality energy resources due to the intensification and transformation of the mechanization and automation of all industries. The growth of the energy needs of society is parallel to the awareness of the need to ensure the environmentally friendly development of society. There are a number of reasons for the search for new energy sources, including the limited reserves of traditional sources, dependence on oil-exporting countries, the greenhouse effect due to the entry of carbon dioxide into the atmosphere and air pollution by harmful gases. The biofuel sector offers the potential for both the development of national agriculture and for increasing its energy independence. Global trends in the rapid development of bioenergy in combination with the systemic crisis of the energy sector in Ukraine have necessitated a detailed study on the possibility of increasing the yield of biofuels from crops. The economic and mathematical modeling of the possibility of increasing the yield of bioethanol and vegetable oil from agricultural crops has been carried out. An economic optimization model has been formed, which made it possible to study an increase in the yield of bioethanol from sugar-containing and starch-containing crops and vegetable oil from oil crops from 1 ton per 1 hectare of area. Also, an assessment of the lost yield for the investigated crops has been carried out using the method of analysis of the functioning environment (Farrell’s method).

The intensive agricultural use of the land affects both quantity and quality of river water in the catchment area. Such impact is visible also in the Szreniawa River catchment in the Małopolskie Voivodeship. The combination of intensive plowing and soil susceptibility to water erosion are the main causes of soil and nutrients depletion during the heavy rainfall. The aim of the study is to determine changes in the water quality in the Szreniawa River catchment compared to the agri-culture use and precipitation level.

The quality of surface water has been analysed in the river catchment area in three sampling points. The concentration of the total suspended soils in the samples collected after heavy rainfall in August 2017 reached a value of 837 mg·dm–3. The average concentrations of N-NO3 in the years of 2016–2019 ranged from 0.16 to 13.46 mg·dm–3, with the highest val-ues in the summer (up to 13.46 mg·dm–3). The concentration of N-NH4 and P-PO4 in the Szreniawa water was affected by precipitation. The highest value of average concentration of N-NH4 3.00 mg·dm–3 was recorded in the autumn of 2019 in the middle section of the river. The highest value of P-PO4 0.90 mg·dm–3 was recorded in the autumn of 2019 mostly due to water erosion of the loess areas. Erosion has been caused by the short-term heavy rainfall. As a result, suspended solids, soluble and insoluble phosphorus compounds leaked to the river.