Bioenergetic assessment of sewage sludge application under Silphium perfoliatum L. on sod-podzolic soils of Precarpathians

Many countries around the world are paying close attention to the search and use of the alternative energy sources that could replace fossil hydrocarbons: oil and gas. The grown biomass of the green plants is considered as an alternative energy source for biofuel production. One of the energy crops, which is able to form high yields of the biomass and can be used as a source of the bio raw materials, is Silphium perfoliatum L. Studies have determined the bioenergetic efficiency of the growing sylphia perforated with the introduction of different rates of the sewage sludge on sod-podzolic soils of the Precarpathian region. A comparative analysis of the morphometric parameters of the plants of the Silphiumper foliatum L. was held and it showed the changes in height and diameter of the shoots, length and width of the leaves, there was determined its productivity and energy yield with the Silphiumper foliatum L. biomass and there was also held a statistical analysis of the experimental parameters. It is established that the addition of the fertilizer based on the sewage sludge and straw at a rate of 30–40 t/ha and mineral fertilizers N10-50P14-52K58-74 under the sylphiaperforated provides an increase in the crop productivity at the level of 20.5–22.4 t/ha, the highest gross energy yield 356–385 GJ/ha with biomass and the highest energy efficiency. The energy efficiency coefficient is 1.2–1.3, and its correlation dependence on the yield of the dry biomass and energy reserves in humus is close. On the basis of the field research the mathematical equation of the forecast of the bioenergy efficiency depending on the norms of these wage sludge addition is made, the coefficients of the energy efficiency on the basis of an output of the dry biomass and energy stocks in humus of sodpodzolic soil are defined.