THE ASPECTS OF GROWING AND USE OF DIFFERENTENERGY CROPS

This article analyses some aspects of use of selected energy crops: Miscanthus x giganteus J.M. Greef et Deuter ex Hodkinson et Renvoize, Panicum virgatum L., Sorghum saccharatum (L.)Pers. (Switchgrass). The first stage of the research was to determine the content of mineral elements (potassium, sodium, calcium) in biomass of aboveground part of energy crops as well as in soil after energy crops’ growing. The fallow soils and areas where perennial grasses (test area) and cereal agricultural crops are grown were taken for comparison purposes. The soil samples were taken on a 10 × 10 m plot from two levels of tilth top soil with a soil depth of 0–20 and 20–40 cm.The yield of the abovementioned mineral elements caused by the energy crops was evaluated by the biological absorption coefficient(BAC). The ash content in the biomass of the studied energy crops was determined. The second stage of the study was to test the methodology of self-made pellets production with-out using any binders from the biomass of the studied energy crops. The mechanical strength of the pellets was measured by fixing the force required to break the pellets. The results obtained were divided by area of pellet breakdown by determining the ratio of the force index to the breakdown area.The total contents of the analyzed elements in soil and biomass of energy crops was determined by atomic absorption spectrometry method, ash content was determined by calculating the mass of the residue after slow ashing of the sample in a muffle furnace.It was found that all the studied energy crops absorb less sodium and potassium removal from the soil than Calcium. S. saccharatum absorbs more potassium and P. virgatum absorbs more calcium. It was shown that biomass of aboveground part of M. x giganteus and P. virgatum is characterized by higher ash content in comparison with S. saccharatum which is explained by significant leaf mass proportion. It was revealed that for all of the studied energy crops the mechanical strength of the pellets made from the leaves is lower compared to the stem part. According to the natural adhesive properties of the raw materials, the studied energy crops can be placed in the following descending row: Sorghum saccharatum (L.) Pers.) → Miscanthus sp. → Panicum virgatum L