The Use of Macroelements from Municipal Sewage Sludge by the Multiflora Rose and the Virginia fanpetals

Municipal sewage sludge contains many valuable nutrients which can be used in the cultivation of energy crops. Application of large doses of sewage sludge can be a cause of environmental pollution, especially with nutrients. The multiflora rose and the Virginia fanpetals are plants with high nutritional requirements. The use of municipal sewage sludge in the cultivation of energy crops will allow recycling the nutrients from this organic waste. The aim of the study was to evaluate the use of macroelements from municipal sewage sludge by the multiflora rose var. "Jatar" (Rosa multiflora Thunb. ex Murray) and the Virginia fanpetals (Sida hermaphrodita Rusby). Four levels of sewage sludge fertilization were applied in the 6-year field experiment: 0, 10, 20, 40, 60 Mg DM sludge ∙ ha^-1. Sewage sludge was applied once before planting energy crops. Due to the low potassium content in sewage sludge, a single supplementary fertilization with 100 kg K ∙ ha^-1 in the form of 40% potassium salt (KCl) was applied on each plot. The study involved the evaluation of the yield, uptake and use by energy plants of N, P, K, Ca, Mg, and Na from sewage sludge. It was found that the increasing doses of sewage sludge significantly raised the multiflora rose and the Virginia fanpetals biomass yields. The yield of the Virginia fanpetals was one and a half times higher than that of the multiflora rose. The increasing doses of sewage sludge significantly raised the contents and uptake of N, P, K, Ca, Mg, and Na by these plants. The highest uptake of macronutrients by the multiflora rose and the Virginia fanpetals crops was determined for 60 Mg DM ∙ ha^-1 fertilization dose. The results show that the Virginia fanpetals used N, P, K, Ca, Mg, and Na from the sewage sludge to a greater extent than the multiflora rose. The analyses indicate that due to the greater yields, bioaccumulation and uptake of macronutrients, Virginia fanpetals is more effective in the ‘purification’ of the substrate from excess nutrients that may pose a threat to the environment.