The material for the study originated from identical field experiments conducted on a soil classified as medium loam and light loamy sand. The experiments included two levels of fertilisation with nitrogen (100 and 200 kg ha-1 N) and phosphorus (39.3 and 52.4 kg ha-1 P). Determinations of the content of crude ash, N, P, K, Mg, Ca, Na, S, Cl, Cu, Fe, Mn, Ni, Pb and Zn were made in accordance with commonly accepted methods. The biomass of Sida from the culture on the light loamy sand had a significantly higher content of crude ash, N, P, K, Mg, Ca, S and Ni, and a lower content of Cl. The content of the other elements was not affected by the soil type. The two levels of nitrogen and phosphorus fertilisation did not modify significantly the levels of the elements under study, with the exception of nickel and chlorine. Intensive fertilisation with nitrogen significantly reduced the content of chlorine and increased the content of nickel. The higher dose of phosphorus fertiliser caused a decrease in the content of nickel in the biomass of Sida.