The study was carried out in pot experiment on loamy strong silty clayey sand of pH(KCl) 4.1 in the years 1992 - 1994. The nutrients in g kg of soil were applied in quantities: 0.142 N, 0.025 P, 0.174 K, 0.007 Mg i 0.017 S. The 6 fertilization levels, with constant ratio of nutrients were applied in doses: full dose as well as 3/4, 1/2, 1/4. 1/8 and 0 of basis dose. Spring cereals: wheat, barley and oat were the test plants. The root dry weights and overground-parts and total biomass as well as N, P, K, Ca, Mg, Fe, Mn, Zn and Cu content in roots was determined at the flowering stage. It was found that mass of roots, overground-parts and total biomass as well as nutriens content (without Cu and Zn) increased along with the increase of fertilization attaing the bigest level on full dose and 3/4 her value. I be content of Cu and Zn were the bigest on level without fertilization. The root dry weight/overground-parts ratio was highier for spring wheat than for spring barley and oat.