Method of preparation of nitrogen containing fertilizer, enriched by microelements (copper and zinc), with increased resistance to nitrogen leaching by water, based on impregnation of support from aspen bark by urea and potassium sulphate solutions was proposed. The data about composition and properties of nitrogen containing fertilizer based on porous support from aspen bark was provided. Influence of K2SO4 on fertilizer resistance for nitrogen leaching by water was determined. It was shown, that the impregnation of urea containing support from aspen bark by potassium sulphate solution leads to significant (in 1.8 times) reduction of a nitrogen leaching by water from obtained fertilizer. The ability of nitrogen containing fertilizer based on aspen bark to slow leaching of mineral components by water during long time was found, that determine his prolonged action. It was shown, that after water treatment at room temperature during 12 days the fertilizer content 43.2% nitrogen, 36.7% potassium, 32.6% copper and 33.8% zinc. Vegetative experiments at greensprouting of oat seeds were shown the growth stimulate action of nitrogen containing fertilizer based on aspen bark.