EN
The influence of Mg-fertilization on a change in chemical composition of fodder plants was investigated in three series of pot experiments. Different doses and forms of Mg were used in the experiments conducted on different soils. Magnesium was introduced every year as MgS04; once before the experiments outset dosed lHh as CaCO 3,MgCO3 and MgSO4,and increasing doses: 0,5; 1,0 and 2,0 Hh were used in the third series. Throug Mg-fertilization, there is a possibility to narrow Ca:P and K:(Ca+Mg) ratios, and to a lesser extent, K:Na ratio which improves the fodder quality of fodder plants.