The aim of the present research was to determine the effect of fertilization applying various doses of manure on the selenium content in soil and red clover on the background of the activity of selected soil oxidoreductases. The soil was affected by organic fertilization in a form of manure in the doses of 0, 20, 40, 60, and 80 t·ha^-1. The content of total selenium in control soil was, on average, 0.101 mg·kg^-1. A comparison of results reported in literature shows that the studied soil was poor in that element. The application of the highest manure dose resulted in a 1.7-fold increase in the content of Se in soil. Fertilization with manure resulted in an increase of dehydrogenases and catalase activities in soil with increasing doses of manure. The bioaccumulation and translocation coefficients of selenium demonstrated that above-ground red clover biomass absorbed and transported selenium more easily from soil without manure or treated with FYM at a dose of 20 t·ha^-1.