To evaluate the N-availability and N-efficiency of liquid fertilizers two neighbouring fields under different management but same use and fertilization were locally labelled with 15-N species of ammonia and nitrate. The label was applied to the seed furrow after seeding and fertilization. Hereby three different forms of fertilizers in liquid and solid form were investigated in triplicates. The sampling of soil and plants will be conducted three times during the vegetation period starting after germination. This experiment aims to evaluate and quantify the conversion, distribution and uptake-efficiency of different forms of fertilizers.