Subject of diploma thesis is assessment of influence addition inhibitors in liquid urea–ammonium nitrate (UAN) fertilizer on the yield and oiliness of rape. The experiment was solved in two-years (2017, 2018) form small-field experiment in research station Žabčice. In experiment was included four variants of fertilization: 1. ANCS (ammonium nitrate with calcium sulfate) + UAN (urea ammonium nitrate), 2. ANCS +UAN + IN (nitrification inhibitor), 3. ANCS + UAN + IU (urease inhibitor), 4. ANCS + UAN + IN + IU. Addition of inhibitors in liquid fertilizer UAN didn't has statically conclusive effect on rape seed yield. The highest yield was achieved in variant ANCS + UAN with yield of 4,1 t/ha. The lowest yield was achieved in variant ANCS + UAN + IN with yield 3,9 t/ha. Weather was above average warm and dry in both reference years. The efficiency of nitrification inhibitors with rising temperature decreases linearly. The found oiliness of rape seeds from individual fertilization variants was relatively balanced. The applied inhibitors didn't significantly affect the oil content in the seeds. The highest oiliness was achieved in variant ANCS + DAM with oiliness of 40,7 %. The lowest oiliness was achieved in variant ANCS + UAN + IN + IU with oiliness of 40,4 %.