Evaluation of agronomic affect of SULFAN 24/6 fertilizer on model crop of onion (Allium cepa L.) compared to ANAS 26/13 and DAN 27 fertilizers

Small–plot nutrionists experiments were based on medium–heavy brownsoil with neutral soil reaction in years 2014 a 2015 in terms of agricultural enterprise in Madunice with onion (Allium cepa L.), variety Bingo. The effect of N–S fertilization of onion by fertilizers SULFAN 24N 6S and ANAS 26/13 on yield and fertilization economy was monitored in the experiment. The effect of N–S fertilizers was compared to fertilizer DAN 27, that was applied be-fore sowing. There were relatively unfavourable weather conditions for growing onion, in both experimental years 2014 and 2015. Significant rainfall deficit during the grow-ing season negatively affected the inadequate and irregu-lar germination and sprouting of seeds and later uneven development of onion plants. This state significantly re-flected at very low onion yield at unfertilized control treat-ment as well as at N and N–S treatment of nutrition. Ap-plication of fertilizers DAN 27, ANAS 26/13 and SULFAN 24/6 caused highly significant yield increase compared to unfertilized control treatment by from 19.54% to 37.20% (by 2.07 – 3.94 t·ha–1). In comparisson to unfertilized con-trol treatment, the highest average yield increase 3.94 t·ha–1 (by 37.20%) was noticed at treatment, where ANAS 26/13 was applied. There was also the highest average coefficient of natural efficiency found at this treatment. Ap-plication of SULFAN 24/6 increased the yield by 2.95 t·ha–1(by 27.86%), compared to unfertilized control treatment. There was coefficient of natural efficiency 36.9 kg of onion per 1 kg applied nitrogen and yield increase reached 590 € per hectare, at treatment fertilized by SULFAN 24/6. There was statistically significant difference between agrochemi-cal effect of fertilizers with nitrogen and sulphur content (ANAS 26/13 and SULFAN 24/6). Statistically significant difference was reached by application of ANAS 26/13 compared to SULFAN 24/6. It means increase by 0.99 t·ha–1 and 198 € per hectare.