The effect of top dressing fertilizer forms applied at different periods on yield and some yield components in durum wheat varieties

This research was conducted to determine the effects of nitrogen fertilizer forms and application times used in the top dressing of some durum wheat varieties on yield and some yield parameters in GAP International Agricultural Research and Training Center Directorate (GAPUATEM) test fields between 2019-2021. In the study, the effect of six different application times using three nitrogen fertilizer forms (Urea (U 46% N), ammonium sulfate (AS 21% N) and calcium ammonium nitrate (CAN 26% N)) in Burgos, Eyyubi and Hasanbey durum wheat cultivars were treated according to the split-split plots in randomized complete block design. As a result of the study; the effect of wheat varieties on grain yield was found to be important in the first year of the experiment and insignificant in the second year. Although the effect of fertilizer varieties on the characteristics examined in both production seasons is insignificant, it has been observed that the effect of urea fertilizer is better than other fertilizer forms in terms of grain yield. As a result, when considering the climate conditions, in cases where precipitation is sufficient between January and March at the fourth application period, it can be recommended to use slow-release fertilizers (Urea 46%). If the amount of precipitation is insufficient in the same periods, it can be recommended to prefer fast-acting fertilizers (ammonium nitrate) at the third application time.