The study looked at how adding nitrogen fertilizer and irrigation affected the yield of two types of winter wheat. One type of wheat, Zvezdana, had a higher yield than the other type, Simonida. Surprisingly, the wheat that didn't receive any extra fertilizer or irrigation had the highest yield. This unexpected result might be because the weather that year was very good for growing wheat, with lots of rain and warm temperatures. So, adding more fertilizer or water didn't make much of a difference in the end.