The researchers studied how different levels of nitrogen fertilizer affect wheat yield and nutrient accumulation in the E-mai 18 variety. They found that as nitrogen application increased, wheat yield and nitrogen content in shoots also increased. However, after reaching a certain point, further nitrogen application only slightly increased yield. Nitrogen content in shoots decreased as the wheat plants matured, possibly due to nitrogen loss. The optimal nitrogen application rate for E-mai 18 in medium-fertility soil was found to be 225 kg.hm-2, resulting in a yield of 6,948 kg.hm-2.