The researchers studied the effects of adding nitrogen to winter wheat at a specific growth stage in northern Henan. They found that adding nitrogen at the jointing stage increased grain yield up to a certain point, then decreased. The best results were seen with 140-180 kg of nitrogen added on top of a base of 120 kg. This method improved nitrogen translocation to the grain, leading to higher yields and benefits. However, as nitrogen topdressing increased, nitrogen recovery efficiency decreased while nitrogen agronomic efficiency initially increased then decreased. Overall, adding 120 kg of nitrogen as a base with 140-180 kg at the jointing stage was the most effective nitrogen application method for winter wheat in northern Henan.