The study looked at how different types of nitrogen fertilizers affect the yield and nitrogen use efficiency of summer maize. They found that using controlled-release nitrogen fertilizer led to higher yields and better nitrogen use efficiency compared to common urea. Increasing nitrogen application rates boosted maize yield but too much nitrogen decreased it. The soil's mineral nitrogen content increased with higher nitrogen application rates, and nitrogen content in plants and grains also rose with nitrogen fertilizer use. However, after the maize season, most treatments showed a soil nitrogen deficit, which decreased with higher nitrogen application rates.