Nitrogen fertilizer levels have a big impact on the growth and quality of barley plants. By giving barley different amounts of nitrogen, researchers found that higher levels led to better growth and higher yields. The best results were seen with 90 kg of nitrogen per hectare. Different barley varieties also responded differently to nitrogen levels, with some showing higher grain yields and others showing more plant growth. Splitting the nitrogen application into multiple doses also improved yields. Overall, nitrogen levels up to 90 kg per hectare increased crop growth and yield, but beyond that, the benefits leveled off.