The study looked at how different amounts of nitrogen fertilizer affect rice grain yields and nitrogen use. They tested two rice varieties in China and found that one variety, 4007, had higher yields with more nitrogen. The number of panicles per square meter was key for high yields. As nitrogen levels increased, the rice plants took up more nitrogen, but the efficiency of nitrogen use for grain yield decreased. Variety 4007 had better nitrogen use efficiency than ELIO. It was also better at using nitrogen for growth and productivity. Overall, the study suggests that choosing the right rice variety can help increase productivity and reduce environmental pollution in rice farming.