The article explores how different levels of nitrogen in the soil affect the growth, yield, and grain filling rate of a type of rice called Oryza sativa. The researchers studied a specific breeding line and variety of rice to see how they responded to varying nitrogen levels in the soil. They found that the amount of nitrogen in the soil had a significant impact on the growth, yield, and grain filling rate of the rice plants. This information can help farmers understand how to optimize nitrogen levels in the soil to improve the productivity of their rice crops.