The study looked at how different types of nitrogen and levels of water stress affect rice growth and yield. They found that a balanced mix of ammonium and nitrate nitrogen helped increase rice grain yield under moderate water stress. Increasing nitrate levels promoted nitrogen accumulation in the rice plant, leading to better growth and higher nitrogen use efficiency. Moderate water stress also helped rice plants absorb more nitrogen, produce more seeds, and improve grain quality. Both hybrid indica and conventional japonica rice responded similarly to nitrogen and water stress during the grain-filling stage.