The study explored how water and nitrogen affect rice growth in paddy fields. By using a computer model, researchers tested different nitrogen levels and irrigation methods in South China. They found that the right amount of nitrogen and water can significantly impact rice yield, especially with specific irrigation practices and low nitrogen levels. The study suggests using 150-200 kg/ha of nitrogen for early rice and 200-250 kg/ha for late rice, along with specific irrigation thresholds and quotas for each season. Overall, the study shows that managing water and nitrogen together can improve rice production in South China.