The researchers studied how to improve water and nitrogen management for rice farming in tropical areas. They wanted to see how different water and nitrogen strategies affect rice growth and yield. They did experiments in Indonesia using different water levels and nitrogen amounts. They found that using less water didn't affect rice yield but could save water. They also learned that nitrogen levels in the soil changed at different stages of rice growth. Their goal was to create a model to help farmers make better decisions about water and nitrogen use in rice fields.