The study looked at how different sources of nitrogen, like soil and crop residues, affect the growth of rice crops. They tested if adding nitrogen at different times could improve rice yield. The researchers found that nitrogen from crop residues and soil was not always beneficial for the rice crop, as some nitrogen was lost before the rice could use it. Late incorporation of legume residues helped reduce nitrogen loss. Maize residues slowly released nitrogen and protected it from being lost. The rice crop took up more nitrogen from inorganic fertilizers applied at permanent flood compared to planting or panicle initiation. Overall, the study showed that timing and sources of nitrogen can impact rice crop growth and yield.