The study looked at how efficiently nitrogen fertilizer is used in a rotation of rapeseed, wheat, and rice crops in Southwest China. They found that more nitrogen was absorbed by rapeseed than wheat, and different fertilizer application rates affected nitrogen accumulation in the crops. A specific fertilizer management model during the rice season led to higher nitrogen accumulation in the rice plants. This model also increased nitrogen efficiency in rice crops without significantly affecting overall crop yield. The study suggests that this specific fertilizer management approach is a good, stable way to save nitrogen in rapeseed-rice rotation systems in southern China.