Returning straw to the field with reduced nitrogen fertilizer maintained high maize yield in Northeast China. The study compared different fertilizer treatments and found that using straw with reduced nitrogen produced similar grain yield as using full NPK fertilizers. This approach resulted in three times higher yield compared to using only phosphorus and potassium fertilizers or no fertilizers at all. The study also showed that the combination of nitrogen, phosphorus, and potassium fertilizers is crucial for increasing grain yield in maize. Additionally, the dynamics of nitrogen, phosphorus, and potassium in the plant parts were found to be important factors in determining maize yield. Overall, returning straw with reduced NPK fertilizers can help improve yield and reduce the need for chemical fertilizers in the long term.