The study looked at how different amounts of nitrogen and phosphorus fertilizer affect the yield of spring corn in north-central Shanxi. They found that using a ratio of 1 part nitrogen to 0.6 parts phosphorus is best for low and medium yield fields, while a ratio of 1 part nitrogen to 0.8 parts phosphorus is best for high yield fields. The more fertilizer the corn plants absorbed, the higher the grain yield. However, the efficiency of phosphorus fertilizer decreased as the nitrogen dose increased and the phosphorus dose decreased.