The study looked at how different fertilizers affect soil nutrients and crop yields in Liaohe Plain. Results showed that N and P fertilizers increased maize production, while P and K fertilizers boosted soybean yields. The amount of nutrients added was higher than the increase in crop yields, showing not all nutrients were used efficiently. Soybean fields retained more P than maize fields. Over time, the amount of leftover P and K decreased, affecting nutrient availability differently.