A study in Hubei Province looked at how combining nitrogen, phosphorus, and potassium fertilizers affected rice yield and profit. They found that using all three fertilizers together significantly increased rice yield and profit. The average yields of rice with NPK fertilization were much higher than those without fertilization. The profits from NPK-treated rice were also higher. The fertilizers contributed around 33.3% to early-season rice yield, 28.6% to mid-season rice, and 27.8% to late-season rice. This shows that using a balanced combination of N, P, and K fertilizers can greatly boost rice production and income.