The soil in Yugan County has changed over the past 30 years, with the carbon-to-nitrogen ratio increasing. This ratio is important for soil quality and nutrient balance. Factors like soil type, terrain, and fertilizer use influence these changes. The soil in the eastern region showed the most significant increase in the C/N ratio. The study used soil samples from 1982 and 2012 to analyze these changes and found that different factors played a role in the soil's nutrient balance over time.