The study looked at soil in farmland in a specific area in Southwestern Chongqing. They used soil samples and historical data to estimate the amount of organic carbon in the soil. The results showed that the soil in this area had lower organic carbon levels compared to other places in China. The distribution of organic carbon in the soil was not even, with higher levels near rivers and lower levels in other areas. Most of the organic carbon was found in paddy and purple soil. This means that managing the organic carbon levels in these types of soil is important for maintaining soil health in the area.