The study looked at how policies to protect farmland in China's Ningbo region have affected the land over time. They used maps and data to see how the land changed from 2005 to 2013. Despite the rules to protect farmland, the land kept getting worse. The policies helped keep the total amount of farmland the same, but didn't consider the quality of the soil or where the land was. In the first few years, the farmland changed a lot, with some turning into buildings or water areas. Later on, most of the farmland was taken over by cities, while new farmland was made from coastal areas. This new farmland is not good for growing crops. The loss of good farmland to cities could cause problems for food and the environment.