Before the Northern Song Dynasty, Huaibei (淮北) had been known as "fertile land" and was the most important economic zone in China. It gradually declined since the Southern Song Dynasty. After the Song Dynasty, the folk saying "As long as there is a bumper harvest in the Yangtze and Huai River basins, there will be no famine all over the country" transformed into "As long as the crops of Su (苏) and Hu (湖) prefectures is ripe, the whole country will be full of food". The original "land of fish and salt", "fertile land of fish and rice" and "land of fish and rice" in Huaibei were replaced by "barren hills and evil rivers" after the Ming and Qing Dynasties. Huaibei had experienced a dramatic decline from fertile land to barren soil. The primary purpose of the Ming and Qing governments' water control in Huaibei was not to prevent and reduce disasters, but to maintain water transportation, which seriously damaged the hydrological and ecological environment of Huaibei, making Huaibei, which was extremely rich in water resources formerly, a region of shortage of engineering water and even of seasonal concurrence of water shortage with floods. As a result, Huaibei dialect has long called farmland as "lake", and people forget the differences between lands and lakes.