In 22 1 year BC, the army of Wang Ben, commander-in-chief of the Qin Dynasty, suddenly attacked from Yannan to the north and hit Linzi all the way. Qi was unprepared for this battle, and there were no soldiers to fight. After King Qixiang successfully persuaded him to surrender, Jian surrendered without a fight. At the same time, we got Tiki-Shandong, a big granary.
Bashu, today's Sichuan Basin, was a natural granary two thousand years ago. After Qin owned Bashu, the military grain reserve developed greatly. However, more than 2000 years ago, Chengdu Plain could not provide Qin Jun with stable grain and pasture. The Minjiang River is often flooded and droughts occur from time to time. After Sima Cuo, Li Bing came to Bashu and became the chief executive. Li Bing divides the Minjiang River in two at the most suitable place. During the flood season, the river overflowed the dam and discharged water from the dry river in the distance. In the dry season, the Minjiang River water is sent from Li Bing's dam to the narrow channel of Baojoukou, which irrigates ten thousand mu of fertile land in Chengdu Plain. This is the greatest project in the history of ancient water conservancy-Dujiangyan.
Xianyang, the capital of Qin State, was built on the Guanzhong Plain, which is a veritable national heartland. However, due to the scarcity of rainfall, the strategic grain reserve in the capital has been affected. Korean Zheng suggested that Ying Zheng, king of Qin, dig a grand canal between Shuijing and Luoshui in Guanzhong Plain to connect the two rivers, and use the rich water in Shuijing to irrigate the dry land in Luoshui area, so that Guanzhong would not be afraid of drought. The Grand Canal will be 250 kilometers long and will require a lot of manpower and material resources. Halfway through the canal, Qin Shihuang realized that the construction of Zheng Guoqu was a plot of South Korea, and in order to consume the national strength of Qin, the Qin people were unable to attack South Korea. But he forgave the spy Zheng Guo and let him continue to build the canal. Zheng Guoqu has a total length of more than 250 miles and irrigated more than 2.8 million mu of farmland. It is another large-scale water conservancy project after Dujiangyan in Qin Dynasty. Longxi (Hanzhong) has become fertile land, and three granaries in Qin have been built.