What is Niu Geng promoted by Zhao?

According to the research of archaeology and ancient philology, although Niu Geng in China originated from Shang Dynasty, it did not get much development before the Warring States Period. In the early years of Emperor Wu of the Han Dynasty, Niu Geng was confined to the homes of the rich, and ordinary farmers still mainly used wooden or iron lei. The Niu Geng promoted by Zhao State is "coupling cows" and "two cows and three people", that is, when operating, two cows pull a plow, two people lead the cows, and one person helps the cows plow. During the Eastern Han Dynasty, this farming method was extended to Liaodong. At the beginning, it was also "two people holding, one person holding." Before liberation, the Naxi people in Ninglang, Yunnan Province also inherited the farming methods of two cows and three people. When plowing the land, one person leads two cows together, the other holds the cows, and the middleman presses the cow shaft to master the depth of the cultivated land. The farming method of "two cows and three people" reflects the early situation in Niu Geng, because the technology of driving cattle was not skilled at that time, and the parts and functions of iron cattle were not complete.