Farming was not popularized until the Han Dynasty. Iron plows have been unearthed not only in the provinces of the Central Plains, but also in the northwest and northeast border areas. Even in the Jiangnan area, known as "Huogeng Pond" in history, as far away as Fujian, Guangxi, Guangdong and other places, an iron plow or Niu Geng model was unearthed, which became one of the main symbols of the remarkable improvement of agricultural productivity in the Han Dynasty. There are many kinds of iron plows in the Han Dynasty, with different sizes. The small one is about 20 cm long and 20 cm wide, and the big one can reach more than 40 cm long and wide. Shaanxi, Henan and other places have also unearthed the iron plow wall of the Han Dynasty, which is single-sided, diamond-shaped or slab-tile-shaped and can be turned over to one side; There are also double-sided, saddle-shaped, which can be turned over at the same time, suitable for ditching and ridging. Plough wall is an important device for turning and breaking soil. This invention marks that China's plow has embarked on a mature road, which is a great achievement in the history of plow. From the maps of Niu Geng with stone reliefs and murals in various places, we can also see the specific structure of the plough in the Han Dynasty. The plows in the Han Dynasty already had parts such as plow shaft, plow arrow, plow bed and plow tip, which indicated that they were mature and stereotyped. Generally speaking, the plows in northwest China (such as Shaanxi and Inner Mongolia) are clearly distinguished from the plow tips and belong to long-bed plows or frame plows (Figure 28). The eastern regions (such as Shandong and Jiangsu) have different plowshares. The plow bed and the plow tip are connected into an arch, which is made of a curved piece of wood, so there is no obvious plow bed, so it is also called a seedless plow (Figure 29). These two kinds of plows are both straight-axis plows, including a long straight-axis plow pulled by two cows and a short straight-axis plow pulled by one cow. The long straight-axis plough is suitable for large fields, and the short straight-axis plough is flexible in turning and suitable for small fields. It is an invention and creation adapted to local conditions.
The plows in the Wei, Jin, Southern and Northern Dynasties basically inherited from the Han Dynasty, but the shape of the plowshare still changed, and the plowshare crown changed from the long wing to the short wing in the Han Dynasty. The iron plow in the Western Han Dynasty was close to the isosceles triangle, which was shaped from the Eastern Han Dynasty to the Southern and Northern Dynasties and improved into a tongue shape. There are three types of plowshares, large, medium and small, which embodies the diversity of plowshares. Judging from the murals of Niu Geng in Wei and Jin Dynasties, the plow at that time was still a long-handled plow pulled by two cows. However, Qi Yaomin's Book has pointed out: "It is ok to plow the ground with a long axis, and it is not necessary between mountains and streams. It is laborious to turn around, which is not as flexible as Qi Wei Li." It shows that plows suitable for ravines have appeared in Shandong Province. Compared with long-axis plough, Wei plough should be a short-axis plough with flexible and light operation. The appearance of this kind of plow may have laid the foundation for the birth of Qu Yuan's plow in the Tang Dynasty.