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roman empire got a Chinese tech in 20 AD

what if Roman get Han dynasty technology in 20 AD as

Multiple-tube seed drill: This was invented to decrease the time needed to implement the seed drill in full (the seed drill is explained under Technique). By using the multiple-tube seed drill, the farmer was able to till the land while sowing his seeds simultaneously. Although wooden multiple-tube seed drills existed during the Warring States, by the Han dynasty these were replaced with ones made completely out of iron. Such devices were said to automatically plant seeds 3 inches beneath the soil, and land tilled by the seed drill looked like it had been gone over by a small plough.

Heavy moldboard iron plough: Although partly ironed ploughs existed from the Zhou dynasty, Warring States ploughs included a moldboard which prevents the ploughshare from being clogged with soil. The Han dynasty further improved upon the implement by constructing the entire plough and moldboard in iron, unlike Warring States ploughs which only has an iron blade. The plough was sophisticated enough to allow the depth of the furrow to be determined, while its curved design gives minimum drag when pushed against the soil.

Horse harness (chest) collar: The horse harness existed in China by at least the 4th century BC. By placing the yoke across the horses’ chest, it allowed horses to plough much more efficiently from alternative harness systems. This allowed poorer farmers to adopt horses for beasts of burden as substitutes to oxen, because horses were much cheaper to maintain. Although an ox is stronger than a horse, a horse has the advantage of greater endurance. As such horses may be the preferred animal over oxen in areas of light soil. Another advantage for raising horses is that it allows the family to avoid conscription.

Rotary winnowing fan: The practice of winnowing was usually done by hand in order to separate the chaff from the grain. This involves simply throwing the grain into the air with a basket, hoping that the wind will pick up the lighter chaff while the heavier grain falls to the ground. The Han dynasty invented a rotary winnowing fan. Instead of throwing the mixture into the air, it was put within the winnowing machine while the “wind” was produced by a crank handle.

Trip hammer: This device is used for pounding, as a way to decorticate grain. The Xin Lun, written in 20 AD, claimed that just the human operated the trip hammer is 10 times more efficient than the pestle and mortar. The Xin Lun also mentions trip hammers operated by various beasts of burden as well as those that are hydraulically powered by a waterwheel. By the Three Kingdoms period a single waterwheel could operate multiple trip hammers.

Alternating fields: The Lushi Zhunjiu written during the Qin dynasty described the method of plowing followed by distributing seeds along the ridges created by the furrows. This system was replaced by the Alternating fields system. During the reign of emperor Wu, the government official Zhao Guo speculated that crop yield would increase by reversing each year’s furrows and ridges. In other words, during one year a farmer would sow his crops on the furrows and not in the ridges, while in the following year the position of the furrows and ridges are switched. This not only allowed the ridges to protect the seeds from the elements, but it also allowed a system equivalent to biennial fallowing but without the necessity of having half the land lie fallow. After Zhao Guo was able to confirm his speculations by experimenting with such methods in his own field, instructions were sent out to diffuse the knowledge throughout the rest of the empire. Due to this, yields were claimed to be increased by 1 hu per mou (20 liters per .057 acres under Western Han units of measurement), and even 2 hu when under efficient management. Indirect advantages of the alternating fields method is the introduction of new agricultural tools, including the long handled hoe for weeding and an improved oxen-driven plough of two shares. This system demands much energy for poor peasant families who cannot afford oxen for plowing. Plowing fields is still possible with only human labor, although to do so is exhausting. However, given that a field is ploughed, utilizing the system of alternating fields requires no additional resources.

cast iron blast furnace

The oldest extant blast furnaces were built during the Han Dynasty of China in the 1st century BC. However, cast iron farm tools and weapons were widespread in China by the 5th century BC, while 3rd century BC iron smelters employed an average workforce of over two hundred men.These early furnaces had clay walls and used phosphorus-containing minerals as a flux.The effectiveness of the Chinese blast furnace was enhanced during this period by the engineer Du Shi (c. 31 AD), who applied the power of waterwheels to piston-bellows in forging cast iron
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