Why did Emperor Qin Shihuangdi work to increase farming?
He wanted to increase food surpluses for disasters.
He hoped to improve Chinese diets by increasing crop variety.
He wanted to use new lands to produce more food for trade.
He hoped to gain the support of poor laborers with jobs on farms.

He wanted to use new lands to produce more food for trade.

Explanation:

During his reign, Emperor shihuangdi need a lot of money for the construction of the wall of China along with strengthening military to sustain the attack from the barbarian. So, he felt the need to increase more trade in order to add additional fund for the government.

This is why he used a lot of unoccupied land and use it for farming. To accomplish this operation he also mandated around 700,000 people into forced labor to work on the agricultural land.

in the 1800s, chinese workers migrated to the united states, first to work in the gold mines, but also to take agricultural jobs, and factory work, especially in the garment industry. chinese immigrants were particularly instrumental in building railroads in the american west, and as chinese laborers grew successful in the united states, a number of them became entrepreneurs in their own right. as the numbers of chinese laborers increased, so did the strength of anti-chinese sentiment among other workers in the american economy. this finally resulted in legislation that aimed to limit future immigration of chinese workers to the united states, and threatened to sour diplomatic relations between the united states and china.

according to worldatlas.com, the u.s. has an 86% literacy rate.