What did the farmers have to do in order to serve the government?

Farmers had to work for the government for about one month each year. They served in the military or worked construction projects like building canals, palaces, and city walls. Farmers also had to pay a tax by giving the government a percentage of their crops

Explanation:

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.