Final answer:
The king of Ghana used military force to maintain control over local rulers by commanding a large army and integrating conquered territories. Economic incentives, through control over trade routes, were also vital for ensuring loyalty and managing the empire's wealth.
Step-by-step explanation:
In Ghana's government, the king of Ghana maintained control over local rulers and subordinate kings through various means. One key strategy was the use of military force. The evidence points to a significant military presence, with the Ghanaian king commanding an army of some 200,000 soldiers at the height of the empire's power in the early eleventh century CE.
This military might was used to conquer independent chiefdoms and kingdoms, integrate them into the empire, and ensure their loyalty and payment of tribute. Additionally, the king's control encompassed economic incentives, playing a crucial role in trade by controlling the lucrative trans-Saharan trading routes without converting to Islam, as maintained by the Muslim traders.
The Ghanaian strategy involved not only hard power but also economic leverage, which was fundamental to sustaining the empire's wealth and control over its diverse subjects.