Answer:
The Civil war ended with the defeat of the Confederacy by the Union and the Emancipation of enslaved people in the United States. This 'robbed' Southern Landowners of their means to free/ cheap labor and so they became innovative in order to keep free labor legally.
The primary way they did this was through Debt peonage which refers to making a person work for no pay in order to pay off a debt owed.
Some ways they got black freemen into Debt Peonage include;
Sharecropping
Black people would lease land from Southern White Land owners and in return would promise to give them a share of the harvest.
The landowners would give them tools, seeds and other things needed to farm but the cost of those would be added to the share of the harvest to give to the whites.
This meant that when harvests or prices were low, the blacks would get into debt with the whites which they would have to pay off in subsequent periods thereby potentially keeping them in perpetual slavery as they were not allowed to leave the farms until their debt was done.
Corruption
Sometimes State and local police would pick up black people for the most minor of crimes and charge them high legal and bail fees which could be paid off by a wealthy landowner if they agreed to work off the debt. Sometimes the documents relating to the debt would then be lost leading to the black people being unable to escape the system.