What happened to farms and plantations varried heavily between when, where, and who captured the plantation. Generally, for most of the War slaves were freed in some way. Even before the Proclamation, slaves were treated as contraband property (literally called "contrabands" in many Memoirs) which the Union army could impound at their leisure. This was doubly so of blacks who were forced to work for the Confederate Army. These people, usually men, were taken into Union lines where they might be resettled or put to work. Some black men found jobs digging ditches and trenches, driving supply trains, or helping the army. Others were resettled and put back to work. The most famous example of this was the Port Royal Experiment in which former slaves were put to work farming for the Union. Abolitionist and military leaders attempted to use the Port Royal plantations as a test lab for future policies. However it is not the only example of slaves been returned to plantations to work for the Union.

Later in the war things were somewhat different. In 1863, the Union began to form the first US Colored Troop Regiments. These segregated regiments gave freedmen and formers slaves alike the chance to fight for their freedom and the freedom of blacks across the south. In addition, tens of thousands of slaves fled their plantations to the safety and freedom of the Union lines. Those who remained home were forced to support and increasingly desperate Confederacy. The success of the Union Blockade really destroyed cotton production in the South. Increasingly, plantations switched from cotton to wheat and other staple foods. And thanks to the Levee of wagons, horses, and most importantly men, the burden was increasingly placed on Slaves. And if all that wasnt enough, armies under Grant, Sherman, Sheridan, and other Union Generals gradually embraced a policy of forced requisition and destruction of enemy property. By 1865, the Union Army regularly burned crops, and barns, confiscated livestock, and either took or destroyed anything of material or economic value to the Confederate Army. For slaves who were unable or unwilling to escape their masters and overseers, the passing of the Union Army (and then the even more terrifying train of deserters and hangers-on which followed the Army) was immensely destructive.

Work’s song, composed in 1862, is a parody of southern slaveowners, a celebration of abolitionist war aims (still contested in 1862), and an astoundingly prescient description of the actual process of emancipation for a great number of enslaved people in the Confederacy.

In the song, enslaved people laugh at the vision of THE MASTER running away, a hilarious inversion of pre-war roles, in which masters, self-described as honorable, expressed frustration at ungrateful and conniving blacks who had a tendency and temerity to escape bondage. In Work’s song, the master gets his come-uppance at the sight of approaching United States gunboats, and in his fright, is revealed to be the true dishonorable coward.

I’m not certain of the exact context of Work composing this tune, but in 1862, as United States armies plunged into the Tennessee River valley and the Virginia peninsula, the unexpected occurred. Whenever a US army or naval ship pulled into view, hundreds, if not thousands of enslaved African Americans took the opportunity to slip away from plantations and flood into Federal lines. This contingent factor resulted in the crisis at Fort Monroe, when Union General Benjamin Butler declared slaves runaway from their masters to be contraband of war, thus able to avoid recapture. The name stuck but the policy was reversed by Lincoln—but not for long. A series of confiscation acts in 1862 built the legal groundwork for the establishment of freedom for enslaved people who entered Union lines, culminating with the Emancipation Proclamation in 1863.

Not all enslaved people had this experience of emancipation. Those in the Confederate interior, where few Union armies roamed (until 1865), did not have the opportunity to flee to nearby Union lines. But in those places—Northern Virginia, Eastern North Carolina, the Mississippi Valley, central Tennessee—where Federal armies reached, they did. Escape to Federal lines (not portrayed in Work’s song) was no doubt a fraught and tense moment. After arrival within the protection of Union armies, freedpeople did congregate in a series of “freedman’s colonies” and “refugee camps” established by the Army and staffed mostly by religious missionaries. [Here in North Carolina, the two most famous were the Roanoke Island and James City colonies.] In those places, reunions took place that no doubt matched the joy that Work portrayed. In freedman’s colonies, African Americans quickly set about establishing a civic life in freedom, including going to school, establishing religious congregations, and forming political parties.

So, the short answer is that while Work’s song is a parody of the conventions of the master-slave relationship, it is rather accurate in its portrayal of actual events.

See:

Christian McWhirter, Battle Hymns: The Power and Popularity of Music in the Civil War (2014)

Leon Litwack, Been in the Storm So Long: The Aftermath of Slavery (1980)

Glenn David Brasher, The Peninsula Campaign and the Necessity of Emancipation: African Americans and the Fight for Freedom (2012)

David S. Cecelski, The Fire of Freedom: Abraham Galloway and the Slaves’ Civil War (2012)

Patricia Click, Time Full of Trial: The Roanoke Island Freedmen’s Colony, 1862-1867 (2001)

Visualizing Emancipation: http://dsl.richmond.edu/emancipation/