The Southern economy was overwhelmingly agrarian and so land-ownership was the main source of wealth in that part of the world. Therefore, if the freed slaves were ever going to take their rightful place as equal members of society, it was essential that they be given sufficient land to be able to provide for themselves and their families.

Unfortunately, the main emphasis during Reconstruction was on providing wage labor for African Americans rather than land. This represented a departure from the so-called "Forty Acres and a Mule" field order proclaimed by Abraham Lincoln during the last few months of the Civil War. But then, Lincoln's successor, Andrew Johnson, was much less enthusiastic about any notion of racial equality, and under his presidency, all of the gains in land-ownership made by freed slaves during the Civil War were completely reversed, making it harder for black people to enjoy the kind of independence envisaged in the "Forty Acres and a Mule" proclamation.

Land ownership was important to the freed slaves because it would have allowed them (they felt) to truly become free and independent.

During slavery, slaves were completely dependent.  They had little or nothing that they could call their own.  This meant that they were completely vulnerable to the whims of others.  Most slaves would have hated this situation and would have wanted to experience its opposite.  Once they were freed, the slaves wanted to stop being vulnerable.  They felt that land ownership would prevent vulnerability.  They felt it would allow them to finally be their own masters in every way.