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.