Black people were moved out of farming deliberately by the agricultural industry by virtue of the racist policies of the time. So looking for work folks moved to the cities they call it the great migration. So literally generations of black folks having been divorced from the land living in urban areas with no connection to where food comes from is the problem.
The racist legacy of the USDA comes from the work of white people in positions of power working to keep black people oppressed. They wouldn’t help black farmers. So the goal of white supremacy is to make sure that white people stay superior and the folks that worked for the USDA at the time identified with the racist ideologies and operated accordingly to keep black people marginalized. When whites got fearful of having to compete with freed african Americans i.e. former slaves they horded all the resources the USDA had to offer for themselves and discriminated against blacks so they could access those resources.
The USDA admittedly discriminated against black farmers denying loans and credit; then land was taken through black folks inability to compete in the market with white farmers who were getting access to all the programs and assistance the USDA had to offer. The notion is that land is power and using it to produce economically is powerful. So because the folks were racist the agency is complicit in the decline of black farmers. It was deliberate. They didnt want black people to own land or farm on a equal playing field so they discriminated so they can get all the money for themselves.