The US government did those things, though we should notice MLK did not state any malicious aversion or discrimination to blacks in the practice as it was not a main theme at an institutional level.

He is referring to the assignment or release of unoccupied lands in the American Midwest and the creation of land grant colleges by states (and eventually the federal government). The release often was accompanied by low-interest loans and free homestead kits. When the farms failed on the ill-suited plains without proper soil conservation practices, the defaulting loans helped spur the great depression.

Some starting places (as I am not an expert) might be to use the keywords/phrases Land Rush of 1889 and Morrill Land-Grant Acts.