Historically there has been a strong Southern military tradition, part of the Southern tradition of patriotism.
Many of the states in the southern United States have a large number of Army bases and counties where military bases are located often have a recruitment rate higher disproportionate to their total population.
By extension, many military folks retire near their last base and many children of military members follow in parental footsteps and enlist.
: Southern culture still contains a strong element of honor, wherein exists a high degree of sensitivity to insults and a tendency to respond with violence and aggression. When translated onto a national stage, this means more Southerners join the military to defend the honor of America.
In addition, Southern culture also includes a strong element of religiosity, a feature also of military life, making military life feel like a good and moral choice.
Many areas of the South are rural, with the lack of job diversity and opportunity typical of rural areas. Young people looking for jobs frequently consider the military with its enlistment bonuses, travel possibilities, and educational opportunities.
Poverty is not cited as a reason in any of these studies.