The reason that the South could not maintain its high level of food production was that a lot of its farmers had to join the war effort.
Even though the South had relied on a lot of enslaved labor, not many people actually owned enslaved people or used them for work.
When the war broke out therefore, the farmers who were the backbone of agriculture in the South, had to join the war which reduced labor for farming. This therefore reduced food production capabilities.
Find out more on southern farmers at https://brainly.com/question/15886548.