The food will be a supply for the land

Here "land" refers to the people. Alternate translation: "This food will be for the people" (See: rc://en/ta/man/jit/figs-metonymy)

In this way the land will not be devastated by the famine

Here "land" stands for the people. This can be stated in active form. Alternate translation: "This way the people will not starve during the famine" (See: rc://en/ta/man/jit/figs-metonymy and rc://en/ta/man/jit/figs-activepassive)