An unplowed field

"A field that is not prepared for food production" or "An empty field not ready for planting"

but it is swept away by injustice

"Swept away" represents completely removing something. This can be stated in active from. Alternate translation: "but injustice takes away that food" or "but unjust people take the food away" (See: rc://en/ta/man/translate/figs-metaphor and rc://en/ta/man/translate/figs-activepassive)