Complex sentence: Both the Pawnee National Grasslands and Comanche National Grasslands are located in the Eastern Plains; they are composed of marginal farmlands which were withdrawn from agriculture and consolidated under federal control beginning during the Dust Bowl.
Split into simpler sentences: Both the Pawnee National Grasslands and Comanche National Grasslands are located in the Eastern Plains. They are composed of marginal farmlands that were withdrawn from agriculture and consolidated under federal control beginning in the Dust Bowl.