What country sent explorers to claim land south and west of the Mississippi river for gold ranching and farming?

Spain sent explorers to claim land south and west of the Mississippi River, primarily for the purposes of gold, ranching, and farming. Notable explorers such as Hernando de Soto ventured into this region during the 16th century. Their expeditions aimed to expand Spanish territory and exploit the resources of the New World, including agricultural land and precious metals.