Frederick was keenly interested in land use, especially draining swamps and opening new farmland for colonisers who would increase the kingdom's food supply. He called it (peopling policy). About 1,200 new villages were founded in his reign. He told Voltaire, "Whoever improves the soil, cultivates land lying waste and drains swamps, is making conquests from barbarism". Using improved technology enabled him to create new farmland through a massive drainage programme in the country's Oderbruch marshland. This programme created roughly of new farmland, but also eliminated vast swaths of natural habitat, destroyed the region's biodiversity, and displaced numerous native plant and animal communities. Frederick saw this project as the "taming" and "conquering" of nature, considering uncultivated land "useless", an attitude that reflected his enlightenment era, rationalist sensibilities. He presided over the construction of canals for bringing crops to market, and introduced new crops, especially the potato and the turnip, to the country. For this, he was sometimes called Der Kartoffelkönig (the Potato King).
