Skinning the Earth for Food

Mining the soil, the interface between the atmosphere and the lithosphere is unsustainable.
David Montgomery, professor of Earth and space sciences claims that skinning the Earth for food also constitutes an 'erosion of civilisations' in his book 'Dirt: The Erosion of Civilizations'. "Soil loss through conventional agriculture is in a range of 10 to 100 times greater than the rate at which soil is created...We are skinning our agricultural fields"
Previously human populations could just move on to some one's elses land and continue their 'agri-culture' there. With 6.6 billion people today unable to embrace a paradigm shift with respect to food security, there would have to be another planet to 'harvest' elsewhere.