Topsoil is being lost 13 to 40 times faster than it is being replaced
"Topsoil is being lost 13 to 40 times faster than it is being replaced"
David Pimentel et al., "Impact of a Growing Population on Natural Resources: The Challenge for Environmental Management," Frontiers: Interdisciplinary Journal of Study Abroad, Vol. 3, no. 12 (1997), accessed November 24, 2014.