Recent decline in crop water productivity in the United States: a call to grow “more crop per drop”
Michael T Marshall, World Agroforestry Centre (ICRAF), Nairobi, Kenya, Kevin P Tu, Theiss Research, La Jolla, United States, Prasad Thenkabail, USGS, Flagstaff, AZ, United States and Jesslyn F Brown, USGS/EROS, Sioux Falls, United States
