cosponsored by U.S. Geological Survey, Agricultural Research Service, Soil Conservation Serivce, Reston, Virginia, February 5-8, 1990 ; compiled by Madge Ertel
by G.N. Delin ... [and others] ; prepared in cooperation with the University of Minnesota Department of Soil Science, the U.S. Department of Agriculture, Agricultural Research Service, and the Minnesota Pollution Control Agency