John A. Adams is Soil Scientist, U.S. Department of the Interior, Bureau of Land Management, Riverside, California; Albert S. Endo is Supervisory Natural Resource Specialist, Bureau of Land Management, Riverside; Peter G. Rowlands is Botanist, Bureau of Land Management, Ridgecrest, California; Hyrum B. Johnson is Ecologist, Grasslands, Soil, and Water Research Laboratory, U.S. Department of Agriculture, Temple, Texas. Lewis H. Stolzy is Professor of Soil Physics, Department of Soil and Environmental Sciences, University of California, Riverside;