Tarweed is well adapted for survival as a nuisance plant on California ranges. While expensive control measures may not be justified, effective methods are needed for minimizing the use of soil moisture by tarweed seedlings in the spring. Clipping or heavy grazing and nitrogen fertilization offer possibilities for reduction in density of tarweed seedlings in favor of the more desirable forage species.

Investigations reported here were in cooperation with the Crops Research Division, ARS, USDA, and the University of California Agricultural Experiment Station. The Madera field plot at the San Joaquin Experimental Range was made available through the cooperation of the Pacific Southwest Forest and Range Experiment Station, U. S. Forest Service. Harry S. Hinkley, Farm Advisor, Tuolumne County, and James T. Elings, Farm Advisor, Sacramento County (now Extension Animal Husbandry Specialist, University of California, Davis), assisted with field work on this project. Enos Shaubach, Coarsegold rancher, Madera County, also made field plots and ranch facilities available for this study.