...::: Three issues of sustainable management :::... Introduction Objectives Methodology Study area Coquillo Yellow Nutsedge flower head General Yellow nutsedge Purple nutsedge Comparison Control strategies Strategies for the valley Summary Sandmining Coquillo Drought Portal THREE ISSUES OF SUSTAINABLE MANAGEMENT IN THE OJOS NEGROS VALLEY, BAJA CALIFORNIA ...::: Ojos Negros Valley, Baja California :::...