...::: Three issues of sustainable management :::... Introduction Objectives Methodology Study area Coquillo COMPARISON Yellow Nutsedge Purple Nutsedge 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 :::...