Water use efficiency as a method for predicting water use by weeds.
Water use by weeds is one type of loss that contributes to the cost of weeds to agriculture. Water use efficiency provides a mechanism by which water use by weeds can be estimated. Uncontrolled weed growth could result in estimated irrigation costs exceeding $50.00/ha. Weeds like barnyardgrass (Echinochloa crus-galli) at threshold densities in irrigated crops such as sugarbeet or tomato are estimated to increase production costs by about $20.00/ha depending on water cost.