One of the biggest misconceptions about cotton is that it is a water-intensive plant. In fact, cotton is a very drought-tolerant plant; almost two-thirds of all cotton grown in the U.S. is done so without irrigation, using only natural rainfall. When irrigation is used, it is simply to supplement rainfall during dry periods.
Since water is a costly and limited resource, cotton producers are prudent in managing it. A number of approaches are used to decide when to irrigate, including computer models that can predict how much rainfall to expect; probes that can monitor moisture levels in the soil; and thermal infrared thermometers that can measure the temperature of the cotton leaves, which increases with dryness.
For other cotton areas that are irrigated, a small amount of irrigation at key times in the growing season can greatly improve yields. Viewed in this light, irrigated agriculture is consistent with the goals of sustainability because it maximizes efficiency in land use.
Conservation tillage practices, which protect against soil erosion, have also reduced runoff. And since cotton is so drought-tolerant, it responds favorably to water stress sufficient to hamper vegetative growth.