Sustainable Water Usage
Existing natural water resources can sustain cotton production in many areas of the world with minimal environmental impact. Cotton has been wrongly cited as a water intensive crop, when in reality it is very drought tolerant. In fact, in many regions of the world, cotton gets all of its water from rainfall — water that would be used by whatever vegetation is present. For example, about 64% of the U.S. cotton crop is produced without irrigation, and irrigation is used in most of the remaining 35% of U.S. cotton crop only to supplement crop needs . The cotton plant is drought-adapted and responds favorably to periods of water stress sufficient to slow vegetative growth.
Water quality is also preserved in modern cotton productions systems. The increase in conservation tillage practices has resulted in a reduction of runoff from agricultural lands, decreasing non-point source pollution of fertilizer and pesticides. Intensive local monitoring of surface water and sub-soils has demonstrated the benefits of no-till cotton in protecting both ground and surface water resources . Better nutrient management and precision technologies are insuring inputs are used by the crop and are not entering ground or surface waters.
Modern Water Management Practices
Since water is a limited resource, and due to economic constraints related to costs of water, pumping and labor needed to apply irrigation, producers are prudent in managing this resource. A number of approaches are used to decide when to irrigate, including:
Computer models that predict water use based on the growth stage of the plant and weather data
Soil moisture probes that determine if there is sufficient water present to meet crop needs
Thermal infrared thermometers (IRTs) that measure the temperature of the cotton leaves — as the plant begins to run out of water, its leaf temperature will increase. Some companies are now offering thermal images so producers can see leaf temperatures across the entire farm.