Accounting for roughly 40% of the value of U.S. ag production, irrigated farms also represent 80-90% of consumptive water use in the U.S., fueling growing concern about conservation and water quality.
A new USDA ERS study examining the situation found that growing demand for water between agriculture, the energy sector and other non-farm uses will present new challenges for agricultural water use and conservation.
Though efficiency has increased, the ERS report explains that there is "significant potential" for improvement. At least half of the U.S. cropland acreage in the U.S. is irrigated with traditional systems that are less efficient than modern systems.
However, installing irrigation has been a priority. The ERS found that operators increased investments in irrigation systems by 92% from 2003 to 2008, with only less than 10% of farms financing irrigation through assistance programs such as the Environmental Quality Incentives Program through the USDA.
Report authors Glenn Schaible and Marcel Aillery note that agricultural water conservation is "both a farm and basin-level resource conservation issue." They say integrating the use of improved on-farm irrigation efficiency with State and Federal watershed water-management tools encourages producers to "recognize and respond to differing values of water across competing uses, improving the potential for sustainable irrigation while facilitating water reallocation to other uses."
Another impending situation facing agricultural water use is Native American water rights, which allow Native American tribes to maintain reservation land, report authors note. These rights include the water needed to irrigate "all irrigable acreage" on the reservation, as determined by decisions in the U.S. Supreme Court.
Though the report explains that these claims to groundwater may move slowly in the courts, it is a source of demand.
Source: USDA ERS Report "Water Conservation In Irrigated Agriculture"
Even biofuels and advanced energy factor in to irrigation needs and are expected to strengthen demand for water. But, report authors explain that the full impact of biofuel expansion on agricultural land and water resources is expected to be complex, "involving the substitution of land and water among crops, cropland expansion, reduced use of idled cropland, expanded use of applied inputs, and increased double-cropping depending on where biofuel development occurs."
The report suggests that due to the variety of demands on water, overall sustainability of irrigated agriculture could improve through efficient gravity and pressurized irrigation systems along with improved management practices focused on efficiency.
Report authors say practices could include soil or plant moisture sensors, irrigation scheduling services, and computer-based growth models that allow producers to determine optimum irrigation times.
Read the full report here.