Deficit irrigation
Application of irrigation water during drought-sensitive growth stages of a crop. Outside these periods, irrigation is limited or even unnecessary if rainfall provides a minimum supply of water. Water restriction is limited to drought-tolerant phenological stages, often the vegetative stages and the late ripening period.
Advantages / Benefits
Maximises productivity of water without significantly compromising yield
Stabilises crop yileds compared to rainfed cultivation
Reduces nutrient loss and leaching of the root zones, resulting in better groundwater quality and less fertilizer requirements compared to full irigation
Disadvantages
Requires extensive knowledge of crop water requirements and dependable water supplies
Increases risk of soil salinisation
Who involved
Governments, farmers, research institutes
Costs
Low
Information sources
Evidence of success
Drought-Ready Communities: Different institutions: the project has been piloted in three communities in the USA: Nebraska City, NE; Decatur, IL; and Norman, OK.These communities benefited from an enhanced public awareness of water, climate, and drought issues (http://droughttest.unl.edu/Planning/PlanningProcesses/DroughtReadyCommunities.aspx)
Feasibility
Feasible when crop water requirements are well known and there is access to irrigation water during periods of high demand (during drought sensitive stages of the crop)
