Deficit irrigation for reducing agricultural water use

Abstract

At present and more so in the future, irrigated agriculture will take place under water scarcity. Insufficient water supply for irrigation will be the norm rather than the exception, and irrigation management will shift from emphasizing production per unit area towards maximizing the production per unit of water consumed, the water productivity. To cope with scarce supplies, deficit irrigation, defined as the application of water below full crop-water requirements (evapotranspiration), is an important tool to achieve the goal of reducing irrigation water use. While deficit irrigation is widely practised over millions of hectares for a number of reasons - from inadequate network design to excessive irrigation expansion relative to catchment supplies - it has not received sufficient attention in research. Its use in reducing water consumption for biomass production, and for irrigation of annual and perennial crops is reviewed here. There is potential for improving water productivity in many field crops and there is sufficient information for defining the best deficit irrigation strategy for many situations. One conclusion is that the level of irrigation supply under deficit irrigation should be relatively high in most cases, one that permits achieving 60-100% of full evapotranspiration. Several cases on the successful use of regulated deficit irrigation (RDI) in fruit trees and vines are reviewed, showing that RDI not only increases water productivity, but also farmers' profits. Research linking the physiological basis of these responses to the design of RDI strategies is likely to have a significant impact in increasing its adoption in water-limited areas.

Effects of long-term summer deficit irrigation on ‘Navelina’ citrus trees

“…Although in citrus, water use efficiency (WUE, Table 3) may be affected by the timing 425 and fruit stage where the water restriction is applied (Carr, 2012), in this case, it is evident 426 that summer RDI treatments provided significantly higher WUE than the control treatment, as 427 is generally associated (Fereres and Soriano, 2007) LIST OF TABLE CAPTIONS Table 1. Rainfall and evaporative demand (ETo) registered at the meteorological station nearest to the experimental plot during the studied period.…”

Water Use Efficiency of Irrigated and Rainfed Crops of Great Importance in Serbia

“…Značaj proučavanja efikasnosti korišćenja vode od strane različitih ratarskih i hortikulturnih biljaka je proučavano širom sveta. U Španiji se istražuju modeli redukovanog navodnjavanja radi povećanja EKV (Fereres, 2007). Kini je proučavanjem ustanovljeno (Deng et al, 2004) da je efikasnot korišćenja vode soje značajno niža nego u Evropi, a smernice daljeg istraživanja idu u pravcu povećanja genetskog potencijala tj stvaranje novih sorti s jedne strane i potreba za boljim upravljanjem vode s druge strane.…”

Evaluation of optimal irrigation scheduling and groundwater recharge at representative sites in the North China Plain with SWAP model and field experiments

“…Therefore, irrigated agriculture is facing critical challenge to produce sufficient food for a continuously increasing population but with limited water supply. Efficient irrigation water management has to be carried out to aim at saving water and maximizing its productivity (Fereres and Soriano, 2007).…”

“…Supplemental irrigation and limited or deficit irrigation are effective ways to reduce irrigation water use and improve crop water use efficiency (WUE) (Kang et al, 2002;Fereres and Soriano, 2007). In the past two decades, many field experiments were conducted in the NCP to investigate soil water balance and crop yield response under deficit irrigation.…”