Deficit Irrigation Practices

The scope for further irrigation development to meet food requirements in the coming years has been strongly diminished as a result of decreasing water resources and growing competition for clean water. The great challenge for the future will be the task of increasing food production with less water, particularly in countries with limited water and land resources. In the context of improving water productivity, there is a growing interest in ”deficit irrigation” — an irrigation practice whereby water supply is reduced below maximum levels and mild stress is allowed with minimal effects on yield. This publication presents a range of studies, carried out for several crops and under different ecological conditions, showing the various options and practices of deficit irrigation and the impacts of reduced irrigation water supply on crop yield. The synthesis shows that deficit irrigation can result in substantial water savings with little impact on the quality and quantity of the harvested yield. However, to be successful, an intimate knowledge of crop behaviour is required, as crop response to water stress varies considerably.