Deficit Irrigation Practices

Deficit Irrigation Practices

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.

Deficit Irrigation Practices

Deficit Irrigation Practices

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. Under conditions of scarce water supply and drought, deficit irrigation can lead to greater economic gains than maximizing yields per unit of water for a given crop; farmers are more inclined to use water more efficiently, and more water-efficient cash crop selection helps optimize returns. However, this approach requires precise knowledge of crop response to water as drought tolerance varies considerably by species, cultivar and stage of growth. The studies present the latest research concepts and involve various practices for deficit irrigation. Both annual and perennial crops were exposed to different levels of water stress, either during a particular growth phase, throughout the whole growing season or in a combination of growth stages. The overall finding, based on the synthesis of the different contributions, is that deficit or regulated-deficit irrigation can be beneficial where appropriately applied. Substantial savings of water can be achieved with little impact on the quality and quantity of the harvested yield. However, to be successful, an intimate knowledge of crop behavior is required, as crop response to water stress varies considerably.