Deficit irrigation: greenhouse

The great challenge for the coming decades will therefore be the task of increasing food production with less water, particularly in countries with limited water and land resources. In areas with dry and hot climates, greenhouse cultivation has improved water-use efficiency (WUE) mainly by reducing runoff and evapotranspiration (ET) losses. The cover utilized on these structures changes locally the radiation balance by entrapping long-wave radiation and creates a barrier to moisture losses. However, complementary approaches are still needed to increase WUE in greenhouse cultivation. This overview presents the results of a number of deficit irrigation (DI) and partial root-zone drying (PRD) studies carried out for various crops under greenhouse conditions, with a review of the impact of reduced water supplies on crop yield. In this chapter, DI concepts are first reviewed and then some management and scheduling in relation to different types of greenhouses are described. Afterward, DI in greenhouse, WUE, crop growth, yield and quality of different ornamental and vegetable crops are investigated. However, high technology greenhouses will facilitate crop management under DI conditions.