The application of climatic data for planning and management of

Sustainable food production will depend on the judicious use of water resources as fresh water for human consumption and agriculture is becoming increasingly scarce. To meet future food demands and growing competition for clean water, a more effective use of water in both irrigated and rainfed agriculture will be essential. Options to increase water use efficiency include the conservation of rainfall, the reduction of irrigation water losses and the adoption of cultural practices that will increase production per unit of water. Water use for crop production is depending on the interaction of climatic parameters that determine crop evapotranspiration and water supply from rain. The compilation, processing and analysis of meteorological information for crop water use and crop production will therefore constitute a key element in developing strategies to optimize the use of water for crop production and to introduce effective water management practices. In the 1970s, FAO developed practical procedures to estimate crop water requirements and yield response to water stress which have become widely accepted standards in the planning and management of irrigated and rainfed agriculture. As a follow-up to recommendations of a panel of high-level experts convened in 1990, further studies have been carried out which have led to the development of revised procedures for reference evapotranspiration and crop evapotranspiration. The new procedures and guidelines have been recently published in the FAO Irrigation and Drainage series and include the adoptio