Energy balance: latent heat and sensible heat. Soil water: water potential and its component, soil water conductivity, permeability, soil water storage. Crop water use: evaporation and transpiration.Estimating evapotranspiration according to Penman-Monteith equation (method FAO paper n°56) : estimating reference evapotranspiration, estimating evapotranspiration for specific crops using the grass-related crop coefficients. Estimating reference evapotranspiration using measured pan evaporation. Crop water evapotranspiration when soil water is limiting. Relationship between crop yield and crop water use. The quality of water for irrigation. The production and the irrigation of the crops in saline soils and with the use of salt water.