Crop Evapotranspiration (Crop-ET0)

Crop Evapotranspiration (Crop-ET0) presents an updated procedure for calculating reference and crop evapotranspiration from meteorological data and crop coefficients. It offers a revision and expansion of the procedure first presented in 1977 in FAO Irrigation and Drainage Paper No. 24 ‘Crop Water Requirements’. The revised procedure allows estimation of the amount of water used by a crop, taking into account the effect of climate and crop characteristics. It is based on advances in research and more accurate procedures for determining crop water use, as recommended by a panel of high-level experts organized by FAO in May 1990. The first part of the guidelines includes procedures for determining reference crop evapotranspiration according to the FAO Penman-Monteith method. The second part deals with updated procedures for estimating the evapotranspiration of different crops for different growth stages and ecological conditions. Reference: R.A. Allen, L.S. Pereira, D. Raes, M. Smith. 1998. Crop Evapotranspiration. Guidelines for computing crop water requirements. FAO Irrigation and Drainage Paper 56, 300 pp. Food and Agriculture Organization of the United Nations, Rome, Italy.