ASCE-EWRI standardized Penman-Monteith evapotranspiration (ET) equation performance in southeastern Colorado

Quantification of crop water use or evapotranspiration (ETc) is required for efficient irrigation water management. The ASCE-EWRI Standardized Penman-Monteith (PM) evapotranspiration equation (ETsz) has been recommended by the American Society of Civil Engineers (ASCE) to estimate reference ET. The reference alfalfa ET obtained from the standardized ET equation (ETrs) along with alfalfa crop coefficients (Kcr) can be used to estimate a given crop ETc. In this study, the ETsz equation was evaluated using measured alfalfa ET (ETr) from a large monolithic precision weighing lysimeter located near Rocky Ford, Colorado, USA, using data from 2009 to 2012.