Evaluation of an Evapotranspiration Model for Corn1

Many empirical evapotranspiration models, used for scheduling irrigation, require meteorological measurements not routinely compiled by the National Weather Service. Thus, difficulties and expense are incurred in obtaining the needed measurements. Therefore, an empirical evapotranspiration model, requiring few meteorological measurements was developed and tested for corn [Zea mays (L.) cv. ‘Dekalb XL72A’] at two sites in Kansas. Daily inputs required by the model include leaf area index, solar radiation, effective precipitation, and maximum and minimum air temperatures. Daily outputs include transpiration, evaporation, advective contribution, and soil water content. Model estimates of soil moisture in the 150-cm profile were compared with neutron attenuation estimates. Model estimates were within 6% of neutron attenuation estimates during the growing season, and since the meteorological measurements can be routinely obtained at the field site, the model has potential for scheduling irrigation on a regional basis in Kansas.