Water-Use Production Functions of Selected Agronomic Crops in Northwestern New Mexico, Phase 3

摘要

The water requirement for growth of spring barley, pinto beans, corn and alfalfa was investigated in northwestern New Mexico. Results strongly suggest that the level of nitrogen fertility does not alter the seasonal evapotranspiration requirement associated with the production of a given yield level. The seasonal evapotranspiration required to produce that yield may differ in response to factors affecting the evaporation component of evapotranspiration. Crop coefficients based on various methods of calculating potential evapotranspiration were found to vary as much as 50% between years for identical yield levels. Evidence presented suggests that to adequately predict the evapotranspirational requirement of a targeted yield level, soil evaporation will have to be identified and quantified. Consequently, relying solely on crop coefficients to predict seasonal and intraseasonal water requirements for full and deficit irrigation under conditions requiring frequent, light irrigation in an environment of high atmospheric evaporative demand, is subject to error and caution is needed when using this approach.