Crop Coefficient Development and Application to an Evapotranspiration Network

Crop coefficients derived from properly designed, operated and maintained lysimeters provide the most accurate values throughout the growing season and are critical in the computation of hourly and daily, regionally based, crop evapotranspiration (ET) values. Multi-stage crop coefficients can be derived from continuously recording lysimeters, increasing the accuracy of both daily and seasonal irrigation crop demand estimates. These crop coefficients can be used with calculated, network based, reference crop ET to develop and disseminate locally representative crop water use estimates. Subsequently, using these accurate values in estimating crop water demand results in improved validity of regional water demand models, better assessments of proposed water policy measures, and enhanced integrity with crop consultants, water districts, and agricultural producers, ultimately resulting in better (more efficient) irrigation management and water conservation.