Estimating Evapotranspiration of Fully-and Deficit-irrigated Alfalfa in Commercial Fields with the Eddy Covariance and Surface Renewal Methods

摘要

Evapotranspiration (ET) of fully irrigated and deficit irrigated (no irrigation in July, August, and September) was measured in four commercial alfalfa fields with the eddy covariance (EC) and surface renewal (SR) energy balance methods. Both EC and SR methods were used in the fully irrigated part of the fields, while the SR method only was used in the deficit irrigated part. Deficit irrigation reduced ET, but the amount of reduction was highly site specific. Good agreement was found between the EC and SR methods. However, patterns of the daily differences between the EC and SR methods differed between the four fields.