Evapotranspiration of flood-irrigated pecans under drought conditions in El Paso; TX

摘要

As drought continues in the Rio Grande Project area, pecan growers in the region have to use brackish groundwater to augment a shortage of surface water. They have concerns about potential impacts on pecan trees and soil conditions. In this paper theauthors assessed evapotranspiration (ET) of pecan trees under drought conditions based on Eddy Covariance monitoring data in a pecan orchard. The ET tower with an Open Path eddy Covariance (OPEC) system is located in a mature pecan field on the Rio Grande floodplain in El Paso County, Texas. The pecans are usually irrigated with Rio Grande water, but supplemented by brackish groundwater during droughts. During a normal irrigation season, a total of 14 irrigations were applied. Daily ET value can be derived by using the ASCE standardized reference evapotranspiration equation based on the data from the OPEC system measurements, including net radiation at the crop surface, soil heat flux density at the soil surface, mean hourly air temperature, mean hourly wind speed and mean actual vapor pressure. These research results are expected to help farmers develop strategies for irrigation scheduling and water conservation.