Authors

MH Rahimian, S Taghvaeian, MR Nouri, SH Tabatabaei, MH Mokhtari, Y Hasheminejhad, E Neshat

Description

Seasonal evapotranspiration (ET) of mature pistachio orchards in central Iran was estimated on a distributed basis by applying the SEBAL model to MODIS imagery. A downscaling approach was adopted to increase the spatial resolution of generated ET maps to a level that is useful for managing water resources in small-scale orchards of the region. SEBAL-ET for a sub-area of pistachio orchards was 1,275 mm in the 2012 growing season, significantly larger than the estimate obtained by applying a soil-water balance analysis (759 mm). The difference may be attributed to the fact that the soil-water balance analysis was conducted for the top 1.2 m of soil, while tap roots of pistachio trees can extract water from deeper layers. Assuming that SEBAL has provided accurate estimates, 82% of applied irrigation water was consumed through evapotranspiration process during the pistachio growing season.