Articles | Volume 15, issue 10
Hydrol. Earth Syst. Sci., 15, 3061–3070, 2011
Hydrol. Earth Syst. Sci., 15, 3061–3070, 2011

Research article 05 Oct 2011

Research article | 05 Oct 2011

Determining water use of sorghum from two-source energy balance and radiometric temperatures

J. M. Sánchez1, R. López-Urrea2, E. Rubio1, and V. Caselles3 J. M. Sánchez et al.
  • 1Applied Physics Department, School of Industrial Engineering, University of Castilla-La Mancha, Av. España, s/n 02071 Albacete, Spain
  • 2Instituto Técnico Agronómico Provincial de Albacete and FUNDESCAM, Av. Gregorio Arcos, s/n 02006 Albacete, Spain
  • 3Earth Physics and Thermodynamics Department, Faculty of Physics, University of Valencia, C/Dr. Moliner, no. 50, 46100 Burjassot, Spain

Abstract. Estimates of surface actual evapotranspiration (ET) can assist in predicting crop water requirements. An alternative to the traditional crop-coefficient methods are the energy balance models. The objective of this research was to show how surface temperature observations can be used, together with a two-source energy balance model, to determine crop water use throughout the different phenological stages of a crop grown. Radiometric temperatures were collected in a sorghum (Sorghum bicolor) field as part of an experimental campaign carried out in Barrax, Spain, during the 2010 summer growing season. Performance of the Simplified Two-Source Energy Balance (STSEB) model was evaluated by comparison of estimated ET with values measured on a weighing lysimeter. Errors of ±0.14 mm h−1 and ±1.0 mm d−1 were obtained at hourly and daily scales, respectively. Total accumulated crop water use during the campaign was underestimated by 5%. It is then shown that thermal radiometry can provide precise crop water necessities and is a promising tool for irrigation management.