1. Professor, Agronomy Engineering, Univ. Centroccidental Lisandro Alvarado, Barquisimeto, Venezuela. E-mail: jortiz@ucla.edu.ve
2. Professor, Agronomy Engineering, Centro Regional de Estudios del Agua, Castilla-La Mancha Univ. Campus Universitario, s/n. E02071, Albacete, Spain. E-mail: Jesus.Montero@uclm.es
3. Researcher, Agronomy Engineering, Convenio Provincia de Rio Negro-INTA, CC153, 8500 Viedma, Argentina. E-mail: rsmartinez@correo.inta.gov.ar
4. Professor, Agronomy Engineering, Centro Regional de Estudios del Agua, Castilla-La Mancha Univ. Campus Universitario, s/n. E02071, Albacete, Spain. E-mail: Jose.Tarjuelo@uclm.es