1. IFAPA; Centro Las Torres-Tomejil; 41200 Alcalá del Rio Spain
2. USDA-ARS-EMFSL; Beltsville MD 20705 USA
3. Agrosphere (IBG-3), Institute of Bio- and Geosciences; Forschungszentrum Jülich GmbH; 52428 Jülich Germany
4. Dep. of Agronomy; Univ. of Cordoba; 14071 Cordoba Spain
5. USDA-ARS; Hydrology and Remote Sensing Lab.; Beltsville MD 20705 USA