The task of providing reliable and accurate information from scales of farmer fields to
entire river basins, encompassing millions of hectares of irrigated land, is far from trivial.
Space-borne remote sensing measurements can, however, provide regular information on
agricultural and hydrological conditions of the land surface for vast areas. The capability
of remote sensing to identify and monitor crop growth and other related biophysical
parameters has undergone major improvements during the last 20 years, albeit several
issues remain unresolved. Comprehensive reviews on remote sensing applications for
agricultural water management are presented by Choudhury et al. (1994), Vidal and
Sagardoy (1995), Rango and Shalaby (1998), Bastiaanssen (1998) and Stewart et al.
(1999).