Abstract

LOPEZ LOPEZ, Rutilo et al. Water stress index as an indicator of irrigation timing in agricultural crops. Agric. Téc. Méx [online]. 2009, vol.35, n.1, pp.97-111. ISSN 0568-2517.

Crop water stress index (CWSI) is based on the determination of the actual crop transpiration rate by means of the measurements of canopy temperature and vapor pressure deficit. The objectives of this assay were: to present theoretical and methodological aspects of CWSI and its practical application for irrigation scheduling. The CWSI method has been of practical use in arid and semiarid regions mainly because the required equipment to calculate it is easy to use. This method can also be utilized in humid regions where irrigation is needed during the dry season and there is high solar radiation. The CWSI is based on the theory of energy balance on a surface, the linear functions of the differential temperature between the crop and the air and the vapor pressure deficit; which depends on the crop water status and the weather conditions. Infrared thermometry is a simple, practical and reliable tool to estimate crop water stress, irrigation scheduling and yield prediction.

Keywords : water stress; irrigation timing; yield prediction.