Irrigation automation based on soil electrical conductivity and leaf temperature

Two automated drip irrigation systems: one based on soil electrical conduct ivity and the other based on leaf-air temperature differential were develop ed and tested for Okra (Abelmoschus esculentus). Different sensors were eva luated for monitoring the soil moisture content based on electrical resista nce variation with moisture content. The sensor with washed sand as porous medium was found to be the most efficient one for the study area. A low cos t, commercially available button type thermistor was used as the leaf and a ir temperature sensors. The amount of water applied per day, leaf-air tempe rature and soil moisture content were monitored during the study period. Th e systems maintained the designed soil moisture content and air-leaf temper ature differential through out the study period. (C) 2000 Elsevier Science B.V. All rights reserved.