Water use of irrigated oil palm at three different arid locations in Peninsular India

The water requirement of irrigated oil palm (Elaeis guineensis) in Andhra Pradesh, Karnataka and Maharashtra, India, were estimated using the Penman-Monteith equation. Microclimate parameters measured using an automated weather station showed that the 3 geographically separated sites also had climatic differences. The temperature at the study sites ranged between 12 and 35°C and the vapour pressure deficit (VPD) of the atmosphere ranged between 0.3 and 4.5 kPa. Stomatal conductance measured on fully irrigated plants showed a maximum of 500 mmol m-2 s-1. The stomatal conductance was highly correlated with the VPD. Closure of stomata started when the VPD was greater than 1.0 kPa. The stomatal conductance was severely reduced when the VPD reached values >1.9 kPa. All the sites had a prolonged dry season. At none of the sites could oil palm be grown as a rainfed crop. Water loss by transpiration as estimated for a dry day (without rain) ranged from 2.0 to 5.5 mm. The transpiration/evaporation ratio was approximately 0.8 at all 3 locations