Salinity stress decreases water use of eggplant

areas affected by salinity are increasing at a rate of about 2 million hectares per year. Mean air temperature is expected to rise and rainfall to decrease in the temperate regions of the planet, thus increasing the risk of salinization in marginal lands. This study was aimed at quantifying eggplant water use under moderate salinity stress. The experiment was conducted in 2001 at the experimental field station of the CNR-ISAFoM in Vitulazio, Italy, located in the Volturno river plain. Cima di Viola eggplant was mechanically transplanted on 22 May, following a previous eggplant crop during 2000. Two water regimes were compared, one providing irrigation with water containing 0.5 % NaCl (S) and the other irrigated with tap water (C). Treatments were arranged in a randomised block design with three replicates. All plots were irrigated at weekly intervals, by applying a water depth in order to replenish water lost by evapotranspiration which was determined by soil hydrological balance. Evapotranspiration was monitored with the residual energy balance approach, on the basis of the net radiation, the soil heat flux and the radiative surface temperature of the crop canopy. Midday leaf water potential was only slightly reduced, while stomatal conductance decreased by over 50% in the second part of the growth season. Peak LAI and total plant dry matter of S treatment were half that of the control. Seasonal water consumption decreased by an average 10% due to saline stress.