Olive tree response to irrigation with wastewater from the table olive industry

A field experiment was conducted to examine the effect of drip irrigation u sing wastewater from a table olive industry on physiological, nutritional a nd yield parameters of olive trees (Olea europaea L.). Very limited informa tion, if any, exists, on the potential of recycling this kind of wastewater in agriculture. Two types of wastewater were used in the experiment, the f irst with SAR and EC values of 12-56 and 3.5-4.2 dS m(-1) respectively, and the second 73-90 and 4.3-6.0 dS m(-1). In general, this kind of wastewater has a highly variable composition and SAR values that are too high for agr icultural purposes. Olive trees rapidly responded to wastewater application . Compared to the control (fresh water), the more saline wastewater caused important decreases in leaf water potential, stomatal conductance to H2O an d the photosynthesis rate after only 15 days of irrigation, the reduction b eing more pronounced after 2 months of irrigation. This treatment also caus ed a rapid, significant reduction in leaf N concentration, as compared with the N level in the trees before irrigation. Both types of wastewater signi ficantly reduced olive yield, compared to that obtained in the control. The se results indicate that this kind of wastewater is unsuitable for applicat ion to olive orchards under irrigation.