Complementary irrigation with saline water and soil organic amendments modified soil salinity, leaf Na+, productivity and oil phenols of olive trees (cv. Chemlali) grown under semiarid conditions

• Published in: Agricultural water management 2020-07, Vol.237, p.106183, Article 106183
• Main Authors: Chehab, Hechmi, Tekaya, Meriem, Hajlaoui, Hichem, Abdelhamid, Sofiane, Gouiaa, Mohamed, Sfina, Hanene, Chihaoui, Badreddine, Boujnah, Dalenda, Mechri, Beligh
• Format: Article
• Language: English
• Subjects: compost; legumes cover crops; olive mill waste; organic orchard; phenols
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/j.agwat.2020.106183

•The effects of compost, olive mill wastewater (OMWW) and the use of legumes as cover crops combined with complementary irrigation by saline water on soil salinity, olive tree productivity and phenol contents in fruit and oil were assessed during 2016 and 2017 cropping seasons.•High interaction between complementary irrigation by saline water and organic amendments was observed on soil salinity, nutrients statut and trees performances.•The use of saline water and OMWW accentuated the soil salinity and the sodium toxicity on olive leaves.•The use of compost and legumes reduced the negative effects of water salts, while only legumes cover crop maintain high phenol levels in fruit and olive oil. Compost, olive mill wastewater and legume cover crops combined with complementary irrigation by saline water were tested under field conditions during 2016 and 2017 cropping seasons (‘Off’ and ‘On’ years respectively), in an organic mature olive grove cv Chemlali, grown at a density of 100 trees. ha-1. The experiment was conducted with four agronomic practices (TC-no amendment; TP-olive trees amended with compost, TM-olive trees amended with olive mill wastewater and TL-olive trees intercropped with legumes) factorially combined with two irrigation treatments (NI: non-irrigated olive trees and IR: olive trees irrigated with saline water of 4 g.l-1). The complementary irrigation by a limited quantity of saline water (4 m3.tree-1 per season) applied during the fruit growth (May-September) increased significantly the soil water content (SWC) mainly in the plot amended with compost. In both irrigated and rain-fed plots, the soil electrical conductivity (SEC) increased significantly during the dry season mainly in the control and the plot amended with olive mill wastewater (OMWW). Under rain-fed conditions, leaf sodium contents decreased by about 30 and 50%, respectively in olive trees amended by compost and those intercropped with legumes. Complementary irrigation with saline water increased leaf sodium levels in all plots, mainly in trees amended with OMWW, by about 40% compared to those of OMWW plot grown under rain-fed conditions. The level of leaf nitrogen increased by the application of both soil organic amendments and irrigation, while leaf phosphorus level was only affected by irrigation salinity, except for trees intercropped with legumes. Shoot growth, oil yield and fruit pomological characteristics were significantly improved either by the soil organic amendment