title: Dose and frequency dependent effects of olive mill wastewater treatment on the chemical and microbial properties of soil.
abstract: Olive mill wastewater (OMW) is a problematic by-product of olive oil production. While its high organic load and polyphenol concentrations are associated with troublesome environmental effects, its rich mineral and organic matter contents represent valuable nutrients. This study aimed to investigate the valorization of this waste biomass as a potential soil conditioner and fertilizer in agriculture. OMW was assayed at three doses 50, 100, and 200 m(3) ha(-1) year(-1)) over three successive years in olive fields. The effects of the effluent on the physico-chemical and microbial properties of soil-layers were assessed. The findings revealed that the pH of the soil decreased but electrical conductivity and organic matter, total nitrogen, sodium, and potassium soil contents increased in proportion with OMW concentration and frequency of application. While no variations were observed in phosphorus content, slow increases were recorded in calcium and magnesium soil contents. Compared to their control soil counterparts, aerobic bacteria and fungi increased in proportion with OMW spreading rates. The models expressing the correlation between progress parameters and OMW doses were fitted into a second degree polynomial model. Principal component analysis showed a strong correlation between soil mineral elements and microorganisms. These parameters were not related to phosphorus and pH.
authors.affiliation: Laboratoire d'Amélioration de la Productivité Oléicole et des Arbres Fruitiers, Institut de l'Olivier de Sfax, B.P. 1087, 3000 Sfax, Tunisia; UR Etude et Gestion des Environnements Urbains et Côtiers, Université de Sfax, Ecole Nationale d'Ingénieurs de Sfax, B.P. 1173, 3038 Sfax, Tunisia; Laboratoire d'Ecologie Végétale, Faculté des Sciences de Sfax, B.P. 1082, 3018 Sfax, Tunisia.
authors.forename: Salwa
authors.initials: S
authors.lastname: Magdich
authors.forename: Chedlia
authors.initials: C
authors.lastname: Ben Ahmed
authors.forename: Raja
authors.initials: R
authors.lastname: Jarboui
authors.forename: Béchir
authors.initials: B
authors.lastname: Ben Rouina
authors.forename: Makki
authors.initials: M
authors.lastname: Boukhris
authors.forename: Emna
authors.initials: E
authors.lastname: Ammar
mesh_terms: D001673:Biodegradation, Environmental; D004305:Dose-Response Relationship, Drug; D007220:Industrial Waste / Q000032:analysis*; D000069463:Olive Oil; D010938:Plant Oils; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D007220:Industrial Waste; D000069463:Olive Oil; D010938:Plant Oils; D012987:Soil; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Microbial flora; Olive mill wastewater (OMW); Physico-chemical properties; Principal component analysis (PCA); Soil layers; Spreading