Olive mill wastewater (OMW) is generated seasonally a large amount during the olive oil production in southern Tunisia and it is often discharged in the open environment. OMW has a high amount of phototoxic compounds, high salinity and acidity and therefore is challenging when disposed on soil. However, in southern Tunisia, the condition climatic is arid and semis-arid region. The soil sandy is in degradation and erosion processes.
New strategies have been developed to reduce these impacts in soil and to valorize a waste product as olive mill wastewater (OMW) loaded with minerals and organic matters as fertilizer in agronomy. The major aim of this study was to investigate the effects of OMW spraying onto on soil biochemical properties and Faba bean crop productivity was investigated.
The result showed that the irrigation of sandy soils by different OMW doses strongly influenced their chemical and microbiological characteristics. Indeed, spreading amounts from 15 m³/ha to 45 m³/ha for three consecutive years induced a considerable improvement of soil fertility. The pH and soil phosphorus content remain stable during the three years of study, while the soil salinity was increased for the 45 m³/ha treatment where it exceeded to 6 dS/m.
In conclusions, the dose 15 m³/ha is suitable for the vegetative development of the Faba bean tested plant according to the soil characteristics evolution.