Agronomic Application Of Olive Mill Waste Water: Short-Term Effect On Soil Chemical Properties And Barley Performance Under Semiarid Mediterranean Conditions

Abstract

The extraction of oil produces olive mill waste water “OMW” which has a very high polluting power resulting in high levels of COD (chemical oxygen demand), high salinity and a strong phenolic compounds causing environmental pollution. Thus, the exploitation of this waste without preliminary treatment is very limited considering the toxic effect on soil and plants.The search for new technologies or processes for recovery of the effluent is necessary. The spreading of OMWW in the sandy soil in arid conditions of Southern Tunisia is a potential alternative for this purpose.The identification of a recovery method of “OMW” as a fertilizer in agriculture is an initiative with both agronomic and environmental interest. In this study, the spreading of 15, 30 and 45 m³/ha for three consecutive years was tested in the presence of irrigated barley crop in order to assess the impact of the incorporation of these effluent on soil chemical and biological characteristics and plant behaviour.The results of the study showed that spreading amounts from 15 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 increased for the 45 m3/ha treatment where it exceeded 6 dS /m.In addition, all the components of barley yield, except 1000 grain weight, were negatively affected by “OMW”, in particular yield plots that received higher doses as 30 m³/ha and 45 m³/ ha.Obviously, the straw, spikels and grain yield, are negatively affected with relatively different degrees depending on the dose applied but also on the cumulative effect of successive applications during the three years of study.

Keywords

• OMW, soil, Barley crop, yield.