Impact of mixing treated industrial water with olive mill wastewater on vetch (Vicia sativa L.) germination and early seedling growth

Abstract

Vetch is a forage crop that is widely grown in high rainfall areas in Jordan for forage production and grazing. Growing vetch species out of the season will need irrigation, which is very expensive. In here, we propose application of wastewater or olive mill wastewater as alternative to the fresh water. An experiment was carried out to evaluate the effect of diluting the industrial water (IND) with olive mill wastewater (OMWW) on the vetch germination (GR) and early seedling growth under controlled conditions. The water treatments consisted of T1 (pure IND100%), T2 (mix of IND75% + OMWW25%), T3 (IND50% + OMWW50%), T4 (IND25% + OMWW75%) and T5 (pure OMWW100%) and tap water (control). This experiment was designed in a CRD with three replications for each treatment. Several measurements on the morphological and biochemical analysis were taken during this study such as seed germination (GR), as well as the seedlings fresh weight of shoot (FWS), dry weight of shoot (DWS), fresh weight of shoot (FWR), dry weight of root (DWR), shoot length (SL), root length (RL) and the ratios of DWS/DWR and SL/RL. The water treatments had a significant influence on data taken, in which the highest mean values of morphological characteristics were obtained under the T1, while the lowest were obtained under the T5 due to high phenols concentrations. The OMWW treatment showed an adverse effect on GR, DWS, DWR, SL, and RL due to low pH values (4.5) and high phenols concentration (1700 mg/L). In contrast, the industrial water showed low to moderate effect on the vetch seed germination. The means of DWS and DWR under T3 and T4 were not significantly different from each other but were different comparing with control. It is recommended that the use of a mixture of OMWW and the Industrial water will have a positive effect on Vetch growth.