Olive wastewater as an ecological fertiliser

Abstract

The effects of untreated and treated olive mill wastewater on seed germination, plant growth and soil fertility were studied. Tomato (Lycopersicon esculentum), chickpea (Cicer arietinum), bean (Vicia faba), wheat (Triticum durum) and barley (Hordeum vulgare) were tested for the germination index and growth in soil irrigated by olive mill wastewater. Lepidium sativum was used as the standard species for the germination index and phytotoxicity evaluation. We measured soil properties, crop growth, herbage biomass, leaf elongation and productivity. The results show beneficial effects using treated olive mill wastewater. The treated plants showed an improvement in seed biomass, spike number, plant growth, and a similar or even better dry productivity than plants irrigated with water, e.g. Hordeum vulgare 102%, Triticum durum 105%, Cicer arietinum 101% and Vicia faba 102%. An increase in the germination index from 100% to 115% was observed. Soil organic matter, respiration and enzymatic activities were also enhanced by treated olive mill wastewater ferti-irrigation. However, even diluted 10 times, untreated olive mill wastewater inhibited the species germination, e.g. 1.2% for Hordeum vulgare and 40% for Cicer arietinum and Vicia faba, and plant growth (16-42.5%). Leaf necrosis and low productivity were observed in crops ferti-irrigated by untreated olive mill wastewater. olive mill wastewater / germination index / phytotoxicity / crop growth / soil fertility

Effect of olive mill wastewater on growth and bulb production of tulip plants infected by bulb diseases

“…A common adverse effect of OMW treatment is the reduction in fresh and dry biomass production in different crops and other plants such as tomato, spearmint, peppermint, and wheat (Mekki et al, 2006;Ouzounidou et al, 2008;El Hassani et al, 2009a,b). This can be attributed to a number of factors such as: a) decrease of leaf chlorophyll and carotenoids concentrations (Asfi et al, 2012), which can affect plant photosynthesis, b) root growth reduction, since phytotoxic substances existing in OMW such as phenols, organic acids, and fats affect root membrane structure and modify its functions including metabolic efficiency and stability (El Hadrami et al, 2004), c) nutrients depletion which severely affects metabolism and resulting in growth inhibition (Wulff-Zotelle et al, 2010) and d) low water use efficiency mainly due to decreased CO 2 assimilation (Asf i et al, 2012).…”

“…However, apart from its antimicrobial properties, OMW may become phytotoxic (Bonari et al, 1993;Capasso et al, 1995), since uncontrolled OMW ap-plication could inhibit seed germination (Casa et al, 2003;D'Annibale et al, 2004), shoot and root elongation and biomass production (Asfi et al, 2012), plant growth (Ouzounidou et al, 2010), uptake and translocation of nutrients (Ouzounidou et al, 2008) and cause various physiological changes (Mekki et al, 2006;Ouzounidou et al, 2008;El Hassani et al, 2010) including decreased water use efficiency mainly due to decreased CO 2 assimilation rate (Asfi et al, 2012). The presence of phenols as well as short and long-chain fatty acids is believed to contribute to the phytotoxic nature of OMW (Casa et al, 2003;Kistner et al, 2004;Isidori et al, 2005).…”

Effects of Olive Mill Wastewater on Soil Microarthropods and Soil Chemistry in Two Different Cultivation Scenarios in Israel and Palestinian Territories

“…On the other hand, the Israeli Ministry of Environmental Protection allows land application at rates up to 40 m , which is expected "to be on a safe side" [7]. OMW could serve as fertilizer [8][9][10], but it may also render soils water repellent or modify the sorptive capacity of soil for organic pollutants on a long-term scale [9,[11][12][13], and leaching of OMW components to groundwater cannot be excluded [14,15]. Moreover, OMW is phytotoxic to, for instance, spinach [16] and cress [17].…”

Effect of irrigation with olive mill wastewater on soil hydraulic and solute transport properties

“…About 30 million m 3 of OMW is generated worldwide (mainly in the Mediterranean region) every year from olive oil production (Niaounakis and Halvadakis 2006). The production of such a high amount of OMW in a short period (3-5 months), its pollution load of high biological oxygen demand (40-80 g l ), and its phytotoxic properties are serious problems for OMW disposal (Rinaldi et al 2003;Mekki et al 2006;Mahmoud et al 2012). As an illustration of the level of the environmental problem of OMW, 10 million m 3 year -1 of OMW corresponds to the same load of sewage water generated from about 20 million people (McNamara et al 2008).…”