Effect of Effluent on Soil Physico-chemical Properties and Tomato (Solanum Lycopersicum L.) Growth Performance: The Case of Ambo Mineral Water Factory, Oromia, Ethiopia

Abstract

The release of untreated wastewater into the environment can lead to the contamination of crops, and pollution of soils, rivers, streams and other surface water bodies. This study was undertaken to assess the effect of Ambo Mineral Water factory effluent on soil properties, and the performance of tomato crop. Water and soil samples were collected for laboratory analysis. A pot experiment was conducted using tomato as a test crop. The effluent was analyzed for (pH, total alkalinity, bicarbonate Cl-, soluble sodium, total acidity, Total Dissolved Solids, Total Suspended Solids, Cl-, Mg, Ca, total hardness, NH4-N, PO43- and Sodium Adsorption Ratio). Analysis revealed that the majority of parameters were found within permissible limits for irrigation water quality except for bicarbonate, Magnesium, ammonium nitrogen, and phosphate. Some of the parameters (total alkalinity, soluble Na, Cl-, total dissolved solids, and sodium adsorption ratio) were high in the effluent water. However, Sodium Adsorption Ratio and heavy metals (Pb, Cr, Mn, Zn and Fe) were within permissible limits for irrigation. The effluent was in a range of moderate toxicity hazards of alkalinity, salinity, sodicity, and chloride with high bicarbonate alkalinity hazard hazards. Bulk density, total porosity, exchangeable K, Mg, Ca; total N, and heavy metals in soil solution along the effluent channel did not show significant differences. Soil physicochemical properties (pH, electrical conductivity, exchangeable Na, Exchangeable Sodium Percentage, Soluble Cl-, CO32-and HCO3-; and Cr highly significantly increased in the soils along the effluent channel. Cation Exchange Capacity and organic matter decreased in the same channel by 37.46% and 49%, respectively. Tomato local variety treated with five levels of effluent concentrations for irrigation resulted in significantly good growth performance (dry biomass, leaf number, growth rate and heights) at 75 and 100 % effluent water concentrations.