Influence of Sludge Compost on Soil Properties and Tomato Plant Uptake of Metals | Biomed Grid

The Sultanate of Oman is one of the countries that are hamstrung by scarcity of water. This is, obviously, a problem limiting the production of crops. Oman, therefore, needs to leverage the wastewater that is produced in the sewage system. Moreover, Wastewater Company, Haya, converts the biosolid output of the wastewater processing into composting process. But unfortunately, this type of soil amendment is likely to contain various toxic materials. Therefore, it is important to identify the forms of various metals such as Mg, Ca, Al, Zn, Cu, Co, Cr, As, Cd, Fe, Mn and Ni, etc. which could exist in the soil as a result of the application of sludge fertilizer to land - so as to enable us to spot their existence as also to evaluate the extent of their movement. It could also help us determine the bioavailability and toxicity of these metals. Chemical fractionation is a chemical process used to identify the metal fractions in soil samples or in sediment. The sequential extraction technique has been used for this purpose and it has been revealed that some metals could bind with different materials and compounds in soil such as carbonate, iron oxide, manganese and organic matter. The presence of metals fractions in Omani soil and nutrients like Mg and Ca was studied; it had found that Ba was appeared as exchangeable in columns which were amended with 34.8g/kg and other elements like Al, Ni. Na and Zn were available as organic fractions, but Ca and Mg were available in all types of fractions. The rest of the metals were not strong enough to appear due to the weakness of the extract solution and high rate of pH. Besides, most of the fractions were found to be more in columns irrigated at a rate of 60 ml/min than 120 ml/min. The plant uptake of metals was studied as well, and it was found that the roots of the tomato plant recorded a high concentration of elements compared to the fruit, leaves and stem. The study also found that the metals had accumulated in the order of root, fruit, leaves and stem. And that may interpret as metals translocation from lower parts to upper parts. Moreover, compost addition increased the yield of tomato plants in terms of height of stems and the weight of biomass of tomato organs.