MUNICIPAL BIO-SOLIDS SOIL APPLICATION: SOIL AND PLANT QUALITY AND ENVIRONMENTAL IMPLICATIONS

Abstract

Biosolids are utilized worldwide as an organic fertilizer and can enrich barren soils in Qatar, especially if the proper dosage is used.However, it is crucial to study this newly introduced product to the Qatari environment and specify its chemical and physical characteristics along with assessing all the related consequences from using it. Furthermore, it is crucial to know information about biosolid, including its quality, effects on soil and plants as a fertilizer, the ideal and benign application rates, the potential adverse impacts on groundwater, and the possibility to use it as a fertilizer for edible plants. All these are vital to applying the best agricultural practices to use biosolid and to get the best benefits from this recycled material. Studies acknowledge that biosolids have their advantages and disadvantages that should be considered before their usage in soil and the production of both ornamental and edible plants. The main disadvantage is that although biosolids are rich in nutrients, they have heavy metals that are risky pollutants to human health and can lead to cancer and other chronic illnesses due to their harmful effects. Similarly, it can contaminate soils in case of accumulation. Nevertheless, biosolids have been shown to improve crop production significantly in many areas around the world. It is worth noting that Qatar has recently approved the use of biosolids in the production of ornamental plants only. This study was conducted to evaluate the efficiency of biosolid as organic fertilizer in Qatar and address different concerns associated with its use in the production of food crops. The study attempted to check the effectiveness and efficiency of the biosolid quality via a temporal period of three months for almost one year. Moreover, the study also aimed at checking the efficiency of the recommended dosage of 5kg/m2 biosolid by Qatar's government. Different combinations of biosolid were used to review applications rates that are feasible to the soil whereas the development of plants characteristics was good and the contents of nutrients especially nitrogen and phosphorus were much better and the level of pollutants was below the international levels which makes it benign to be used. The study trialed rates of 3Kg, 5kg, and 7Kg of biosolid in the soil to specify the ideal application rate, all planted with Petunia atkinsiana plants as indicators. There was also a control treatment with only soil planted with plants. The rates of 5 and 7 kg/m2 achieved the best plants development for the tested biological parameters, meanwhile, both rates approved rich contents of nutrients along with benign contents of pollutants sufficient to nominate them as the best application rates. . Another crucial component that was investigated is the potential effect on groundwater and leachability behavior of the biosolids whereas the study discovered insignificant potential effects to contaminate the groundwater by applying these application rates. The biosolid of class A as an organic fertilizer was tried to produce tomato, an edible fruit. Chemical and physical characteristics of the soils and plants are grown using the different application rates of biosolid were discussed in-depth. The study was concluded with recommendations on whether municipal biosolid should be used to produce tomatoes and other edible plants.