Evaluation of Coal Fly Ash for Modulating the Plant Growth, Yield, and Antioxidant Properties of Daucus carota (L.): A Sustainable Approach to Coal Waste Recycling

In search of a safe, cost-effective, and sustainable method for the disposal and management of coal fly ash (CFA), seeds of carrot were sown in earthen pots containing growth substrate consisting of field soil amended with different concentrations of weathered CFA at w/w % ratios. Results suggested that CFA added many essential plant nutrients to the growth substrate and improved some important soil characteristics such as pH, electric conductivity, porosity, and water holding capacity. The growth substrate containing 15% of CFA proved most suitable for growing carrots. Plants grown in 15% CFA amended soil had significantly ( p ≤ 0.05) enhanced plant growth, yield, photosynthetic pigments, nitrate reductase activity, protein, and carbohydrate contents as compared to the control. The activity of antioxidant enzymes such as SOD and CAT was significantly upregulated in 15% CFA amended soil as compared to the control. The biomineralization of various elements in the edible part of the carrot was well under the limits and no toxic metal was detected in the edible part of the carrot. The present study, therefore, attempts to delineate the application of weathered CFA as a soil amendment in agroecosystems to improve the productivity of lands through a cost-effective and an ecofriendly manner.