Utilization of Fly Ash as a Sustainable Waste Management Technique

Fly ash is an important combustion residue and the most familiar industrial by-product. It is a source of various micronutrients and macronutrients which are essential for plant growth. The striking variations towards the sensitivity of fly ash are observed in the plant growth performance as fly ash comprises heavy metals which may alter the physical, biochemical, and biological properties of the plant thereby alter the plant growth. The growth and metabolism of different plant species were studied by various researchers in different soil–fly ash amendments. Certain observations were made for cotton yield and grain yield of wheat which revealed that 20% fly ash application is significant for increased growth and rice yield or wheat crops. An improved yield and growth in potato, barley and rye was reported at optimum rate of application of fly ash. Ten percent fly ash doses with soil increased the growth of tomato, petunia, and Boston fern as it increased the height of seedling and plant, increased the girth, enhanced the number of leaves, area of leaves, length of spike, and the plant dry weight. Plant growth and yield, carotenoids and chlorophyll contents of leaves were significantly increased at high fly ash rates in chilly, eggplant, and tomato. Changes in the soil characteristics and the cropping system due to the addition of fly ash were also studied and investigated by various workers that show an enhanced production of food crops. This study is an attempt to know the impact of fly ash on morphological and biochemical parameters of different plant species and also to determine the possible utilization in various agricultural practices. At high concentration of fly ash–soil doses, the experiment shows deleterious effect, the maximum being 100% fly ash with no amendment of soil. This shows that at high concentration of heavy metals generated from fly ash can cause genetic damage to plants due to their toxic concentration. At low concentration of fly ash–soil doses, heavy metals are better for the plant growth performance as well as plant productivity. Large-scale use of fly ash in agriculture holds the prospective to increase on an average 10–15% of yield and growth performance of the plants. This agro based technique can also be used with the concept of sustainable waste management by using fly ash–soil combination as a suitable growing medium for growing different plant species.