Fly ash can be used for reclaiming the problem soil and enhance the crop productivity depending upon the nature of soil and fly ash. Fly ash may improve the physical, chemical and biological properties of problem soils and enhance the available macro and micronutrients for plants. The high concentration of elements (K, Na, Zn, Ca, Mg and Fe) in fly ash increase yield of agricultural crops. However, application of fly ash, particularly unweathered ones, shows a tendency of accumulating elements like B, Mo, Se and Al. The accumulations of these elements to toxic levels are responsible for reductions in the crop yields and consequently influence animal and human health. This book explores the possibility of using fly ash to improve the soil environment and subsequently increase the growth and yield of crops.