ABSTRACT
Fly ash, a by-product of coal combustion, is produced in large quantities in many countries and is partially disposed of in soils. Physically, fly ash consists mainly of silt-sized particles, is characterized by moderate to extremely high water-holding capacity, and possesses cementing properties. Chemically, fly ash is a ferro-alumino-silicate material and contains substantial amounts of macroand micronutrients for plants (except C and N). Fly ash can be a strongly acidic or a strongly alkaline material, depending on its composition. Consequently, its application to soils can enhance soil fertility, improve soil’s physical properties, and raise the pH of acid soils, if it is alkaline in reaction.
