17 - Effects of fly ash on growth, productivity, and diseases of crop plants

Abstract

Fly ash, a coal combustion residue is a solid waste of thermal power plants all over the world. Therefore fly ash management and its potential uses are of a great concern in different parts of world. Fly ash has efficacy in the modification of soil health therefore great potential in agriculture. The high concentration of some useful elements in fly ash increases the yield of many crops. It has also been used to some extent for the management of plant diseases caused by fungi, bacteria, and parasitic nematodes. Use of fly ash as a soil amendment has been suggested but its use in some cases is associated with undesirable changes in soil, such as soil pH, imbalance in nutrients, and toxicity in plants, due to excess of sulfate, boron, and toxic elements. Generally, the excess or inappropriate use of fly ash is usually associated with different problems. The organic compounds, such as PAHs and PCBs, have effects on soil biota, uptake by plants and soil persistence even at low levels. However, coapplication of fly ash with organic manures or sewage sludge in soil is effective in soil health improvements. Therefore use of fly ash is possible if used in appropriate amounts in plant disease management and sustainable agriculture.