Bulk use of pond ash for cultivation of wheat–maize–eggplant crops in sequence on a fallow land

In India, presently 85 existing thermal power plants (TPPs), contributing to about 70% of the total energy requirement, produce 118 million tons of fly ash per year. This huge quantity of fly ash not only poses serious problems of environmental concerns but occupies large areas of land for its dumping and needs urgent and appropriate measures for its safe disposal and gainful utilization on sustainable basis. Besides, reclamation of a vast area of uncultivated wasteland for agriculture and forestry is another challenge for the fast-growing population of the country. A field experiment was conducted to evaluate the effect of pond ash application on the yield and nutrient composition of wheat, maize and eggplant crops grown in sequence on an uncultivated fallow land. Pond ash collected from the Anpara TPP, India was mixed with soil at 100 t ha−1. Ash application had a beneficial effect on the wheat yield. Addition of pond ash resulted in a significant increase in the contents of N, P, K, S, Ca, Mg, and micro-nutrients. The uptake of toxic trace elements (Pb, Se, Cr, and Cu) was below the threshold levels. The residual effect of ash on crop yield and nutrient composition of the subsequent maize and eggplant crops were also significant. The overall beneficial effect of pond ash on crops could be attributed to the improvement in the soil physical quality due to ash amendment. The results indicated that pond ash could be applied safely for reclamation of uncultivated fallow soils.