Managing metolachlor and atrazine leaching losses using lignite fly ash

Application of low cost amendment for pesticide retention in soil is an important area of research in environmental sciences. The present study reports the potential of coal fly ash (Inderprastha and Badarpur), a waste from thermal power stations, for retaining soil applied metolachlor and atrazine within the application zone. Both the fly ashes were highly effective in reducing the leaching losses of metolachlor and atrazine and at 2% and 5% fly ash amendment levels the herbicides were retained in the top 15cm profile of the column. However, fly ashes varied in their capacity in reducing the downward mobility of herbicides, as the Inderprastha fly ash was more effective than the Badarpur fly ash. Although fly ash contained heavy metals like Cr, Cu or Pb, but they were not detected in the leachate. Also, concentration of other metals like Zn, Mn and Fe in leachate decreased after fly ash amendment. Results of this study have implications in reducing the leaching losses of these herbicides in agricultural soils. ► Effect of two fly ashes on metolachlor and atrazine leaching in two soils was studied. ► Both fly ashes significantly decreased the leaching losses of the herbicides. ► Effect of fly ash on herbicide leaching varied with soil type and nature of fly ash. ► Fly ashes did not increase the concentration of leachable metals in the leachate.