The influence of fly ash on atrazine and alachlor persistence in corn cultivation soil

Abstract

The influence of fly ash (raw material lignite from thermal station, pH = 11.2) in the fate of atrazine and alachlor was studied in an experimental corn cultivation soil, under environmental conditions of Ioannina region (N.W. Greece). An amount of fly ash equal to 0.15% p.w. of soil for a depth 0–10 cm was used in a sandy‐clay‐loam soil on the 18th of May 1988 when the sowing of the corn and the application of two herbicides took place. Analyses of soil samples for 240 days, in a period between May 18, 1988 and January 14, 1989 showed that the addition of fly ash decreases the half life of atrazine, from 54 to 47 days and of alachlor from 25 to 22 days. The final results of fly ash addition showed a decrement of atrazine residues of about 42.6% in soil without corn cultivation and 46.6% in soil with corn after 240 days. For the alachlor residues the corresponding decrements were 40.6% in the reference soil and 52.8% in corn cultivation soil, after 118 days.