Effect of Fly Ash on Yield and Heavy Metal Content of Maize (Zea mays) Grown in an Alfisol

Abstract

A field experiment was conducted for three consecutive seasons during 2013 and 2014 in order to study the effect of fly ash with lime and gypsum with and without FYM on heavy metal content of maize as well as its yield in an Alfisol. The experiment was laid out in a randomized block design (RBD) with eight treatments namely, T -control (received no amendments), T -lime @ 0.2 LR, T -gypsum @ 2.5 q ha^-1, T -FA @ 40 t ha^-1, T -lime @ 0.2 LR + FYM @ 10 t ha^-1, T -gypsum @ 2.5 q ha^-1 + FYM @ 10 t ha^-1, T -FA @ 40 t ha^-1 + FYM @ 10 t ha^-1 and T -lime @ 0.2 LR+FA @ 40 t ha^-1 + FYM @ 10 t ha^-1 . The Fe and Cu accumulation in fly ash treatment was comparable with that under lime treatment and observed lower in Mn and Zn content. The accumulation of Fe, Mn and Cu due to combined application of lime or fly ash with FYM was at par with their sole application. Combined application of FYM with fly ash significantly lowered the Pb accumulation as compared to fly ash alone, whereas Cd and Cr accumulation was at par in both the treatments. Similar trend was observed for Cd, Cr and Pb uptake. Grain yield of maize was increased due to lime application (48.89 q ha^-1) over control (38.6 q ha^-1) by 27%. Inclusion of FYM enhanced the use efficiency of lime, gypsum or fly ash. Combined application of fly ash with FYM was as effective as lime treatment. Conjunctive application of lime + flyash + FYM recorded the maximum grain yield of 57.72 q ha^-1 among all treatment combinations. One time application of fly ash to first crop stabilized maize yield up to third season. Heavy metal (Pb, Cd, Cr) accumulation in flyash treatments were below toxic level and could be used in acidic soils without affecting the soil health.