Alteration in yield and chemical composition of essential oil of Mentha piperita L. plant: Effect of fly ash amendments and organic wastes

Fly ash (FA), containing considerable amounts of K, Ca, Mg and S can be potentially used as a soil amendment. Experiments were conducted to evaluate the effect of various concentrations of FA (0%, 25%, 50%, 75% and 100%) along with Garden soil (GS) and organic wastes in the form of oil cakes (Jatropha and mustard) on growth responses, element accumulation, yield and composition of volatile oil of Mentha piperita plant (essential oil bearing crop). Application of FA at >50% reduced plant growth, oil yield and its composition, whereas addition of FA at level of ≤50% exhibited positive results. Supplementation of Jatropha oil cake (OC1) along with FA had better response compared to other treatments. Treatment of FA (50% FA + 50% GS) along with OC1 was the best ameliorant to support growth and essential oil yield of M. piperita. It is recommended that M. piperita may be grown in a region where fly ash is used for amendment of agricultural soil.