Fly Ash and Sewage Sludge Application on an Acid Soil and Their Influence on Some Soil Properties and Wheat Biomass Production

摘要

A pot experiment was conducted with wheat on an acid soil (pH 5.0) amended with fly ash and sewage sludge. The experimental design was complete randomized blocks with seven treatments each replicated four times. The treatments were: C, control - soil alone, IF -soil with inorganic fertilizers, T1 - soil plus 30 g fly ash/2.5 kg soil, T2 - soil plus 90 g fly ash/2.5 kg soil, SS1 - soil plus 2.65 g sewage sludge/2.500 kg soil, SS2 - soil plus 5.25 g sewage sludge/2.5 kg soil, SS3, soil plus 10.5 g sewage sludge/2.5 kg soil. All the treatments included sewage sludge, included also fly ash, at the amount of the treatment T1. The results showed that fly ash alone didn't increase significantly wheat biomass as did inorganic fertilization and sewage sludge application at the higher levels. Fly ash addition increased soil pH, electrical conductivity, hot water extractable boron and total Cu, Pb, Ni, and Zn while decreased available forms of these heavy metals. Sewage sludge increased wheat biomass along with soil pH, and ammonium and nitrate N in soil. However, it also increased heavy metal content especially their total concentration but not their available forms.