Influence of sewage sludge on some soil properties, yield and concentration of lead and cadmium in roots and shoots of Maize

Sewage sludge contains abundant organic matter and essential nutrients such as nitrogen and phosphorus for plant. In addition to having economic benefits, using sewage sludge as fertilizer in agricultural lands is an excellent option for sewage sludge management problem. The main limitation of the use of sewage sludge is high concentrations of heavy metals such as lead and cadmium. The purpose of this study was to evaluate the effect of sewage sludge on soil properties, nutrient uptake, heavy metals and maize yield. Thus, a greenhouse experiment with different levels of sewage sludge application (0, 15, 20 and 25% w/w) was conducted as a completely randomized design with four replications. The Results showed that the application of sewage sludge leads to significant increase of of soil organic matter, electrical conductivity and significant decrease of soil pH at 1% level. Sewage sludge application increased significantly (at 1% level) maize yield, nitrogen, phosphorous and sodium concentration in maize. The results also revealed that the application of sewage sludge increased the lead concentration in maize above ground biomass, but this increase was statistically significant (at 1% level) only in 20% rate of sewage sludge in comparison with control treatment. The application of sewage sludge significantly increased (at 1% level) lead and cadmium concentration in roots.