Uptake of metals in maize as affected by irrigation water quality and clay content of the soil

A pot experiment was carried out under controlled conditions to evaluate the combined effects of chemical oxygen demand (C.O.D.) and heavy metal content in synthetic irrigation water and clay content of the soil on the metal uptake by maize plants, Maize (Zea Mag's L.) was grown during 30 days on two soils, an acidic sandy soil and the same soil amended with 5% polder clay, These soils were continuously irrigated with synthetic irrigation water before and during plant growth, The dry matter yield of maize decreased and heavy metal concentrations in the plant tissue increased with increasing heavy metal concentration in the irrigation water. A higher C.O.D. concentration in the irrigation water also resulted in an overall increase of the dry matter yield and metal concentrations in the plant tissue. Addition of 5% clay to the acidic soil reduced these effects. The clay content of the soil was by far the most important factor in controlling plant growth and metal uptake