The effect of waste compost on soil properties and heavy metal content of plant and soils with different pH level

The waste compost, derived from city solid waste, are commonly used as an organic soil regulator and a fertilizer in agriculture areas in many countries. However, the waste compost may cause some negative effects in agriculture areas. The heavy metal and salt contents of waste composts are one of the factors that must be known before using them in agriculture areas. In this study, the effects of the waste compost on some properties of soil with different pH, heavy metal content of soil and heavy metal content of plant grown on it (barley). The study was carried out as pot experiment with three replications. The waste compost was applied to the pots in the rates of 0, 5, 10, 15 t da-1 (dry weight). According to the results of study, compost application significantly increased the Cu and Zn contents of the soils. However, compost application didn't cause an important increase in the contents of Pb, Ni, Mn and Fe. Application of waste compost increased Cu and Zn contents of the plants significantly (P<0.01), but it had no effect on Pb, and Ni contents of plants. None of the compost application has increased heavy metal content above the upper limit values in both soil and plants. According to soil-plant ratio, plants grown on asidic soils had the highest level of heavy metal contents (in the all heavy metals). According to the study results, the waste compost application increased organic carbon, electrical conductivity (EC), cation exchange capacity (CEC) and pH (in acidic soils) in all soils. The compost application increased the salt content of the soil significantly (P <0.01), although the soil salt contents did not exceed the limit values. The research results showed that the waste compost which was used in study, is a material that can be used as Zn and Cu source in the fields where the nutrition element deficiency is observed. Also, in this study, it is revealed that the waste compost can be a good soil regulator due to the reason of its high organic matter content.