Changes in Soil Chemical Properties and Tomato Mineral Composition and Yield in Response to Municipal Solid Waste Compost

Environmental and economic problems of urban wastes and increasing loss of soil organic matter have necessitated production and application of fertilizers from municipal waste. Therefore، to investigate the effects of three types of urban municipal solid waste (MSW)، a field experiment was conducted on tomato with the following treatments: sulfurous granular compost with or without thiobacillus bacteria and powdery compost، all at five levels: 0، 15، 30، 45، 60 t/ha. The experimental was factorial with completely randomized block design in three replications and was conducted in Khorasan Razavi province، Iran، in 2008-2010. The results showed that application of MSW compost decreased soil pH، but increased soil electrical conductivity (ECe)، sulfate concentrations in soil solution، and soil organic carbon. With continuation of the experiment، after initial decreas، pH of soils gradually increased. In contrast، soil salinity، sulfate concentrations in soil solution، and soil organic carbon were reduced after the initial increase. The use of sulfurous granular compost (with and without thiobacillus) increased ECe، soil organic carbon، and sulphate concentrations in soil solution and decreased soil pH more than the powdery compost. The highest tomato yield was obtained from the treatment with 45 t/ha MSW. Sulfurous granular MSW was superior to the others، such that the use of this compost increased tomato yield by 40% compared to the control. Also، K and Zn concentrations in tomato leaves increased with increase in the rate of MSW، but Mn concentrations was reduced significantly (P <0. 05).