Influence of heavy metals on agrochemical indicators of the South Ural soils

The results of a study on the effect of heavy metals on soil fertility in various regions of the Chelyabinsk region are presented. As a result of the large-scale removal of basic nutrients with crop yields and the lack of necessary measures to compensate them, the balance of nutrients in all the studied soils is negative. The content of heavy metals due to anthropogenic pollution in some soils exceeds the permissible value, which leads to low content of both hydrolyzable nitrogen and extractable phosphorus, at high content of gross forms. The condition of heavy metals in the soil solution and the nature of their distribution in the arable horizons are affected both by granulometric and chemical composition of soils, the composition and properties of organic humus compounds. The analysis of the studied soils has shown that the content of humus in arable soils and virgin soil in all studied areas of the Chelyabinsk region tends to decrease. This is due not only to the low level of organic matter entering the soil, but also to the influence of heavy metals on the binding of humic acids and their transformation into humates. The availability of nutrients is influenced by the reaction of the soil solution in acid soils; even these small doses of mineral fertilizers cannot be used by plants.