Copper content in soils of agrarian landscapes of Omsk Irtysh region

The aim of the study was to establish the regularities of the content and distribution of tightly bound and mobile forms of copper in different types of soils of the southern taiga, forest-steppe and steppe of the Omsk Irtysh region. In 2008-2012 incisions were laid and soil samples were taken from genetic horizons. The content of acid-soluble copper in 5M HNO3 and its mobile form in 1 n. of ammonium acetate buffer with pH 4.8 according to Krupskiy and Aleksandrova was determined in the soils. In light and medium loamy soddy-podzolic and gray forest soils, little copper was found: 4.8-7.7 and 5.7-7.2 mg/kg, respectively, in leached chernozems - up to 17 mg/kg. Its average content in the humus level of the southern forest-steppe and steppe was higher: in chernozems - 19.3, in meadow-chernozem soils - 20.5, in solonetz - 21.3 mg/kg. A strong correlation of the copper content in the humus horizons of the soils to its content in the parent rocks (r = 0.83) has been established. For a layer of 0-20 cm of soils, the dependence of the amount of trace element on the content of physical clay (r = 0.85), silt (r = 0.75), humus (r = 0.50), cation exchange capacity (r = 0.75) was determined. The distribution of copper over soil profiles was influenced by the same factors with a weaker connection with silt and humus. The content of mobile copper in soddy-podzolic, gray forest soils, leached chernozems (0.8-1.1 mg/kg) is estimated as medium and high. In the soils of the southern forest-steppe and steppe agrarian landscapes, the copper content is low (0.05-0.23 mg/kg). A significant influence of the environment reaction on the content of mobile copper in soils from different zones (r = -0.71) was established. In the 0-20 cm layer of forest-steppe and steppe soils, the amount of mobile copper depended on the content of its tightly bound form; the distribution of the trace element along the soil profiles was also determined by the content of silt and physical clay.