Effects of the Composition and Properties of Soils and Soil-Sand Substrates Contaminated with Copper on Morphometric Parameters of Barley Plants

In a multifactorial vegetation experiment, the effect of the composition and properties of soils and soil-sandy substrates contaminated with various doses of copper acetate on the morphometric parameters of spring barley seedlings was studied. It has been shown that the germination and vigor of seed germination, as well as the length of roots, aboveground parts, and dry biomass of plants depend in a complex way on the concentration of Cu in soils and substrates, as well as their buffering capacity to heavy metals. The presence of two mechanisms of Cu influence on plant development was established: metabolic at С_Cu < 500 mg/kg of soil and diffusion at С_Cu > 500 mg/kg. Using methods of regression analysis on experimental data, a multiple regression equation was obtained that combines morphometric parameters of plants, concentration of Cu in the substrates, and the buffering capacity of soils to heavy metals. On its basis, in the coordinates of soil buffering capacity – Cu concentration, a curve of values f the maximum permissible concentration of Cu in soils in the concentration range from 17 to 2047 mg/kg. It makes the possibility to separate the zone of permissible development of barley plants (reduction of morphometric parameters by no more than 15%) from the zone of exceeding the accepted value of maximum permissible concentration of Cu. Thus, maximum permissible concentration of Cu is considered not as a fixed value, but as a function of Cu concentration, soil buffering capacity, and plant species.