Cadmium accumulation in soil and plants of soybean under the influence of mineral fertilizers

Heavy metals (HM) in excess are the pollutants of the biosphere. Their presence in agro-ecosystems and their dangerous symptoms depend both upon technogenic load and intensity of use of alien chemicals applied with fertilizers and other agrochemicals, which influence is due to the presence of pollutants in the composition of impurities, as well as an indirect effect upon physical and chemical soil processes. The aim of our research was to find out the\ effect of different doses of total and mobile forms of cadmium in artificially contaminated soil upon its content in plants in the micro field experiment on the meadow brown ashy soil, as well as the possibility to reduce cadmium intake into soybean harvest at high concentrations in the soil on the background of mineral fertilizers and without them. It was defined that fertilizers contributed to decrease concentration of cadmium in soil, and made it more accessible to plants, thus increasing the accumulation of cadmium in soybean plants. The experiment began on the territory of experimental fields of Research institute of agriculture “Primorsky” in 2014. The experimental scheme provided 7 variants. Forartificialsoilcontaminationtheauthorsusedsaltchemicalpurecadmiumindosesexceedingtwiceandfourtimesmaximumvalueofthemaximumpermissibleconcentration(MPC)forthesoil.Cadmiuminsoil,insoybeangrainandstrawwasdefinedbyatomicabsorptionspectrometryintheair-acetyleneflameonspectrometerAA-6200accordingtotheapprovedmethodicinstructions.Todefinecadmiummobileformsthesolutionof1Mnitricacidwasused. As a result of the study there was found out that soybean yield was reduced in the variants with the introduction of cadmium salts in comparison with the variants without salt application on the background of mineral fertilizers.It was revealed that on the background of the double dose of fertilizer and a quadruple dose of cadmium, the concentration of the gross form in the soil was 12.36 mg / kg, and mobile was 13.90 mg / kg, which corresponds to an increased dose of application, however, the concentration of cadmium in this variant was reduced in comparison with the variant with the same dose of cadmium, but without fertilization. Consequently, fertilizer can decrease cadmium concentration in soil. In the variants with application of cadmium into the soil in the background of fertilizer, cadmium concentration in plants was higher than in variants with cadmium application, but without fertilizer and it was for the straw 0.49-0.78 mg / kg, for grain 0.28-0. 50 mg / kg in the first case and 0.95-1.55 mg / kg for straw and grain it was 0.95-1.69 for the second case. It was defined that fertilizers contributed to the decrease of cadmium concentration in soil, and made it more accessible to plants, thus increasing the accumulation of cadmium in soybean plants.