Effect of fertilizers and meliorants on the mobility of Cd, Pb, Cu and Zn in layers of leached heavy loam chernozem

The degree of mobility (DM) of Cd, Pb, Cu and Zn in arable (0–20 cm) and sub-arable (21–40 cm) soil layers was studied when applying phosphorus-potassium and nitrogen fertilizers on the background of liming and without it. It was revealed that the values of the DM of heavy metals (HM) were mainly lower during liming. In Cu, it varied less significantly compared to other metals. Fertilizers on the background of liming significantly lowered the Cd loss compared to the control, and without it – increased it in both layers. The vector of changes in the DM of the metal in the layers during liming depended on the doses of nitrogen in the NPK complex. Phosphorus-potash fertilizers reduced the DM of metals, and liming enhanced their effect. The values of DM decreased to a minimum with the use of PK- and NK-fertilizers with a low dose of nitrogen in liming conditions and without it, and increased with a maximum dose of nitrogen. Liming increased the differences in the joint venture between the layers in the nitrogen-free versions, and significantly reduced them when applied. Liming did not change the location of the metals in terms of their DM under experimental conditions: Cd > Pb > Zn > Cu.