YIELD, CHEMICAL COMPOSITION AND THE LEVEL OF ACCUMULATION OF HEAVY METALS IN THE VEGETATIVE MASS AND SEEDS OF MILK THISTLE (SILYBUM MARIANUM L.) IN DIFFERENT TYPES OF ORGANIC FERTILIZERRazanov S.F., Razanova A.M., Àmons S.E. and Gutsol G.V.
The article presents the results of research on the influence of organic fertilization of gray forest soils on the level of lead, cadmium, zinc and copper in sheet mass and seeds of milk thistle. When fertilizing with humus, the concentration of lead, cadmium, zinc and copper in the mass of the leaves of the milk thistle increased by 5.1%, 18.2%, 53.1% and 20.4%, respectively. When fertilizing with a sugar beet lime sludge compost, the concentration of lead, cadmium, zinc and copper in the leaf mass of the milk thistle increased by 25.9%, 13.6%, 10.2% and 10.5%, respectively. In the cultivation of milk thistle after green manure and leguminous perennial grasses, the concentration of lead decreased by 8.6% and 2.4 times, respectively, and of cadmium by 9.1% and 2.6 times. The concentration of zinc with the use of green manure (mustard) remained on the background of the control variant, while with the predecessor of alfalfa sowing it was 9.0 times lower. The concentration of copper in the leaf mass of milk thistle when grown after green manure was 1.05 times higher, and after the four-year predecessor of alfalfa - 6.1 times lower compared to the control. The results of the research also showed that the concentration of heavy metals in the leaves of milk thistle exceeded the MPC in all variants, except for the use of a four-year predecessor of alfalfa. Characterizing the concentration of heavy metals in the seeds of milk thistle it should be noted that this figure ranged from 0.5 mg kg-1 to 4.1 mg kg-1, cadmium -from 0.08 mg kg-1 to 0.68 mg kg-1, zinc - from 27 mg kg-1to 98 mg kg-1and copper -from 7.5 mg kg-1 to 19.2 mg kg-1. Comparing compliance of the concentration heavy metals with the maximum permissible levels (MPC) in the seeds of milk thistle, it should be noted that when used as fertilizer humus, sugar beet lime sludge compost and green manure, this figure was higher than the established norm, while growing this crop after four years, lower.