The content of heavy metals (lead and cadmium) in soils and plants of non-conventional forage crops and their ecological and toxicological assessment in forest steppe of Eastern Siberia

The researches on heavy metals identification conducted in 2014-2016 in soils and plants of rare forage crops in the forest-steppe of the region showed high efficiency of green and dry material: respectively 38-870 and 92-176 c/hectare (on av-erage in three years) with an exit of fodder units to 175-86 c/hectare. Power efficiency made thus to 179-84 GJ /hectare. Introduced plants accumulate a large number of organic substances, have high ecological efficiency. Arable lands experience con-siderable anthropogenous strain connected with emissions in the environment of the heavy metals (HM) by industrial enterprises, combined heat and power plant and motor transport. The Purpose of researches was ecological and -toxicological as-sessment of the content of lead and cadmium in soils and solid of one-year forage crops of the for-est-steppe of Eastern Siberia and monitoring of the contents during the main periods of their vegeta-tion. It was revealed that the amount of lead and cadmium in the soil during the main periods of de-velopment of rare forage crops was low in compari-son with UEC (mg/kg). The tendency of reduction of their concentration in soils from the beginning by the end of vegetation was noted: 2.--8.0% o f lead, and 19-21 % of cadmium. In the initial stage of vegetation of cultures the content of lead averaged 4.75-2.26 mg/kg of solid (at UEC of 8 mg/kg), i.e. 40.6-71.7 % lower than optimum quantity. During shoots formation - seeds appearance in cultures the content of compound of lead made 3.9- 1.44 mg/kg that was lower than UEC for 50.5- 82 %. The concentration of compounds of cadmium in vegetable samples of forage crops averaged to 0.48-0.20 mg/kg (at UEC of 0.5 mg/kg). The con-tent of cadmium was the greatest in the period of the beginning of growth and the development of plants (0.49-0.40 mg/kg), the smallest was during cleaning of green material (0.27-0.20 mg/kg) in payza and sugar sorghum (the UEC is 46-60 % lower). Rather high content of cadmium in annual clover in relation to UEC during vegetation was es-tablished. The greatest number of compounds of cadmium was noted in the period of the beginning of bud formation (0.45) the smallest was during blossoming (0.28 mg/kg of solid) that in limits and the UEC for 10-44 % was lower.