CHANGES IN CONCENTRATION OF HEAVY METALS IN SOILS OF MIDDLE AMUR LOWLAND UNDER CONDITIONS OF LONG PERIOD OF AGRICULTURAL USE

Abstract

Relevance of the research is caused by the need to assess the ecological state of the restored arable soils located in the border areas of the Middle Amur Lowland. The study was conducted on the example of the Leninsky district of the Jewish Autonomous Region. Mostly in this region, Chinese farmers grow soybeans. Large number of mineral fertilizers, plant growth promoters and plant protection chemicals are used for cultivation of soybeans, which leads to degradation of agricultural soils. The aim of the research is to analyze the changes in concentrations of heavy metals in the soils of the Middle Amur Lowland during long-term agricultural use. Object: non-ameliorated and ameliorated meadow-gley arable soils used in agricultural land turnover. Methods: atomic absorption spectrometry method on the «Solaar 6M» spectrometer and calculation of total soil contamination coefficients. Results. The study showed that the change in concentrations of heavy metals of soils of the Middle Amur Lowland during prolonged agricultural use could be influenced by atmospheric moisture of the summer-autumn period. It is shown that in reclaimed soils by the end of the agricultural season there is a decrease in the content of heavy metals and in the total pollution coefficient, while in untreated soils – the opposite process – the increase in pollution. The authors have studied the influence of the extent of flooding of the floodplains on humus content and soil acidity, which determine the migration, and the formation of concentration series of heavy metals. In dry years, metal concentrations remained virtually unchanged, during the flood period (2013–2014), with heavy precipitation the processes leading to increase in concentrations of zinc, lead and copper prevailed. Flooding of soils changed the content of heavy metals due to mechanical runoff, decrease of humus content and change of soil acidity.

Keywords

• middle amur lowland
• meadow-gley soils
• heavy metals
• border area
• drainage melioration