Physical properties of technosols at brown coal mine wastes in Eastern Siberia

Abstract

Recultivation of disturbed lands is very important task of science and practice at large territories of mining in Siberia as in other regions of Russia and other countries. Condition of physical properties of new-formed soils technozems (Technosols) is one of key questions for future state and usage of these lands. Changes of technozem's physical properties over time as part of land restoration and reclamation at Nazarovsky brown coal mine wastes (Eastern Siberia) were studied at one, three, ten and twenty years after the beginning of reclamation. Technozems here are artificially formed soil-like formations, which were made by the method of filling a material of fertile soil layer (fertile soil material or FSM) on the leveled surface of technogenic deposits. In the process of keeping of FSM and mechanical formation of technozems, there was a marked deterioration of the physical state of the FSM. In order to restore physical properties of FSM, perennial herbs were sown on recultivated areas. Studies of physical properties at different age sites have shown that at the meliorative stage they are gradually restored by climatic, biological and pedogenic factors. Exposure to perennial herbs contributes to soil structure formation and reduction of compounding density. In case of prolonged (10–20 years) meliorative action physical properties are restored to norm of soils which are widespread in this geographical zone. However, the sharp interface between FSM and technogenic material remains, which can have a negative impact on the water regime of recultivated soils. In order to accelerate formation of optimal physical conditions in technozems it is necessary to carry out deep, irrevocable loosening, which contributes to reduction of density of both bulk layer and underlying technogenic rock. Some physical properties (bulk density, porosity) were gradually improving over time reaching Haplic Chernozems levels at the reference site.