Ferrum concretions forms in the mollic gley soils of Low (Male) Polissya

In the humid conditions, the most common ground forms are the ferruginous ones: ferrum concretions, marsh ore, ocher spots, etc. Mollic gley soils are widely spread along the periphery of marshes and are formed under the influence of mollic and gley processes on various soil-forming rocks under conditions of sporadically pulsating water regime and excessive moisture under the meadow and swamp biocenoses. The ferrum concretions are characteristic of all genetic horizons of mollic gley soils, except for the soil-forming rock, and their content ranges from 3.3% in the mollic to 47.1% in the lower transitional horizon. The gross iron content in the fine mollic gley soils, as well as in the ferrum concretions forms, increases with depth, and the maximum values are characteristic of the lower transition horizon. The lowest values of the gross iron content are characteristic of the fine soil-forming rock (16.0 mg / 100 g soil) and the mollic soil (66.4 mg / 100 g soil). It was established that the gross chemical content of the ferrum concretions forms is dominated by the iron oxides with the highest content in the ferrum concretions of the mollic soils (48.75%). Also the ferrum concretions forms of iron are characterized by a rather high content of aluminum oxides (5.59–7.92%). The highest values of the accumulation coefficient are characteristic of the iron oxide (Kx = 7.21–2.58), which confirms the hypothesis of the dominant role of its compounds in the formation of the ferrum concretions forms.