Бюллетень Почвенного института им. В.В. Докучаева (Jul 2016)
The organic and organo-mineral components of phosphate regime of eroded soils in the centre of Russian Plain
Abstract
The phosphate state of arable layers of eroded soils from the Centre of Russian plain was investigated. The investigation was conducted at the background of the parameters of sorption of phosphate-ion from different components of the organic matter. In terms of the assessment of the phosphate state of eroded soils was shown the informativity of phosphate-ion sorption characteristics of organic and organo-mineral fractions. The organic and organo-mineral fractions of the arable layers of non-eroded soils from the zonal range are characterized by the high level of phosphorus mobility and their ability to support the constant level of phosphates available for plants: agrosoddy-podzolic soils (17.9 ± 1.0 mg/kg) → agrogray soils (16.4 ± 1.7 mg/kg) → agrochernozems (15.5 ± 1.1 mg/kg). Рoc forms a range: agrosoddy-podzolic soils (96.4 ± 0.5 mg/kg) → agrogray soils (118.2 ± 3.0 mg/kg) → agrochernozems (140.7 ± 3.1 mg/kg). In the Centre of Russian Plane, among the investigated zonal soils with maximal humus saturation of clay fractions, the soils with full profile within this complex are the most sustainable to erosion in conditions of particular ecologic situation. Agroecological features of eroded soils are increased sorption of phosphate-ion. The sorption characteristics alter in the direction of increasing the strength of phosphate-ion binding, reducing the amount of available phosphorus to plants: for agrosoddy-podzolic soils Рlab - 10.8 ± 0.2 mg/kg, for agrogray soils - 9.2 ± 0.6 mg/kg, for agrochernozems - 9.1 ± 1.8 mg/kg. Рoc forms a range: agrosoddy-podzolic soils (229.6 ± 3.5 мг/кг) → agrogray soils (230.9 ± 1.4 мг/кг) → agrochernozems (275.0 ± 4.6 mg/kg). This is due to the exposure of lower layers less humified, clay fractions which are enriched in the smectite component, contributing to an increase in the quantity of sorbed phosphorus soil solid phase. Therefore, in general, eroded soils are characterized by significantly lower sustainability, and, in particular, energetically less balanced phosphorus cycle.
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