BASIC PROPERTIES OF SOD-PODZOLIC SOIL OF NORTH TERRITORIES OF TYUMEN REGION - Ecological Consequences of Increasing Crop Productivity - page 74

Phosphorus is available in mobile forms H 2 PO 4 − и HPO 4 − ; it is contained in the
soil in large amount. Its accumulation is conspicuous over time: the maximum was
observed in 2011 and the minimum in 2009 (Figure 8.3).

FIGURE 8.3 Mobile forms of phosphorus in the soil of experimental site (H 2 PO 4 − и HPO 4 − ).

The humus content (I.V. Tyurin method in modifi cation of V.N. Simakov) in the
soil is not high and it varied slightly: year 2009—1.86 percent, year 2010—1.45 per-
cent, year 2011—1.76 percent.
The total content of the chemical elements (As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn,
Mo, Ni, Pb, Sb, Sr, Zn) was estimated in soil samples, as well as their stationary and
mobile forms, by atomic emission methods of inductively coupled plasma on the spec-
trometer OPTIMA-7,000 DV (Perkin Elmer).
According to research years average data on the total composition, it was found
that the topsoil contained, mg/kg: As—16.95 ± 0.18; Ca—456.00 ± 18.66; Cd—6.83
± 0.00; Co—16.85 ± 0.00; Cr—16.43 ± 0.00; Cu—0.99 ± 0.19; Fe—301.73 ± 21.62;
Mg—288.93 ± 29.66; Mn—96.65 ± 1.97; Mo—16.23 ± 0.00; Ni—17.04 ± 0.64; Pb—
25.71 ± 1.64; Sr—1.89 ± 0.12; Zn—21.72 ± 1.28.
The reference points, such as Clarke for chemical elements, are necessary for the
detection of natural soil-geochemical changes and correct assessment of the soil com-
position of elements, as well as hygienic standards: maximum and approximate per-
missible concentration (MPC) and APC. The study used the conventional world soil
Clarke, proposed by D.P. Malyuga [12].
As a result of determination of chemical substance concentrations (C с ) in soil, it
was found that chemical elements form two groups in background sample compared to
conventional world Clarke [6]. The excess over the MPC is not revealed.