# Biogeochemical State of Salinized Irrigated Soils of Central Fergana (Uzbekistan, Central Asia)
## 3 Results and Discussion
According to the obtained data, the content of Na\({}^{+}\) and Mg\({}^{2+}\) in genetic horizons of old-irrigated and newly irrigated meadow-takyr, meadow-saz soils varies between 0.42-2.57%. Their content in arable horizons is 0.71-0.92%. Concentrations of sodium and magnesium in genetic horizons of old-irrigated soils are practically equally located, but in general the quantity of Mg\({}^{2+}\) is more than Na\({}^{+}\). The gypsum content in agricultural soils results in limited water and nutrient retention and the potential for dissolution, primarily in response to irrigation [39]. The absence of Na\({}_{2}\)CO\({}_{3}\) in soil horizons and its presence in ground waters concerns the low stability of this chemical compound in soil porous media. The soil concentrations of water-soluble salts are quite important in the regulation of osmotic and physiological states of agricultural plants [40; 41] and should be taken into account in planning of land-use practices. The content of trace elements is given in Table 4. At the end of the table the lithosphere clarke is given for every chemical element in Table 4. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Soil** & **Depth, cm** & **Na\({}_{2}\)CO\({}_{3}\)** & **Ca(HCO\({}_{3}\))\({}_{2}\)** & **CaSO\({}_{4}\)** & **MgSO\({}_{4}\)** & **Na\({}_{2}\)SO\({}_{4}\)** & **NaCl** & **Bulk Salts Content** \\ \hline \multirow{8}{*}{1} & 0–29 & - & 0.015 & 0.236 & 0.214 & 0.023 & 0.014 & 0.502 \\  & 29–44 & - & 0.029 & 0.294 & 0.255 & 0.027 & 0.012 & 0.617 \\  & 44–67 & - & 0.016 & 0.296 & 0.235 & 0.021 & 0.012 & 0.580 \\  & 67–102 & - & 0.017 & 0.301 & 0.245 & 0.027 & 0.014 & 0.604 \\  & 102–132 & - & 0.020 & 0.408 & 0.245 & 0.027 & 0.019 & 0.719 \\  & Ground & \multirow{2}{*}{0.135} & 0.201 & 3.795 & 2.104 & 0.801 & 0.604 & 7.640 \\  & water, g L\({}^{-1}\) & & & & & & & \\ \hline \multirow{8}{*}{12} & 0–28 & - & 0.021 & 0.341 & 0.228 & 0.024 & 0.013 & 0.627 \\  & 28–42 & - & 0.031 & 0.338 & 0.275 & 0.024 & 0.011 & 0.679 \\  & 42–72 & - & 0.015 & 0.358 & 0.245 & 0.028 & 0.012 & 0.658 \\  & 72–131 & - & 0.016 & 0.421 & 0.256 & 0.038 & 0.014 & 0.745 \\  & 131–152 & - & 0.017 & 0.460 & 0.301 & 0.032 & 0.014 & 0.824 \\  & 152–200 & - & 0.020 & 0.478 & 0.310 & 0.038 & 0.018 & 0.864 \\  & Ground & \multirow{2}{*}{-} & 0.301 & 4.201 & 2.204 & 0.821 & 0.505 & 8.032 \\  & water, g L\({}^{-1}\) & & & & & & & \\ \hline \multirow{8}{*}{20} & 0–30 & - & 0.035 & 0.381 & 0.238 & 0.028 & 0.015 & 0.697 \\  & 30–45 & - & 0.039 & 0.341 & 0.301 & 0.027 & 0.015 & 0.723 \\ \cline{1-1}  & 45–62 & - & 0.038 & 0.328 & 0.304 & 0.038 & 0.064 & 0.772 \\ \cline{1-1}  & 62–97 & - & 0.051 & 0.438 & 0.333 & 0.041 & 0.014 & 0.877 \\ \cline{1-1}  & 97–120 & - & 0.058 & 0.470 & 0.337 & 0.041 & 0.020 & 0.926 \\ \cline{1-1}  & Ground & \multirow{2}{*}{0.100} & \multirow{2}{*}{0.585} & \multirow{2}{*}{4.308} & \multirow{2}{*}{2.308} & \multirow{2}{*}{0.841} & \multirow{2}{*}{0.644} & \multirow{2}{*}{8.786} \\ \cline{1-1}  & water, g L\({}^{-1}\) & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Content and amount of salts in irrigated meadow soils, %. The scandium content is lower than the clarke in the lithosphere. These rare elements do not show any trends in vertical soil distribution within the soil profile, in spite of the recently published fact of biogenic accumulation in some soils of boreal climatic belt [42]. According to [PERSON]'s data, scandium adsorbs very quickly in soils, making it similar to the alkaline earth elements [43]. The chromium content is also lower than the clarke but higher in sax soils than in takyr ones. According to some reports, chromium accumulation in soils may be associated with alluvial deposits and river waters [44], which is quite possible in the Fergana Valley. Mobility of cobalt increases in wet soils, in connection with what is the possible removal of this element in irrigation; in any case, its accumulation is at a level two times lower than clarke [45].