# Biogeochemical State of Salinized Irrigated Soils of Central Fergana (Uzbekistan, Central Asia)
## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{\begin{tabular}{c} **Soil** \\ **Section No** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Depth,** \\ **cm** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **pH** \\ **H2O** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **CaCO\%, \%** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **MgCO\%, \%** \\ \end{tabular} } & \multirow{2}{*}{**TOC, \%**} & & \multicolumn{3}{c}{**Bulk Gravimetric**} & \multicolumn{3}{c}{**Available Gravimetric**} \\  & & & & & & & **Concentrations, \%** & & **Concentrations, mg kg\({}^{-1}\)** \\ \hline \multirow{3}{*}{\(1\)} & 0–29 & 7.01 & 5.60 & 2.10 & 0.66 \(\pm\) 0.05 & 5.50 & 0.12 & 0.31 & 1.86 & 17.3 & 19.6 & 187 \\  & 29–44 & 7.05 & 7.20 & 2.68 & 0.54 \(\pm\) 0.02 & 5.40 & 0.10 & 0.23 & 1.77 & 12.1 & 17.8 & 135 \\ \hline \multirow{3}{*}{\(12\)} & 0–28 & 7.10 & 3.24 & 2.21 & 0.69 \(\pm\) 0.05 & 4.92 & 0.14 & 0.32 & 1.90 & 18.5 & 20.1 & 210 \\  & 28–42 & 7.15 & 4.31 & 2.67 & 0.56 \(\pm\) 0.05 & 5.09 & 0.11 & 0.25 & 1.81 & 13.2 & 18.5 & 143 \\ \hline \multirow{3}{*}{\(20\)} & 0–30 & 7.30 & 7.50 & 2.30 & 0.48 \(\pm\) 0.04 & 5.33 & 0.09 & 0.30 & 1.73 & 15.2 & 17.8 & 175 \\  & 30–45 & 7.30 & 7.60 & 2.20 & 0.37 \(\pm\) 0.03 & 5.28 & 0.07 & 0.22 & 1.65 & 11.0 & 16.2 & 118 \\ \hline \multirow{3}{*}{\(24\)} & 0–30 & 7.10 & 7.20 & 2.56 & 0.44 \(\pm\) 0.05 & 5.50 & 0.08 & 0.26 & 1.70 & 14.9 & 17.0 & 168 \\  & 30–46 & 7.15 & 7.40 & 2.70 & 0.37 \(\pm\) 0.05 & 5.28 & 0.07 & 0.21 & 1.61 & 10.6 & 15.7 & 112 \\ \hline \multirow{3}{*}{\(28\)} & 0–35 & 7.10 & 6.78 & 2.80 & 0.81 \(\pm\) 0.08 & 5.79 & 0.14 & 0.34 & 1.94 & 21.5 & 20.7 & 229 \\  & 35–54 & 7.25 & 6.90 & 2.95 & 0.53 \(\pm\) 0.06 & 5.30 & 0.10 & 0.32 & 1.85 & 14.7 & 17.2 & 192 \\ \hline \multirow{3}{*}{\(35\)} & 0–30 & 7.20 & 5.90 & 2.35 & 0.55 \(\pm\) 0.05 & 5.00 & 0.11 & 0.30 & 1.86 & 16.8 & 17.1 & 172 \\  & 30–43 & 7.25 & 6.45 & 2.50 & 0.45 \(\pm\) 0.08 & 5.62 & 0.08 & 0.25 & 1.75 & 11.2 & 12.0 & 114 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Soil agrochemical properties. general, the content of nutrients is higher in old, irrigated soils than in recently irrigated ones. The biological accumulation of ammonium in superficial soil horizons is more pronounced than the mobile forms of phosphorous and potassium. The pH is neutral or slightly alkaline which is an indicator of the absence of sodium salinization [26]. The content of carbonate of calcium and magnesium is also not very high, which is caused by year by year leaching of these materials from soil under the influence of the irrigation process. Data on soil particle distribution are given in Table 2. The soil investigated belongs to the loamy or sandy loam class according to the texture triple (Figure 3). Fine particle content is increased in toposils in comparison to middle and deep soil horizons. It could be the result of colmatage (accumulation of fine particles in the toposit from turbid water with suspended matter) [37]. In most Eurasian soils, the content of fine particles strongly depends on the humus content, but in this case, a very low humus content did not affect the granulometric composition of the soil [26]. One could assume that the vertical distribution of fine particles is inherited from the parent materials and may therefore be non-homogeneous, but the content of sand and fine sand fractions shows no heterogeneity, hence fine particles were accumulated during soil formation, in particular under the influence of irrigation. The presence of the fraction with diameter 0.05-0.01 mm in soils and sediments is one of the key indicators of loess origin of material [38]; thus, our soils belong to the loess soil group