# Short-Term Effects of Pine Plantations on Vegetation and Soil in Northern Mongolia
## 3 Results
### Changes in Chemical and Physical Properties of the Top Soil
#### 3.2.1 Changes in Chemical and Physical Properties of the Subsoil
\begin{tabular}{l c c c c c c c} \hline \hline
**Variables** & **Unit** & **BBS** & **NRS** & **STP** & **BDS** & **NFM** & **MGS** & **F Value** \\ \hline pH & & \(6.81\pm 0.02\,^{\mathrm{d}}\) & \(6.78\pm 0.03\,^{\mathrm{d}}\) & \(7.66\pm 0.01\,^{\mathrm{s}}\) & \(7.06\pm 0.01\,^{\mathrm{s}}\) & \(7.26\pm 0.01\,^{\mathrm{s}}\) & \(6.67\pm 0.03\,^{\mathrm{d}}\) & \(62.0\,^{\mathrm{s}}\) \\ AN (N-NO\({}^{-3}\)) & mg kg\({}_{-1}^{-1}\) & \(2.2\pm 0.34\,^{\mathrm{b}}\) & \(1.75\pm 0.19\,^{\mathrm{b}}\) & \(3.89\pm 0.39\,^{\mathrm{s}}\) & \(1.41\pm 0.05\,^{\mathrm{b}}\) & \(1.97\pm 0.19\,^{\mathrm{b}}\) & \(1.41\pm 0.05\,^{\mathrm{b}}\) & \(8.17\,^{\mathrm{s}}\) \\ OC & g kg\({}^{-1}\) & \(14.9\pm 2.33\,^{\mathrm{s}}\) & \(15.1\pm 7.33\,^{\mathrm{d}}\) & \(10.16\pm 1.82\,^{\mathrm{d}}\) & \(15.4\pm 0.71\,^{\mathrm{s}}\) & \(13.2\pm 1.92\,^{\mathrm{s}}\) & \(18.05\,^{\mathrm{s}}\) & \(1.21\,\mathrm{ns}\) \\ SOCs & mg h\({}^{-1}\) & \(23.1\pm 3.58\,^{\mathrm{d}}\) & \(24.3\pm 2.71\,^{\mathrm{d}}\) & \(16.92\pm 21\,^{\mathrm{d}}\) & \(24.77\pm 0.99\,^{\mathrm{d}}\) & \(21.1\pm 3.19\,^{\mathrm{d}}\) & \(29.5\pm 1.41\,^{\mathrm{d}}\) & \(1.44\,\mathrm{ns}\) \\ AP (P-O\({}_{\mathrm{s}}\)) & mg kg\({}^{-1}\) & \(31.1\pm 3.41\,^{\mathrm{d}}\) & \(27.1\pm 2.05\,^{\mathrm{d}}\) & \(15.4\pm 1.65\,^{\mathrm{d}}\) & \(19.8\pm 2.32\,^{\mathrm{b}}\) & \(24.14\pm 2.9\,^{\mathrm{d}}\) & \(208.30\,^{\mathrm{b}}\) & \(3.95\,^{\mathrm{s}}\) \\ AK (S(0.0)) & mg kg\({}^{-1}\) & \(88.4\pm 4.06\,^{\mathrm{d}}\) & \(84.1\pm 2.71\,^{\mathrm{d}}\) & \(59.6\,^{\mathrm{d}}\) & \(70.5\,^{\mathrm{d}}\) & \(70.5\,^{\mathrm{d}}\) & \(78.6\pm 2.71\,^{\mathrm{d}}\) & \(99.6\,^{\mathrm{d}}\) + & \(12.8\,^{\mathrm{s}}\) \\ Sand (\(2\)-0.05 mm) & \(\%\) & \(85.1\pm 25\,^{\mathrm{d}}\) & \(88.01\pm 21\,^{\mathrm{d}}\) & \(85.5\pm 0.42\,^{\mathrm{d}}\) & \(87.3\pm 0.36\,^{\mathrm{d}}\) & \(87.3\pm 0.47\,^{\mathrm{d}}\) & \(88.1\pm 0.27\,^{\mathrm{d}}\) & \(2.22\,\mathrm{ns}\) \\ Slit (0.05-0.002 mm) & \(\%\) & \(3.53\pm 0.76\,^{\mathrm{d}}\) & \(4.86\pm 0.2\,^{\mathrm{d}}\) & \(3.77\pm 0.34\,^{\mathrm{d}}\) & \(3.86\pm 0.44\,^{\mathrm{d}}\) & \(3.66\pm 0.29\,^{\mathrm{d}}\) & \(3.66\pm 0.24\,^{\mathrm{d}}\) & \(0.61\,\mathrm{ns}\) \\ Clixy (\(<\)0.002 mm) & \(\%\) & \(11.4\pm 0.68\,^{\mathrm{d}}\) & \(7.01\pm 0.4\,^{\mathrm{d}}\) & \(10.6\pm 0.33\,^{\mathrm{d}}\) & \(8.8\pm 0.09\,^{\mathrm{d}}\) & \(8.95\pm 0.36\,^{\mathrm{d}}\) & \(82.2\pm 0.09\,^{\mathrm{d}}\) & \(9.55\,^{\mathrm{ns}}\) \\ BD & g cm\({}^{-3}\) & \(1.55\pm 0.01\,^{\mathrm{s}}\) & \(1.6\pm 0.01\,^{\mathrm{s}}\) & \(1.59\pm 0.002\,^{\mathrm{d}}\) & \(1.6\pm 0.02\,^{\mathrm{s}}\) & \(1.58\pm 0.01\,^{\mathrm{s}}\) & \(1.63\pm 0.002\,^{\mathrm{s}}\) & \(4.54\,^{\mathrm{s}}\) \\ SM & \(\%\) & \(3.67\pm 0.51\,^{\mathrm{d}}\) & \(4.43\pm 0.1\,^{\mathrm{d}}\) & \(3.95\pm 0.27\,^{\mathrm{d}}\) & \(3.67\pm 0.25\,^{\mathrm{d}}\) & \(3.02\pm 0.28\,^{\mathrm{d}}\) & \(3.21\pm 0.03\,^{\mathrm{d}}\) & \(1.32\pm 0.03\,^{\mathrm{d}}\) & \(1.32\pm 0.03\,^{\mathrm{d}}\) \\ ST & \(\%\) & \(14.3\pm 0.26\,^{\mathrm{d}}\) & \(12.9\pm 0.4\,^{\mathrm{d}}\) & \(18.2\pm 0.25\,^{\mathrm{d}}\) & \(16.4\pm 0.51\,^{\mathrm{d}}\) & \(17.4\pm 0.49\,^{\mathrm{d}}\) & \(13.2\pm 0.41\,^{\mathrm{d}}\) & \(30.9\,^{\mathrm{s}}\) \\ \hline \end{tabular}   
* Notes: Values are mean \(\pm\) standard error, \(\@vec{\cdot}\)\(p<0.05\); \(\@vec{\cdot}\)\(surrounding the trend line denotes the 95% confidence interval. The intervals expand near the extremes of the pH, signifying more uncertainty in predictions for extremely high or low pH levels. Although the association is positive, the \(p\)-value (0.289) indicates that the correlation lacks statistical significance, perhaps due to the limited sample size (\(n=6\)). The trend line indicates that for each unit increase in the pH, the Shannon index rises by roughly 0.26 units, as shown by the regression slope. As the pH rises from 6.8 to 8.2, the Shannon index correspondingly increases, signifying that mildly alkaline soils (elevated pH) foster enhanced species diversity.