## 3 Results
### Correlation Between Landscape Patterns and Surface Water Quality  
#### 3.3.1 Landscape Composition and Surface Water Quality  
Correlation analysis showed that the _PLAND_ of farmland was significantly negatively correlated (\(p<0.05\)) with TP and DO concentrations within the 1500 m radius buffer zones. _LPI_ began to have a significant positive correlation (\(p<0.01\)) with EC when the radius of the buffer zone was larger than 1500 m. Within the 200 m radius buffer zones, _PLAND_ and _LPI_ of forest land had significant negative correlations (\(p<0.05\)) with COD concentration, and _LPI_ had a significant positive correlation with EC (\(p<0.05\)). The landscape indices of grassland had no significant correlation with any surface water quality indicators, as the area of grassland was quite small in the study area. For the urban area, _PLAND_ had significant positive correlations (\(p<0.05\)) with COD, TP, EC, and the general surface water quality in 2000 m radius buffer zones. _LPI_ also had significant positive correlations with NH\({}_{3}\)-N, TP, EC, and the general surface water quality within 2000 m radius buffer zones (Table 3).  
\begin{table}
\begin{tabular}{c c c} \hline
**Surface Water Quality Indicators** & **Principal Component 1** & **Principal Component 2** \\ \hline COD & 0.42 & 0.66 \\ NH\({}_{3}\)–N & 0.74 & 0.11 \\ TP & 0.85 & 0.01 \\ DO & \(-\)0.32 & 0.81 \\ EC & 0.78 & \(-\)0.15 \\ Variance contribution rate (\%) & 42.98 & 42.42 \\ Accumulating contribution rate (\%) & 42.98 & 85.40 \\ \hline \end{tabular}
\end{table}
Table 2: The capacity and variance contribution rate of the principal components.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Radius (m)**} & \multirow{2}{*}{**Indicator**} & \multicolumn{2}{c}{**Farmland**} & \multicolumn{2}{c}{**Forest Land**} & \multicolumn{2}{c}{**Grass Land**} & \multicolumn{2}{c}{**Urban Area**} \\ \cline{3-10}  & & **PLAND** & **LPI** & **PLAND** & **LPI** & **PLAND** & **LPI** & **PLAND** & **LPI** \\ \hline \multirow{4}{*}{200} & COD & \(-\)0.33 & \(-\)0.32 & \(-\)0.60 * & \(-\)0.60 * & — & — & 0.43 & 0.39 \\  & NH\({}_{3}\)–N & \(-\)0.07 & \(-\)0.07 & \(-\)0.40 & \(-\)0.40 & — & — & 0.13 & 0.14 \\  & TP & \(-\)0.40 & -0.31 & 0.01 & 0.12 & — & — & 0.29 & 0.14 \\  & DO & \(-\)0.15 & \(-\)0.25 & 0.07 & 0.27 & — & — & \(-\)0.12 & \(-\)0.06 \\  & EC & \(-\)0.25 & \(-\)0.34 & \(-\)0.24 & 0.55 * & — & — & 0.29 & 0.13 \\  & Score 1 & \(-\)0.35 & \(-\)0.32 & \(-\)0.43 & \(-\)0.39 & — & — & 0.37 & 0.33 \\ \hline \multirow{4}{*}{600} & COD & 0.09 & \(-\)0.07 & \(-\)0.15 & \(-\)0.15 & \(-\)0.20 & \(-\)0.20 & 0.20 & 0.31 \\  & NH\({}_{3}\)–N & 0.04 & \(-\)0.04 & \(-\)0.36 & \(-\)0.33 & \(-\)0.30 & \(-\)0.30 & 0.25 & 0.20 \\  & TP & \(-\)0.45 & \(-\)0.42 & -0.32 & \(-\)0.28 & \(-\)0.30 & \(-\)0.30 & 0.43 & 0.41 \\  & DO & 0.57 * & 0.46 * & \(-\)0.01 & \(-\)0.003 & 0.50 & 0.50 & \(-\)0.38 & \(-\)0.32 \\  & EC & \(-\)0.25 & \(-\)0.21 & \(-\)0.35 & \(-\)0.33 & \(-\)0.20 & \(-\)0.20 & 0.45 * & 0.42 \\  & Score & \(-\)0.10 & \(-\)0.20 & \(-\)0.37 & \(-\)0.32 & \(-\)0.40 & \(-\)0.40 & 0.39 & 0.38 \\ \hline \multirow{4}{*}{1000} & COD & 0.12 & 0.06 & \(-\)0.29 & \(-\)0.26 & \(-\)0.57 & \(-\)0.54 & 0.25 & 0.23 \\  & NH\({}_{3}\)–N & 0.09 & 0.08 & \(-\)0.34 & \(-\)0.39 & \(-\)0.21 & \(-\)0.11 & 0.27 & 0.27 \\  & TP & \(-\)0.44 & \(-\)0.27 & \(-\)0.27 & \(-\)0.29 & \(-\)0.11 & 0.00 & 0.40 & 0.43 \\  & DO & 0.35 & 0.39 & \(-\)0.22 & \(-\)0.14 & 0.39 & 0.43 & \(-\)0.33 & \(-\)0.34 \\  & EC & 0.10 & 0.13 & \(-\)0.41 & \(-\)0.43 & \(-\)0.36 & \(-\)0.43 & 0.40 & 0.37 \\  & Score & \(-\)0.04 & -0.03 & \(-\)0.36 & \(-\)0.40 & \(-\)0.43 & \(-\)0.36 & 0.40 & 0.39 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Correlations between _PLAND_, _LPI_, and surface water quality indicators.