## 3 Results
### Comprehensive Index Score and Evaluation Analysis  
Three principal components were designated by PCA for overall soil fertility, water and fertilizer use efficiency, and economic yield and efficiency of cabbage by taking eigenvalues >1. As can be seen from Table 4, the contribution of PC1 was 59.65%, economic yield, water use efficiency, and fertilizer bias productivity index had a heavy load on PC1 and the contribution of PC2 was 19.11%. Overall soil fertility had the highest load of 0.864 on PC2, and average moisture content and economic efficiency had a larger load on PC3. From this, it can be inferred that cabbage water utilization, fertilizer bias productivity, overall soil fertility, average water content, and economic efficiency mainly influenced the score and evaluation of different treatments.  
By performing a principal component analysis and calculating the score for each index, the comprehensive evaluation D-values were obtained and ranked by combining the affiliation functions u(X\({}_{1}\)), u(X\({}_{2}\)), and u(X\({}_{3}\)) with weight processing (Table 5). After comprehensive performance analysis in terms of overall soil fertility, enzyme activity, water and fertilizer use efficiency, and economic yield and efficiency, the overlay black and white mulch (WBCM) treatment had the highest overall evaluated D value, followed by  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Project** & **PC1** & **PC2** & **PC3** \\ \hline Total enzymatic activity & \(-\)0.691 & 0.489 & 0.322 \\ Total soil fertility & 0.437 & 0.864 & \(-\)0.056 \\ Average temperature & \(-\)0.841 & 0.349 & 0.059 \\ Average water & \(-\)0.332 & \(-\)0.496 & 0.771 \\ Content & 0.946 & 0.100 & 0.195 \\ Economic yield & 0.667 & 0.365 & 0.623 \\ Water utilization & 0.987 & \(-\)0.125 & \(-\)0.022 \\ Fertilizer partial & 0.986 & \(-\)0.128 & \(-\)0.025 \\ productivity & & & \\ Eigenvalues & 4.772 & 1.528 & 1.132 \\ Contribution rate & 59.651 & 19.105 & 14.147 \\ Cumulative & & & \\ contribution rate & 59.651 & 78.756 & 92.903 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Principal component analysis rotation factor loading, eigenvalues, and cumulative variance contribution.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Treatment** & **Yield** & **Economic Yield** & **Economic** & **Total Income/** & **Mulch Cost/** & **Economic Income/** \\  & **(t/ha)** & **(t/ha)** & **Coefficient** & **(Million RMB/ha)** & **(RMB/ha)** & **(Million RMB/ha)** \\ \hline WCM & \(99.91\pm 5.4\)  & \(0.75\pm 0.08\)  & \(1100\) & \(2.49\pm 0.29\)  & \(75.81\pm 7.2\)  & \(3.04\pm 0.61\)  \\ WBM & \(114.14\pm 6.3\)  & \(0.68\pm 0.11\)  & \(2.23\pm 0.42\)  & \(89.23\pm 7.0\)  & \(3.60\pm 0.91\)  \\ BPM & \(122.73\pm 8.7\)  & \(0.67\pm 0.13\)  & \(2000\) & \(2.69\pm 0.22\)  & \(78.61\pm 5.2\)  & \(3.14\pm 0.33\) [FOOTNOTE:]Footnote : The the black biodegradable mulch (BBM) and permeable mulch treatment (BPM). The white biodegradable mulch (WBM), white common mulch (WCM), and black common mulch (BCM) treatments had the lowest overall evaluated D-values. Through the above analysis, the main reason could be the low water and fertilizer use efficiency and economic yield and efficiency.