## 3 Results
### The Influencing Factors of Rs among Three Plot Types under Different Sampling Scales  
Figure 3 displays the regression relationship between Rs and several environmental factors at different sampling scales. Among them, the relationships between Rs and SLA, TP, and AN were weak at the 5 m \(\times\) 5 m scale (\(p>0.05\), Figure 3\(f\),i), and the relationship between Rs and other factors was more obvious (\(p<0.05\), Figure 3). At the 10 m \(\times\) 10 m scale, except for SLA, other influencing factors were significantly correlated with Rs (\(p<0.05\), Figure 3). Figure 2: Comparison of soil respiration (**a**), soil properties (**b**–**k**), and plant traits (**l**–**t**) in different plot types and at different sampling scales. Uppercase letters indicate significant differences between plots (\(p<0.05\)), while “**” indicate significant differences between sampling scales in specific plots (\(p<0.05\)). SWC: Soil water content; ST: Soil temperature; pH: Soil pH; AP: Soil available phosphorus; TP: Soil total phosphorus; TN: Total nitrogen content; SOC: Soil organic carbon content; AN: Soil ammonium nitrogen; NN: Soil nitrate nitrogen; SSC: Soil salinity content; H\({}_{\max}\): Maximum plant height; LL: Leaf length; LW: Leaf width; LT: Leaf thickness; LDMC: Leaf dry matter content; SLA: Specific leaf area; LPC: Leaf phosphorus content; LNC: Leaf nitrogen content; LCC: Leaf carbon content. The results of RDA and variation partitioning showed that plant traits (H\({}_{\text{max}}\), LL, and LP) at the 5 m \(\times\) 5 m scale explained 17% of the spatial variation of Rs, and soil nutrients (AP and NN) and plant traits explained 49% of the spatial variation (Figure 4). At the sampling scale of 10 m \(\times\) 10 m, soil microclimate (SWC), soil nutrients (pH, AP, and NN) and plant traits (LT) jointly explained 51% of the spatial variation of Rs. Among them, soil microclimate and soil nutrients accounted for a large proportion (32% and 16%, respectively), and plant traits explained 3% of the variation of Rs. The spatial change of Rs explained by soil nutrients and plant traits at both scales was significant (\(p<0.05\)), while soil microclimate only explained a large part of the variation of Rs at the 10 m \(\times\) 10 m scale (\(p<0.05\)). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{2}{c}{**Plot 1**} & \multicolumn{2}{c}{**Plot 2**} & \multicolumn{2}{c}{**Plot 3**} \\ \cline{2-7}  & **5 m**\(\times\) **5 m** & **10 m**\(\times\) **10 m** & **5 m**\(\times\) **5 m** & **10 m**\(\times\) **10 m** & **5 m**\(\times\) **5 m** & **10 m**\(\times\) **10 m** \\ \hline Soil respiration & 58.0 & 52.8 & 41.9 & 41.7 & 37.0 & 35.4 \\ Maximum plant height & 29.3 & 16.0 & 53.8 & 62.4 & 55.4 & 31.9 \\ Leaf length & 29.0 & 24.5 & 88.3 & 81.5 & 29.3 & 25.0 \\ Leaf width & 26.8 & 32.3 & 46.3 & 37.1 & 29.6 & 18.1 \\ Leaf thickness & 20.0 & 14.4 & 34.9 & 55.3 & 24.1 & 17.0 \\ Leaf dry matter content & 12.8 & 6.1 & 17.7 & 22.4 & 23.9 & 21.4 \\ Specific leaf area & 21.9 & 19.0 & 28.6 & 19.6 & 27.8 & 13.5 \\ Leaf carbon content & 11.9 & 5.4 & 13.3 & 13.7 & 17.8 & 11.6 \\ Leaf nitrogen content & 12.3 & 7.7 & 16.2 & 12.7 & 26.0 & 11.2 \\ Leaf phosphorus content & 15.1 & 10.0 & 21.1 & 14.7 & 24.9 & 14.0 \\ Soil organic carbon & 27.1 & 14.1 & 52.7 & 31.0 & 35.6 & 25.2 \\ Soil water content & 8.0 & 8.8 & 3.5 & 4.3 & 3.7 & 4.1 \\ Soil temperature & 28.3 & 25.7 & 39.0 & 25.6 & 33.7 & 23.4 \\ Soil available phosphorus & 4.5 & 1.6 & 2.5 & 1.5 & 2.8 & 1.4 \\ Soil salinity content & 66.8 & 33.3 & 40.1 & 22.2 & 26.9 & 23.1 \\ Soil pH & 31.8 & 20.0 & 18.1 & 15.9 & 29.6 & 11.5 \\ Soil total phosphorus & 19.5 & 9.3 & 28.7 & 32.7 & 46.1 & 22.3 \\ Total nitrogen content & 37.5 & 17.0 & 33.9 & 17.1 & 48.8 & 27.2 \\ Soil ammonium nitrogen & 31.4 & 25.9 & 28.0 & 16.1 & 49.8 & 20.6 \\ Soil nitrate nitrogen & 55.4 & 33.1 & 22.3 & 10.9 & 43.6 & 25.8 \\ \hline \hline \end{tabular}
\end{table}