## 2 Materials and Methods
### Soil Enzyme Assay  
The soil enzyme activities were determined according to [15] and [17]. Specifically, soil sucrose activity was determined using 5 g of fresh soil (sieved to \(<\)1 mm), 15 mL of 8% glucose solution as substrates, 5 mL of 0.2 M phosphate buffer (in pH 5.5), and 5 drops of toluene; this mixture was incubated at 37.7 \({}^{\circ}\)C for 24 h. Then, the mixture was filtered and a 1 mL aliquot was transferred to a volumetric flask with 3 mL of 3,5-dinitrylsalicylate and then heated for 5 min. After reaching room \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample Sites** & **CK20** & **CK30** & **CK40** & **SC** \\ \hline Location & 36\({}^{\circ}\)52\({}^{\prime}\) N 109\({}^{\circ}\)21\({}^{\prime}\) E & 36\({}^{\circ}\)53\({}^{\prime}\) N 109\({}^{\circ}\)21\({}^{\prime}\) E & 36\({}^{\circ}\)52\({}^{\prime}\) N 109\({}^{\circ}\)21\({}^{\prime}\) E & 36\({}^{\circ}\)52\({}^{\prime}\) N 109\({}^{\circ}\)21\({}^{\prime}\) E \\ Slope aspect (\({}^{\circ}\)) & 18 & 15 & 10 & 15 \\ Slope degree (\({}^{\circ}\)) & NbyW10 & SkyW60 & NbyE12 & SkyW50 \\ Elevation (m) & 1258 & 1260 & 1318 & 1263 \\ pH & 8.30 \(\pm\) 0.13 & 8.41 \(\pm\) 0.10 & 8.33 \(\pm\) 0.06 & 8.48 \(\pm\) 0.17 \\ SBD (g/cm\({}^{3}\)) & 1.04 \(\pm\) 0.02 & 1.12 \(\pm\) 0.03 & 1.15 \(\pm\) 0.02 & 1.17 \(\pm\) 0.03 \\ SOC (g/kg) & 3.94 \(\pm\) 0.46 & 3.73 \(\pm\) 0.41 & 2.73 \(\pm\) 0.24 & 1.39 \(\pm\) 0.22 \\ TN (g/kg) & 0.49 \(\pm\) 0.06 & 0.46 \(\pm\) 0.06 & 0.44 \(\pm\) 0.05 & 0.19 \(\pm\) 0.05 \\ TP (g/kg) & 0.55 \(\pm\) 0.04 & 0.54 \(\pm\) 0.02 & 0.46 \(\pm\) 0.02 & 0.47 \(\pm\) 0.03 \\ FRB (kg/hm\({}^{2}\)) & 1518 \(\pm\) 47.12 & 2448 \(\pm\) 40.38 & 2605 \(\pm\) 32.74 & - \\ LB (kg/hm\({}^{2}\)) & 1233 \(\pm\) 23.65 & 990 \(\pm\) 8.77 & 719 \(\pm\) 10.09 & - \\ Gleason SR & 2.17 \(\pm\) 0.04 & 3.22 \(\pm\) 0.03 & 3.50 \(\pm\) 0.13 & - \\ CD (\%) & 71.12 \(\pm\) 3.82 & 78.22 \(\pm\) 1.32 & 80.44 \(\pm\) 2.96 & 40.29 \(\pm\) 4.05 \\ AGB (kg/hm\({}^{2}\)) & 11023 \(\pm\) 171.21 & 15130 \(\pm\) 103.12 & 14500 \(\pm\) 341.21 & 900 \(\pm\) 23.25 \\ \hline \hline \end{tabular}  
* CK and SC represent the _Caraguna horskinsii_ Kom and slope cropland. NbyW, SkyW, and NbyE represent North by West, South by West and North by east, respectively. SBD, SOC, TN, TP, FRB, Gleason SR, CD, and AGB represent soil bulk density, soil organic carbon, soil total nitrogen concentration, soil total phosphorus concentration, fine root biomass, litter biomass, species richness, canopy density, and aboveground biomass, respectively. All these indexes were measured in June, and soil properties were measured from the average of 0–20 cm soil layer.  
\end{table} 
Table 1: Characteristics of the sampling lands. temperature, the soil solution was quantified in an ultraviolet spectrometer subsystem (UVS) at 508 nm, and finally, the soil sucrase activity was expressed as mg glucose g\({}^{-1}\) soil h\({}^{-1}\). The soil catalase activity was determined by mixing 2 g of fresh soil, 5 mL of 0.3% H\({}_{2}\)O\({}_{2}\) as substrates, and 40 mL of distilled water in a triangular flask; the flask was then shaken for 20 min at 150 rpm and filtered immediately. Then, the filtrate was titrated with 0.1 mol L\({}^{-1}\) KMnO\({}_{4}\) in the presence of sulfuric acid. Finally, the soil catalase activity was expressed as mL 0.1 N KMnO\({}_{4}\) g\({}^{-1}\) soil h\({}^{-1}\). The soil alkaline phosphatase activity was determined by mixing 10 g of fresh soil, 2 mL of toluene, 10 mL of 0.05 M borate buffer at pH 9.6, and 10 mL of disodium phenyl phosphate solution. After being incubated at 37.8 \({}^{\circ}\)C for 2 h, the solutions were filtered, 0.5 mL of 2% 4-aminoantipyrine and 8% potassium ferrocyanide were added to the filtrate for color development, and the released phenol was quantified in the UVS at 510 nm. Finally, the soil alkaline phosphatase activity was expressed as mg phenol g\({}^{-1}\) soil h\({}^{-1}\).