## 3 Results
### The Effects of Two Practices on Soil Microbial Community  
DGGE profiling showed that the bacterial community compositions of three treatments were much different from each other, and the five replicate samples of each treatment grouped well (Figure 2). Generally, the bacterial community compositions of CaCO\({}_{3}\) and Control were similar to each other, while that of OM was separated apart from CaCO\({}_{3}\) and Control for both _S. guianensis_ and _P. natatum_. Moreover, the diversity index, species abundance and species evenness were not affected by either CaCO\({}_{3}\) or OM for _P. natatum_ (Table 3). In contrast, for _S. guianensis_, the diversity index was significantly increased by both CaCO\({}_{3}\) and OM, while species abundance was significantly increased by only CaCO\({}_{3}\)Figure 2: Denaturing Gradient Gel Electrophoresis profiles of the bacterial community in the rhizosphere of _S. guianensis_ (**A**) and _P. natatum_ (**B**) and the corresponding clustering analysis. CaCO\({}_{3}\), liming; OM, plant residue incorporation.  
\begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline
**Plant Species** & **Treatment** & \(\alpha\)**-**CLU** & \(\beta\)**-**CLU** & \(\beta\)**-**XYL** & **CEL** & **URA** & **NR** & **CHI** & **ACP** & **ALP** \\ \hline  & Control & 0.23 \(\pm\) 0.01 s & 0.24 \(\pm\) 0.01 s & 0.15 \(\pm\) 0.00 s & 0.16 \(\pm\) 0.01 s & 335.4 \(\pm\) 11.6 s & 3.38 \(\pm\) 0.07 s & 0.06 \(\pm\) 0.00 s & 5.27 \(\pm\) 0.70 s & 0.63 \(\pm\) 0.11 s \\ \hline  & CaCO & 0.26 \(\pm\) 0.01 s & 0.25 \(\pm\) 0.01 s & 0.16 \(\pm\) 0.01 s & 0.15 \(\pm\) 0.01 s & 436.1 \(\pm\) 9.1 s & 5.09 \(\pm\) 0.36 s & 0.07 \(\pm\) 0.00 s & 7.61 \(\pm\) 1.00 s & 5.65 \(\pm\) 0.70 s \\  & OM & 0.25 \(\pm\) 0.01 s & 0.08 \(\pm\) 0.01 s & 0.16 \(\pm\) 0.00 s & 436.1 \(\pm\) 9.0 s & 5.12 \(\pm\) 0.22 s & 0.10 \(\pm\) 0.12 s & 4.22 \(\pm\) 11.5 s & 0.73 \(\pm\) 0.12 s \\  & Control & 0.20 \(\pm\) 0.01 s & 0.27 \(\pm\) 0.02 s & 0.13 \(\pm\) 0.01 s & 0.15 \(\pm\) 0.00 s & 197.6 \(\pm\) 6.7 s & 3.37 \(\pm\) 0.17 s & 0.21 \(\pm\) 11.5 s & 0.82 \(\pm\) 0.28 s \\ \hline  & CaCO & 0.23 \(\pm\) 0.01 s & 0.33 \(\pm\) 0.03 s & 0.16 \(\pm\) 0.01 s & 0.16 \(\pm\) 0.00 s & 541.2 \(\pm\) 16.9 s & 3.55 \(\pm\) 0.2 s & 0.08 \(\pm\) 0.01 s & 4.55 \(\pm\) 11.1 s & 2.60 \(\pm\) 0.41 s \\  & OM & 0.23 \(\pm\) 0.01 s & 0.41 \(\pm\) 0.02 s & 0.16 \(\pm\) 0.00 s & 0.16 \(\pm\) 0.00 s & 589.7 \(\pm\) 7.5 s & 6.30 \(\pm\) 0.11 s & 0.10 \(\pm\) 0.01 s & 4.79 \(\pm\) 0.88 s & 1.71 \(\pm\) 0.16 s \\ \hline  & & & & & & & & & \\ Plant species (P) & & 0.036 & 0.497 & 0.004 & 0.800 & 0.001 & 0.420 & 0.150 & 0.820 & 0.052 \\ Soil treatments (T) & & 0.124 & 0.000 & 0.002 & 0.405 & 0.000 & 0.000 & 0.001 & 0.140 & 0.000 \\  & P\(\times\)T & & 0.447 & 0.015 & 0.323 & 0.286 & 0.000 & 0.000 & 0.408 & 0.045 & 0.000 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Influences of limiting (CaCO\({}_{3}\)) and plant residue incorporation (OM) on soil enzyme activities. \(\alpha\)-CLU, \(\alpha\)-glucosidase; \(\beta\)-GLU, \(\beta\)-glucosidase; \(\beta\)-XYL, \(\beta\)-syolsidase; CEL, cellolbisolosidase; URA, urease; NH, nitrate reductase; CHI, chitinase; ACP, acid phosphatase; ALP, alkaline phosphatase. Data followed by the same letter are not significantly different for each plant species ([PERSON] post hoc test, \(p=0.05\), \(n=5\)). Enzymatic activity unit of URA, NR, ACP, ALP is Ug\({}^{-1}\), and that of others is \(\mathrm{\mu molL^{-1}MUFg^{-1}h^{-1}}\).