Effects of stand type of artificial forests on soil microbial functional diversity.

We explored the changes of soil microbial biodiversity in response to forest ecological restoration. Soil samples were collected from the close-to nature managed Chinese fir plantation (CF), Moso bamboo plantation (MB), and natural secondary forest (NF). Soil microbial community diversity was analyzed by Biolog-Eco micro-plate technique. The results showed that plant diversity was significantly different among the three stands. Plant diversity of NF was significantly higher than MB and CF, and MB was higher than CF. Soil pH and bulk density showed a great difference, while there was no difference of other soil physiochemical properties among the three stands. Avera-ge well color development (AWCD) of soil in various stands followed the order of NF＞MB＞CF, consistent with the changes of utilization of six types of carbon sources. Shannon index of NF was the highest, and the index of MB was significantly higher than that of CF. Soil physical and chemical properties in different stands were not significantly different, except soil pH and bulk density. The Shannon diversity index (H), Shannon species richness index (S), Simpson dominance index (D) and McIntosh index (U) were the highest in NF, second in MB, and the lowest in CF. Results from principal component analysis (PCA) showed that two factors from 31 carbon sources could explain 60.0% and 12.4% of the variation and that carboxylic acids, carbohydrates and its derivatives, amino acids were the main carbon sources of the two principal component factors. Correlation analysis indicated that plant species richness and Shannon diversity indexes, soil bulk density were significantly correlated to soil microbial community diversity. The microbial community of NF was more efficient in carbon utilization than that in MB and CF, while that in MB was more efficient than that of CF. Based on plant diversity and soil microbial carbon utilization, MB is much better than CF in the artificial forest restoration and improvement in South China.