Abstract: Soil microbes play an important role in forest ecosystem and are the driving factor of material cycling. Few studies have been conducted on the seasonal changes and the influencing factors of soil microbial communities in urban forests. Using high-throughput sequencing methods, we investigated the seasonal changes of soil microbial community in the urban forest of Dongguan and analyzed their influencing factors. The results showed that the structure and diversity of soil microbial community significantly differed among seasons. The total abundance of soil microbes was significantly lower in wet season than in dry season. In contrast, both Chao1 index and Shannon index showed the opposite seasonal patterns compared with that of microbial abundance, with higher diversity and structure in the bacterial and fungal community in wet season. In adaptation to the seasonal change, bacteria mainly adjusted their total abundance, while fungi changed their total abundance and species composition. Soil available boron was the major factor influencing bacterial community structure, while soil pH was the major factor influencing fungal community structure. Exchangeable calcium and exchangeable magnesium in soil were the important factors influencing both bacterial and fungal communities.

Key words: nitrogen retention effect, multiple timescales, ecological dynamic model, Shanmei Reservoir., influencing factors