Soil microbes play an important role in carbon (C) and nutrient cycling in forest ecosystems. However, the response of soil microbial community and function to chemical fertilization in different growth seasons along forest succession is less documented. Here, we examined soil bacterial and fungal communities and functions (enzyme activity and C resource metabolic activity) in a 4-year experiment of nitrogen (N) and phosphorus (P) addition in three growth seasons (April, August, and November) under two successional stages (young and mature) in a Chinese subtropical forest. The richness of total, saprotrophic, ectomycorrhizal (EM) fungi and bacteria was higher in April and August than in November, while the pathogenic fungal richness was higher in NP fertilization compared to other treatments. The community composition of bacteria, total and functional group fungi differed between young and mature forests and between November and April/August. Furthermore, the community composition of bacteria, total, saprotrophic and EM fungi was affected P fertilization, and pathogenic fungal community composition was influenced by N fertilization. In addition to season, the C, N and P cycling related soil enzyme activities were affected by N and/or P fertilization, and the metabolic activity of C sources was influenced by forest stage. This finding may enhance our understanding of the soil microbial community and function in response to N and P addition in three growing seasons along subtropical forest succession.
Less...