Abstract: [Objective] In order to provide a scientific basis for evaluating the management measure of Phyllostachys praecox stand with mulching in winter, the impact of mulching on soil bacterial structure and biodiversity was studied.[Method] Soil samples from P. praecox stands with different mulching age (0, 3 a, 6 a, 9 a, 12 a) at Jinshan, Yuhang, Zhejiang Province were collected. V3-V4 regions of 16S rDNA from soil bacteria were sequenced by Illumina Miseq High Throughput Sequencing technique and soil bacterial groups were identified. The soil nutrient indexes such as total N, total P and OM were analyzed with standard experimentalmethod. The impact on soil bacterial community and diversity through mulching management were analyzed.[Result] 1) There were 280 548 bacterial 16S rDNA sequences and 598 OTU types obtained from the soil samples. The dominant bacterial communities at phyum level were Proteobacteria, Acidobacteria and Actinobacteria, and their relative abundance was 30.80%, 22.0% and 13.9%, respectively. 2) The diversity (Shannon Wiener Index) and abundance (Ace Index) of soil bacterial community showed a greater difference among different mulching ages. At the initial stage Shannon Wiener index and Ace showed increasing tendency with the mulching age. These indexes reached the maximum at 6 years of mulching. After that time these indexes showed a decline, and these values were very close to the control at the 12 years of mulching. 3) The mulching management showed certain impact on the bacterial structure in the soil. The relative abundance of Proteobacteria was raised from 17.60%(CK) to 37.77%(12 a), and the relative abundance of Acidobacteria showed a downward trend, while the Actinobacteria hadlittle change. 4) The changes of soil physical and chemical property caused by mulching management influenced the bacterial community structure. With the increase of mulching time, the relationship between the bacterial structure and the environmental factors became more complicated. Mulching management caused a severe soil acidification. The pH of the soil in control and 12 a mulching were 5.23 and 3.42, respectively. However, the abundance of Acidobacteria in the soil, which is known as a kind of acidophil bacteria, was decreased. 5) The first two RDA axes collectively explained 88.5% of the species-environment variation. The diversity of Proteobacteria and Bacteroidetes was correlated with available K, total N and OM. The diversity of Chloroflexi was correlated with pH.[Conclusion] This study showed that the mulching management had a marked influence on the structure and diversity of soil bacterial communities. The short-term mulching (less than 6 a) could increase the abundance and diversity of soil bacteria. However, with the increase of mulching age, the abundance and diversity of soil bacteria were decreased. Theresult indicated that the soil bacterial community was closely related to environmental variables.Changes of soil environmental factors will affect the soil bacterial community's structure. Analysis of soil bacterial diversity in soil can analyze the degree of soil degradation from the view of microorganism, and provide theoretical basis for soil remediation of P. praecox stands.

Key words: Phyllostachys praecox, mulching management of bamboo stand, soil microbe, bacterial biodiversity, temporal change