Agroforestry alters the rhizosphere soil bacterial and fungal communities of moso bamboo plantations in subtropical China

Abstract

Bamboo agroforestry is currently being promoted as a viable land use option to improve the management benefits of bamboo forest. However, little is known about bamboo rhizosphere soil bacterial and fungal community structures in bamboo-based agroforestry systems. In the present study, we compared the soil bacterial and fungal community structures of the moso bamboo rhizosphere in bamboo-based agroforestry systems (moso bamboo + Paris polyphylla, BP; moso bamboo + Tetrastigma hemsleyanum, BT; moso bamboo + Bletilla striata, BB) and their adjacent bamboo plantations (Con). The results showed that intercropping with medical herbs could significantly decrease (p < 0.05) the total organic carbon (TOC) in the bamboo rhizosphere soil. Compared with those in Con, the soil pH and available nitrogen (AN) significantly increased (p < 0.05) in BP and significantly decreased (p < 0.05) in BT and BB. The available phosphorus (AP) was significantly higher in BP and BT than in Con and BB, whereas the available potassium (AK) was significantly lower in BP and BB (p < 0.05). The rhizosphere soil bacterial and fungal community structures of the bamboo forest were markedly influenced by intercropping. Based on relative abundance values, BP significantly decreased the Actinobacteria and Mucoromycota and significantly increased (p < 0.05) the Gemmatimonadetes relative to Con; Acidobacteria, AD3, WPS-2, and Gemmatimonadetes were significantly higher (p < 0.05) in BT than in Con; and BB increased (p < 0.05) Acidobacteria and WPS-2 relative to Con. The fungal phylum Mortierellomycota was significantly lower in abundance (p < 0.05) in the BT and BB treatments than in Con. The correlation analysis indicated that the TOC, AN, AP and pH were significantly correlated (p < 0.05) with the bacterial community compositions, while the AK and pH were significantly correlated (p < 0.05) with the fungal community compositions. In terms of the characteristics of microbial community structures and soil properties, Paris polyphylla could be a very suitable medical herb for intercropping in pure moso bamboo forest.