Effects of grass cultivation on soil arbuscular mycorrhizal fungi community in a tangerine orchard

Abstract

Grass co-cultivation has been widely adopted to increase fruit quality by improving soil fertility. However, the response characteristics of soil arbuscular mycorrhizal fungi (AMF) community in tangerine orchards under grass co-cultivation environments is still poorly understood. Therefore, in order to reveal the effects of the co-cultivation of different grasses in tangerine orchards on the community structure and diversity of rhizospheric arbuscular mycorrhizal fungi (AMF), as well as soil properties, a 10 year study was undertaken at a tangerine orchard with four treatments: sod cultures with either white clover, ryegrass, natural grass or clear tillage as the control. The results showed that grass co-cultivation increased soil nutrient contents and AMF community richness, but had no significant effect on AMF community diversity (P > 0.05). The AMF detected in all soil samples belonged to one phylum, three classes, four orders, five families and five genera. The composition and structure of the AMF community varied among four treatments. Redundancy analysis (RDA) revealed that ​soil physicochemical properties impacted variations in the AMF community characteristics diversely. Furthermore, network analysis showed that grass co-cultivation increased the scale and complexity of the microbial co-occurrence network. In summary, grass co-cultivation in tangerine orchards not only improved soil fertility and soil structure, but also improved the stability and stress resistance of soil AMF community, which is conducive to promoting the sustainable development of the tangerine industry.