Soil labile organic carbon sequestration is tightly correlated with the abundance and diversity of arbuscular mycorrhizal fungi in semiarid maize fields

Plastic film mulching can affect soil organic carbon (C) lability in semiarid regions. Arbuscular mycorrhizal (AM) fungi represent an important route for plant-derived C into soil and can be influenced by agricultural practices. Whether the changes of AM fungal community affect soil organic C sequestration is a fundamental question in semiarid environments. To this end, we conducted two field experiments investigating the influence of a Funneliformis mosseae inoculation and mycorrhizal-suppression using benomyl application on maize growth, soil fractions of organic C, AM fungal parameters, including diversity profiling using the Illumina MiSeq. The results showed that AM fungal community composition was significantly altered by plastic film mulching and fungicide applications, soil organic C fractions and nitrogen were most important factors in influencing the AM fungal community. AM fungal inoculation significantly increased particulate organic C and light fraction organic C content, due to enhance dextramatrical hyphal length (EMH), glomalin content, and root biomass. Conversely, fungicide applications reduced labile organic C, possibly through decreasing EMH, glomalin content and soil AM fungal diversity. Increases in relative abundance of F. mosseae in rhizosphere soil, coupled with increases in AM fungal root colonization from F. mosseae inoculation indicates successfully established by outcompeting the existing natural AM fungal community. Plastic film mulching resulted in significant increases in maize yield and water use efficiency, and AM fungal inoculation was found to amplify the effects. Thus, AM fungal inoculation may act as an effective farming practice to improve soil organic C fractions, which can boost maize productivity.