Effects of living cover on the soil microbial communities and ecosystem functions of hazelnut orchard

Abstract Background: Living covers are an important management measure for orchards in China, which has a certain influence on soil properties, microorganisms and micro-ecological environment. However, there are few studies on the effects of living covers on the soil changes in hazelnut orchard. In this study, we compared living cover treatment by Vulpia myuros and no cover treatment, and analyzed the changes on the soil properties, microorganisms and microbial function by using high-throughput ITS rDNA and 16S rRNA gene Illumina sequencing. Results: The consequences demonstrated that the total organic carbon content of living cover treatment in the 20-40 cm soils increased by 32.87 % and 14.82 % respectively in May and July compared with no cover treatment, and living cover treatment by Vulpia myuros can also significantly increased the contents of total phosphorus (TP), total nitrogen (TN), available phosphorus (AP) and available potassium (AK) in the soil samples. Moreover, the influence of seasons is not as significant as that of soil depth. The living cover treatment significantly improved the soil enzymes activity levels. Among the four kind of soil enzymes, the soil invertase activity of living cover treatment was 50.94 % greater than that of no cover treatment in 0-20 cm soils and 52.17 % in 20-40 cm soils in May. The consequences demonstrated that Ascomycota, Mortierellomycota and Basidiomycota were the dominant fungal phylum in all samples, while Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes and Chloroflexi were the dominant bacterial phylum, but different treatments impacted the composition of fungal and bacterial communities. Principal component analysis (PCA) showed that living cover with Vulpia myuros significantly changed the soil fungal community structure whereas the bacterial community structure may be more sensitive to seasonal changes. At the microbial functional level, the pathotrophs, saprotrophs and symbiotrophs accounted for approximately 36.69 %, 49.80 % and 2.59 % of no cover treatment fungal OTUs respectively whereas in living cover treatment was 19.76 %, 41.51 % and 6.89 %. Conclusions: According to this study, we believe that the living cover with Vulpia myuros has a favorable regulating influence on soil properties, microbial community and microbial function, and can be considered as a management measure for hazelnut orchards management.