Impact of agro-farming activities on microbial diversity of acidic red soils in a camellia oleifera forest

Abstract

The production of Camellia oleifera (oil tea), typically planted in acidic red soils in southern China, is limited by low soil fertility. Agro-farming is one way to promote soil fertility by increasing organic matter and microbial communities. To understand the impact of agro-farming activity on soil fertility, three types of agro-farming, namely, raising laying hens under forest (RLH), cultivating Lolium perenne grass under forest (LPG), and maintenance of native grass (MNG), were employed in an oil tea farm with acidic red soil in Changsha, China. Soil samples were collected from the farm to estimate microbial communities, pH, and total organic carbon (TOC) in different seasons. The results indicated that TOC and temperature were the dominant factors influencing the variations of bacterial communities, while temperature and pH affected the fungal communities in the soil. The most abundant bacterial phyla were Acidobacteria, Proteobacteria, Actinobacteria, and Chloroflexi, while the most abundant fungal phyla were Ascomycota, Basidiomycota, and Zygomycota. Regardless of treatment, the bacterial richness and diversity were both low in spring, and the fungal richness and diversity in summer and autumn were higher than in spring and winter. The TOC content and pH in LPG were significantly higher than in other treatments. Microbial communities in LPG and MNG were more stable than in RLH. In summary, cultivating grass under forest treatment was the best way to improve the microenvironment with the highest TOC content and fewer pathogenic microorganisms.