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.

Seasonal Variation in the Rhizosphere and Non-Rhizosphere Microbial Community Structures and Functions of Camellia yuhsienensis Hu

“…The dominant bacteria, Chloroflexi, Proteobacteria, Acidobacteria, Actinobacteria, and Planctomycetes, and fungi, Ascomycota and Basidiomycota, in the rhizosphere of C. yuhsienensis were similar to previous studies in C. oleifera rhizosphere or bulk soil [ 10 , 30 ], but a little different from the rhizosphere soil of Camellia sinensis [ 69 ]. These results indicated that nutrient utilization patterns of the plant might significantly alter microbial communities.…”

“…Numerous studies have shown that seasonal variation strongly regulates soil physiochemical properties and microorganisms [ 10 , 59 , 60 , 61 , 62 ]. However, no studies have assessed the seasonal variation in soil properties and microbial communities in the rhizosphere of C. yuhsienensis .…”

“…Exploring the rhizosphere microbial function is a great way to understand the interactions between plants and microorganisms. Although there are already some researchers focusing on microbial communities associated with oil tea [ 10 , 30 ], the microbial functions in the oil tea rhizosphere have never been noticed. Indicator analysis showed that the number of biomarkers in the rhizosphere was much higher than in the non-rhizosphere ( Figure 4 ).…”

“…Some fungi are interdependent with the plant rhizosphere, such as arbuscular mycorrhizal fungi, while others can cause plant disease, such as Venturia inaequalis [ 7 , 8 , 9 ]. Due to their sensitive features, microorganisms are significantly regulated by many factors, such as plant roots and seasonal variation [ 10 , 11 , 12 ].…”

“…Cook et al [ 29 ] found that plants tend to regulate microbial communities for their own benefit. Previous studies have reported on the significant carbon metabolic activity in the rhizosphere and bulk soil of Camellia oleifera plantations, another species of oil tea [ 10 , 30 ]. Hartmann et al [ 31 ] revealed that specific microenvironments around the rhizosphere lead to specific interactions among microbes with the development of plant roots, resulting in the biological protection of plants from pathogenic microbes.…”