Shifts in Bacterial Community Associated with Green Manure Soybean Intercropping and Edaphic Properties in a Tea Plantation

Abstract

The continuous cultivation with excessive application of agrochemicals has led to the deterioration of soils. Incorporating leguminous green manure (GM) was found to improve the physicochemical and biological properties of soils. However, the influence of GM soybean intercropping on the temporal distribution of bacterial communities in strongly acidic soils is less explored. In this study, a nine-month field trial of soybean intercropping was conducted in a deteriorated tea plantation. This was used to test the hypothesis that GM treatment ameliorates tea-cultivated environments through changing bacterial communities as well as edaphic properties. GM treatment was demonstrated to increase both functional and population diversity during all the months that were considered. An alteration of life strategies exhibited by bacterial communities in GM treatment was observed, which shifted from oligotrophy (Acidobacteria, Chloroflexi, and the candidate phylum WPS-2) to copiotrophy (Bacteroidetes and Proteobacteria). This also contributed to the remarkable increase in metabolic potential of bacterial communities toward all six carbon source categories. The potentially versatile organic matter decomposers and/or plant growth-promoting bacteria, such as Burkholderiaceae, Chitinophagaceae, Sphingobacteriaceae, and Sphingomonadaceae bacteria, were identified as the most effective biomarkers in GM treatment. These bacterial groups showed strong correlation with soil pH; organic matter; and available K, Ca, and Mg. The increased diversity, metabolic potential, and copiotrophic taxa provided insight into the benefits brought by soybean intercropping, with enhanced community stability, facilitated nutrient cycling, and microbe–plant interactions in the strongly acidic tea plantation.

A photosynthetic bacterial inoculant exerts beneficial effects on the yield and quality of tomato and affects bacterial community structure in an organic field

“…Smit et al (2001) proposed that the ratio between the abundances of Proteobacteria and Acidobacteria (P/A) could indicate the general nutrient status of soils. Low P/A ratios (0.16-0.46) suggest that the soils are oligotrophic, while high ratios (0.87 or above) indicate that they are copiotrophic (Smit et al, 2012;Shen and Lin, 2021). As shown in Figures 5B,D, the average P/A ratios in the OF+M control and the OF+PS3 treatment were 2.46 and 3.64, respectively, suggesting an improvement in soil nutritional status Frontiers Microbiology 14 frontiersin.org after PS3 inoculation.…”