Continuously Monocropped Jerusalem Artichoke Changed Soil Bacterial Community Composition and Ammonia-Oxidizing and Denitrifying Bacteria Abundances

Abstract

Soil microbial communities have profound effects on the growth, nutrition and health of plants in agroecosystems. Understanding soil microbial dynamics in cropping systems can assist in determining how agricultural practices influence soil processes mediated by microorganisms. In this study, soil bacterial communities were monitored in a continuously monocropped Jerusalem artichoke (JA) system, in which JA was successively monocropped for 3 years in a wheat field. Soil bacterial community compositions were estimated by amplicon sequencing of the 16S rRNA gene. Abundances of ammonia-oxidizing and denitrifying bacteria were estimated by quantitative PCR analysis of the amoA, nirS, and nirK genes. Results showed that 1–2 years of monocropping of JA did not significantly impact the microbial alpha diversity, and the third cropping of JA decreased the microbial alpha diversity (P < 0.05). Principal coordinates analysis and permutational multivariate analysis of variance analyses revealed that continuous monocropping of JA changed soil bacterial community structure and function profile (P < 0.001). At the phylum level, the wheat field was characterized with higher relative abundances of Latescibacteria, Planctomycetes, and Cyanobacteria, the first cropping of JA with Actinobacteria, the second cropping of JA with Acidobacteria, Armatimonadetes, Gemmatimonadetes, and Proteobacteria. At the genus level, the first cropping of JA was enriched with bacterial species with pathogen-antagonistic and/or plant growth promoting potentials, while members of genera that included potential denitrifiers increased in the second and third cropping of JA. The first cropping of JA had higher relative abundances of KO terms related to lignocellulose degradation and phosphorus cycling, the second cropping of JA had higher relative abundances of KO terms nitrous-oxide reductase and nitric-oxide reductase, and the third cropping of JA had higher relative abundances of KO terms nitrate reductase and nitrite reductase. The abundances of amoA genes decreased while nirK increased in the third cropping of JA, nirS continuously increased in the second and third cropping of JA (P < 0.05). Redundancy analysis and Mantel test found that soil organic carbon and Olsen phosphorus contents played important roles in shaping soil bacterial communities. Overall, our results revealed that continuous monocropping of JA changed soil bacterial community composition and its functional potentials.

Beneficial Effects of Mixing Kentucky Bluegrass With Red Fescue via Plant-Soil Interactions in Black Soil of Northeast China

“…This result is consistent with the general findings that the mixture has positive function in soil microbial community compositions (Zeng et al, 2019). As already shown in other studies, effects of mixed cropping or intercropping on microbial abundance, diversity, and community structure are remarkably different from those of monoculture soil (Zhou et al, 2017(Zhou et al, , 2018. Similarly, Latz (2015) reported that the mixture increases microbial community, diversity, and structure in the rhizosphere soil.…”

“…Compared with PP, the PF mixture increased the relative abundance of Proteobacteria and Acidobacteria by 6.36 and 21.90%, respectively, whereas that of Actinobacteria decreased by 38.78% (Figure 3). The difference of relative abundance in Actinobacteria between PF mixture and PP monoculture might be much more related to the different quality of SOM released by turfgrass roots in PP and PF soils, resulting in changes of the groups with the ability to degrading specific organic substrates (i.e., lignocellulose degradation) as reported by several authors (Větrovský et al, 2014;Zhou et al, 2017Zhou et al, , 2018. Moreover, Actinobacteria is positively related with the pH (Zhou et al, 2017); the pH value decreased by 6.67% from the PP to the PF, which might be one of the reasons for decreasing the relative abundance of Actinobacteria.…”

“…It has been an observation point that changes of microbial abundance, diversity, and structure in the soil occur due to diverse cropping systems (Latz et al, 2015;Zhou et al, 2018, Gong et al, 2019. This study examined some aspects of influences of the PF mixture model on soil microbial abundances and communities by qPCR and high-throughput sequencing.…”

“…Soil microorganisms can be classified as beneficial, neutral, and harmful for plant growth (Lynch, 1990;Zhou et al, 2018).…”

Diversity patterns of soil microbial communities in the Sophora flavescens rhizosphere in response to continuous monocropping

“…As a major determinant, plants can shift their soil microbial communities through the accumulation of litter and rhizodepositions in the soil under continuous monocropping conditions, thereby altering subsequent plant growth [11,12]. Moreover, other factors such as phytotoxic compounds, soil-borne pathogens, soil physicochemical property changes, and nutrient de ciency can also contribute to the diversity of microbial communities [7,13,14]. Many plants have been reported to suffer from high mortality, declines in yield and quality, and stunting caused by continuous monocropping systems, such as notoginseng [15], soybean [16,17], rice [18], peanut [7], and cucumber [19].…”