Effect of Elaeagnus angustifolia Linn. on the Physicochemical Properties and Microbial Community Structure of Inter-Rhizosphere Soils

Abstract

Aims: The aim of this study was to elucidate the effect of Elaeagnus angustifolia Linn. (E. angustifolia L.) on the structure and abundance of the soil microbial community. This paper provides a theoretical foundation for guiding the establishment of E. angustifolia L. forests to enhance the physicochemical properties of soil.

Methods: This study employed high-throughput sequencing technology to analyse the composition, diversity, and structural changes of various soil fungal and bacterial communities and correlated the results with soil physicochemical properties.

Results: The results indicated a significant increase in the total nitrogen (0.66 g/kg-0.87 g/kg), ammonium nitrogen (3.60 mg/kg-6.56 mg/kg), and organic matter (1.06-1.38%) contents of the inter-rhizosphere soil of E. angustifolia L. after 3, 4, and 5 months of planting. Additionally, the total phosphorus, potassium, and nitrate nitrogen contents increased, whereas soil pH and salinity decreased. The abundance of soil microbial communities also increased. The fungal phyla with relative abundances greater than 1% were Ascomycota, Fungi_unclassified, Basidiomycota, Zygomycota, and Glomeromycota. Chytridiomycota, Rozellomycota, Mortierellomycota, and Olpidiomycota were not found in the bare soil control but were observed in the rhizosphere soil of the date palm. The relative abundance of bacteria from the phyla Proteobacteria, Acidobacteria, Actinobacteria, Gemmatimonadetes, and Chloroflexi in the inter-root soil of jujube dates showed an increase in comparison with the control group. At the same time, correlation analysis found that soil total phosphorus, nitrogen content, and soil enzyme activity were positively correlated with the bacterial level, with TN (p < 0.01) and NO₃^--N (p < 0.05) showing significant positive correlations. Conversely, soil pH and salinity were mostly negatively correlated with the fungi, and soil enzyme activity was significantly correlated with the fungal and bacterial at different RAD levels.

Conclusions: The introduction of E. angustifolia L. markedly affected the physicochemical properties and microbial community composition of the soil.

Keywords: high-throughput sequencing; inter-rooted soils of E. angustifolia L.; properties of soil in terms of physics and chemistry; soil microbial community structure.

Figure 1

Changes in rhizosphere soil nutrient contents between W and E from July to September. (A) Nitrogen content; (B) phosphorus content; (C) potassium content; (D) soil organic matter content; (E) NO₃⁻-N content; (F) NH₄⁻-N content. Note: W: Uncultivated soil with E. angustifolia L.; E: soil for planting E. angustifolia L. Error bars represent the standard error of the mean (n = 3). Different letters above the columns indicate significant differences according to the LSD test (p < 0.05).

Figure 2

Rhizosphere soil (in water) pH and salt concentration in W and E from July to September. (A) Potential hydrogen of soil; (B) soil salt content. (‰ is a thousandth of a cent.) Note: W: Uncultivated soil with E. angustifolia L.; E: soil for planting E. angustifolia L. Error bars represent the standard error of the mean (n = 3). Different letters above the columns indicate significant differences according to the LSD test (p < 0.05).

Figure 3

Changes in enzyme activities in rhizosphere soil between W and E from July to September. (A) Soil phosphatase activity; (B) catalase activity; (C) soil urease activity; (D) soil sucrase activity. Note: W: Uncultivated soil with E. angustifolia L.; E: soil for planting E. angustifolia L. Error bars represent the standard error of the mean (n = 3). Different letters above the columns indicate significant differences according to the LSD test (p < 0.05).

Figure 3

Changes in enzyme activities in rhizosphere soil between W and E from July to September. (A) Soil phosphatase activity; (B) catalase activity; (C) soil urease activity; (D) soil sucrase activity. Note: W: Uncultivated soil with E. angustifolia L.; E: soil for planting E. angustifolia L. Error bars represent the standard error of the mean (n = 3). Different letters above the columns indicate significant differences according to the LSD test (p < 0.05).

Figure 4

Venn diagram of OTUs in W and E. (A) Venn diagram of bacterial OTUs; (B) Venn diagram of OTUs fungi. Note: W: Uncultivated soil with E. angustifolia L.; E: soil for planting E. angustifolia L.

Figure 5

Abundance map of bacteria communities at the phylum level (A) and genus level (B) in W and E. Note: W: Uncultivated soil with E. angustifolia L.; E: soil for planting E. angustifolia L.

Figure 5

Abundance map of bacteria communities at the phylum level (A) and genus level (B) in W and E. Note: W: Uncultivated soil with E. angustifolia L.; E: soil for planting E. angustifolia L.

Figure 6

Abundance map of fungal communities at the phylum level (A) and genus level (B) in W and E. Note: W: Uncultivated soil with E. angustifolia L.; E: soil for planting E. angustifolia L.

Figure 7

Heatmap of Spearman’s correlation between bacterial (A) and fungal (B) communities and soil properties. Note: W: Uncultivated soil with E. angustifolia L; E: soil for planting E. angustifolia L. ∗ Correlation is significant at the 0.05 level; ∗∗ correlation is significant at the 0.01 level.

Figure 8

RDA was performed to analyse Spearman’s correlations between soil properties and bacterial communities (A) and fungal communities (B) at the phylum level, respectively. Note: W: Soil uncultivated with E. angustifolia L; E: soil for planting E. angustifolia L.