Distinct Weathering Ability and Populations of Culturable Mineral-Weathering Bacteria in the Rhizosphere and Bulk Soils of Morus Alba

In this study, we isolated and compared the weathering effectiveness and population of mineral-weathering bacteria from the rhizosphere and bulk soils of Morus alba grown in a mineral-rich soil. Eighty-four isolates could release Si, Al, K, and Fe from potash feldspar. Weathering effectiveness and pattern of the isolates differed between the rhizosphere and bulk soils. The proportion of the highly effective Si, Al, K, and Fe solubilizers was significantly higher in the rhizosphere soils than in the bulk soils. Notably, the proportion of the highly effective acid-producing isolates was also significantly higher in the rhizosphere soils. The 84 mineral-weathering isolates were affiliated with 15 bacterial genera. Distinct mineral-weathering genera were observed between the rhizosphere and bulk soils. The results suggested that the highly effective mineral-weathering bacteria were selected in the rhizosphere soils and the mineral-weathering bacteria from the rhizosphere and bulk soils might weather potash feldspar through different mechanisms.