Soil bacterial communities exhibit systematic spatial variation with landform across a commercial potato field.

Topography drives spatial variation of soil edaphic factors at the landscape scale however, it is unclear how it influences the spatial distribution of bacterial communities in distances relevant to agro-ecosystem management. This study examined the influence of soil physico-chemical properties and topographic features on bacterial communities and diversity in a commercial potato field with a rolling landform. Eighty-three soil samples were systematically collected across a transect 1100 m long. A significant negative correlation ( r  = −0.73) between soil pH (range 4.3–7.0) and slope gradient (range 1.8–11.9%) was observed. Regressions and/or a canonical correspondence analysis showed that pH, slope gradient and organic carbon were the major factors influencing bacterial α-diversity based on 16S rRNA gene sequences. Semivariogram analyses revealed that the bacterial α-diversity, the relative abundance of most phyla, pH and slope gradient showed strong to medium spatial autocorrelations with a range between 20.8 and 217.8 m. These results evidenced that soil pH and slope gradient were the major factors explaining variation in the spatial structure of the bacterial community. Our results showed that the soil bacterial communities varied in a systematic and predictable pattern in an agricultural field in response to variation in soil physico-chemical properties and topographic features. [ABSTRACT FROM AUTHOR]