Soil bacterial and fungal communities across a pH gradient in an arable soil were studied to understand the direct influence of pH on their abundance and composition. The research used quantitative PCR (qPCR) and bar-coded pyrosequencing to analyze bacterial and fungal communities across a 180-meter pH gradient (4.0–8.3) in a long-term liming experiment. The study found that bacterial communities were strongly influenced by pH, with their abundance and diversity increasing as pH increased. In contrast, fungal abundance and diversity were less affected by pH. Bacterial community composition was closely linked to soil pH, showing significant variation across the gradient, comparable to variation across different biomes. Fungal community composition was less affected by pH, consistent with pure culture studies indicating fungi have broader pH tolerance ranges. The study highlights that pH is a major factor in structuring bacterial communities, while fungal communities are less directly influenced. The results suggest that pH is a key driver of microbial community composition in soils, with bacteria being more sensitive to pH changes than fungi. The study also compared bacterial community variation across the pH gradient with variation in soils from different biomes, finding similar levels of variation. Overall, the findings emphasize the critical role of pH in shaping soil microbial communities.Soil bacterial and fungal communities across a pH gradient in an arable soil were studied to understand the direct influence of pH on their abundance and composition. The research used quantitative PCR (qPCR) and bar-coded pyrosequencing to analyze bacterial and fungal communities across a 180-meter pH gradient (4.0–8.3) in a long-term liming experiment. The study found that bacterial communities were strongly influenced by pH, with their abundance and diversity increasing as pH increased. In contrast, fungal abundance and diversity were less affected by pH. Bacterial community composition was closely linked to soil pH, showing significant variation across the gradient, comparable to variation across different biomes. Fungal community composition was less affected by pH, consistent with pure culture studies indicating fungi have broader pH tolerance ranges. The study highlights that pH is a major factor in structuring bacterial communities, while fungal communities are less directly influenced. The results suggest that pH is a key driver of microbial community composition in soils, with bacteria being more sensitive to pH changes than fungi. The study also compared bacterial community variation across the pH gradient with variation in soils from different biomes, finding similar levels of variation. Overall, the findings emphasize the critical role of pH in shaping soil microbial communities.