Soil bacterial communities exhibit distinct biogeographical patterns influenced primarily by edaphic factors, particularly soil pH. A study analyzing 98 soil samples from North and South America revealed that soil pH was the strongest predictor of bacterial diversity and richness, with neutral soils showing the highest diversity and acidic soils the lowest. Bacterial community composition was largely independent of geographic distance, suggesting that edaphic variables, rather than geographic distance, drive microbial biogeography. Unlike plant and animal diversity, which are often linked to temperature, latitude, and water-energy balance, soil bacterial diversity is mainly determined by soil pH. The study also found no significant latitudinal gradient in bacterial diversity, indicating that factors like mean annual temperature and potential evapotranspiration had little effect on soil bacterial diversity. These findings suggest that microbial biogeography is fundamentally different from that of macroorganisms, with environmental factors such as soil pH playing a dominant role in structuring soil bacterial communities at the continental scale. The results highlight the importance of edaphic variables in shaping microbial diversity and community structure, offering new insights into the biogeography of soil microorganisms.Soil bacterial communities exhibit distinct biogeographical patterns influenced primarily by edaphic factors, particularly soil pH. A study analyzing 98 soil samples from North and South America revealed that soil pH was the strongest predictor of bacterial diversity and richness, with neutral soils showing the highest diversity and acidic soils the lowest. Bacterial community composition was largely independent of geographic distance, suggesting that edaphic variables, rather than geographic distance, drive microbial biogeography. Unlike plant and animal diversity, which are often linked to temperature, latitude, and water-energy balance, soil bacterial diversity is mainly determined by soil pH. The study also found no significant latitudinal gradient in bacterial diversity, indicating that factors like mean annual temperature and potential evapotranspiration had little effect on soil bacterial diversity. These findings suggest that microbial biogeography is fundamentally different from that of macroorganisms, with environmental factors such as soil pH playing a dominant role in structuring soil bacterial communities at the continental scale. The results highlight the importance of edaphic variables in shaping microbial diversity and community structure, offering new insights into the biogeography of soil microorganisms.