The study investigates the impact of land conversion to agriculture on the taxonomic and functional homogenization of soil microbial communities. A continental survey of 1185 soil samples from agricultural fields and adjacent natural ecosystems (forest, grassland, and wetland) was conducted, complemented by a global meta-analysis of over 2400 samples across six continents. The results show that land conversion to agriculture leads to a significant reduction in β-diversity, indicating biotic homogenization. Specifically, 20% of phylotypes decrease and 23% increase in abundance, with croplands enriched in *Chloroflexi*, *Gemmatimonadota*, *Planctomycetota*, *Mycococcota*, and *Latescibacterota*. While there is no significant difference in functional composition between natural ecosystems and agricultural land, functional genes involved in nitrogen fixation, phosphorus mineralization, and transportation are depleted in croplands. The study highlights the multifaceted process of biotic homogenization, influenced by species invasion, extinction, and landscape heterogeneity. It also underscores the importance of microbial traits and environmental filtering in regulating microbial community shifts. The findings provide a comprehensive understanding of how agricultural land-use change affects soil microbial diversity and function, emphasizing the need for conservation and ecological restoration to maintain landscape-scale biodiversity and ecosystem services.The study investigates the impact of land conversion to agriculture on the taxonomic and functional homogenization of soil microbial communities. A continental survey of 1185 soil samples from agricultural fields and adjacent natural ecosystems (forest, grassland, and wetland) was conducted, complemented by a global meta-analysis of over 2400 samples across six continents. The results show that land conversion to agriculture leads to a significant reduction in β-diversity, indicating biotic homogenization. Specifically, 20% of phylotypes decrease and 23% increase in abundance, with croplands enriched in *Chloroflexi*, *Gemmatimonadota*, *Planctomycetota*, *Mycococcota*, and *Latescibacterota*. While there is no significant difference in functional composition between natural ecosystems and agricultural land, functional genes involved in nitrogen fixation, phosphorus mineralization, and transportation are depleted in croplands. The study highlights the multifaceted process of biotic homogenization, influenced by species invasion, extinction, and landscape heterogeneity. It also underscores the importance of microbial traits and environmental filtering in regulating microbial community shifts. The findings provide a comprehensive understanding of how agricultural land-use change affects soil microbial diversity and function, emphasizing the need for conservation and ecological restoration to maintain landscape-scale biodiversity and ecosystem services.