Purpose <p>This study investigated the impact of biochar, compost, and elemental sulfur amendments, alone and in combination, on soil microbial communities in an irrigated turf grass field after three months of application.</p> Methods <p>From the field soil samples were collected and a combination of multiple analytical approaches was used, including microbial enumeration, respiration, enzyme activities, relative abundance of 30 functional genes (qPCR), and taxonomic diversity by 16&#xa0;S and ITS gene sequencing.</p> Results <p>The combined compost, biochar, and elemental sulfur field co-amendment showed the highest bacterial and fungal abundance. Compost improved dehydrogenase activity by 413% and FDA hydrolase activity by 55%, whereas biochar increased urease activity and reduced the metabolic quotient compared to the control (unamended). Sulfur reduced urease activity but increased the abundance of diverse nitrogen and sulfur functional genes, whereas biochar increased the abundance of C-cycle genes. The triple combination of amendments increased the abundance of carbon and nitrogen cycle genes and enriched sulfur-oxidizing taxa. Compost exhibited the highest RaoQ (0.88) and functional gene diversity due to the lower dominance of specific traits, whereas sulfur or biochar decreased trait evenness and enhanced functional specialization.</p> Conclusions <p>The joint application of compost, biochar, and elemental sulfur enhanced bacterial and fungal abundance and urease and FDA hydrolase activities. In addition, upregulated carbon, nitrogen, and sulfur cycling genes and enriched sulfur-oxidizing taxa; showing high potential for promoting a balanced microbial health and functional diversity in degraded aridland soils.</p> Graphical Abstract <p></p>