The combination of mineral fertilizers with organic fertilizer materials has been shown to enhance crop performance more effectively than the sole application of mineral nutrients. This improvement is largely attributed to the stimulation of soil biological parameters. This study was designed to evaluate the effects of sugarcane-derived organic amendments (bagasse and filter cake), combined with varying levels of urea and triple superphosphate, on soil microbial characteristics under sugarcane cultivation, aiming to assess the potential synergistic benefits of integrated nutrient management. The treatments included organic amendments (no amendment, sugarcane bagasse 50-t ha-1, filter cake 50-t ha-1, and a combination of 25-t ha-1 of bagasse and 25-t ha-1 filter cake), urea (without urea, and 150 kg ha-1of urea), and triple superphosphate (250 kg ha-1 and 187.5 kg ha-1). After 1 year, filter cake applied in combination with mineral phosphate fertilizer significantly increased soil respiration, microbial biomass carbon, enzymatic activities (catalase, dehydrogenase, and phosphatases), and potential nitrification compared to the control. These results support the hypothesis of a synergistic interaction between organic and mineral inputs.