Protecting soil quality-particularly its chemical and biological components-is essential for sustaining agricultural productivity and conserving soil resources in rainfed agroecosystems. The Zagros region of western Iran, characterized by sloping rainfed croplands and recurrent drought stress, is particularly vulnerable to soil degradation under conventional management. Inappropriate crop and tillage management practices are among the primary drivers of soil degradation, leading to declines in soil organic carbon (SOC), nutrient availability, and biological activity. This study aimed to evaluate the long-term effects of tillage systems and crop residue management on soil quality indicators including SOC concentration and stock, nutrient dynamics, soil microbial respiration and soil bulk density in rainfed lands of western Iran. A five-year field experiment was conducted at the Sararoud Rainfed Research Station using a split-split plot arrangement within a randomized complete block design with three replications. Tillage systems-including conventional tillage, combined tillage, chisel tillage, and direct seeding (no-till)-were assigned to main plots, while residue management levels (0, one-third, and two-thirds residue retention) were allocated to subplots under a rainfed wheat-chickpea rotation. Soil samples were collected annually from 0 to 15 and 15 to 30 cm depths to determine SOC stocks, macronutrients (N, P, K), micronutrients (Fe, Zn, Mn, Cu), and biological indicators, including microbial respiration. Treatment effects were assessed using analysis of variance and Duncan's multiple range test at the 5% significance level. The results demonstrated that conservation agriculture practices significantly enhanced soil quality compared to conventional tillage. Integrated application of no-till or reduced tillage with residue retention increased SOC stocks by up to 65% over the study period. Nutrient availability, particularly phosphorus and iron, improved markedly under residue-retained conservation treatments. Soil microbial respiration showed high sensitivity to management practices, increasing from 0.21 mg COQ g-1 soil 24 h-1 under conventional tillage to 0.34 and 0.32 mg COQ g-1 soil 24 h-1 under no-till and two-thirds residue retention, respectively. Soil bulk density was significantly reduced under no-tillage (1.432 g cm-3)compared to conventional tillage (1.626 g cm-3). Overall, the findings highlight the effectiveness of conservation tillage combined with residue retention in restoring soil chemical fertility, enhancing biological activity, and increasing carbon sequestration in sloping rainfed systems of the Zagros region.