Straw return and nitrogen (N) fertilizer strongly regulate soil carbon (C) cycling in croplands. However, the differential responses of soil respiration (Rs) and its components, including heterotrophic respiration (Rh) and autotrophic respiration (Ra), to straw, straw-derived biochar, and N fertilizer remain unclear in semi-arid systems. A three-year (2019-2021) field experiment was conducted to quantify the effects of these management practices on Rs, Rh, Ra, their temperature sensitivity (Q10), and soil-crop interactions in a semi-arid maize farmland. This study evaluated three straw management methods (straw removal, straw incorporation, and straw-derived biochar incorporation) with or without N fertilizer application (300 kg ha(-1)). Results indicated that N fertilization increased mean C emissions through Rs by 24.0 %, with Rh and Ra increasing by 9.9 % and 62.9 %, respectively, compared with the unfertilized control (P < 0.05). Under conventional N fertilization, straw incorporation substantially stimulated Rh, increasing it by 85.5 % (P < 0.05) relative to the biochar treatment, which accelerated soil organic carbon (SOC) mineralization and partially offset the benefits of straw-derived C input. In contrast, straw-derived biochar increased the SOC sequestration rate (SOCr) by 8.9 % (P < 0.05) relative to straw incorporation and enhanced C emission efficiency (CEE) by 56.1 %. The Q10 of Rs ranged from 1.63 to 2.88, and Ra consistently showed higher Q10 than Rh. Soil temperature, soil moisture, and leaf area index together explained 42.7 % to 70.7 % of the seasonal variability in Rs, indicating strong coupling between soil hydrothermal conditions and crop canopy development. Overall, straw-derived biochar combined with N fertilizer resulted in significantly higher SOCr (2.45 Mg C ha(-1) yr(-1)) and reduced microbial C losses compared with straw incorporation. This demonstrates its greater potential for improving soil sustainability and mitigating C emissions in semi-arid agricultural regions.