Objective As a pivotal process in the terrestrial carbon cycle, accurate quantification of soil respiration is critical for deciphering global carbon budget balance. This study aimed to overcome the regional applicability limitations of traditional models by reconstructing model coefficients, to analyze the spatial distribution characteristics of soil respiration in Northeast China and to elucidate the mechanisms of environmental drivers, in order to provide scientific support for carbon sink management in China's black soil region.

Method Based on four mainstream soil respiration estimation models, the model coefficients were calibrated using field-measured data to optimize the estimation model (R²=0.40, RMSE=0.16). The random forest algorithm was employed to quantify the influence of environmental factors. Subsequently, hierarchical analyses of soil respiration were conducted across provinces, climatic zones, soil types, and land-use patterns.

Result Soil respiration rates in Northeast China ranged from 0.02 to 1.34 kg C m⁻² a⁻¹ (with an average of 0.37 kg C m⁻² a⁻¹). Spatially, higher respiration rates were observed in northern and southeastern regions, while lower values dominated western and central areas. Regions with higher evapotranspiration and temperature exhibited lower soil respiration, whereas areas with elevated net primary productivity, organic carbon stocks and humidity showed higher values. Heilongjiang Province recorded the highest mean soil respiration (0.45 kg C m⁻² a⁻¹), while Liaoning Province had the lowest (0.24 kg C m⁻² a⁻¹). The Greater and Lesser Khingan Mountains region displayed the maximum respiration (0.62 kg C m⁻² a⁻¹), contrasting with the minimum in the Liaohe Plain (0.19 kg C m⁻² a⁻¹). Among soil types, brown coniferous forest soil exhibited the highest respiration (0.81 kg C m⁻² a⁻¹), while solonetz showed the lowest (0.15 kg C m⁻² a⁻¹). Forest land-use displayed the maximum respiration (0.56 kg C m⁻² a⁻¹), whereas paddy fields had the minimum (0.26 kg C m⁻² a⁻¹).

Conclusion Soil respiration in Northeast China demonstrated pronounced spatial heterogeneity, synergistically regulated by hydrothermal conditions and carbon pool quality. Significant regional disparities existed, with mountain ecosystems exhibiting substantially higher respiration than plains. Forest soils and natural vegetation zones dominated soil carbon efflux. This research will advance the understanding of soil carbon cycling mechanisms in Northeast China and provide critical insights for evaluating carbon budget equilibrium in black soil ecosystems and their responses to global climate change.