Land degradation neutrality assessment in China’s black soil region: integrating multi-source LULC data and innovative quantitative indicators

• A fused LULC dataset was developed to reduce inconsistencies in multi-source data. • A new Land Degradation Neutrality Index enables quantitative LDN assessment. • Human activities, especially urbanization and GDP growth, hinder LDN achievement. • There exists a mismatch between land use patterns and natural ecological capacity. Land degradation threatens sustainable development in China’s black soil region, a key grain-producing area renowned for its fertile soils and high organic matter content but highly sensitive to anthropogenic pressures and climate variability. This study aimed to assess land degradation neutrality (LDN) at multiple spatial scales by integrating a fused land use/land cover (LULC) dataset. A harmonized LULC product was developed through spatial consistency analysis of multi-source datasets, and a novel Land Degradation Neutrality Index (LDNI) was introduced to quantify the balance between degraded and improved land areas at the county level. Additionally, a structural equation model was employed to explore the relative contributions of human and natural factors to LDN outcomes. Results showed that between 1995 and 2020, land degradation and improvement covered 17.79 × 10 4 km 2 and 13.32 × 10 4 km 2 , respectively. The net negative balance of −4.47 × 10 4 km 2 indicates that degradation exceeded improvement, implying a failure to achieve LDN. Furthermore, 66.6 % of physiographic regions, 62.5 % of cities, and 69.4 % of counties failed to reach LDN targets. Across different physiographic regions, the Food Production Function LDNI (FPF_LDNI) ranged from −0.90 to 0.00, whereas the Ecosystem Service Function LDNI (ESF_LDNI) ranged from −0.32 to 0.38, suggesting higher LDN achievement in ecological land (forest, grassland, and wetland) than in cropland. Economic and social factors related to human activities were the main drivers influencing the achievement of LDN. The standardized direct effects of population on ESF_LDNI and FPF_LDNI were 0.890 and 0.601, respectively, whereas GDP exhibited significant negative effects of −0.715 and −0.759. These results indicate that increasing population tended to promote land management, whereas rapid economic growth intensified land degradation around metropolitan areas. This study offers a transferable framework for LDN assessment and provides scientific support for sustainable land-use strategies and policymaking in China’s black soil region and other vulnerable agricultural areas worldwide.