Response of nitrogen emissions to land use changes and driving forces analysis in Jiangxi province under multiple scenarios

In recent decades, accelerated economic growth has positioned non-point source pollution as a critical threat to China's ecological security. Jiangxi Province, a pivotal ecological barrier in the middle-lower Yangtze River Basin, confronts escalating challenges in mitigating nitrogen pollution. This study systematically examined spatiotemporal land use dynamics in Jiangxi from 2000 to 2020 through statistical analysis and transition matrices, followed by multi-scenario projections (natural development, ecological conservation, and urban expansion) for 2030 using the Patch-generating Land Use Simulation (PLUS) model. The Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model was subsequently employed to simulate historical and scenario-based nitrogen emissions, while an optimal parameter geographical detector quantified driving mechanisms. Results revealed that 2,588 km² of cultivated and forest land was converted to construction land during 2000-2020. By 2030, the natural development scenario maintained historical trends, while the ecological protection scenario slowed construction land growth and increased ecological land area. Conversely, urban expansion intensified built-up land sprawl. Total nitrogen emissions initially rose then declined during 2000-2020, spatially characterized by localized growth in northern urban clusters and large-scale reductions in central-northern cropland emissions. Projected emissions for 2030 under natural development, ecological protection, and urban sprawl scenarios reached 5.05 × 10⁴ tons, 4.59 × 10⁴ tons, and 5.02 × 10⁴ tons, respectively. Cultivated land use intensity (X6) emerged as the dominant driver of spatial heterogeneity (highest q-value), while its interaction with the human footprint index (X10) exhibited the strongest explanatory power. This study provides actionable insights for optimizing land use patterns and mitigating nitrogen pollution in Jiangxi Province.