How does urban-rural integration shape land green use efficiency? Spatial and non-linear effects from Northeast China

Urban-rural integration(URI) is a key pathway to promoting the equitable distribution of land resources and achieving sustainable land use in developing countries. However, how URI influences land green use efficiency (LGUE) remains insufficiently understood, especially in the context of regions characterized by pronounced urban-rural disparities. This study constructs a systematic analytical framework combining the Super-SBM model for LGUE measurement, a Spatial Durbin Model (SDM) to decompose the direct and spillover effects of URI on LGUE, and a TabPFN-SHAP pipeline capable of capturing nonlinear threshold effects to identify vital drivers across production, living, and ecological functions. The results reveal that: (1) URI and LGUE display divergent temporal patterns, with URI following an S-shaped trajectory(increased by 28.23%) and LGUE exhibiting a fluctuating upward trend (rose by 49.72%), accompanied by significant heterogeneity across city types; (2) URI significantly promotes the improvement of LGUE, with evident spillover effects on neighboring cities, showing marked regional heterogeneity;(3)SHAP decomposition reveals that labor mobility and asset allocation within production function, alongside ecological greening levels in ecological function, are the primary drivers of LGUE, all exhibiting significant nonlinear dose-response patterns. The findings provide empirical evidence and policy insights for developing countries undergoing industrial structural transitions on the potential role of URI in optimizing land green use transformation.