The digital economy is a new economic form that has a significant impact on urban land green use efficiency (ULGUE). With the provincial panel data between 2013 and 2021, this paper empirically tests how the digital economy development level (DEDL) promotes the improvement of ULFUE in China. The key findings include the following: (1) There were significant spatial differences for the ULGUE and DEDL of China. For China’s ULGUE, China shows an ascent after an initial decline trend from 2013 to 2017, but a decline trend after 2017. China’s DEDL took on a rising tendency during the research period. In 2021, China’s DEDL increased by 143.8% compared with that in 2013. (2) The digital economy can obviously promote the ULGUE, but the promotion effect is affected by the urbanization level; with improvements in urbanization level, the impact of that may strengthen. (3) Technological innovation demonstrates a complete intermediary effect between the digital economy and ULGUE; the mediation transmission mechanism of technological innovation is evident. These results have been verified by robustness tests, proving their stability and reliability. The research results will provide new insights into the high-quality utilization of urban land resources.

Farmland use transition (FUT) not only reshapes agricultural production systems but also significantly impacts cross-regional carbon sink transfers in the grain trade. However, comprehensive studies exploring connections between FUT and grain carbon sink transfer (GCST) are limited. We constructed an indicator system and transformation framework for FUT by considering dominant and recessive dimensions. Moreover, we estimate GCST based on grain supply–demand balance and fixed carbon coefficients. Fixed effects and threshold models are employed to identify both linear and nonlinear relationships between FUT and GCST. Results show that FUT significantly reshapes carbon sink flows. In terms of dominant FUT indicators, cultivation land rate (CLR) and grain planting area proportion (GPAP) positively drive GCST by expanding the carbon sink supply and exporting ecological services. Regarding recessive FUT indicators, both grain yield per unit area (GYield) and pesticide-fertilizer intensity (PFI) promote GCST, highlighting the role of efficiency and inputs, while rural per capita disposable income (RPCDI) suppresses GCST due to agricultural marginalization. A grain yield threshold of 2.092 t/ha is identified. Below this value, FUT exerts substantial positive effects on GCST. Above it, the effects weaken. This study explains the relationship between FUT and ecosystem carbon sinks, providing a scientific basis for advancing green agriculture in karst mountainous areas.

Understanding how ecological quality and human activity co-evolve in densely populated watersheds is essential for sustainable land management, yet spatially explicit long-term evidence remains limited. This study investigated the spatiotemporal dynamics and coupling coordination between ecological quality and multi-dimensional human activity intensity in the Huai River Basin (approximately 269,000 km²) from 2012 to 2024. An Improved Remote Sensing Ecological Index (IRSEI) was constructed by integrating EVI, wetness, dryness, land surface temperature, and a salinity index through annual principal component analysis. A composite Human Activity Intensity (HAI) index combining nighttime light, built-up intensity, and population density was derived with objectively determined weights. The coupling coordination degree (CCD) model and a pixel-level four-quadrant classification were then applied to characterize the human–environment interaction. Results showed that the basin-wide mean IRSEI declined from 0.564 in 2012 to 0.516 in 2020, before recovering to 0.566 in 2024, while HAI increased moderately by 16.9%. CCD improved slightly from 0.451 to 0.480, indicating limited but positive coordination gains. Four-quadrant transitions revealed that high-ecology, low-activity areas expanded, low-ecology, low-activity areas contracted, whereas low-ecology, high-activity zones persisted as stable pressure cores. These findings demonstrate that ecological recovery and human activity intensification can coexist spatially, but persistent high-pressure areas require targeted management interventions.

Composite environmental risks accumulate unevenly along urban–rural gradients, yet the conditional and nonlinear interaction between built environment quality (BEQ) and urban–rural functional connectivity (URFC) remains poorly quantified at fine resolution. This study aims to determine whether, and under what conditions, BEQ moderates the relationship between URFC and a population-weighted composite risk index (CRI), and to translate the result into spatia targeted green-infrastructure priorities. We use 744,714 grid cells at 100 m resolution over Guangzhou, China. The framework couples entropy-weighted BEQ from satellite and street-view imagery, gravity-model URFC computed on the real road network, and a two-stage population-weighted CRI of heat and air hazards. We apply nested ordinary least squares with incremental F-tests, spatial-lag and spatial-error models, generalised additive models with B-spline bases, gradient-boosted trees with SHAP interaction values, and Baron–Kenny mediation analysis. The main BEQ × URFC estimates are negative across the parametric and machine-learning specifications. The interaction is, however, small: a spatial-lag model on a 10,000-cell subsample returns β = −5.4 × 10⁻⁴, but a scalable generalised-method-of-moments spatial regression on the full grid—where the spatial autoregressive coefficient reaches ρ ≈ 0.99—shows the coefficient to be negative yet not statistically significant, and a five-seed re-estimation confirms that the subsample-based significance is draw-dependent. We therefore interpret the buffering as directionally supported but small and not robustly significant once spatial autocorrelation is fully modelled. The buffering response is nonlinear in the GAM main effects, and BEQ buffers across the entire observed connectivity range rather than switching sign at an interior threshold; URFC functions predominantly as a moderator rather than a mediator. Population-stratified estimation shows that the buffering is exposure-conditional: it is strongest where population exposure is high and weakens or reverses in sparsely populated cells, consistent with the risk = hazard × exposure structure of CRI. Sensitivity tests across values of the distance-decay parameter, 100 entropy perturbations and spatial scales corroborate the buffering direction. The framework provides an evidentiary basis for prioritising green infrastructure in functionally connected, populated but environmentally degraded transition zones.

Narrowing the urban–rural divide is a critical challenge for developing countries and a core concern of the United Nations 2030 Agenda for Sustainable Development (particularly Sustainable Development Goals (SDGs) 10 and 11). To this end, China has launched pilot reforms of the rural homestead system to optimize the allocation of land resources, revitalize idle rural construction land, and advance the sustainable development of urban–rural integration (URI). Treating the rural homestead system reform pilots as a quasi-natural experiment, this study employs the difference-in-differences (DID) method based on panel data of 1380 counties (districts and county-level cities) in China from 2010 to 2021 to identify the reform’s impacts on county-level URI (an inverse measure of the urban–rural divide) and its transmission channels. The results show that the rural homestead system reform increases the URI index of pilot counties by an average of 0.102 units relative to non-pilot counties (cluster-robust standard error = 0.046, significant at the 5% level). This finding remains robust after a battery of tests including placebo tests, winsorization, lagged treatment and the exclusion of potentially affected controls. The policy effect exhibits obvious heterogeneity and is more pronounced in regions with higher baseline URI, municipal districts, county-level cities, as well as eastern and northeastern China. Mechanism tests further indicate that the reform functions through three channels: optimizing the allocation of urban and rural labor, accelerating the flow of capital factors, and promoting industrial structure upgrading. Specifically, labor, capital and industrial structure indicators at the county level rise significantly by approximately 1.5%, 3.2%, and 0.8%, respectively (coefficients equal to 0.0150, 0.0314, and 0.0076, all significant at the 1% level). The URI evaluation index constructed in this paper covers five dimensions: population, space, economy, society and ecology. Incorporating the ecological dimension enables the measurement of URI to reflect the multiple goals of sustainable development. The findings provide policy implications for deepening rural land system reform and advancing high-quality URI.

This study examines the spatiotemporal evolution and driving mechanisms of urban expansion in the Guangxi Zhuang Autonomous Region, China, from 2013 to 2023. Using Suomi-NPP VIIRS nighttime light (NTL) data, we combine Standard Deviational Ellipse (SDE) analysis, centroid migration, kernel density estimation (KDE), landscape metrics, Local Moran’s I (LISA), and system Generalised Method of Moments (system-GMM) estimation. The results show that the centroid of urban development remained within Binyang County while moving overall toward the southeast with recurrent north–south oscillations. The SDE results indicate a stable northeast–southwest orientation, with secondary expansion in other directions. The urban structure is dominated by a strong Nanning core, accompanied by secondary clusters in Liuzhou, Guilin, and other prefecture-level cities. Nanning recorded the largest absolute expansion, followed by secondary centres, including Liuzhou, Guilin, Yulin, Wuzhou, Fangchenggang, Qinzhou, and Beihai, whereas western and northern Guangxi expanded more slowly. The system-GMM results indicate that financial deepening has a marginally significant positive effect on built-up area expansion and fiscal pressure has a marginally significant constraining effect, both at the 10% level; land finance dependency does not emerge as an independent driver in this small panel. We interpret these findings through a Source–Channel–Valve framework, in which financial deepening provides the capital source, land finance represents a hypothesised institutional channel, and fiscal pressure acts as a regulatory constraint. The study provides empirical evidence for sustainable and regionally coordinated urban development in Guangxi and comparable geographically constrained regions.