Water conservation areas play an important role in regional ecological security patterns. The Funiu Mountain water conservation area is located in the densely populated central region of China, where human disturbance to the ecosystem is strong and ecosystem services are facing a very serious situation. Identifying and evaluating the factors leading to changes in the ecosystem service value (ESV) of the Funiu Mountain water conservation area can provide scientific guidance for ecological management and sustainable development. Using multi-source data and machine learning methods, our research reveals the characteristics of the spatio-temporal variation in the ESV, constructs a system of ESV influencing factors from the comprehensive perspectives of the natural environment and human activities, and discusses the comprehensive effects of the influencing factors on the Funiu Mountain area from 2000 to 2015. The results are as follows. (1) From 2000 to 2005, the ESV increased 375 million yuan, and from 2005 to 2015, it decreased 154 million yuan. (2) Hydrological regulation, biodiversity maintenance, soil conservation, gas regulation, and climate regulation were the main types of ecosystem services in the Funiu Mountain area. (3) The ESV was influenced by the comprehensive effects of the natural environment and human activities. Population was the most important influencing factor of the ESV; in addition, the normalized difference vegetation index (NDVI), precipitation, and economic factors had important influences on the ESV. (4) With the intensification of human activities, humanistic factors have surpassed the relatively stable natural factors, becoming the main factors of the ESV. With economic development, the effect of human activities on the ESV may be further intensified in the future.

Crop yield stability and soil mineral nitrogen (Nmin) have rarely been evaluated from a long-term perspective in the extremely arid cropland regions of China. Therefore, a nationwide experiment aimed to optimize fertilizer application and increase productivity and nitrogen use efficiency in gray desert soils was initiated in 1990. Eight combinations of chemical fertilizers (CK, N, NK, NP, and NPK), straw return (NPKS), and manure amendments (NPKM and NPKM+) were tested for 24 years on spring wheat, winter wheat, and maize. The results displayed that the yield of three crops from balanced fertilizer treatments (NPK, NPKS, NPKM, and NPKM+) did not differ significantly after 24 years; however, reliable yield stability due to lower coefficient of variation (CV) and higher nitrogen harvest index (NHI) were recorded for manure amendment treatments. Compared to NPKM, NHI was lower for the NPKM+ treatment, but crop yield and stability did not improve, suggesting that the appropriate choice for manure amendment is important for guaranteeing food security in extremely arid regions. Balanced fertilizer treatments resulted in lower Nmin residual in the 300 cm soil profile, compared to unbalanced fertilizer treatments. The NPKS treatment gave the lowest value. In the 0–100 cm soil profile, Nmin was higher in NPKM than in the NPK treatment, suggesting that straw or manure amendment can effectively maintain Nmin in the topsoil undercurrent cropland management in arid areas. The NPKM treatment had the highest crop nitrogen recovery rate and the lowest nitrogen losses, further illustrating that manure amendment has higher N retention potential. Overall, although Nmin residues are relatively high in these regions, balanced fertilizer treatments, especially NPKM and NPKS, are the optimum strategies in extremely arid regions.

Against the backdrop of urban–rural integrated development, special ecological function zones, as spatial carriers with significant regional ecological value and rural development functions, are confronted with a striking conflict between ecological conservation and regional advancement. This contradiction is comprehensively reflected in the interactions among land use functions (LUFs) that differ in nature and intensity. Therefore, exploring the trade-off and synergy (TOS) among regional LUFs is not only of great significance for optimizing territorial spatial patterns and advancing rural revitalization but also provides scientific evidence for the differentiated administration of regional land use. Taking 185 townships in the Funiu Mountain area of China as research units, this study constructs a land use assessment system based on the ‘Production–Living–Ecological’ (PLE) framework, utilizing multi-source datasets from 2000 to 2020. Spearman correlation analysis, geographically weighted regression (GWR), and bivariate local spatial autocorrelation methods are employed to examine the spatio-temporal dynamics of LUFs and the spatial non-stationarity of their TOSs. The findings indicate that, throughout the research period, the production function (PF) displayed a fluctuating declining trend, whereas the living function (LF) and ecological function (EF) demonstrated a fluctuating increasing trend. Notably, EF held an absolute dominant position in the overall structure of LUFs. This is highly consistent with the region’s positioning as a special ecological function zone and also a direct reflection of the effectiveness of continuous ecological construction over the past two decades. Spatially, PF is stronger in southern, eastern, and northern low-altitude townships, correlating with higher levels of economic development; LF is concentrated around townships near county centers; and high EF values are clustered in the central and western areas, showing an opposite spatial pattern to PF and LF. A synergistic relationship is observed between PF and LF, while both PF and LF exhibit trade-offs with EF. The TOSs between different function changes demonstrate significant spatial non-stationarity: linear synergy was the primary type for PF-LF, PF-EF, and LF-EF combinations, but each combination exhibited unique spatial characteristics in terms of non-stationarity. Notably, towns identified as having different types of trade-off relationships in the study of spatial non-stationarity are key areas for township spatial governance and optimization. Through the allocation of regional resources and targeted policy tools, the functional relationships can be adjusted and optimized to attain sustainable land use.

A major obstacle to sustainable land management in ecologically sensitive areas is our limited understanding of the complex nonlinear mechanisms and threshold effects that dictate trade-offs between land use functions (LUFs). This study takes the Funiu Mountain area, a typical ecologically sensitive area in China, as a case study. At the township scale, the spatiotemporal patterns of LUFs from 2000 to 2020 were assessed based on the “production-living-ecological” function framework. The root mean square error (RMSE) model was introduced to quantify inter-functional trade-off intensity. Furthermore, the optimal parameters geographical detector (OPGD) and generalized additive model (GAM) were innovatively coupled to systematically analyze their driving mechanisms and nonlinear threshold effects. The results indicate that: (1) LUFs show clear functional complementarity and spatial game characteristics. The production function (PF) exhibits a heterogeneous pattern of “locally high, overall low”; the living function (LF) shows a local central agglomeration feature; and the ecological function (EF) displays a continuous gradient distribution of “high in the northwest, low in the southeast”. (2) The trade-off intensities between PF&EF and LF&EF are relatively strong, with high-value areas mainly distributed in the high-altitude central regions; while the trade-off intensity of PF&LF is weaker, with high-value areas mostly appearing in the central urban areas of each county. (3) The spatial heterogeneity of the trade-off relationship of LUFs is a comprehensive manifestation of the combined effects of the natural environment, socio-economic factors, and landscape patterns. The driving mechanisms of trade-off intensity among different functions show significant heterogeneity. (4) Key driving factors have significant nonlinear threshold effects. POP shows a complex dynamic regulatory effect with multiple thresholds and strong nonlinearity, while SLOPE, PET, and NDVI continuously play a fundamental constraining role in the trade-offs related to ecological functions. The key thresholds identified in this study can provide a direct scientific basis for regional differentiated territorial space governance.

Introduction: Cultivated land ecological security (CLES) is critical for food security and regional sustainability. Existing studies often assess CLES as a static composite index or focus mainly on external drivers, leaving its internal coupling relationships and obstacle mechanisms insufficiently explained. To address this gap, this study examines CLES in the middle and lower reaches of the Yellow River from 2005 to 2020 at the county scale. Methods: A DPSIR-based evaluation system and improved TOPSIS method were used to measure overall and subsystem-level CLES. We further constructed a multidimensional coupling coordination–equilibrium entropy model to quantify coordination among CLES subsystems and determine whether CLES problems stem from an overall decline or structural imbalance. An obstacle degree model identified the dominant obstacle subsystems and limiting factors. Results: High-value CLES areas shifted from the Huang-Huai-Hai Plain to the Northern Arid and Semi-arid Region and the southwestern Loess Plateau, while low-value areas shifted in the opposite direction. Subsystems remained mainly at the primary-to-intermediate coordination stage, indicating limited coupling coordination capacity. Equilibrium entropy showed marked spatial differentiation and staged fluctuations, revealing declining coordination stability and constrained ecological sustainability. Dominant obstacles evolved from agricultural non-point source pollution pressure to population–resource constraints and then to structural weaknesses in the agricultural economy. The Pressure subsystem remained the main obstacle, while the Driving Forces subsystem became increasingly restrictive. Discussion: These findings support more targeted cultivated land governance in ecologically fragile grain-producing regions.

Urban vitality varies systematically within the day, yet its time-specific associations with stable built-environment conditions remain insufficiently understood at fine spatial scales. This study examines two-hourly urban vitality in central Zhengzhou, China, using Baidu Heatmap-derived activity intensity and multi-source built-environment data at the parcel scale. Twelve two-hourly MGWR models form the primary analysis, identifying temporal changes in the direction, magnitude, and spatial distribution of local associations. A daily mean MGWR model with the same independent variables serves as an aggregate benchmark. Results show that: (1) vitality exhibited a clear daily pulse while retaining a persistent center–corridor–node structure, with Global Moran’s I ranging from 0.508 to 0.562; (2) the two-hourly MGWR models explained 69.1–81.8% of spatial variation, compared with 39.2–66.1% for OLS, while the daily mean MGWR achieved an R² of 0.791; and (3) relative to the benchmark, the two-hourly coefficient distributions revealed variable-specific association windows, directional transitions, and changing local dispersion across transportation, land-use, and facility variables. These findings establish the added interpretive value of two-hourly analysis, support time-sensitive management, and provide diagnostic evidence on how observed daily activity patterns are distributed in relation to stable urban configurations.