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C. spectabilis (Crotalaria spectabilis), a large leguminous herb species, is widely distributed in tropical and subtropical regions, and it has important ecological and economic values. However, the ecological adaptation of the major leaf functional traits of the species across different habitats and canopy positions remains poorly understood. To address this gap, we sampled leaves from the upper, middle, and lower canopy positions in two common habitats—forest understory and exposed land—and quantified key leaf traits as well as trait–trait relationships to assess differences. The results showed that irradiance and air temperature were significantly lower in the understory than in exposed land, whereas soil moisture and relative humidity were higher, indicating that habitat exerted a stronger influence on leaf traits than canopy position. Canopy position also significantly affected most traits and showed significant interactions with habitat. In exposed land, middle plants exhibited higher individual leaf dry mass (180.049 ± 68.480 mg), larger vein diameter (1.692 ± 0.288 mm), and longer petioles (5.406 ± 0.940 mm). These traits were accompanied by a higher morphology-based leaf dry matter accumulation rate and greater stability of the leaf-trait network, reflecting an adaptive strategy characterized by increased structural investment. In contrast, understory middle leaves were generally longer (13.361 ± 2.714 cm) and wider (7.005 ± 1.464 cm), along with lower photosynthate accumulation rates and weaker trait-network stability, indicating a strategy that enhances light-use efficiency under low-light conditions. In both habitats, leaves from the middle canopy position generally exhibited the highest values for most measured traits. Overall, leaf traits of C. spectabilis and their interrelationships showed considerable plasticity in response to external environmental pressures, primarily differences in light availability. However, from a practical production perspective, minimizing shading is recommended to maximize its ecological benefits. Full article

Maize–soybean intercropping can improve land use efficiency and increase crop yields, thereby contributing to sustainable agricultural development. This study aimed to investigate the marginal effects of intercropping on dry matter accumulation and the extinction coefficient (K) of maize and soybean canopies, thereby providing theoretical guidance for efficient resource utilization and the realization of high-yield and high-efficiency maize–soybean intercropping systems. This experiment employed maize variety Jincheng 316 and soybean variety Heinong 531. Two intercropping treatments (S4M4: four rows soybean alternating with four rows maize; S6M4: six rows soybean alternating with four rows maize) and two sole cropping controls (M: sole maize; S: sole soybean) tested the marginal effects of different intercropping patterns on crop dry matter accumulation, SPAD, and K. Combined with analyses of yield, land equivalent ratio (LER), and intercropping advantage (IA), we determined the optimal row ratio configuration for intercropping. The results showed that, compared with monocropped maize, the leaf SPAD at the R1 stage and grain dry matter accumulation at the R6 stage under S4M4 and S6M4 treatments increased by 17.28%/20.12% and 8.07%/5.35%, respectively, while K values decreased by 21.80% and 14.37%. For soybean, relative to monocropping, the R4 leaf SPAD and R8 grain dry matter accumulation under S4M4 and S6M4 were elevated by 23.87%/19.40% and 26.66%/13.56%, respectively, with corresponding K values reductions of 21.94% and 21.82%. Moreover, S4M4 exhibited a 51.67% higher IA and a 9.48% higher LER than S6M4. In summary, maize–soybean intercropping significantly boosts dry matter accumulation and resource use efficiency, with the S4M4 configuration exhibiting the most distinct advantages. Full article

Agrivoltaic (AV) systems offer a promising solution to global challenges, such as land scarcity, food insecurity, and increasing energy demand, by enabling the simultaneous production of photovoltaic (PV) electricity and agricultural outputs on the same land. This review synthesizes more than two decades of interdisciplinary research on solar–agriculture integration, including agrivoltaic systems, biomass-based approaches, and greenhouse-integrated photovoltaic technologies, with particular emphasis on their relevance to arid and semi-arid environments, such as those found in the Middle East. The impacts of different PV configurations (such as semi-transparent, bifacial, vertical, and sun-tracking modules) on crop productivity, microclimatic conditions, and land-use efficiency are critically examined. The findings indicate that AV systems, particularly in water-scarce, high-irradiance regions, can enhance climate resilience, reduce competition for land, and improve both energy and water-use efficiency. Recent advances in crop selection strategies, adaptive PV system designs, and smart irrigation technologies further strengthen the feasibility of these systems for Middle Eastern agricultural systems. Nevertheless, key challenges remain, including the need for region-specific design optimization, improved understanding of crop light requirements, and robust assessments of economic viability under diverse policy and market conditions. Overall, life cycle assessments and techno-economic analyses confirm the environmental and economic benefits of AV systems, especially for sustainable irrigation, agricultural productivity, and rural development in the Middle East context. This review provides strategic insights to support the sustainable deployment and scaling of agrivoltaic systems across Middle Eastern agricultural landscapes, informed by global experience. A dedicated regional assessment summarizes existing agrivoltaic pilots and feasibility studies across the Middle East and North Africa, highlighting technology choices, crop compatibility, and policy drivers. Full article

Agriculture in semi-arid regions faces increasing challenges from temperature extremes and moisture stress, necessitating climate-smart and resource-efficient production systems. This study examined maize–mushroom intercropping as a climate-smart strategy for semi-arid regions. Field experiments conducted at Tamil Nadu Agricultural University evaluated four maize planting geometries, with and without mulch, in 2022. Results showed that close-maize spacing (45 × 25 cm) with mulch moderated temperature, increased humidity, and improved mushroom yield and biological efficiency. The treatment achieved a land equivalent ratio above one, indicating superior land use efficiency. Optimal microclimatic conditions (26–33 °C; 80–98% RH) enhanced paddy straw mushroom growth, demonstrating that simple field-level modifications can stabilize microclimate and promote resilient farming in semi-arid ecosystems. Full article

In the rapidly urbanizing Global South, megacities face a perplexing “paradox of idleness”: acute land scarcity in the urban core coexisting with inefficient rural homesteads in the hinterland. Using Shanghai as a representative case, this study integrates spatial autocorrelation analysis with Geographical Detector modeling to quantify the spatial differentiation patterns and driving mechanisms of this phenomenon. The results reveal a distinct core-periphery gradient, with vacancy density increasing from the inner suburbs to the remote hinterland. Four regional typologies were identified: dispersed-inefficient, high-density accumulation, sparse-stable, and intensive-efficient. Quantitative analysis identifies demographic aging and low agricultural efficiency as dominant drivers. Counter-intuitively, the study finds that top-down institutional pilots alone exert a negligible direct impact. Instead, interaction analysis confirms a significant policy-bundling effect, in which institutional tools promote revitalization only when coupled with economic and locational incentives. These findings expose a mechanism of “involuntary vacancy” trapped by institutional rigidity, distinct from the market-driven abandonment seen in shrinking or remote Western contexts. Consequently, a gradient-based governance framework is proposed to transition from “one-size-fits-all” regulation to targeted spatial restructuring pathways. Full article

For a long time, low efficiency in the transfer of rural collective land use rights and the ambiguous attribution of collective land property rights have not only restricted the mobility of rural labor factors but have also hindered the release of vitality in the rural collective economy. This has resulted in lagging growth in the income that rural residents obtain from collective economic factors, contributing to the persistent widening of the urban/rural income gap. As an important institutional innovation to address these issues, the effects of the reform of the rural collective property rights system urgently need to be clarified. The reform of the rural collective property rights system constitutes a major initiative in the transformation of the rural land system. Centered on asset verification and valuation, as well as the demarcation of membership rights and the restructuring towards a shareholding cooperative system, it aims to establish a collective property rights regime characterized by clearly defined ownership and fully functional entitlements. This study takes the national pilot reform of rural collective property rights launched in 2016 as a quasi-natural policy experiment, systematically examining the impact of this pilot policy on the internal income gap within households and its spillover effects on the urban–rural income gap. Based on microdata from the China Household Finance Survey (CHFS) and the China Longitudinal Night Light Data Set (PANDA-China), this study constructs a five-period balanced panel dataset covering 2304 rural households across 25 provinces. A relative exploitation index based on the Kawani index is constructed, and empirical analysis is conducted using a combination of multi-period difference-in-differences (Multi-period DID), discrete binary models, and propensity score matching-difference-in-differences (PSM-DID) models. The results show that: First, the pilot reform significantly reduced the level of income inequality within rural areas in the pilot regions, and its policy benefits further generated positive spillovers via market-driven factor allocation mechanisms, effectively bridging the urban–rural income gap. Second, institutional reforms activated the potential of rural non-agricultural economic factors, establishing new channels for a two-way flow of urban and rural factors, becoming an important path to achieve the goal of common prosperity. Third, the policy effects exhibited significant heterogeneity, specifically manifested in the attributes of major grain-producing regions, initial household income levels, and the human capital characteristics of household heads having significant moderating effects on reform outcomes. This study not only provides theoretical support and empirical evidence for deepening rural property rights reforms under the new rural revitalization strategy, but it also reveals the driving role of institutional innovation in factor mobility, thereby influencing the transmission mechanism of income distribution patterns. This finding offers a China-based solution for developing countries to address the imbalance in urban–rural development and the widening income gap. Full article

With accelerating urbanisation, extreme rainfall events have become increasingly frequent, leading to rising urban flooding risks that threaten city operation and infrastructure safety. The rapid expansion of impervious surfaces reduces infiltration capacity and accelerates runoff responses, making cities more vulnerable to short-duration, high-intensity storms. Although the SWMM is widely used for urban stormwater simulation, its application is often constrained by the lack of detailed drainage network data, such as pipe diameters, slopes, and node connectivity. To address this limitation, this study focuses on the main built-up area within the Second Ring Expressway of Chengdu, Sichuan Province, in southwestern China. As a regional core city, Chengdu frequently experiences intense short-duration rainfall during the rainy season, and the coexistence of rapid urbanisation with ageing drainage infrastructure further elevates flood risk. Accordingly, a technical framework of “open road data substitution–automated modelling–SWMM-based assessment” is proposed. Leveraging the spatial correspondence between road layouts and drainage pathways, open road data are used to construct a virtual drainage system. Combined with DEM and land-use data, Python-based automation enables sub-catchment delineation, parameter extraction, and network topology generation, achieving efficient large-scale modelling. Design storms of multiple return periods are generated based on Chengdu’s revised rainfall intensity formula, while socioeconomic indicators such as population density and infrastructure exposure are normalised and weighted using the entropy method to develop a comprehensive flood-risk assessment. Results indicate that the virtual drainage network effectively compensates for missing pipe data at the macro scale, and high-risk zones are mainly concentrated in densely populated and highly urbanised older districts. Overall, the proposed method successfully captures urban flood-risk patterns under data-scarce conditions and provides a practical approach for large-city flood-risk management. Full article

District heating systems are central to Europe’s decarbonisation strategy and its 2050 climate-neutrality objective. However, district heating is deeply embedded in the socio-economic system and the built environment. This makes compliance with policy targets at the local level particularly challenging. The issues are attributable to two factors. Firstly, the process is characterised by a high degree of complexity and multidimensionality. Secondly, there is a scarcity of local resources (e.g., land, surface waters, waste heat, etc.). In Bucharest, Romania, the largest district heating system in the European Union, the process of decarbonisation represents a particularly complex challenge. The system is characterised by large physical dimensions, high technical wear, heavy dependence on natural gas, significant heat losses and complex governance structures. This paper presents a strategic planning exercise for aligning the Bucharest system with the Energy Efficiency Directive 2023/1791. Drawing on system data, investment modelling, and local resource mapping from the LIFE22-CET-SET_HEAT project, the study evaluates scenarios for 2028 and 2035 that shift heat generation from natural gas to renewable, waste heat, and high-efficiency sources. The central objective is the identification of opportunities and issues. Options include large-scale heat pumps, waste-to-energy, geothermal and solar heat. Heat demand profiles and electricity price dynamics are used to evaluate economic feasibility and operational flexibility. The findings show that the decarbonisation heat supply in Bucharest is technically possible, but financial viability hinges on phased investments, interinstitutional coordination, regulatory reforms and access to EU funding. The study concludes with recommendations for staged implementation, coordinated governance and socio-economic measures to safeguard heat affordability and system reliability. Full article

Urban Air Mobility, including electric vertical takeoff and landing vehicles (eVTOL), offer a promising solution to alleviate road traffic congestion and enhance transportation efficiency in cities. However, to ensure its sustainability and operational safety, there is a need for the integrated optimization of eVTOLs and power systems which power these vehicles. Sensors play an important role in data acquisition for the model optimization especially for an environment with high uncertainty. Meanwhile, a quantitative assessment of the eVTOL’s safety level is essential for effective and intuitive supervision. This paper addresses the challenge of achieving both green and safe eVTOLs by proposing an integrated optimization framework. The framework minimizes the costs of eVTOLs and power system operation, and maximizes passenger capacity, by considering the energy stored in the eVTOL as a safety measure. IEEE 2668, a global standard that uses IDex to evaluate application maturity, is incorporated to assess the safety level during the optimization process. A case study for three Chinese cities showed that eVTOLs can utilize inexpensive surplus energy. Full article

Land degradation issues are getting complicated worldwide. Kazakhstan’s land use has sharply deteriorated over several decades, necessitating comprehensive assessment and restoration. Farmlands in Kazakhstan are grappling with multiple challenges related to climate change, intense anthropogenic disturbances, and aggressive industrial agricultural practices involving monoculture crop production. Soil depletion is widespread in Kazakhstan due to flood erosion and drought expansion, causing desertification. The land sustainability of farmland improvement, including the soil, geology, and water retention assessment, is currently under investigation through our project activities in North Kazakhstan. Nature-based methods for forest plantation along contour strips and topography-based design landscapes are rarely applied or are absent in many rural areas these days. The land use issues have resulted in the loss of the soil moisture protective functions and a reduction in agricultural efficiency. Geodesy geomatics tools were applied for a topography investigation with digital elevation, digital terrain model preparation, and potential retention ponds’ location identification for managed aquifer recharge introduction. The combination of effective water accumulation methods, considering topography, with the development of protective forest shelterbelts should enhance the land use strategies for sustainable development. This strategy is expected to reduce soil erosion, promote moisture accumulation, by improving the soil’s quality as a sponge in water collection, and increase crop yields. Alongside this, a system for developing the retention ponds with managed aquifer recharge locations for proper water collection to improve the agrolandscapes was presented. Full article

This study investigates the impact mechanism of distorted land supply structures on green economic efficiency in Chinese cities, with a particular focus on the mediating and moderating role of the real estate market. Innovatively, the study constructs a comprehensive index to measure land supply structure distortion and employs spatial econometric methods for empirical analysis using panel data from 285 prefecture-level and above cities in China from 2010 to 2022. The findings reveal that: (1) distortions in land supply structure significantly hinder the improvement of urban green economic efficiency (GEE); (2) this inhibitory effect exhibits a significant spatial spillover effect; (3) housing prices play a notable mediating and moderating role in the relationship between land supply structure distortion and green economic efficiency; (4) the impact mechanisms demonstrate significant regional heterogeneity. These findings offer important policy implications for optimizing urban land supply structures and promoting green economic development. Full article

With the acceleration of digitalization, smart cities have emerged as a key institutional practice reshaping urban governance and spatial development. However, the impact of smart cities on land use efficiency and the conditions under which these effects are shaped by interactions among different policy tools remain insufficiently understood. This study adopts a policy mix perspective, situating smart city pilots within an institutional environment shaped by regulatory, incentive-based, and enabling policy tools, and systematically examines their impact on land use efficiency and underlying mechanisms. Based on data of 285 Chinese prefecture-level cities over 2000–2021, the study treats smart city pilot as a quasi-natural experiment and applies a staggered difference-in-differences (DID) design, supplemented by moderation and triple-difference models. The results indicate that the smart city pilot significantly enhances land use efficiency overall, although the effects vary across regions and topographical conditions. Further analysis reveals that policy tools with different functional attributes exert differential moderating effects: regulatory policy tools, represented by environmental regulation intensity, negatively moderate the land use efficiency gains of smart cities, while incentive-based tools, such as science and technology fiscal incentives, positively amplify these effects. Additionally, cities implementing both smart city pilots and the “Broadband China” Strategy pilot experience significantly greater improvements, highlighting the enabling policy tools in amplifying smart city performance. Overall, the impact of the smart city pilot on land use efficiency is not isolated but highly contingent on the surrounding policy mix. Interactions among policy tools systematically shape land use outcomes under digital urban governance, offering actionable insights for coordinated policy design. Full article

This study examines how investment efficiency and risk jointly shape sustainable grain supply-chain upgrading. Using firm-level panel data for 25 listed grain supply-chain firms in China from 2015 to 2023, this study examines efficiency–risk structures and their heterogeneity across upstream, midstream, and downstream segments. A three-stage data envelopment analysis (DEA) is applied to measure investment efficiency while controlling for environmental heterogeneity and statistical noise, and a multidimensional investment risk index is constructed using principal component analysis (PCA), with an emphasis on sustainability metrics. The results reveal a clear supply-chain gradient: downstream firms exhibit the highest mean third-stage investment efficiency (crete = 0.633) and scale efficiency (scale = 0.634), midstream firms are intermediate (crete = 0.308; scale = 0.326), and upstream firms remain lowest (crete = 0.129; scale = 0.138). This ordering is also visible year by year, while risk profiles indicate higher exposure upstream and pronounced volatility midstream. Efficiency decomposition shows that upstream inefficiency is mainly driven by scale inefficiency rather than insufficient pure technical efficiency. Overall, efficiency–risk mismatch—manifested as persistent low scale efficiency and elevated risk exposure in upstream, volatility in midstream, and stability in downstream—constitutes a key micro-level barrier to long-term and resilient upgrading. The study thus offers policy-relevant insights for segment-specific interventions that align with sustainable agricultural development: facilitating land consolidation and integrated risk management for upstream scale inefficiency, promoting supply-chain finance and digital integration for midstream risk volatility, and leveraging downstream stability to drive coordinated upgrading and sustainable value creation through market-based incentives. Full article

Drawing on evidence from China’s land market, this study systematically investigates the impact of land misallocation on economic resilience and reveals the underlying mechanism that operates by suppressing technological advancement. A theoretical model of economic resilience is developed, incorporating technology and factor allocation. Empirical analysis is conducted using a panel dataset of 95 Chinese cities (2012–2024) through spatial econometric and mediation models. The findings indicate that land misallocation significantly reduces local economic resilience and exhibits negative spatial spillover effects. The core mechanism is identified as follows: subsidies via low-priced industrial land delay the market exit of low-efficiency firms, hindering the reallocation of production factors to more productive sectors. This suppression of technological progress ultimately weakens a region’s capacity to withstand external shocks. Based on the findings, policy implications include optimizing land supply structure, accelerating fiscal system reform, and strengthening policy coordination. Full article

The accumulation of municipal sewage sludge is a worldwide problem, although when properly treated, it can be utilized for various purposes in industry and agriculture. Due to its high nutrient content, one of its possible uses is the application as fertilizer on agricultural or degraded lands with the purpose of non-food plant production. In the present study, the sustainability of dehydrated sewage sludge application was tested in Szarvasi-1 energy grass (Thinopyrum obtusiflorum cv. Szarvasi-1) plantations, with special focus on the turnover of nutrients and trace elements in two experiments conducted outdoors between 2016 and 2019. Experiment 1 was conducted in 1 m³ containers, and the treatment was started on two-year old plants in 0, 15, 22.5, and 30 Mg ha⁻¹ doses per year applied in two or three portions to reveal the upper limit of sludge application. Experiment 2 was conducted in 100 m² field quadrates with 0, 7.5, 15, and 22.5 Mg ha⁻¹ doses per year applied once a year, which is in the range of the currently permitted application dose in Hungary. Soil, sludge, and plant samples, as well as physiological data, were collected. Aboveground biomass yield was measured 2–3 times per year. Increasing doses of sewage sludge significantly increased the yield compared to the controls, but the increment between the second and third doses was small. Chlorophyll content (SPAD values) increased tendentiously and partly significantly. The maximal quantum efficiency of PSII and the stomatal conductance was not improved compared to the control, whereas the relative water content of the plants was increased in Experiment 1 but not in Experiment 2 compared to the control. Malondialdehyde concentration was increased by the largest dose in Experiment 1. The concentration of macroelements, Ca, Mg, N, and S, increased in the aboveground biomass with increasing doses of sewage sludge, but even after three years, the cumulative amount removed with the harvested biomass was much smaller than the amount remaining in the soil. The total amount of K in the harvested biomass exceeded that introduced to the soil by the treatments. Micro- and trace-element concentrations did not show increasing tendency in the biomass, suggesting a slower uptake and removal rate than macroelements. The results point to the necessity to assess the real nutrient requirement and trace-element uptake by the plants as compared to the sewage sludge treatment to avoid their uncontrolled accumulation in the soil and ensure a sustainable fertilization of the plantations. Full article