Salt stress is one of the environmental factors that greatly limits crop production worldwide because high salt concentrations in the soil affect morphological responses and physiological and metabolic processes, including root morphology and photosynthetic characteristics. Soil aeration has been reported to accelerate the growth of plants and increase crop yield. The objective of this study was to examine the effects of 3 NaCl salinity levels (28, 74 and 120 mM) and 3 aeration volume levels (2.3, 4.6 and 7.0 L/pot) versus non-aeration and salinity treatments on the root morphology, photosynthetic characteristics and chlorophyll content of potted tomato plants. The results showed that both aeration volume and salinity level affected the root parameters, photosynthetic characteristics and chlorophyll content of potted tomato plants. The total length, surface area and volume of roots increased with the increase in aeration volume under each NaCl stress level. The effect was more marked in the fine roots (especially in ≤1 mm diameter roots). Under each NaCl stress level, the photosynthetic rate and chlorophyll content of tomato significantly increased in response to the aeration treatments. The net photosynthetic rate and chlorophyll a and t content increased by 39.6, 26.9, and 17.9%, respectively, at 7.0 L/pot aeration volume compared with no aeration in the 28 mM NaCl treatment. We also found that aeration could reduce the death rate of potted tomato plants under high salinity stress conditions (120 mM NaCl). The results suggest that the negative effect of NaCl stress can be offset by soil aeration. Soil aeration can promote root growth and increase the photosynthetic rate and chlorophyll content, thus promoting plant growth and reducing the plant death rate under NaCl stress conditions.

Transport infrastructure and logistics are gradually becoming important factors affecting global trade. At the same time, with the international logistics corridor along the Belt and Road Initiative (BRI) going deep into construction, China is emerging as a unique case to study how logistics affects international trade. Therefore, based on the evaluation index system of logistics development level of China’s provinces by using the entropy method, this paper systematically analyzed the impact of logistics development level on bilateral trade from 31 China’s provinces to 65 countries along the BRI by using the improved gravity model with data for the period 2008–2018. Empirical results show: (1) Logistics development level had significantly promoted international trade development. (2) Compared with partner countries, China’s provincial logistics development level presented a greater impact on bilateral trade. (3) Influence of logistics development level was manifested in different periods, different international and regions, especially, logistics development level coefficient of the western region was negative, while that in eastern region was positive. In view of the above research results, we argue that strengthening domestic and international logistics construction is not only conductive to the sustainable development of China’s future trade, but also help to realize the coordinated development between China’s eastern, central and western regions.

Land space underpins an ecological civilization. A thorough grasp of regional natural resources and subsequent optimization of the ecological security pattern are both essential for the comprehensive development and overall planning of the management of natural resources. In this study, we established and optimized the ecological security pattern in Shaanxi Province, China. Landscape patches distinguished by high importance of ecosystem services (carbon fixation and oxygen release, water conservation, habitat maintenance, and soil conservation) and high sensitivity of ecological environment to human interference (ecological sensitivity index) were extracted as ecological sources. An ecological resistance surface was built based on the following resistance factors: land-use type, topographic position index, and soil erosion intensity. A minimum cumulative resistance model was used to identify ecological corridors. Our results showed that those ecological sources with high to extreme ecological importance and sensitivity together covered an area of 67,457 km² (32.8% of the total land area of Shaanxi Province). A total of 32 ecological nodes were identified at the center of important ecological sources to serve as main areas for implementing ecological protection projects. In addition, 72 ecological corridors were identified, towards which efforts should be targeted to maintain their functions for the inter-connection and serial connection of ecological nodes and source patches. The ecological corridors create favorable habitats for wildlife and superior spaces for ecological migration based on the blue and green linear corridor system. According to these findings, we propose establishing an ecological security pattern featuring “two barriers, three belts, and multiple corridors” in Shaanxi Province and that the green ecological security barriers should be strengthened based on their natural background and resource endowments.

The spatial pattern of rural poverty and its influencing factors are unique in regions located in the “double zone”, overlaying the Loess Plateau landform and interprovincial border socioeconomic zone. Using Huining County, located in the interprovincial border area of the Loess Plateau, as a case study, this paper examines the spatial heterogeneity of rural poverty patterns and poverty-causing factors by using geographically weighted regression (GWR) modeling. The potential accessibility indicator is employed to identify the formative mechanism of rural poverty. The results show that rural poverty is significantly correlated with county-level accessibility, water resource accessibility, and town-level accessibility. County-level accessibility and town-level accessibility have significant border effects on rural poverty. The arid characteristics in certain areas of the Loess Plateau mean that the impact of water resource accessibility on the incidence of rural poverty is second only to that of county-level accessibility. Forestland resources have a positive correlation with the incidence of rural poverty in the region dominated by farming. Finally, targeted poverty reduction policies are proposed based on the results of the analysis of poverty-causing factors. The findings derived from this paper can help other developing countries in designing their own poverty reduction policies.

The Qinghai-Tibet Plateau area (QTP) is the most unique environmental-population region and an important natural laboratory for the study of human-land relations. The poor transportation conditions have long restricted socio-economic development. The research on the transport infrastructure and spatial effect in the QTP is of significance to the sustainable development of the region. Accordingly, a spatial accessibility model was used to analyze the spatial pattern of accessibility in QTP from 1976–2016, examine the accessibility evolution trend on the township scale and reveal the spatial fairness and changes in accessibility. The main conclusions are as follows: (1) The accessibility to major cities improved and the time-space convergence effect was significant. (2) The spatial autocorrelation analysis results showed that the improvement in transport infrastructure had a significant impact on the agglomeration of the accessibility level. (3) Access time from towns to the nearest major city are much shorter. More Tibetan people have more opportunities to access cities. (4) The accessibility coefficient and relative accessibility revealed distributive effects and spatial fairness of accessibility. (5) The global coefficient of variation value demonstrated an increasing trend, which indicates that spatial unfairness of transport is increasing.