As one of the bibliometric analysis tools, CiteSpace software was applied to quantitatively and visually evaluate global scientific documents of research on haze from 2000 to 2016. Five thousand six ...hundred six documents from the Science Citation Index Expanded (SCI-Expanded) and Social Science Citation Index (SSCI) of the Web of Science database were statistically analyzed and examined. The distributions on authorship, countries/territories, institutes, and keywords were generated. The amount of publications has increased nearly for the past 17 years. The most productive author was Li J. with 46 articles. The publications on haze research were primarily originated from the USA, China, Germany, and France. By synthetically analyzing the keywords, the dominant hot spots of haze research could be concluded as “aerosol,” “atmosphere,” “particle,” “PM
2.5
,”and “air quality.”
Industrial spatial agglomeration is the most prominent geographical feature of economic activities. This paper examined the current situation of manufacturing industry agglomeration in Hebei Province ...by using the industrial location quotient and exploratory spatial data analysis. The results showed that (1) the industrial location quotient of 11 cities’ 31 manufacturing industries in Hebei Province indicated that there was a significant difference among manufacturing industry agglomeration of the 11 cities in Hebei Province. (2) Global spatial autocorrelation of manufacturing industry agglomeration showed that TA (Manufacture of Textile, Apparel), T (Manufacture of Textile), PFM (Manufacture and Processing of Ferrous Metals), CF (Manufacture of Chemical Fibre), LFF (Manufacture of Leather, Fur, Feather and Its Products and Footwear), AAE (Manufacture of Articles for Culture, Arts and Crafts, Education, Sport Activities and Entertainment Goods) and RP (Manufacture of Rubber and Plastic) showed agglomeration characteristics. (3) According to the industrial location quotient and local spatial autocorrelation, the spatial cluster of manufacturing industry agglomeration in Hebei Province was divided into “Diffusion Centre”, “Primary Diffusion Centre”, “Polarization Centre” and “Less Developed Area”.
•The concept of cultivated land quality (CLQ) was deduced from the concept of “quality”.•CLQ emphasizes the satisfaction of cultivated land conditions to human well-being.•The elements, connotations, ...and dimensions of CLQ were clarified from the perspective of farmland ecosystems.•An CLQ evaluation analysis framework was proposed.
Historically, the cognition and management of cultivated land quality (CLQ) have been fragmented, leading to an inability to meet contemporary scenarios and requirements of China’s agricultural development and cultivated land protection. This study aimed to systematically recognize the concepts, elements, connotations, and dimensions of CLQ and build a new cultivated land quality evaluation (CQE) system. Initially, we deduced the concept of CLQ through the clear concept of “quality” in line with international standards. Next, we connected CLQ with the framework of farmland ecosystem service cascades and clarified the element structure of CLQ based on the structure of farmland ecosystems. Then, based on the multi-level human well-being that farmland ecosystems can provide, the connotations and dimensions of CLQ was determined. Using Wen County within Henan Province as a case study site, we constructed a CQE system for empirical analysis and comparative verification, showing that the new system was better than the existing one. This study helped to clarify the CLQ and provided a theoretical basis and technical reference for sustainable intensification (SI) and multi-directional protection and supervision of cultivated land.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Achieving the goals of global food security and sustainable agricultural land use requires research that understands the processes and mechanisms of change in agricultural land systems. Agricultural ...land function is a suitable research area. Therefore, this paper collected 1643 papers on agricultural land function from the Web of Science Core Collection as research materials. HistCite, CiteSpace, and VOSviewer were used as the bibliometrics analysis tools to study basic information, research progress, hotspots, and frontiers in agricultural land function. The results showed that over the past 30 years, publications on agricultural land function have increased, and the dominant authors and institutions were located in the United States, China, Europe, etc. Land use, agriculture, and multifunctionality were research hotspots in this field. The research frontier included the interaction analysis between land use pattern and function, the evaluation and valuation of agricultural land function, the interaction and driving factors between agricultural land functions, and the relationship between agricultural land function and sustainability. This study could help researchers further understand the research status on agricultural land function, playing a fundamental role in the sustainable utilization of the agricultural land system and the realization of global food security goals.
Given that farmland serves as a strategic resource to ensure national food security, blind emphasis on the improvement of food production capacity can lead to soil overutilization and impair other ...soil functions. Hence, the evaluation of soil health (SH) should comprehensively take soil productivity and ecological environmental effects into account. In this study, five functions from the perspective of functional soil management were summarized, including primary productivity, provision and cycling of nutrients, the provision of functional and intrinsic biodiversity, water purification and regulation, and carbon sequestration and regulation. For each soil function, in view of the natural and ameliorable conditions affecting SH, basic indicators were selected from the two aspects of inherent and dynamic properties, and restrictive indicators were chosen considering the external properties or environmental elements, with the minimum limiting factor method coupled with weighted linear model. The new evaluation system was tested and verified in Yixing City, China. The healthy and optimally functional soils were concentrated in the northeast and mid-west of Yixing City, whereas unhealthy soils were predominant in the south and around Taihu Lake. The main limitations to SH improvement included cation exchange capacity, nutrient elements, and soluble carbon. The SH evaluation method was verified using the crop performance validation method, and a positive correlation was noted between food production stability index and soil health index, indicating that the evaluation system is reasonable.
Soil is an important natural resource. The excessive amount of heavy metals in soil can harm and threaten human health. Therefore, monitoring of soil heavy metal content is urgent. Monitoring soil ...heavy metals by traditional methods requires many human and material resources. Remote sensing has shown advantages in the field of monitoring heavy metals. Based on 971 heavy metal samples and Sentinel-2 multi-spectral images in Tai Lake, China, we analyzed the correlation between six heavy metals (Cd, Hg, As, Pb, Cu, Zn) and spectral factors, and selected As and Hg as the input factors of inversion model. The correlation coefficient of the best model of As was 0.53 (p < 0.01), and of Hg was 0.318 (p < 0.01). We used the methods of partial least squares regression (PLSR) and back propagation neural network (BPNN) to establish inversion models with different combinations of spectral factors by using 649 measured samples. In addition, 322 measured samples were used for accuracy evaluation. Compared with the PLSR model, the BP neural network builds the model with higher accuracy, and B1-B4 combined with LnB1-LnB4 builds the model with the highest accuracy. The accuracy of the best model was verified, with an average error of 19% for As and 45% for Hg. Analyzing the spatial distribution of heavy metals by using the interpolation method of Kriging and IDW. The overall distribution trend of the two interpolations is similar. The concentration of As elements tends to increase from north to south, and the relatively high value of Hg elements is distributed in the east and west of the study area. The factories in the study area are distributed along rivers and lakes, which is consistent with the spatial distribution of heavy metal enrichment areas. The relatively high-value areas of heavy metal elements are related to the distribution of metal products factories, refractory porcelain factories, tile factories, factories and mining enterprises, etc., indicating that factory pollution is the main reason for the enrichment of heavy metals.
Urban expansion occurs in horizontal and vertical directions, but the construction process of a traditional planar ecological network (EN) ignores the ecological protection of the vertical space. ...Birds, as representative species in urbanized areas, are important for expanding the vertical analysis dimension of ENs. In this study, urban parks with good habitat quality were extracted as ecological sources from the perspective of birds. Then, 2D and 3D ecological resistance surfaces were constructed on the basis of the perspective of influencing bird migration, and planar and 3D ecological corridors were extracted and compared for analysis. Finally, accessibility analysis was performed to identify the parks in the study area that need priority protection. Results show that building height is an important factor affecting bird migration, and the introduction of 3D resistance surfaces into EN construction is important for adapting to the trend of vertical urban expansion. The combination of accessibility and EN analyses can help identify ecological spaces having the dual role of “species conservation” and “human well-being enhancement.” This study can provide a reference for refining the service species of ENs, exploring the vertical dimension of ENs, and improving the health of urban ecosystems and the rationality of urban planning.
The climate and ancient human activities changed with the Yangshao village soil over time. Although most of the changes disappeared from a macro perspective, they were preserved in the soil ...micromorphology. Therefore, this study adopted the soil micromorphology method to conduct multi-point sampling in a cultural layer of the Yangshao village site. By comparing the differences in the soil micromorphology characteristics of ancient soil, cultural layer, and topsoil, this study investigated the impact of climate change and ancient human activities on soil micromorphology, providing a basis for exploring relics of ancient human activity and agricultural development during the Yangshao culture period. First, the results showed that the soil experienced a strong degree of chemical weathering. At the same time, sedimentation and viscosity were obvious, and the clay gel film was fully developed. As the iron element was added and oxidized, the color became reddish-brown. The gel film moved downward or measured seepag
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