Intensive mining activities in large-scale opencast coal mines have had a significant impact on the local environment. Elements that are potentially harmful to the environment are brought to the surface from deep underground, altering the geochemical conditions for their transport and redistributing them to the surface, causing serious local pollution. However, in-depth studies of toxic metal contamination in soils of arid coal mining areas have not yet received the attention they deserve. Although previous studies have conducted a great deal of research on heavy metal elements in surface coal mine soils, there are few studies related to the more seriously polluted surface coal mines in the arid regions of Northwest China, and there are no in-depth studies on the ecology of soil heavy metal contamination, health risks and source analysis according to the authors’ knowledge. To make up for this shortcoming, the present study takes Zn, Cu, Cr, Pb, Hg, and As in the surroundings of the tertiary coal mines in the Hongsachuan Mining Area (northern Xinjiang, China) as an example. The health, ecological risks, and pollution sources of heavy metal elements in surface coal mine soils were comprehensively analyzed. The results showed that the average concentrations of Cr, Hg, and As in the soils of open-pit coal mines greatly exceeded the corresponding provincial background values, with the Cr content exceeding China’s soil environmental quality standard Ⅰ and the As content even higher than standard Ⅱ (GB15618-1995). Geostatistical and multivariate statistical results showed that the six metals analyzed in this study can be divided into four groups, as follows. Group 1 included Zn and Cu and was mainly controlled by natural sources related to soil parent materials. Group 2 consisted of Cr and Hg and was associated with industrial practices. Group 3 was explained by As and was mainly from coal combustion during the mining activities. Group 4 was Pb and was dominantly from natural sources, together with vehicular emission during the mining activities, indicating a mixed source. Potential ecological risk index (PER) values exhibited low ecological risk in contaminated soils with Zn, Cu, Pb, and Cr, and only 10% of As samples exhibited moderate risks, while 77% of Hg samples posed ecological risks at different level, implying that Hg was the main contributor for comprehensive risk index (RI). Regardless of non-carcinogenic and carcinogenic health risk assessment, As was the primary risk element followed by Cr, and children tended to have a higher health risk than adults. In this paper, statistical methods, pollution assessment methods, and potential ecological risk models are skillfully combined, and relevant conclusions are drawn based on the human and economic geographical background information of the study area. The results can provide references for the investigation and evaluation of soil heavy metals and quantitative analysis of pollution sources in the same type of areas. In order to grasp the pollution level of potential toxic elements in the soil of large open-pit coal mines in arid areas, effective source-cutting measures are taken to provide data support the sustainable management of coal mines and local soil safety utilization measures. Full article

Pig, cow, and sheep manure (PM, CM, and SM) are inevitable byproducts of agricultural economic development. Converting them into high add-on value biochar (PMB, CMB, and SMB) via pyrolysis is an efficient resource utilization measure. Phosphorus (P) speciation analyses help ensure the practical feasibility of the P reclamation of animal manure and their derived biochar and a reduction in environmental risk. This study conducted a modified extraction procedure to separate five inorganic P (IP) (soluble and loosely bound IP, aluminum-bound IP, Fe-bound IP, oxide-occluded IP, and Ca-bound IP) and organic P (OP) speciations, and combined X-ray diffraction (XRD) to investigate the major phosphate compound in the derived biochar after pyrolysis. Results revealed that more than 92% of P is concentrated in the derived biochar during pyrolysis processes carried out at 200–800 °C. The percentages of soluble and loosely bound IP, aluminum-bound IP, and OP in manure decreased significantly due to their transformation into more stable P fractions such as Ca-bound IP (79.01% in PMB, 800 °C) after pyrolysis. The Olsen-P percentages had a distinct reduction at 650 °C, indicating that pyrolysis at 650 °C was the optimal condition for the reduction in Olsen-P in manure. Full article

Straw waste has a large amount of lignocellulose, which shows a strong resistance to biodegradation in the composting process and hinders the formation of humic substances. Therefore, the effects of pH adjustment and inoculation of degradation bacteria on the composting process, lignocellulose degradation and humus formation in secondary fermentation were explored through aerobic composting experiments. The experiment was designed with four treatment groups: CK (conventional composting), T1 (adjusting pH), T2 (inoculating P. chrysosporium), and T3 (adjusting pH and inoculating P. chrysosporium), respectively. Results showed that except for treatment CK, all other treatments met the maturation standards at the end of composting. Adjustment of the pH value and the inoculation of Phanerochaete chrysosporium (P. chrysosporium) can significantly shorten the fermentation time. Among them, the lignin content of treatment T3 was reduced significantly by 14.28% compared to treatment T2; the content of humic acid in T3 increased significantly by 51.32% and 14.04% compared with T1 (adjusting pH) and T2 (p < 0.05), respectively. In terms of key enzyme activity and precursor substance changes, the pH adjustment treatment was superior to other treatments after composting. This study confirmed that the change of pH conditions is an important environmental factor for microorganisms to enhance the humification process; degrading enzymes were used as a “bridge” to enhance the continuous degradation of lignocellulose by microorganisms and increase the supplementation of precursors and the synthesis of humic acid, which is the mechanism to enhance the humification process. Our findings provided a new method to enhance the humification process, which is a valuable and economical technical approach to improve organic fertilizer quality. Full article

Phytoremediation is a promising technique for reducing mercury (Hg) pollution. Little is known about the phytoremediation potential of ramie (Boehmeria nivea L. Gaud.) and the response of its rhizosphere soil microbiome to Hg contamination. In this study, we planted ramie in three plots contaminated with different levels of Hg pollution and evaluated ramie Hg accumulation and translocation. We also analyzed the abundance, composition, and predominant taxa of the rhizosphere soil bacterial community. Results showed that the average THg concentration decreased by 30.80%, 18.36%, and 16.31% in plots L, M, and H, respectively. Ramie displayed strong Hg tolerance and good Hg accumulation performance, especially in soil contaminated with a low level of Hg. After ramie planting, soil SOM and CEC increased while pH, Eh, and THg content decreased in rhizosphere soil. Proteobacteria, Actinobacteriota, Gemmatimonadota, Latescibacterota, and NB1-j were identified as potential Hg-tolerant taxa at the phylum level, and their abundance increased in highly Hg-contaminated soil. Redundancy and correlation analyses indicated that soil bacterial community structure was significantly correlated with soil pH, Eh, and Hg content. This study provides a better understanding of the phytoremediation capacity of ramie and its rhizosphere function and thus lays a theoretical foundation for the phytoremediation of Hg-contaminated soils. Full article

In the current work, the effects of biochar, vermicompost, as well as their combined application on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in soils contaminated with potentially toxic elements (PTEs) were investigated. In this regard, four treatments were performed; among them, treatment A served as a control without additive, treatment B with vermicompost (2%), treatment C with biochar (2%), and treatment D with biochar (2%) plus vermicompost (2%). In addition, the abundance and structure of the AOA and AOB amoA gene were measured using quantitative PCR and high-throughput sequencing. The relationships between the microbial community, physicochemical parameters, and CaCl₂-extractable PTEs were analyzed using the Pearson correlation method. We found that adding biochar and vermicompost promoted the immobilization of PTEs and nitrogen biotransformation. The rational use of biochar and vermicompost is beneficial for the growth of bacterial and fungal communities in soils polluted by PTEs. AOA and AOB amoA genes were stimulated by biochar, vermicompost, and their combination, but their structure was hardly affected. Full article

This study investigates how environmental regulations and social norms affect farmers’ chemical fertilizer reduction behaviors (CFRBs) and investigates the mediating role played by social norms and the moderating role played by social networks. As the analysis tool, a structural equation model is employed to analyze the data collected from a questionnaire survey with 402 valid samples of Chinese citrus growers. This study reveals that (1) environmental regulations and social norms have a significant effect on farmers’ CFRBs; (2) injunctive social norms are a partial mediator of the relationship between incentive-based environmental regulations and farmers’ CFRBs; (3) social networks play a positive moderating role in the relationship between injunctive social norms and farmers’ CFRBs; and (4) large-scale farmers’ CFRBs are more susceptible to the impact of environmental regulations and social norms than small-scale farmers. The result of this study provides a significant scientific foundation for the Chinese agricultural sector to develop policies to combat soil pollution in agriculture. Full article

Gold and copper production is important to the Georgian economy, but at the same time, mineral resources are mined in one of the important agricultural areas of the country. This study evaluated water and soil quality in the region. Soil from 18 villages was analyzed. Some of these villages have not been investigated before and previous information about soil quality was unknown. Ecological risk factors and potential ecological risk were determined for the study area. Atomic absorption spectrometry was used to analyze heavy metals concentration in soil and water samples taken from the study area. Integrated water and soil data allowed us to see how these important natural resources influence each other. After the comparison of the four-year period of the study, we observed an increase of heavy metals increase in the soil in 2017 compared to 2014. Higher lead concentration was discovered within a two kilometer radius of the mining area whereas the highest cadmium concentration was observed in the village Ratevani, 15 km away from the nearest mine, where there was an extremely high ecological risk of Cd concentration. Further investigations are recommended to be done in Ratevani village as the people living in this village are at risk of Cd poisoning. Full article

JUNCAO technology plays a critical role in managing soil ecology and alleviating contradiction between mushroom and forest, as JUNCAO can partially replace the wood chip as mushroom culture medium. At present, few reports focus on exploring the effects of seeding density, nitrogen fertilizers on JUNCAO growth and their overwintering performance. To close the above-mentioned research gaps, five typical types of JUNCAO were evaluated by investigating their grass yield, overwintering germination rates and nutrient adsorption condition. The results indicated that Pennisetum sp. showed the best overwintering performance. In addition, the optimized planting conditions for Pennisetum sp. include cultivation density (60 cm × 50 cm), oblique seeding using stem with double nodes, and 800 kg·ha⁻¹ nitrogen fertilizer. This study gave good insights into low-temperature resisting performance and their overwintering characteristics of diverse JUNCAO species that favor for promoting the safe and efficient productions of the JUNCAO industry in subtropical areas. Full article

Traditional orchards received little attention in ecology. In order to enhance the ecological function of traditional pear orchard, it is an effective strategy to co-plant the ornamental green manure (GM) under the pear forest. In this study, two kinds of GM, i.e., Astragalus sinicus L. (AS) and Lathyrus cicera L. (LC), were co-planted in pear tree orchard to elevate its landscape benefits of spatiotemporal distribution of flowers, the nutrient benefits and oxygen production. The results showed that the flower height of AS and LC arrange between 20~30 cm, and the flowering period covers the March. LC has a large number of flowers, a small area of single flower, and high yield of fresh grass. AS has a small number of flowers, a large area of single flower, and low yield of a single fresh grass. Among them, 35% AS + 65% LC and 50% AS + 50% LC are more suitable in achieving the well tourism value and potential good production of pear orchard. Nutrient accumulation, total carbon fixation and oxygen production, flower number of 35% AS + 65% LC are larger than other treatments, while the flower period of 50% AS + 50% LC is longest. This study proposed a “win-win” GM planting strategy for sustainable orchard development, by enhancing ecology functions and the landscaped value of the traditional fruit orchard. Full article

Due to the rapid population growth and over-application of fertilizers in the Caohai surrounding farmlands, controlling the non-point source pollution in the Caohai Lakeside Zone is significant for the local ecology balance and human health safety. A total of 54 soil and 24 irrigation water samples were collected in the Caohai Lakeside Zone to evaluate the current status of soil fertility and heavy metal pollution by measuring soil and water heavy metal content and soil physicochemical properties such as soil total nitrogen, total phosphorus, organic matter, and soil pH. These results showed that the total amounts of organic matter, nitrogen, phosphorus, potassium, and effective nutrient content in the Caohai Lakeside Zone were all at a rich level according to Chinese soil nutrient grade standard; the content of lead (Pb), chromium (Cr), cadmium (Cd), mercury (Hg), and arsenic (As) in the soil all exceeds the safety standard of Chinese classification of soil environmental quality assessment. In addition, the over-standard rates of Cd and Cr were 24.1% and 14.8%, respectively. On the whole, the comprehensive quality index (CQI) of the soil in the Caohai Lakeside Zone is 6.48, which is attributed to the heavy Cd pollution and the good soil fertility. The heavy metal content of the irrigation water met the requirements of irrigation water quality. It is feasible to use the irrigation water of Caohai Lake in the actual agricultural production process. Therefore, in terms of the comprehensive management and pollution control of Caohai, special attention should be paid to the control of Cd, Pb, As, and Hg pollution sources. Full article

Systemic fungicide use has increased over the last decades, despite the susceptibility of resistance development and the side effects to human health and the environment. Although herbicides and insecticides are detected more frequently in environmental samples, there are many fungicides that have the ability to enter water bodies due to their physicochemical properties and their increasing use. Key factors affecting fungicide fate in the environment have been discussed, including the non-target effects of fungicides. For instance, fungicides are associated with the steep decline in bumblebee populations. Secondary actions of certain fungicides on plants have also been reported recently. In addition, the use of alternative eco-friendly disease management approaches has been described. Constructed Wetlands (CWs) comprise an environmentally friendly, low cost, and efficient fungicide remediation technique. Fungicide removal within CWs is dependent on plant uptake and metabolism, absorption in porous media and soil, hydrolysis, photodegradation, and biodegradation. Factors related to the efficacy of CWs on the removal of fungicides, such as the type of CW, plant species, and the physicochemical parameters of fungicides, are also discussed in this paper. There are low-environmental-risk fungicides, phytohormones and other compounds, which could improve the removal performance of CW vegetation. In addition, specific parameters such as the multiple modes of action of fungicides, side effects on substrate microbial communities and endophytes, and plant physiological response were also studied. Prospects and challenges for future research are suggested under the prism of reducing the risk related to fungicides and enhancing CW performance. Full article