Search Results (6)

In the coal-grain composite area (CGCA) of eastern China with a high groundwater table (HGT), underground coal mining subsidence has caused extensive submergence of farmland, posing a significant threat to regional food security. Currently, land reclamation techniques in mining subsidence areas primarily focus on post-mining reclamation (PMR) of stable subsidence land with a low reclamation rate. This study investigated the application of concurrent mining and reclamation (CMR) technology for unstable subsidence land in a representative HGT mining area, namely the Guqiao Coal Mine in the Huainan Coalfield. Firstly, mining subsidence prediction and geographic information technology were employed to simulate the spatio-temporal evolution of dynamic mining subsidence, taking into consideration the mining plan. Subsequently, phased reclamation parameters were quantitatively designed by integrating the dynamic mining subsidence and surface reclamation measures. Lastly, scenario simulations were conducted to discuss the effectiveness of CMR in comparison with non-reclamation (NR) and PMR. Additionally, reclamation and ecological restoration strategies for coal mining subsidence areas with comprehensive governance modes were proposed. The findings indicated that mining activities have led to a reduction in both the quantity and quality of original farmland, with 70% of the farmland submerged and rendered uncultivable. In contrast to PMR, which achieved a reclamation rate of 29%, CMR can significantly increase the farmland reclamation rate to 69% while also prolonging the service life of farmland. This study provides theoretical support and technical references for promoting sustainable mining practices, protecting farmland, and facilitating the high-quality development of coal resource-based cities. Full article

To provide the population with food, it is very important to re-cultivate “abandoned lands” that have been retired from agricultural use. The conversion of arable land into agricultural abandoned lands in the south of Kazakhstan is, first of all, primarily associated with salinity. For the purposes of sustainable development, there is a need to develop proposals for re-mastering by studying their current state and reviewing world studies on the reclamation of salt-affected soils. Therefore, this study is devoted to the study of the current environmental and reclamation conditions of the abandoned areas of the Otyrar region in southern Kazakhstan. The proposed directions of changes in their development were also presented. In the course of the research, the historical method is used in the study of the emergence and formation of abandoned lands; the method of geographical analysis during the territorial analysis of the research object; the statistical and comparison methods in showing the complexity and intensity of the problems; the cartographic, geo-informational and field research (reconnaissance) methods in the study of the condition of the abandoned lands in the research object and methods of grouping and analysis were used in the work with scientific data on the topic of research. Using Sentinel-2 images, the GIS program created phenological dynamics of crops based on NDVI vegetation indices during the vegetation period of the irrigated range. By classifying them, abandoned lands due to salinization were separated from fields. By deciphering space images with the help of geoinformation technologies, it was revealed that the area of abandoned lands in the research object is 13,688.9 ha, including the area of non-saline soils—83.9 ha, weakly saline soils—984.4 ha, medium saline soils—2398.3 ha, and highly saline soils—10,222.1 ha. A review of the methods and technologies proposed by scientists for the development and amelioration of salt-affected lands was made. Taking into account the ecological and reclamation state of the object of research along with the material and technical capabilities of farms, two methods of developing abandoned lands (organic and agro-innovative) in the research object are proposed and the need for their use in case of soil salinization has been scientifically justified. Full article

With globally more than 100,000 km² impacted by surface mining at present, and with increasing demand for surface-mined products, land managers are challenged to address landscape degradation of decommissioned quarries, especially in urban areas. In this study, soil, microclimate, and vegetation community data were collected from geomorphologically distinct locations (quarry floor, platform with pond, quarry top, highwall edge) within an urban limestone quarry abandoned 70 years ago without reclamation in central Missouri, USA. Results were compared with two nearby reference sites to bookend conditions in the abandoned quarry, including a recently closed quarry and an urban forest. Results of this study showed that abiotic mining legacies gave rise to distinct vegetation communities comprising 74 native species but also 21 non-native species. Species richness was increased near persistent edges (cliff edge, pond edge) and approached the lower range of species richness found in natural areas in the region. The results of this case study are congruent with the growing body of studies about spontaneous succession on abandoned surface mines worldwide in that spontaneous (vs. managed) revegetation can lead to species-rich, near-natural communities. This finding may justify revision of current legislation requiring technical reclamation of surface mines, especially where favorable substrate, such as limestone, is conducive to swift onset of revegetation. To improve the ecological value of such areas, the provision of funding for long-term invasive species management should also be considered. Full article

Post-consumer bio-based textile wastes are any type of garment or household article made from manufactured bio-based textiles that the owner no longer needs and decides to discard. According to the hierarchy of waste management, post-consumer textile waste should be organically recycled. However, there is still a problem with the implementation of selective collection of textile waste followed by sorting, which would prepare the waste for organic recycling. A technically achievable strategy for sorted textile waste materials consisting of only one type of fiber material, multi-material textiles are a problem for recycling purposes. Waste textiles are composed of different materials, including natural as well as synthetic non-cellulosic fibers, making bioprocessing difficult. Various strategies for recovery of valuable polymers or monomers from textile waste, including concentrated and dilute acid hydrolysis, ionic liquids as well as enzymatic hydrolysis, have been discussed. One possible process for fiber recycling is fiber recovery. Fiber reclamation is extraction of fibers from textile waste and their reuse. To ensure that organic recycling is effective and that the degradation products of textile waste do not limit the quality and quantity of organic recycling products, bio-based textile waste should be biodegradable and compostable. Although waste textiles comprising a synthetic polymers fractions are considered a threat to the environment. However, their biodegradable part has great potential for production of biological products (e.g., ethanol and biogas, enzyme synthesis). A bio-based textile waste management system should promote the development and application of novel recycling techniques, such as further development of biochemical recycling processes and the textile waste should be preceded by recovery of non-biodegradable polymers to avoid contaminating the bioproducts with nano and microplastics. Full article

Excessive reclamation and improper use of agrochemicals in karst areas leads to serious non-point source pollution, which is of great concern and needs to be controlled, since contaminants can easily pollute groundwater due to the thin patchy soil and developed karst structures. The occurrences of organochlorine pesticides (OCPs) in karst soil were investigated by analyzing 25 OCPs in the karst soils near the Three Gorges Dam, China. The total concentrations of OCPs ranged 161–43,100 (6410 ± 9620) pg/g, with the most abundant compounds being p,p’-DDT and mirex. The concentration differences between the orchard and vegetable field and between upstream and downstream presented the influences of land-use type and water transport on the OCP spatial distributions. Composition analysis indicated the possible fresh inputs of lindane, technical DDT, aldrin, endrin, mirex, and methoxychlor. Their illegal uses implied an insufficient agrochemical management system in undeveloped karst areas. Principal component analysis with multiple linear regression analysis characterized the dominant sources from current agricultural use and current veterinary use in the study area. OCPs in the soils might not pose significant cancer risk for the residents, but they need to be controlled due to their illegal uses and bioaccumulation effect via the food chain. Full article

Reducing agricultural water use is an inevitable choice to alleviate water shortage in arid and semi-arid regions, and high-efficiency irrigation technologies provide conditions for water conservation. However, without unified water resources management policy to redistribute the saved agricultural water, farmers’ behavior will lead to water rebound and large-scale expansion of cultivated areas, especially on the edge of oasis regions. To solve these issues and promote the sustainable development of water resources, it makes sense to explore the impact of unified water resources management policy from the perspective of farmers’ behavior. This study takes the typical irrigation zone in the Heihe River Basin as a case to discuss the response of farmers’ economic behavior to transferring irrigation water and restricting land reclamation, i.e., the unified water resources management policy with the technical efficiency of crop irrigation improved based on the bio-economic model. The results show that in the case of loosening land constraints, farmers will reuse all the saved water for agricultural production by reclaiming unused land or increasing the area of water-intensive crops (vegetables). Although the policy of restricting land reclamation can restrict land expansion, it cannot avoid water rebound caused by adjusting the crop-planting structure. Farmers’ land-expansion behavior can be largely restricted by transferring the saved irrigation water to non-agricultural sectors in irrigation zones with inadequate water, but to contain land-expansion behavior in irrigation zones with surplus water, the policy of restricting land reclamation must be implemented simultaneously. The study also reveals that farmers will choose to grow more cash crops (seed maize, vegetables, tomato, seed watermelon, potato, and rapeseed) and fewer food crops (wheat, maize) to increase the profit per unit of water in the scenario of loosening land constraints or transferring agricultural water. Furthermore, the study indicates that farmers’ economic income can be decreased or at least not increased with the transfer of agricultural water. Both benefit compensation from non-agricultural sectors and increased non-agricultural income can compensate farmers’ economic loss. Therefore, it is necessary to improve water rights trading systems and increase employment opportunities for surplus agricultural labor to promote economic development in rural areas. Full article