The issue of agricultural non-point source pollution has attracted global attention. A buffer zone is an effective, eco-friendly, and economically feasible remediation ecosystem to reduce the impact of agricultural non-point source pollution on water bodies. They can effectively remove pollutants in agricultural drainage through physical processes (infiltration, filtration, deposition, etc.), plant absorption and assimilation, and microbial processes, improving the water quality of water bodies. This article provides a comprehensive review of the current studies on using buffer zones to remediate agricultural non-point source pollution, with a focus on the key affecting factors for pollutant removal efficiencies. The main factors included buffer zone width, vegetation type, slope, seasonal variation, soil variation, and vegetation density. The influencing mechanisms of these factors on the pollutant removal efficiencies of buffer zones were also discussed. This review can serve as a reference for a deep understanding of buffer zones and help optimize their design and management in real ecological remediation projects.

Soil acidification, salinization, and heavy metal pollution pose serious threats to global food security and sustainable agricultural development. Biochar, with its high porosity, large surface area, and abundant functional groups, can effectively improve soil properties. However, due to variations in feedstocks and pyrolysis conditions, it may contain potentially harmful substances. Industrial wastes such as fly ash, steel slag, red mud, and phosphogypsum are rich in minerals and show potential for soil improvement, but direct application may pose environmental risks. The co-application of biochar with these wastes can produce composite amendments that enhance pH buffering capacity, nutrient availability, and pollutant immobilization. Therefore, a review of biochar-industrial waste composites as soil amendments is crucial for addressing soil degradation and promoting resource utilization of wastes. In this study, the literature was retrieved from Web of Science, Scopus, and Google Scholar using keywords including biochar, fly ash, steel slag, red mud, phosphogypsum, combined application, and soil amendment. A total of 144 articles from 2000 to 2025 were analyzed. This review summarizes the physicochemical properties of biochar and representative industrial wastes, including pH, electrical conductivity, surface area, and elemental composition. It examines their synergistic mechanisms in reducing heavy metal release through adsorption, complexation, and ion exchange. Furthermore, it evaluates the effects of these composites on soil health and crop productivity, showing improvements in soil structure, nutrient balance, enzyme activity, and metal immobilization. Finally, it identifies knowledge gaps as well as future prospects and recommends long-term field trials and digital agriculture technologies to support the sustainable application of these composites in soil management.

Green roof systems are regarded as a viable solution for mitigating urban environmental challenges and offering a multitude of environmental benefits. Currently, green roofs are increasingly being utilized for the management of rainwater runoff and wastewater. The integration of decentralized rainwater and sewage on-site treatment technology with urban green buildings is being gradually promoted. Green roofs can also be considered as a form of decentralized rainwater and sewage on-site technology, which holds great potential for widespread adoption in the future. Several studies have suggested that green roofs may serve as a potential source of pollutants; however, there are also studies that clearly demonstrate the efficient removal of nutrients and organic pollutants by green roofs. This article critically examines the existing literature on water treatment aspects associated with green roofs and elucidates their classification and operational mechanisms. Through an analysis of previous research cases, it becomes evident that both substrate and vegetation play a significant role in influencing the treatment performance of green roofs. By designing and configuring appropriate substrate and vegetation, green roofs can play a pivotal role in the purification of water quality. Finally, a brief outlook is presented for the future research directions of green roofs, with the anticipation that green roofs will feature more innovative and environmentally friendly designs, as well as expanded prospects for application.