Objective With the continuous improvement of social and economic development levels, as well as the ongoing urbanization process, there is a growing emphasis on refining conservation and management practices for various green spaces in response to the gradual expansion of urban landscaping construction. Consequently, the issue of rapidly increasing landscaping waste production has become an important concern that cannot be overlooked in urban management. In Chongqing’s central urban area, where large amounts of pruning wastes from trees and shrubs are generated, current disposal methods primarily involve landfilling and incineration with low rates of resourceful utilization. This not only leads to pollution in the atmosphere, water bodies, and soil environment, but also results in wastage of resources. However, it is worth noting that landscaping waste holds significant potential for resourceful utilization; the main products of landscape waste may include biochar, garden mulch, organic compost, soil amendments, cultivation substrates, and wood-plastic products. Among these options, composting technology stands out as an efficient method for dealing with landscaping waste while being a relatively mature organic solid waste treatment technology thus far. Therefore, establishing an industry chain for harmless disposal of landscaping waste through resourceful land utilization holds great significance in promoting the harmless treatment and resourceful utilization of landscaping waste while actively boosting the achievement of carbon peaking and carbon neutrality goals and fostering the development of a green circular economy.
Methods The composting technology aims to raise the temperature within the compositing system by means of metabolic and proliferative reactions of microorganisms under conditions characterized by abundant oxygen, excellent ventilation, suitable temperature, and moisture content. This facilitates the decomposition of composts while further eliminating harmful microorganisms therein, ultimately transforming them into organic fertilizer. Landscaping waste contains a substantial amount of cellulose, lignin, and other components with high carbon content and low moisture content that can effectively adjust the C/N ratio and moisture content of composts, thus becoming an exceptional bulking agent for composting purposes. Urban sludge possesses a dense texture along with high organic and moisture contents. The combination of landscaping waste and domestic waste in composting processes can not only complement their respective deficiencies, but also significantly improve the overall composting effectiveness. Based on the characteristics exhibited by landscaping waste and domestic sludge, the method of coordinated composting is adopted to conduct harmless disposal of sludge and landscaping waste according to the volume ratio of 1∶1.5 − 1∶2.0, and compost products are prepared. According to the demand for soil improvement in green space, the application amount of improved products is calculated after soil testing, the compost products are applied in soil improvement engineering practice according to local conditions, and the landscaping effect and soil quality before and after the improvement are compared to evaluate the application effect of landscaping waste in soil improvement engineering.
Results After improvement, the organic matter and nutrient indexes of soil are significantly improved compared with those before improvement. The composted product resulting from the combination of landscaping waste and municipal domestic sludge plays a pivotal role in enhancing soil quality in urban green spaces. It can not only regulate soil pH but also effectively address the limitations associated with single-component improvement, comprehensively augmenting soil nutrients, improving soil structure, optimizing the microenvironment for plant growth, and facilitating the healthy “soil − plant” cycle. The utilization of landscaping waste for soil improvement can not only enhance landscape aesthetics and ecological restoration but also resolve the issue of resourceful utilization pertaining to urban organic solid waste. In the practical implementation of garden compost products for soil improvement projects, it is crucial to develop scientific improvement plans based on soil survey findings and tailored to the specific needs of plants. Moreover, enhancing technology promotion and training programs is essential for elevating the technical proficiency and operational efficiency of practitioners. Regardless of whether it pertains to upgrading soil quality in urban green spaces or rehabilitating mine soils, there is a promising market prospect for harnessing landscaping waste in land use applications. To fully exploit this potential, we must establish and refine market mechanisms that facilitate the resourceful utilization of landscaping waste while simultaneously encouraging and supporting social enterprises to contribute to the same. Furthermore, reinforcing the development of technical regulations and standard systems pertaining to the use of landscaping waste in soil improvement endeavors is paramount as it can ensure standardized treatment and efficient resourceful utilization.
Conclusion In accordance with the characteristics of urban landscaping waste resources, a mature and low-carbon environmentally friendly composting technology is employed for the harmless disposal of such waste. By integrating it with the demand for soil improvement substrates in projects like soil enhancement and mine restoration, effective resourceful utilization of landscaping waste can be achieved. This approach aligns with the national concept of circular economy and green development, thereby realizing the objective of “coming from green space and returning to green space” for landscaping waste. The aforesaid approach provides a comprehensive and well-established technical industry chain for treating and utilizing urban landscaping waste resources, fostering relatively advanced experiences in product promotion and application, while also driving forward the development of resource recycling industry.
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