Composting of invasive plants in urban watercourses and its application in riverbanks: mechanisms and compost quality assessment

Invasive plants can reinfest straightforwardly if their debris is not disposed of rapidly during cleaning. Composting can kill their reproductive bodies, and the resulting compost product can be used to improve the soil conditions of riverbanks. This study aimed to provide a comprehensive method to reuse invasive plants. The method utilises a mixed fertiliser of Sphagneticola trilobata (L.) Pruski and river sediment to restore rivers while achieving secondary utilisation of green waste.

The study set up two composting methods (A: without adding river sediment; B: adding river sediment) to evaluate the quality of the two compost products of S. trilobata and their capability to improve the soil on riverbanks.

The addition of river sediment shortened the composting period, improved the physicochemical properties of the composting process of S. trilobata, enhanced the nutrient content of the compost products, and increased the presence of microbial communities. Furthermore, the addition of river sediment caused the compost products to attain the compost maturity standards faster. This resulted in a more stable composting process. Among the different compost ratios, the addition of 5% mixed compost product yielded the best results.

The quality of plant compost could be improved by composting S. trilobata with river sediment, and the optimal fertilizer amount was 5%. These results would provide scientific ideas and methods for in-situ remediation and utilization of invasive plants and improvement of river ecological environment.