The effect of green waste as an organic amendment on soil characteristics and the growth performance of sage (Salvia japonica Thunb)

The disposal of green waste in urban areas has become a serious issue. Traditional centralized landfilling and incineration are not optimal solutions. Aerobic composting, however, is a low-cost and low-pollution approach, and the resulting compost also serves as a potential soil amendment. To evaluate the effects of unfermented green waste (UGW) and fermented green waste (FGW) as soil amendments on soil improvement and plant growth, this study collected green waste and open-field soil. UGW and FGW were incorporated into the collected soil at application rates of 0, 50, 100, and 150 g/kg, respectively. After one month of incubation, the soil mixtures were used for pot experiments. After analyzing the soil physicochemical properties, microbial community structure, and the data on the physiological indices of sage （ Salvia japonica Thunb） following different treatments, the results showed that: the organic amendments made from green waste can promote plant growth within a certain application range. However, when the application rate exceeds a certain limit, it will have negative impacts on some physiological indices of the plant. In terms of soil physicochemical indicators, the pH of soils treated with organic additives was significantly lower than that of the control group ( p < 0.05), while indices such as organic matter, total nitrogen, and total potassium were significantly increased ( p < 0.05). Meanwhile, composting is essential for the safe application of garden waste, and fermented garden waste is more conducive to the growth of beneficial microbial communities in the soil. This is crucial for the healthy growth of plants. Finally, the Nemerow comprehensive index method was used to evaluate the soil improvement effect. This has guiding significance for the resource utilization of green waste.