Effects of Different Ratios of Sludge-derived Biochar and Soil on the Growth of Garden Plants

In order to explore the effects of different ratios of Domestic sludge-derived biochar(DS-BC)and soil on the growth and physiology of garden plants, a completely random combination design was adopted to determine the growth, flowering and photosynthesis parameters of plants by carrying out the pot experiment with 0~100% ratio of DS-BC and raw soil/peat moss on April 11, 2021.Salvia splendens and Plectranthus ecklonii 'Mona Lavender' were used as experimental materials.The results showed that the plants in 30%~40% charcoal-soil substrate had more branches and leaves, larger crown width, more flowers, and the longest flowering period.Compared with raw soil/pead moss, the plant height increased by 2~3.5 cm, the SPAD value increased by 9.00%~10.00%, the net photosynthetic rate increased by 21.56%~58.25%, the stomatal conductance increased by 59.81%~100%, the intercellular CO₂ increased by 3.70%~18.21%, and the transpiration rate increased by 38.31%~71.45%.According to the experiment, the growth characteristics of plants in carbonaceous soil under 50% are higher than that in raw soil or peat soil.The meanwhile growth physiological characteristics of plants grown in the same ratio substrate of biochar-peat moss substrate were better than those in biochar-raw soil substrate, which provided theoretical and practical support for the high-value utilization of domestic sludge-derived biochar.