【Objective】 This study aims to investigate the effects of different concentrations of Sophora alopecuroides extract on the growth of tomato seedlings, soil nutrients, and soil enzymes in the hope of providing new insights for the rational utilization of Sophora alopecuroides resources and addressing continuous cropping obstacles. 【Methods】 A soil pot experiment was conducted, with different concentrations of Sophora alopecuroides extract treatments (0, 5, 10, 20, 40 and 80 g/L), to study the effects on tomato seedling growth parameters, soil available nutrients, and soil enzyme activities. 【Results】 After 50 days of treatment, the plant height, stem thickness, quality, and chlorophyll content of tomatoes increased with the concentrations of the treatment, with the T5 treatment exhibiting the most significant promotion effect on tomato growth indicators. Furthermore, compared to the control group, the application of different concentrations of Sophora alopecuroides extract resulted in an increase in soil pH by 0.28-0.72 and an increase in soil EC by 1.55-5.25 times. Additionally, the addition of Sophora alopecuroides extract also altered the soil nutrient content. After T2, T3, T4, and T5 treatments, compared to the control group, the total nitrogen increased by 4.2%-45.5%, available potassium increased by 5.2%-117.6%; soil organic matter increased by 5.6%-23.8%, alkaline nitrogen increased by 31.3%-142.1%; total phosphorus decreased by 11.2%-18.5%, and total potassium decreased by 2.6%-5.0%. Moreover, the activities of the five soil enzymes increased with the concentration of the extract. The T5 treatment significantly increased the activities of invertase, polyphenol oxidase, urease, catalase, and alkaline phosphatase, with increases of 296.42%, 21.86%, 422.01%, 43.13%, and 100.89%, respectively, compared to the control group. The correlation analysis between soil nutrients and soil enzymes showed that the activities of the five soil enzymes were positively correlated with soil pH, EC, organic matter content, total nitrogen, alkaline nitrogen, and available potassium, while negatively correlated with total phosphorus, total potassium, and available phosphorus. 【Conclusion】 Sophora alopecuroides extract can improve the growth of tomato seedlings under continuous cropping conditions, enhance soil nutrient content and soil enzyme activities, thereby improving the root environment of tomatoes, promoting tomato seedling growth, and alleviating the harm caused by continuous cropping.
