Linking soil fertility, enzyme activity, and flavonoid-related enzymes to growth and quality of Tetrastigma hemsleyanum Diels et Gilg amended with pyrogenic organic matter and organic fertilizer

Purpose The utilization of pyrogenic organic matter and organic fertilizers is widespread in agroforestry ecosystems for the purpose of augmenting soil nutrient levels and crop yields. Nonetheless, the impacts of these fertilizers on the yield and quality of Tetrastigma hemsleyanum Diels et Gilg, as well as the underlying mechanisms mediating these processes, remain inadequately understood. Methods In a potting experiment, we studied the effects of pyrogenic organic matter (20 and 40 mg C g −1 soil) and organic fertilizer (5% and 10%) on the yield and quality of T. hemsleyanum . Soil chemical properties (available K, AK; available P, AP; available N, AN; organic matter, OM), soil enzymes (urease, protease, and cellobiohydrolase), plant growth (plant height, stem thick, and fresh root weight), flavonoid-related enzymes (phenylalanine ammonia lyase, PAL; chalcone synthase, CHS; and chalcone isomerase, CHI), and total flavonoids were measured to elucidate the effects of the two fertilizers. Results Compared with the control, plant height, fresh root weight, and total flavonoid concentration (increased by 1.60 and 2.70 times, respectively) were enhanced by low and high biochar applications, whereas organic fertilizer addition only had a positive impact on fresh root weight. Furthermore, biochar supplementation enhanced growth, quality, and total flavonoid content by elevating AK, AP, AN, and OM levels, as well as increasing urease, protease, and CHI activities. Fresh root weight following the addition of organic fertilizer addition was significantly correlated with AK, AP, and protease activity. Conclusions The addition of pyrogenic organic matter addition is found to be a more suitable strategy than organic fertilizer addition for effectively enhancing the yield and quality of T. hemsleyanum . Graphical Abstract